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  • 51. Aad, G.
    et al.
    Jovicevic, Jelena
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Kuwertz, Emma
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Lund-Jensen, Bengt
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Morley, Anthony
    KTH, Skolan för teknikvetenskap (SCI), Fysik.
    Strandberg, Jonas
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Zwalinski, L.
    et al.,
    Search for long-lived stopped R-hadrons decaying out of time with pp collisions using the ATLAS detector2013Ingår i: Physical Review D, ISSN 1550-7998, E-ISSN 1550-2368, Vol. 88, nr 11, s. 112003-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    An updated search is performed for gluino, top squark, or bottom squark R-hadrons that have come to rest within the ATLAS calorimeter, and decay at some later time to hadronic jets and a neutralino, using 5.0 and 22.9 fb -1 of pp collisions at 7 and 8 TeV, respectively. Candidate decay events are triggered in selected empty bunch crossings of the LHC in order to remove pp collision backgrounds. Selections based on jet shape and muon system activity are applied to discriminate signal events from cosmic ray and beam-halo muon backgrounds. In the absence of an excess of events, improved limits are set on gluino, stop, and sbottom masses for different decays, lifetimes, and neutralino masses. With a neutralino of mass 100 GeV, the analysis excludes gluinos with mass below 832 GeV (with an expected lower limit of 731 GeV), for a gluino lifetime between 10 μs and 1000 s in the generic R-hadron model with equal branching ratios for decays to qq̄χËœ0 and gχËœ0. Under the same assumptions for the neutralino mass and squark lifetime, top squarks and bottom squarks in the Regge R-hadron model are excluded with masses below 379 and 344 GeV, respectively.

  • 52. Aad, G.
    et al.
    Jovicevic, Jelena
    KTH, Skolan för teknikvetenskap (SCI), Fysik.
    Kuwertz, Emma
    KTH, Skolan för teknikvetenskap (SCI), Fysik.
    Lund-Jensen, Bengt
    KTH, Skolan för teknikvetenskap (SCI), Fysik.
    Morley, Anthony
    KTH, Skolan för teknikvetenskap (SCI), Fysik.
    Strandberg, Jonas
    KTH, Skolan för teknikvetenskap (SCI), Fysik.
    Zwalinski, L.
    et al,
    Search for nonpointing and delayed photons in the diphoton and missing transverse momentum final state in 8 TeV pp collisions at the LHC using the ATLAS detector2014Ingår i: Physical Review D, ISSN 1550-7998, E-ISSN 1550-2368, Vol. 90, nr 11Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A search has been performed, using the full 20.3fb-1 data sample of 8 TeV proton-proton collisions collected in 2012 with the ATLAS detector at the LHC, for photons originating from a displaced vertex due to the decay of a neutral long-lived particle into a photon and an invisible particle. The analysis investigates the diphoton plus missing transverse momentum final state, and is therefore most sensitive to pair production of long-lived particles. The analysis technique exploits the capabilities of the ATLAS electromagnetic calorimeter to make precise measurements of the flight direction, as well as the time of flight, of photons. No excess is observed over the Standard Model predictions for background. Exclusion limits are set within the context of gauge mediated supersymmetry breaking models, with the lightest neutralino being the next-to-lightest supersymmetric particle and decaying into a photon and gravitino with a lifetime in the range from 250 ps to about 100 ns.

  • 53. Aad, G
    et al.
    Jovicevic, Jelena
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Kuwertz, Emma S
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Lund-Jensen, Bengt
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Strandberg, Jonas
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Zwalinski, L
    Search for resonant WZ production in the WZ -> lvl ' l ' channel in root(s)=7 TeV pp collisions with the ATLAS detector2012Ingår i: Physical Review D, ISSN 1550-7998, E-ISSN 1550-2368, Vol. 85, nr 11, s. 112012-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A generic search is presented for a heavy particle decaying to WZ -> lvl'l' (l, l' = e, mu) final states. The data were recorded by the ATLAS detector in root s = 7 TeV pp collisions at the Large Hadron Collider and correspond to an integrated luminosity of 1.02 fb(-1). The transverse mass distribution of the selected WZ candidates is found to be consistent with the standard model expectation. Upper limits on the production cross section times branching ratio are derived using two benchmark models predicting a heavy particle decaying to a WZ pair.

  • 54. Aad, G.
    et al.
    Kuwertz, Emma
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Lund-Jensen, Bengt
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Morley, Anthony
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Strandberg, Jonas
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Zwalinski, L.
    Search for dark matter in events with a Z boson and missing transverse momentum in pp collisions at root s=8 TeV with the ATLAS detector2014Ingår i: Physical Review D, ISSN 1550-7998, E-ISSN 1550-2368, Vol. 90, nr 1, s. 012004-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A search is presented for production of dark-matter particles recoiling against a leptonically decaying Z boson in 20.3 fb(-1) of pp collisions at root s = 8 TeV with the ATLAS detector at the Large Hadron Collider. Events with large missing transverse momentum and two oppositely charged electrons or muons consistent with the decay of a Z boson are analyzed. No excess above the Standard Model prediction is observed. Limits are set on the mass scale of the contact interaction as a function of the dark-matter particle mass using an effective field theory description of the interaction of dark matter with quarks or with Z bosons. Limits are also set on the coupling and mediator mass of a model in which the interaction is mediated by a scalar particle.

  • 55. Aad, G
    et al.
    Kuwertz, Emma
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Lund-Jensen, Bengt
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Morley, Anthony
    KTH, Skolan för teknikvetenskap (SCI), Fysik.
    Strandberg, Jonas
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Zwalinski, L.
    et al.,
    Measurements of the Total and Differential Higgs Boson Production Cross Sections Combining the H -> gamma gamma and H -> ZZ* -> 4l Decay Channels at root s=8 TeV with the ATLAS Detector2015Ingår i: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 115, nr 9, artikel-id 091801Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Measurements of the total and differential cross sections of Higgs boson production are performed using 20.3 fb(-1) of pp collisions produced by the Large Hadron Collider at a center-of-mass energy of root s = 8 TeV and recorded by the ATLAS detector. Cross sections are obtained from measured H -> gamma gamma and H -> ZZ*. 4l event yields, which are combined accounting for detector efficiencies, fiducial acceptances, and branching fractions. Differential cross sections are reported as a function of Higgs boson transverse momentum, Higgs boson rapidity, number of jets in the event, and transverse momentum of the leading jet. The total production cross section is determined to be sigma(pp -> H) = 33.0 +/- 5.3 (stat) +/- 1.6 (syst) pb. The measurements are compared to state-of-the-art predictions.

  • 56.
    Aad, G.
    et al.
    Aix Marseille Univ, CPPM, CNRS, IN2P3, Marseille, France..
    Leopold, Alexander
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Lundberg, Olof
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Lund-Jensen, Bengt
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Ohm, Christian
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Ripellino, Giulia
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Shaheen, Rabia
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Shope, David R.
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik. Royal Inst Technol, Dept Phys, Stockholm, Sweden..
    Strandberg, Jonas
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Zwalinski, L.
    CERN, Geneva, Switzerland..
    A search for heavy Higgs bosons decaying into vector bosons in same-sign two-lepton final states in pp collisions at √s = 13 TeV with the ATLAS detector2023Ingår i: Journal of High Energy Physics (JHEP), ISSN 1126-6708, E-ISSN 1029-8479, nr 7, artikel-id 200Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A search for heavy Higgs bosons produced in association with a vector boson and decaying into a pair of vector bosons is performed in final states with two leptons (electrons or muons) of the same electric charge, missing transverse momentum and jets. A data sample of proton-proton collisions at a centre-of-mass energy of 13 TeV recorded with the ATLAS detector at the Large Hadron Collider between 2015 and 2018 is used. The data correspond to a total integrated luminosity of 139 fb(-1). The observed data are in agreement with Standard Model background expectations. The results are interpreted using higher-dimensional operators in an effective field theory. Upper limits on the production cross-section are calculated at 95% confidence level as a function of the heavy Higgs boson's mass and coupling strengths to vector bosons. Limits are set in the Higgs boson mass range from 300 to 1500 GeV, and depend on the assumed couplings. The highest excluded mass for a heavy Higgs boson with the coupling combinations explored is 900 GeV. Limits on coupling strengths are also provided.

  • 57. Aad, G.
    et al.
    Lund-Jensen, Bengt
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Lafaye, Remi
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    et, al
    Measurement of the inclusive and dijet cross-sections of b-jets in pp collisions at root s=7 TeV with the ATLAS detector2011Ingår i: European Physical Journal C, ISSN 1434-6044, E-ISSN 1434-6052, Vol. 71, nr 12, s. 1846-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The inclusive and dijet production cross-sections have been measured for jets containing b-hadrons (b-jets) in proton-proton collisions at a centre-of-mass energy of root s = 7 TeV, using the ATLAS detector at the LHC. The measurements use data corresponding to an integrated luminosity of 34 pb(-1). The b-jets are identified using either a lifetime-based method, where secondary decay vertices of b-hadrons in jets are reconstructed using information from the tracking detectors, or a muon-based method where the presence of a muon is used to identify semileptonic decays of b-hadrons inside jets. The inclusive b-jet cross-section is measured as a function of transverse momentum in the range 20 < p(T) < 400 GeV and rapidity in the range vertical bar y vertical bar < 2.1. The b<(b)over bar>-dijet cross-section is measured as a function of the dijet invariant mass in the range 110 < m(jj) < 760 GeV, the azimuthal angle difference between the two jets and the angular variable chi in two dijet mass regions. The results are compared with next-to-leading-order QCD predictions. Good agreement is observed between the measured cross-sections and the predictions obtained using POWHEG + Pythia. MC@NLO + Herwig shows good agreement with the measured b (b) over bar -dijet cross-section. However, it does not reproduce the measured inclusive cross-section well, particularly for central b-jets with large transverse momenta.

  • 58. Aad, G
    et al.
    Lund-Jensen, Bengt
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Morley, Anthony K
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Strandberg, Jonas
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Zwalinski, L
    Al., Et.
    Study of the B-c(+) -> J/psi D-s(+) and Bc(+) -> J/psi D-s*(+) decays with the ATLAS detector2016Ingår i: European Physical Journal C, ISSN 1434-6044, E-ISSN 1434-6052, Vol. 76, nr 1, artikel-id 4Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The decays B-c(+) -> J/psi D-s(+) and B-c(+) -> J/psi D-s*(+) are studied with the ATLAS detector at the LHC using a dataset corresponding to integrated luminosities of 4.9 and 20.6 fb(-1) of pp collisions collected at centre-of-mass energies root s = 7 TeV and 8 TeV, respectively. Signal candidates are identified through J/psi -> mu(+)mu(-) and D-s(()*()+) -> phi pi(+)(gamma/pi(0)) decays. With a two-dimensional likelihood fit involving the B-c(+) reconstructed invariant mass and an angle between the mu(+) and D-s(+) candidate momenta in the muon pair rest frame, the yields of B-c(+) -> J/psi D-s(+) and B-c(+) -> J/psi D-s*(+), and the transverse polarisation fraction in B-c(+) -> J/psi D-s*(+) decay are measured. The transverse polarisation fraction is determined to be Gamma +/-+/-(B-c(+) -> J/psi D-s*(+))/Gamma(B-c(+) -> J/psi D-s*(+)) = 0.38 +/- 0.23 +/- 0.07, and the derived ratio of the branching fractions of the two modes is B-Bc+ -> J/psi D-s*+/B-Bc+ -> J/psi D-s(+) = 2.8(-0.8)(+1.2) +/- 0.3, where the first error is statistical and the second is systematic. Finally, a sample of B-c(+) -> J/psi pi(+) decays is used to derive the ratios of branching fractions B-Bc+ -> J/psi D-s*+/B-Bc+ -> J/psi pi(+) = 3.8 +/- 1.1 +/- 0.4 +/- 0.2 and B-Bc+ -> J/psi D-s*+/B-Bc+ -> J/psi pi(+) = 10.4 +/- 3.1 +/- 1.5 +/- 0.6, where the third error corresponds to the uncertainty of the branching fraction of D-s(+) -> phi(K+ K-)pi(+) decay. The available theoretical predictions are generally consistent with the measurement.

  • 59. Aad, G
    et al.
    Lund-Jensen, Bengt
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Morley, Anthony
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Strandberg, Jonas
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Zwalinski, L.
    et al.,
    Search for massive, long-lived particles using multitrack displaced vertices or displaced lepton pairs in pp collisions at root s=8 TeV with the ATLAS detector2015Ingår i: Physical Review D, ISSN 1550-7998, E-ISSN 1550-2368, Vol. 92, nr 7, artikel-id 072004Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Many extensions of the Standard Model posit the existence of heavy particles with long lifetimes. This article presents the results of a search for events containing at least one long-lived particle that decays at a significant distance from its production point into two leptons or into five or more charged particles. This analysis uses a data sample of proton-proton collisions at root s = 8 TeV corresponding to an integrated luminosity of 20.3 fb(-1) collected in 2012 by the ATLAS detector operating at the Large Hadron Collider. No events are observed in any of the signal regions, and limits are set on model parameters within supersymmetric scenarios involving R-parity violation, split supersymmetry, and gauge mediation. In some of the search channels, the trigger and search strategy are based only on the decay products of individual long-lived particles, irrespective of the rest of the event. In these cases, the provided limits can easily be reinterpreted in different scenarios.

  • 60.
    Aad, G.
    et al.
    Aix Marseille Univ, CPPM, CNRS IN2P3, Marseille, France..
    Lund-Jensen, Bengt
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Ohm, Christian
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Ripellino, Giulia
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Shope, David R.
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Strandberg, Jonas
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Zwalinski, L.
    CERN, Geneva, Switzerland..
    et al.,
    Measurements of jet observables sensitive to b-quark fragmentation in (tt)over-bar events at the LHC with the ATLAS detector2022Ingår i: Physical Review D: covering particles, fields, gravitation, and cosmology, ISSN 2470-0010, E-ISSN 2470-0029, Vol. 106, nr 3, artikel-id 032008Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Several observables sensitive to the fragmentation of b quarks into b hadrons are measured using 36 fb(-1) of root s = 13 TeV proton-proton collision data collected with the ATLAS detector at the LHC. Jets containing b hadrons are obtained from a sample of dileptonic (tt) over bar events, and the associated set of charged-particle tracks is separated into those from the primary pp interaction vertex and those from the displaced b-decay secondary vertex. This division is used to construct observables that characterize the longitudinal and transverse momentum distributions of the b hadron within the jet. The measurements have been corrected for detector effects and provide a test of heavy-quark-fragmentation modeling at the LHC in a system where the top-quark decay products are color connected to the proton beam remnants. The unfolded distributions are compared with the predictions of several modern Monte Carlo parton-shower generators and generator tunes, and a wide range of agreement with the data is observed, with p values varying from 5 x 10(-4) to 0.98. These measurements complement similar measurements from e(+)e(-) collider experiments in which the b quarks originate from a color singlet Z/gamma*.

  • 61. Aad, G.
    et al.
    Lund-Jensen, Bengt
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Sidebo, Edvin
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Strandberg, Jonas
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Zwalinski, L.
    et al.,
    Measurements of Z gamma and Z gamma gamma production in pp collisions at root s=8 TeV with the ATLAS detector2016Ingår i: PHYSICAL REVIEW D, ISSN 2470-0010, Vol. 93, nr 11Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The production of Z bosons with one or two isolated high-energy photons is studied using pp collisions at root s = 8 TeV. The analyses use a data sample with an integrated luminosity of 20.3 fb(-1) collected by the ATLAS detector during the 2012 LHC data taking. The Z gamma and Z gamma gamma production cross sections are measured with leptonic (e(+) e(-), mu(+) mu(-), nu(nu) over bar) decays of the Z boson, in extended fiducial regions defined in terms of the lepton and photon acceptance. They are then compared to cross-section predictions from the Standard Model, where the sources of the photons are radiation off initial-state quarks and radiative Z-boson decay to charged leptons, and from fragmentation of final-state quarks and gluons into photons. The yields of events with photon transverse energy E-T > 250 GeV from l(+) l(-) gamma events and with E-T > 400 GeV from nu(nu) over bar gamma events are used to search for anomalous triple gauge-boson couplings ZZ gamma and Z gamma gamma. The yields of events with diphoton invariant mass m(gamma gamma) > 200 GeV from l(+) l(-) gamma gamma events and with m(gamma gamma) > 300 GeV from nu(nu) over bar gamma gamma events are used to search for anomalous quartic gauge-boson couplings ZZ gamma gamma and Z gamma gamma gamma. No deviations from Standard Model predictions are observed and limits are placed on parameters used to describe anomalous triple and quartic gauge-boson couplings.

  • 62. Aad, G
    et al.
    Lund-Jensen, Bengt
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Sidebo, P. Edvin
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Strandberg, Jonas
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Zwalinski, L.
    et al.,
    Charged-particle distributions in root s=13 TeV pp interactions measured with the ATLAS detector at the LHC2016Ingår i: Physics Letters B, ISSN 0370-2693, E-ISSN 1873-2445, Vol. 758, s. 67-88Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Charged-particle distributions are measured in proton-proton collisions at a centre-of-mass energy of 13 TeV, using a data sample of nearly 9 million events, corresponding to an integrated luminosity of 170 mu b(-1), recorded by the ATLAS detector during a special Large Hadron Collider fill. The charged-particle multiplicity, its dependence on transverse momentum and pseudorapidity and the dependence of the mean transverse momentum on the charged-particle multiplicity are presented. The measurements are performed with charged particles with transverse momentum greater than 500 MeV and absolute pseudorapidity less than 2.5, in events with at least one charged particle satisfying these kinematic requirements. Additional measurements in a reduced phase space with absolute pseudorapidity less than 0.8 are also presented, in order to compare with other experiments. The results are corrected for detector effects, presented as particle-level distributions and are compared to the predictions of various Monte Carlo event generators.

  • 63. Aad, G.
    et al.
    Lund-Jensen, Bengt
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Sidebo, P. Edvin
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Strandberg, Jonas
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Zwalinski, L.
    et al.,
    Measurement of the transverse momentum and phi(eta)*. distributions of Drell-Yan lepton pairs in proton-proton collisions at root s=8 TeV with the ATLAS detector2016Ingår i: European Physical Journal C, ISSN 1434-6044, E-ISSN 1434-6052, Vol. 76, nr 5, artikel-id 291Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Distributions of transverse momentum p(T)(ll) and the related angular variable phi(eta)*. of Drell-Yan lepton pairs are measured in 20.3 fb(-1) of proton-proton collisions at root s = 8 TeV with the ATLAS detector at the LHC. Measurements in electron-pair and muon-pair final states are corrected for detector effects and combined. Compared to previous measurements in proton-proton collisions at root s = 7 TeV, these new measurements benefit from a larger data sample and improved control of systematic uncertainties. Measurements are performed in bins of lepton-pair mass above, around and below the Z-boson mass peak. The data are compared to predictions from perturbative and resummed QCD calculations. For values of phi(eta)*. < 1 the predictions from the Monte Carlo generator ResBos are generally consistent with the data within the theoretical uncertainties. However, at larger values of phi(eta)*. this is not the case. Monte Carlo generators based on the parton-shower approach are unable to describe the data over the full range of p(T)(ll) while the fixed-order prediction of Dynnlo falls below the data at high values of p(T)(ll). ResBos and the parton-shower Monte Carlo generators provide a much better description of the evolution of the phi(eta)*. and p(T)(ll) distributions as a function of lepton-pair mass and rapidity than the basic shape of the data.

  • 64. Aad, G.
    et al.
    Lund-Jensen, Bengt
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Sidebo, P. Edvin
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Strandberg, Jonas
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Zwalinski, L.
    et al.,
    Muon reconstruction performance of the ATLAS detector in proton-proton collision data at root s=13 TeV2016Ingår i: European Physical Journal C, ISSN 1434-6044, E-ISSN 1434-6052, Vol. 76, nr 5, artikel-id 292Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This article documents the performance of the ATLAS muon identification and reconstruction using the LHC dataset recorded at root s = 13 TeVin 2015. Using a large sample of J/.psi -> mu mu and Z -> mu mu decays from 3.2 fb(-1) of pp collision data, measurements of the reconstruction efficiency, as well as of the momentum scale and resolution, are presented and compared to Monte Carlo simulations. The reconstruction efficiency is measured to be close to 99 % over most of the covered phase space (vertical bar eta vertical bar < 2.5 and 5 < p(T) < 100 GeV). The isolation efficiency varies between 93 and 100 % depending on the selection applied and on the momentum of the muon. Both efficiencies are well reproduced in simulation. In the central region of the detector, the momentum resolution is measured to be 1.7 % (2.3 %) for muons from J/psi -> mu mu(Z -> mu mu) decays, and the momentum scale is known with an uncertainty of 0.05 %. In the region vertical bar eta vertical bar > 2.2, the p(T) resolution for muons from Z -> mu decays is 2.9 % while the precision of the momentum scale for low-p(T) muons from J/psi -> mu mu decays is about 0.2 %.

  • 65. Aad, G.
    et al.
    Lund-Jensen, Bengt
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Sidebo, P. Edvin
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Strandberg, Jonas
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Zwalinski, L.
    et al.,
    Search for new phenomena in events with at least three photons collected in pp collisions at root s=8 TeV with the ATLAS detector2016Ingår i: European Physical Journal C, ISSN 1434-6044, E-ISSN 1434-6052, Vol. 76, nr 4, artikel-id 210Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Results of a search for new phenomena in events with at least three photons are reported. Data from proton-proton collisions at a centre-of-mass energy of 8 TeV, corresponding to an integrated luminosity of 20.3 fb(-1), were collected with the ATLAS detector at the LHC. The observed data are well described by the Standard Model. Limits at the 95 % confidence level on new phenomena are presented based on the rate of events in an inclusive signal region and a restricted signal region targeting the rare decay Z -> 3 gamma, as well as di-photon and tri-photon resonance searches. For a Standard Model Higgs boson decaying to four photons via a pair of intermediate pseudoscalar particles (a), limits are found to be sigma x BR(h -> aa) x BR(a -> gamma gamma)(2) < 10(-3) sigma(SM) for 10 GeV < m(a) < 62 GeV. Limits are also presented for Higgs boson-like scalars (H) for m(H) > 125 GeV, and for a Z' decaying to three photons via Z' -> a + gamma -> 3 gamma. Additionally,the observed limit on the branching ratio of the Z boson decay to three photons is found to be BR (Z -> 3 gamma) < 2.2 x 10(-6), a result five times stronger than the previous result from LEP.

  • 66. Aad, G.
    et al.
    Lund-Jensen, Bengt
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Sidebo, P. Edvin
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Strandberg, Jonas
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Zwalinski, L.
    et al.,
    Search for the standard model Higgs boson produced in association with a vector boson and decaying into a tau pair in pp collisions at root s=8 TeV with the ATLAS detector2016Ingår i: Physical Review D, ISSN 1550-7998, E-ISSN 1550-2368, Vol. 93, nr 9, artikel-id 092005Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A search for the standard model Higgs boson produced in association with a vector boson with the decay H -> tau tau is presented. The data correspond to 20.3 fb(-1) of integrated luminosity from proton-proton collisions at root s = 8 TeV recorded by the ATLAS experiment at the LHC during 2012. The data agree with the background expectation, and 95% confidence-level upper limits are placed on the cross section of this process. The observed (expected) limit, expressed in terms of the signal strength mu= sigma/sigma(SM) for m(H) = 125 GeV, is mu < 5.6 (3.7). The measured value of the signal strength is mu = 2.3 +/- 1.6.

  • 67. Aad, G
    et al.
    Lund-Jensen, Bengt
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Sidebo, Per Edvin
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Strandberg, Jonas
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Zwalinski, L
    Al., Et.
    Search for a high-mass Higgs boson decaying to a W boson pair in pp collisions at root s=8TeV with the ATLAS detector2016Ingår i: Journal of High Energy Physics (JHEP), ISSN 1126-6708, E-ISSN 1029-8479, nr 1, artikel-id 032Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A search for a high-mass Higgs boson H is performed in the H -> WW -> l nu l nu and H -> WW -> l nu qq decay channels using pp collision data corresponding to an integrated luminosity of 20.3 fb(-1) collected at root s = 8TeV by the ATLAS detector at the Large Hadron Collider. No evidence of a high-mass Higgs boson is found. Limits on sigma(H) x BR(H -> WW) as a function of the Higgs boson mass m(H) are determined in three different scenarios: one in which the heavy Higgs boson has a narrow width compared to the experimental resolution, one for a width increasing with the boson mass and modeled by the complex-pole scheme following the same behavior as in the Standard Model, and one for intermediate widths. The upper range of the search is m(H) = 1500 GeV for the narrow-width scenario and m(H) = 1000 GeV for the other two scenarios. The lower edge of the search range is 200{300 GeV and depends on the analysis channel and search scenario. For each signal interpretation, individual and combined limits from the two WW decay channels are presented. At m(H) = 1500 GeV, the highest-mass point tested, sigma(H) x BR(H -> WW) for a narrow-width Higgs boson is constrained to be less than 22 fb and 6.6 fb at 95% CL for the gluon fusion and vector-boson fusion production modes, respectively.

  • 68. Aad, G
    et al.
    Lund-Jensen, Bengt
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Sidebo, Per Edvin
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Strandberg, Jonas
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Zwalinski, L
    et al.,
    Measurements of W(+/-)Z production cross sections in pp collisions at root s=8 TeV with the ATLAS detector and limits on anomalous gauge boson self-couplings2016Ingår i: Physical Review D. Particles and fields, ISSN 0556-2821, E-ISSN 1089-4918, Vol. 93, nr 9, artikel-id 092004Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper presents measurements of W(+/-)Z production in pp collisions at a center-of-mass energy of 8 TeV. The gauge bosons are reconstructed using their leptonic decay modes into electrons and muons. The data were collected in 2012 by the ATLAS experiment at the Large Hadron Collider and correspond to an integrated luminosity of 20.3 fb(-1). The measured inclusive cross section in the detector fiducial region is sigma W(+/-)Z -> l'nu ll = 35.1 +/- 0.9(stat) +/- 0.8(sys) +/- 0.8(lumi) fb, for one leptonic decay channel. In comparison, the next-to-leading-order Standard Model expectation is 30.0 +/- 2.1 fb. Cross sections for W(+)Z and W(-)Z production and their ratio are presented as well as differential cross sections for several kinematic observables. Limits on anomalous triple gauge boson couplings are derived from the transverse mass spectrum of the W(+/-)Z system. From the analysis of events with a W and a Z boson associated with two or more forward jets an upper limit at 95% confidence level on the W(+/-)Z scattering cross section of 0.63 fb, for each leptonic decay channel, is established, while the Standard Model prediction at next-to-leading order is 0.13 +/- 0.01 fb. Limits on anomalous quartic gauge boson couplings are also extracted.

  • 69. Aad, G.
    et al.
    Lund-Jensen, Bengt
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Strandberg, Jonas
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Zwalinski, L.
    et al.,
    Measurement of the inclusive W-+/- and Z/gamma* cross sections in the e and mu decay channels in pp collisions at root s=7 TeV with the ATLAS detector2012Ingår i: Physical Review D, ISSN 1550-7998, E-ISSN 1550-2368, Vol. 85, nr 7, s. 072004-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The production cross sections of the inclusive Drell-Yan processes W-+/- -> l nu and Z/gamma* -> ll (l = e, mu) are measured in proton-proton collisions at root s = 7 TeV with the ATLAS detector. The cross sections are reported integrated over a fiducial kinematic range, extrapolated to the full range, and also evaluated differentially as a function of the W decay lepton pseudorapidity and the Z boson rapidity, respectively. Based on an integrated luminosity of about 35 pb(-1) collected in 2010, the precision of these measurements reaches a few percent. The integrated and the differential W-+/- and Z/gamma* cross sections in the e and mu channels are combined, and compared with perturbative QCD calculations, based on a number of different parton distribution sets available at next-to-next-to-leading order.

  • 70.
    Abarr, Q.
    et al.
    Washington Univ St Louis, 1 Brookings Dr,CB 1105, St Louis, MO 63130 USA.;Washington Univ, McDonnell Ctr Space Sci, St Louis, MO USA..
    Iyer, Nirmal
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik. AlbaNova Univ Ctr, Oskar Klein Ctr Cosmoparticle Phys, SE-10691 Stockholm, Sweden..
    Kislat, F.
    Univ New Hampshire, Space Sci Ctr, Dept Phys & Astron, 8 Coll Rd, Durham, NH 03824 USA..
    Kiss, Mózsi
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik. AlbaNova Univ Ctr, Oskar Klein Ctr Cosmoparticle Phys, SE-10691 Stockholm, Sweden..
    Pearce, Mark
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik. AlbaNova Univ Ctr, Oskar Klein Ctr Cosmoparticle Phys, SE-10691 Stockholm, Sweden..
    West, A.
    Washington Univ St Louis, 1 Brookings Dr,CB 1105, St Louis, MO 63130 USA.;Washington Univ, McDonnell Ctr Space Sci, St Louis, MO USA.;Univ New Hampshire, Space Sci Ctr, Dept Phys & Astron, 8 Coll Rd, Durham, NH 03824 USA..
    et al.,
    Performance of the X-Calibur hard X-ray polarimetry mission during its 2018/19 long-duration balloon flight2022Ingår i: Astroparticle physics, ISSN 0927-6505, E-ISSN 1873-2852, Vol. 143, s. 102749-, artikel-id 102749Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    X-Calibur is a balloon-borne telescope that measures the polarization of high-energy X-rays in the 15-50 keV energy range. The instrument makes use of the fact that X-rays scatter preferentially perpendicular to the polarization direction. A beryllium scattering element surrounded by pixellated CZT detectors is located at the focal point of the InFOC mu S hard X-ray mirror. The instrument was launched for a long-duration balloon (LDB) flight from McMurdo (Antarctica) on December 29, 2018, and obtained the first constraints of the hard X-ray polarization of an accretion-powered pulsar. Here, we describe the characterization and calibration of the instrument on the ground and its performance during the flight, as well as simulations of particle backgrounds and a comparison to measured rates. The pointing system and polarimeter achieved the excellent projected performance. The energy detection threshold for the anticoincidence system was found to be higher than expected and it exhibited unanticipated dead time. Both issues will be remedied for future flights. Overall, the mission performance was nominal, and results will inform the design of the follow-up mission XL-Calibur, which is scheduled to be launched in summer 2022.

  • 71.
    Abarr, Q.
    et al.
    Washington Univ, 1 Brookings Dr,CB 1105, St Louis, MO 63130 USA..
    Iyer, Nirmal Kumar
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Kiss, Mozsi
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Pearce, Mark
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Wilson-Hodge, C.
    NASA, ST12 Astrophys Branch, Marshall Space Flight Ctr, Huntsville, AL 35812 USA..
    Observations of a GX 301-2 Apastron Flare with the X-Calibur Hard X-Ray Polarimeter Supported by NICER, the Swift XRT and BAT, and Fermi GBM2020Ingår i: Astrophysical Journal, ISSN 0004-637X, E-ISSN 1538-4357, Vol. 891, nr 1, artikel-id 70Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The accretion-powered X-ray pulsar GX 301-2 was observed with the balloon-borne X-Calibur hard X-ray polarimeter during late 2018 December, with contiguous observations by the Neutron star Interior Composition Explorer Mission (NICER) X-ray telescope, the Swift X-ray Telescope and Burst Alert Telescope, and the Fermi Gamma-ray Burst Monitor spanning several months. The observations detected the pulsar in a rare apastron flaring state coinciding with a significant spin up of the pulsar discovered with the Fermi Gamma-ray Burst Monitor. The X-Calibur, NICER, and Swift observations reveal a pulse profile strongly dominated by one main peak, and the NICER and Swift data show strong variation of the profile from pulse to pulse. The X-Calibur observations constrain for the first time the linear polarization of the 15-35 keV emission from a highly magnetized accreting neutron star, indicating a polarization degree of % (90% confidence limit) averaged over all pulse phases. We discuss the spin up and the X-ray spectral and polarimetric results in the context of theoretical predictions. We conclude with a discussion of the scientific potential of future observations of highly magnetized neutron stars with the more sensitive follow-up mission XL-Calibur.

  • 72. Abarr, Q.
    et al.
    Stana, Theodor-Adrian
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Yamamoto, R.
    XL-Calibur - a second-generation balloon-borne hard X-ray polarimetry mission2021Ingår i: Astroparticle physics, ISSN 0927-6505, E-ISSN 1873-2852, Vol. 126, artikel-id 102529Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    XL-Calibur is a hard X-ray (15-80 keV) polarimetry mission operating from a stabilised balloon-borne platform in the stratosphere. It builds on heritage from the X-Calibur mission, which observed the accreting neutron star GX 301 2 from Antarctica, between December 29th 2018 and January 1st 2019. The XL-Calibur design incorporates an X-ray mirror, which focusses X-rays onto a polarimeter comprising a beryllium rod surrounded by Cadmium Zinc Telluride (CZT) detectors. The polarimeter is housed in an anticoincidence shield to mitigate background from particles present in the stratosphere. The mirror and polarimeter-shield assembly are mounted at opposite ends of a 12 m long lightweight truss, which is pointed with arcsecond precision by WASP - the Wallops Arc Second Pointer. The XL-Calibur mission will achieve a substantially improved sensitivity over X-Calibur by using a larger effective area X-ray mirror, reducing background through thinner CZT detectors, and improved anticoincidence shielding. When observing a 1 Crab source for tdaydays, the Minimum Detectable Polarisation (at 99% confidence level) is similar to 2%.t(day)(-1/2). The energy resolution at 40 keV is-5.9 keV. The aim of this paper is to describe the design and performance of the XL-Caliburmission, as well as the foreseen science programme.

  • 73.
    Abarr, Quincy
    et al.
    Washington Univ, 1 Brookings Dr,CB 1105, St Louis, MO 63130 USA..
    Iyer, Nirmal
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Kiss, Mózsi
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Maeda, Yoshitomo
    ISAS, 3-1-1 Yoshinodai, Sagamihara, Kanagawa 2298510, Japan..
    Pearce, Mark
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Ryde, Felix
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Stana, Theodor-Adrian
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Yoshida, Yuto
    Tokyo Univ Sci, Dept Phys, Chiba 2788510, Japan..
    "XL-Calibur", the Next-Generation Balloon-Borne Hard X-ray Polarimeter2021Ingår i: Space Telescopes and Instrumentation 2020: Ultraviolet to Gamma Ray / [ed] DenHerder, JWA Nikzad, S Nakazawa, K, SPIE-Intl Soc Optical Eng , 2021, artikel-id 114442XKonferensbidrag (Refereegranskat)
    Abstract [en]

    This paper introduces a second-generation balloon-borne hard X-ray polarimetry mission, XL-Calibur.(1) The XL-Calibur will follow up on the X-Calibur mission which was flown from Dec. 29, 2018 for a 2.5 days balloon flight from McMurdo (the Antarctic). X-ray polarimetry promises to give qualitatively new information about high-energy astrophysical sources, such as pulsars and binary black hole systems. The XL-Calibur contains a grazing incidence X-ray telescope with a focal plane detector unit that is sensitive to linear polarization. The telescope is very similar in design to the ASTRO-H HXT telescopes that has the world's largest effective area above 10 keV. XL-Calibur will use the same type of mirror. The detector unit combines a low atomic number Compton scatterer with a CdZnTe detector assembly to measure the polarization making use of the fact that polarized photons Compton scatter preferentially perpendicular to the electric field orientation. It also contains a CdZnTe imager at the bottom. The detector assembly is surrounded by a BGO anticoincidence shield. The pointing system with arcsecond accuracy will be achieved by the WASP (Wallops Arc Second Pointer) from NASA's Wallops Flight Facility. A first flight of the XL-Calibur is currently foreseen for 2022, flying from Sweden.

  • 74.
    Abazov, V. M.
    et al.
    Joint Inst Nucl Res, Dubna, Russia..
    Åsman, Bengt
    KTH.
    Clement, Christophe
    KTH.
    Gollub, Nils
    KTH.
    Lager, S.
    Lund Univ, Lund, Sweden.;Royal Inst Technol, Stockholm, Sweden.;Stockholm Univ, S-10691 Stockholm, Sweden.;Uppsala Univ, Uppsala, Sweden..
    Soeldner-Rembold, S.
    Univ Manchester, Manchester, Lancs, England..
    Strandberg, Jonas
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Search for particles decaying into a Z boson and a photon in collisions p (p)over-bar at root s = 1.96 TeV (vol 641, pg 415, 2006)2009Ingår i: Physics Letters B, ISSN 0370-2693, E-ISSN 1873-2445, Vol. 670, nr 4-5, s. 455-458Artikel i tidskrift (Refereegranskat)
  • 75. Abbott, BP
    et al.
    Axelsson, Magnus
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Larsson, Stefan
    KTH, Skolan för teknikvetenskap (SCI), Fysik.
    Li, Liang
    KTH, Skolan för teknikvetenskap (SCI), Fysik.
    Zweizig, John G.
    et al.,
    Supplement: "Localization And Broadband Follow-Up Of The Gravitational-Wave Transient Gw150914" (2016, Apjl, 826, L13)2016Ingår i: Astrophysical Journal Supplement Series, ISSN 0067-0049, E-ISSN 1538-4365, Vol. 225, nr 1, s. 8-, artikel-id 8Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This Supplement provides supporting material for Abbott et al. (2016a). We briefly summarize pastelectromagnetic (EM) follow-up efforts as well as the organization and policy of the current EM follow-upprogram. We compare the four probability sky maps produced for the gravitational-wave transient GW150914, andprovide additional details of the EM follow-up observations that were performed in the different bands

  • 76. Abdalla, E.
    et al.
    Abellán, G. F.
    Aboubrahim, A.
    Agnello, A.
    Akarsu, Ö.
    Akrami, Y.
    Alestas, G.
    Aloni, D.
    Amendola, L.
    Anchordoqui, L. A.
    Anderson, R. I.
    Arendse, N.
    Asgari, M.
    Ballardini, M.
    Barger, V.
    Basilakos, S.
    Batista, R. C.
    Battistelli, E. S.
    Battye, R.
    Benetti, M.
    Benisty, D.
    Berlin, A.
    de Bernardis, P.
    Berti, E.
    Bidenko, B.
    Birrer, S.
    Blakeslee, J. P.
    Boddy, K. K.
    Bom, C. R.
    Bonilla, A.
    Borghi, N.
    Bouchet, F. R.
    Braglia, M.
    Buchert, T.
    Buckley-Geer, E.
    Calabrese, E.
    Caldwell, R. R.
    Camarena, D.
    Capozziello, S.
    Casertano, S.
    Chen, G. C. -F
    Chluba, J.
    Chen, A.
    Chen, H. -Y
    Chudaykin, A.
    Cicoli, M.
    Copi, C. J.
    Courbin, F.
    Cyr-Racine, F. -Y
    Czerny, B.
    Dainotti, M.
    D'Amico, G.
    Davis, A. -C
    de Cruz Pérez, J.
    de Haro, J.
    Delabrouille, J.
    Denton, P. B.
    Dhawan, S.
    Dienes, K. R.
    Di Valentino, E.
    Du, P.
    Eckert, D.
    Escamilla-Rivera, C.
    Ferté, A.
    Finelli, F.
    Fosalba, P.
    Freedman, W. L.
    Frusciante, N.
    Gaztañaga, E.
    Giarè, W.
    Giusarma, E.
    Gómez-Valent, A.
    Handley, W.
    Harrison, I.
    Hart, L.
    Hazra, D. K.
    Heavens, A.
    Heinesen, A.
    Hildebrandt, H.
    Hill, J. C.
    Hogg, N. B.
    Holz, D. E.
    Hooper, D. C.
    Hosseininejad, N.
    Huterer, D.
    Ishak, M.
    Ivanov, M. M.
    Jaffe, A. H.
    Jang, I. S.
    Jedamzik, K.
    Jimenez, R.
    Joseph, M.
    Joudaki, S.
    Kamionkowski, M.
    Karwal, T.
    Kazantzidis, L.
    Keeley, R. E.
    Klasen, M.
    Komatsu, E.
    Koopmans, L. V. E.
    Kumar, S.
    Lamagna, L.
    Lazkoz, R.
    Lee, C. -C
    Lesgourgues, J.
    Levi Said, J.
    Lewis, T. R.
    L'Huillier, B.
    Lucca, M.
    Maartens, R.
    Macri, L. M.
    Marfatia, D.
    Marra, V.
    Martins, C. J. A. P.
    Masi, S.
    Matarrese, S.
    Mazumdar, A.
    Melchiorri, A.
    Mena, O.
    Mersini-Houghton, L.
    Mertens, J.
    Milaković, D.
    Minami, Y.
    Miranda, V.
    Moreno-Pulido, C.
    Moresco, M.
    Mota, D. F.
    Mottola, E.
    Mozzon, S.
    Muir, J.
    Mukherjee, A.
    Mukherjee, S.
    Naselsky, P.
    Nath, P.
    Nesseris, S.
    Niedermann, Florian
    Nordita SU.
    Notari, A.
    Nunes, R. C.
    Ó Colgáin, E.
    Owens, K. A.
    Özülker, E.
    Pace, F.
    Paliathanasis, A.
    Palmese, A.
    Pan, S.
    Paoletti, D.
    Perez Bergliaffa, S. E.
    Perivolaropoulos, L.
    Pesce, D. W.
    Pettorino, V.
    Philcox, O. H. E.
    Pogosian, L.
    Poulin, V.
    Poulot, G.
    Raveri, M.
    Reid, M. J.
    Renzi, F.
    Riess, A. G.
    Sabla, V. I.
    Salucci, P.
    Salzano, V.
    Saridakis, E. N.
    Sathyaprakash, B. S.
    Schmaltz, M.
    Schöneberg, N.
    Scolnic, D.
    Sen, A. A.
    Sehgal, N.
    Shafieloo, A.
    Sheikh-Jabbari, M. M.
    Silk, J.
    Silvestri, A.
    Skara, F.
    Sloth, M. S.
    Soares-Santos, M.
    Solà Peracaula, J.
    Songsheng, Y. -Y
    Soriano, J. F.
    Staicova, D.
    Starkman, G. D.
    Szapudi, I.
    Teixeira, E. M.
    Thomas, B.
    Treu, T.
    Trott, E.
    van de Bruck, C.
    Vazquez, J. A.
    Verde, L.
    Visinelli, L.
    Wang, D.
    Wang, J. -M
    Wang, S. -J
    Watkins, R.
    Watson, S.
    Webb, J. K.
    Weiner, N.
    Weltman, A.
    Witte, S. J.
    Wojtak, R.
    Yadav, A. K.
    Yang, W.
    Zhao, G. -B
    Zumalacárregui, M.
    Cosmology intertwined: A review of the particle physics, astrophysics, and cosmology associated with the cosmological tensions and anomalies2022Ingår i: Journal of High Energy Astrophysics, ISSN 2214-4048, E-ISSN 2214-4056, Vol. 34, s. 49-211Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The standard Λ Cold Dark Matter (ΛCDM) cosmological model provides a good description of a wide range of astrophysical and cosmological data. However, there are a few big open questions that make the standard model look like an approximation to a more realistic scenario yet to be found. In this paper, we list a few important goals that need to be addressed in the next decade, taking into account the current discordances between the different cosmological probes, such as the disagreement in the value of the Hubble constant H0, the σ8–S8 tension, and other less statistically significant anomalies. While these discordances can still be in part the result of systematic errors, their persistence after several years of accurate analysis strongly hints at cracks in the standard cosmological scenario and the necessity for new physics or generalisations beyond the standard model. In this paper, we focus on the 5.0σ tension between the Planck CMB estimate of the Hubble constant H0 and the SH0ES collaboration measurements. After showing the H0 evaluations made from different teams using different methods and geometric calibrations, we list a few interesting new physics models that could alleviate this tension and discuss how the next decade's experiments will be crucial. Moreover, we focus on the tension of the Planck CMB data with weak lensing measurements and redshift surveys, about the value of the matter energy density Ωm, and the amplitude or rate of the growth of structure (σ8,fσ8). We list a few interesting models proposed for alleviating this tension, and we discuss the importance of trying to fit a full array of data with a single model and not just one parameter at a time. Additionally, we present a wide range of other less discussed anomalies at a statistical significance level lower than the H0–S8 tensions which may also constitute hints towards new physics, and we discuss possible generic theoretical approaches that can collectively explain the non-standard nature of these signals. Finally, we give an overview of upgraded experiments and next-generation space missions and facilities on Earth that will be of crucial importance to address all these open questions. 

  • 77. Abdalla, H.
    et al.
    Abramowski, A.
    Aharonian, F.
    Benkhali, F. Ait
    Akhperjanian, A. G.
    Andersson, T.
    Anguener, E. O.
    Arrieta, M.
    Aubert, P.
    Backes, M.
    Balzer, A.
    Barnard, M.
    Becherini, Y.
    Tjus, J. Becker
    Berge, D.
    Bernhard, S.
    Bernloehr, K.
    Blackwell, R.
    Bottcher, M.
    Boisson, C.
    Bolmont, J.
    Bordas, P.
    Brun, F.
    Brun, P.
    Bryan, M.
    Bulik, T.
    Capasso, M.
    Carr, J.
    Casanova, S.
    Cerruti, M.
    Chakraborty, N.
    Chalme-Calvet, R.
    Chaves, R. C. G.
    Chen, A.
    Chevalier, J.
    Chretien, M.
    Colafrancesco, S.
    Cologna, G.
    Condon, B.
    Conrad, J.
    Couturier, C.
    Cui, Y.
    Davids, I. D.
    Degrange, B.
    Deil, C.
    Devin, J.
    dewilt, P.
    Dirson, L.
    Djannati-Atai, A.
    Domainko, W.
    Donath, A.
    Drury, L. O 'C.
    Dubus, G.
    Dutson, K.
    Dyks, J.
    Edwards, T.
    Egberts, K.
    Eger, P.
    Ernenwein, J. -P
    Eschbach, S.
    Farnier, C.
    Fegan, S.
    Fernandes, M. V.
    Fiasson, A.
    Fontaine, G.
    Forster, A.
    Funk, S.
    Fuessling, M.
    Gabici, S.
    Gajdus, M.
    Gallant, Y. A.
    Garrigoux, T.
    Giavitto, G.
    Giebels, B.
    Glicenstein, J. F.
    Gottschall, D.
    Goyal, A.
    Grondin, M. -H
    Hadasch, D.
    Hahn, J.
    Haupt, M.
    Hawkes, J.
    Heinzelmann, G.
    Henri, G.
    Hermann, G.
    Hervet, O.
    Hillert, A.
    Hinton, J. A.
    Hofmann, W.
    Hoischen, C.
    Holler, M.
    Horns, D.
    Ivascenko, A.
    Jacholkowska, A.
    Jamrozy, M.
    Janiak, M.
    Jankowsky, D.
    Jankowsky, F.
    Jingo, M.
    Jogler, T.
    Jouvin, L.
    Jung-Richardt, I.
    Kastendieck, M. A.
    Katarzynski, K.
    Katz, U.
    Kerszberg, D.
    Khelifi, B.
    Kieffer, M.
    King, J.
    Klepser, S.
    Klochkov, D.
    Kluzniak, W.
    Kolitzus, D.
    Komin, Nu.
    Kosack, K.
    Krakau, S.
    Kraus, M.
    Krayzel, F.
    Kruger, P. P.
    Laffon, H.
    Lamanna, G.
    Lau, J.
    Lees, J. -P
    Lefaucheur, J.
    Lefranc, V.
    Lemiere, A.
    Lemoine-Goumard, M.
    Lenain, J. -P
    Leser, E.
    Lohse, T.
    Lorentz, M.
    Liu, R.
    Lopez-Coto, R.
    Lypova, I.
    Marandon, V.
    Marcowith, A.
    Mariaud, C.
    Marx, R.
    Maurin, G.
    Maxted, N.
    Mayer, M.
    Meintjes, P. J.
    Meyer, M.
    Mitchell, A. M. W.
    Moderski, R.
    Mohamed, M.
    Mohrmann, L.
    Mora, K.
    Moulin, E.
    Murach, T.
    de Naurois, M.
    Niederwanger, F.
    Niemiec, J.
    Oakes, L.
    O'Brien, P.
    Odaka, H.
    Oul, S.
    Ohm, S.
    Ostrowski, M.
    Oya, I.
    Padovani, M.
    Panter, M.
    Parsons, R. D.
    Arribas, M. Paz
    Pekeur, N. W.
    Pelletier, G.
    Perennes, C.
    Petrucci, P. -O
    Peyaud, B.
    Pita, S.
    Poon, H.
    Prokhorov, D.
    Prokoph, H.
    Puehlhofer, G.
    Punch, M.
    Quirrenbach, A.
    Raab, S.
    Reimer, A.
    Reimer, O.
    Renaud, M.
    de los Reyes, R.
    Rieger, F.
    Romoli, C.
    Rosier-Lees, S.
    Rowell, G.
    Rudak, B.
    Rulten, C. B.
    Sahakian, V.
    Salek, D.
    Sanchez, D. A.
    Santangelo, A.
    Sasaki, M.
    Schlickeiser, R.
    Schussler, F.
    Schulz, A.
    Schwanke, U.
    Schwemmer, S.
    Settimo, M.
    Seyffert, A. S.
    Shafi, N.
    Shilon, I.
    Simoni, R.
    Sol, H.
    Spanier, F.
    Spengler, G.
    Spies, F.
    Stawarz, L.
    Steenkamp, R.
    Stegmann, C.
    Stinzing, F.
    Stycz, K.
    Sushch, I.
    Tavernet, J. -P
    Tavernier, T.
    Taylor, A. M.
    Terrier, R.
    Tibaldo, L.
    Tiziani, D.
    Tluczykont, M.
    Trichard, C.
    Tuffs, R.
    Uchiyama, Y.
    van der Walt, D. J.
    van Edik, C.
    van Soelen, B.
    Vasileiadis, G.
    Veh, J.
    Venter, C.
    Viana, A.
    Vincent, P.
    Vink, J.
    Voisin, F.
    Voelk, H. J.
    Vuillaume, T.
    Wadiasingh, Z.
    Wagner, S. J.
    Wagner, P.
    Wagner, R. M.
    White, R.
    Wierzcholska, A.
    Willmann, P.
    Woernlein, A.
    Wouters, D.
    Yang, R.
    Zabalza, V.
    Zaborov, D.
    Zacharias, M.
    Zdziarski, A. A.
    Zech, A.
    Zefi, F.
    Ziegler, A.
    Zywucka, N.
    Ackermann, M.
    Ajello, M.
    Baldini, L.
    Barbiellini, G.
    Bellazzini, R.
    Blandford, R. D.
    Bonino, R.
    Bregeon, J.
    Bruel, P.
    Buehler, R.
    Caliandro, G. A.
    Cameron, R. A.
    Caragiulo, M.
    Caraveo, P. A.
    Cavazzuti, E.
    Cecchi, C.
    Chiang, J.
    Chiaro, G.
    Ciprini, S.
    Cohen-Tanugi, J.
    Costanza, F.
    Cutini, S.
    D'Ammando, F.
    de Palma, F.
    Desiante, R.
    Di Lalla, N.
    Di Mauro, M.
    Di Venere, L.
    Donaggio, B.
    Favuzzi, C.
    Focke, W. B.
    Fusco, P.
    Gargano, F.
    Gasparrini, D.
    Giglietto, N.
    Giordano, F.
    Giroletti, M.
    Guillemot, L.
    Guiriec, S.
    Horan, D.
    Johannesson, G.
    Kamae, T.
    Kensei, S.
    Kocevski, D.
    Larsson, Stefan
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Li, J.
    Longo, F.
    Loparco, F.
    Lovellette, M. N.
    Lubrano, P.
    Maldera, S.
    Manfreda, A.
    Mazziotta, M. N.
    Michelson, P. F.
    Mizuno, T.
    Monzani, M. E.
    Morselli, A.
    Negro, M.
    Nuss, E.
    Orienti, M.
    Orlando, E.
    Paneque, D.
    Perkins, J. S.
    Pesce-Rollins, M.
    Piron, F.
    Pivato, G.
    Porter, T. A.
    Principe, G.
    Raino, S.
    Razzano, M.
    Simone, D.
    Siskind, E. J.
    Spada, F.
    Spinelli, P.
    Thayer, J. B.
    Torres, D. F.
    Torresi, E.
    Troja, E.
    Vianello, G.
    Wood, K. S.
    Gamma-ray blazar spectra with HESS II mono analysis: The case of PKS2155-304 and PG1553+1132017Ingår i: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 600, artikel-id A89Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Context. The addition of a 28 m Cherenkov telescope (CT5) to the H.E.S.S. array extended the experiment's sensitivity to lower energies. The lowest energy threshold is obtained using monoscopic analysis of data taken with CT5, providing access to gamma-ray energies below 100 GeV for small zenith angle observations. Such an extension of the instrument's energy range is particularly beneficial for studies of active galactic nuclei with soft spectra, as expected for those at a redshift >= 0.5. The high-frequency peaked BL Lac objects PKS 2155-304 (z = 0.116) and PG 1553 + 113 (0.43 < z < 0.58) are among the brightest objects in the gamma-ray sky, both showing clear signatures of gamma-ray absorption at E > 100 GeV interpreted as being due to interactions with the extragalactic background light (EBL). Aims. The aims of this work are twofold: to demonstrate the monoscopic analysis of CT5 data with a low energy threshold, and to obtain accurate measurements of the spectral energy distributions (SED) of PKS 2155-304 and PG 1553 + 113 near their SED peaks at energies approximate to 100 GeV. Methods. Multiple observational campaigns of PKS 2155 304 and PG 1553 + 113 were conducted during 2013 and 2014 using the full H.E.S.S. II instrument (CT1-5). A monoscopic analysis of the data taken with the new CT5 telescope was developed along with an investigation into the systematic uncertainties on the spectral parameters which are derived from this analysis. Results. Using the data from CT5, the energy spectra of PKS 2155 304 and PG 1553 + 113 were reconstructed down to conservative threshold energies of 80 GeV for PKS 2155 304, which transits near zenith, and 110 GeV for the more northern PG 1553 + 113. The measured spectra, well fitted in both cases by a log-parabola spectral model ( with a 5.0 similar to statistical preference for non-zero curvature for PKS 2155 304 and 4.5 sigma for PG 1553+113), were found consistent with spectra derived from contemporaneous Fermi-LAT data, indicating a sharp break in the observed spectra of both sources at E approximate to 100 GeV. When corrected for EBL absorption, the intrinsic H.E.S.S. II mono and Fermi-LAT spectrum of PKS 2155 304 was found to show significant curvature. For PG 1553+113, however, no significant detection of curvature in the intrinsic spectrum could be found within statistical and systematic uncertainties.

  • 78. Abdellaoui, G.
    et al.
    Abe, S.
    Acheli, A.
    Adams, J. H. J. H.
    Ahmad, S.
    Ahriche, A.
    Albert, J. -N
    Allard, D.
    Alonso, G.
    Anchordoqui, L.
    Andreev, V.
    Anzalone, A.
    Aouimeure, W.
    Arai, Y.
    Arsene, N.
    Asano, K.
    Attallah, R.
    Attoui, H.
    Pemas, M. Ave
    Bacholle, S.
    Bakiri, M.
    Baragatti, P.
    Barrillon, P.
    Bartocci, S.
    Batsch, T.
    Bayer, J.
    Bechini, R.
    Belenguer, T.
    Bellotti, R.
    Belov, A.
    Belov, K.
    Benadda, B.
    Benmessai, K.
    Berlind, A. A.
    Bertaina, M.
    Biermann, P. L.
    Biktemerova, S.
    Bisconti, F.
    Blanc, N.
    Blecki, J.
    Blin-Bondil, S.
    Bobik, P.
    Bogomilov, M.
    Bonamente, M.
    Boudaoud, R.
    Bozzo, E.
    Briggs, M. S.
    Bruno, A.
    Caballero, K. S.
    Cafagna, F.
    Campana, D.
    Capdevielle, J. -N
    Capel, Francesca
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Caramete, A.
    Caramete, L.
    Carlson, Per
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Caruso, R.
    Casolino, M.
    Cassardo, C.
    Castellina, A.
    Castellini, G.
    Catalano, C.
    Catalano, O.
    Cellino, A.
    Chikawa, M.
    Chiritoi, G.
    Christl, M. J.
    Connaughton, V.
    Conti, L.
    Cordero, G.
    Crawford, H. J.
    Cremonini, R.
    Csorna, S.
    Dagoret-Campagne, S.
    De Donato, C.
    de la Taille, C.
    De Santis, C.
    del Peral, L.
    Di Martino, M.
    Djemil, T.
    Djenas, S. A.
    Dulucq, F.
    Dupieux, M.
    Dutan, I.
    Ebersoldt, A.
    Ebisuzaki, T.
    Engel, R.
    Eser, J.
    Fang, K.
    Fenu, F.
    Fernandez-Gonzalez, S.
    Fernandez-Soriano, J.
    Ferrarese, S.
    Finco, D.
    Flamini, M.
    Fornaro, C.
    Fouka, M.
    Franceschi, A.
    Franchini, S.
    Fuglesang, Christer
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Fujimoto, J.
    Fukushima, M.
    Galeotti, P.
    Garcia-Ortega, E.
    Garipov, G.
    Gascon, E.
    Geary, J.
    Gelmini, G.
    Genci, J.
    Giraudo, G.
    Gonchar, M.
    Alvarado, C. Gonzalez
    Gorodetzky, P.
    Guarino, F.
    Guehaz, R.
    Guzman, A.
    Hachisu, Y.
    Haiduc, M.
    Harlov, B.
    Haungs, A.
    Carretero, J. Hernandez
    Hidber, W.
    Higashide, K.
    Ikeda, D.
    Ikeda, H.
    Inoue, N.
    Inoue, S.
    Isgro, F.
    Itow, Y.
    Jammer, T.
    Joven, E.
    Judd, E. G.
    Jung, A.
    Jochum, J.
    Kajino, F.
    Kajino, T.
    Kalli, S.
    Kaneko, I.
    Kang, D.
    Kanouni, F.
    Karadzhov, Y.
    Karczmarczyk, J.
    Karus, M.
    Katahira, K.
    Kawai, K.
    Kawasaki, Y.
    Kedadra, A.
    Khales, H.
    Khrenov, B. A.
    Kim, Jeong-Sook
    Kim, Soon-Wook
    Kim, Sug-Whan
    Kleifges, M.
    Klimov, P. A.
    Kolev, D.
    Kreykenbohm, I.
    Kudela, K.
    Kurihara, Y.
    Kusenko, A.
    Kuznetsov, E.
    Lacombe, M.
    Lachaud, C.
    Lahmar, H.
    Lakhdari, F.
    Larsson, Oscar
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Lee, J.
    Licandro, J.
    Lim, H.
    Campano, L. Lopez
    Maccarone, M. C.
    Mackovjak, S.
    Mandi, M.
    Maravilla, D.
    Marcelli, L.
    Marcos, J. L.
    Marini, A.
    Martens, K.
    Martin, Y.
    Martinez, O.
    Masciantonio, G.
    Mase, K.
    Matev, R.
    Matthews, J. N.
    Mebarki, N.
    Medina-Tanco, G.
    Mehrad, L.
    Mendoza, M. A.
    Merino, A.
    Memik, T.
    Meseguer, J.
    Messaoud, S.
    Micu, O.
    Mimouni, J.
    Miyamoto, H.
    Miyazaki, Y.
    Mizumoto, Y.
    Modestino, G.
    Monaco, A.
    Monnier-Ragaigne, D.
    de los Rios, J. A. Morales
    Moretto, C.
    Morozenko, V. S.
    Mot, B.
    Murakami, T.
    Nadji, B.
    Nagano, M.
    Nagata, M.
    Nagataki, S.
    Nakamura, T.
    Napolitano, T.
    Nardellis, A.
    Naumov, D.
    Nava, R.
    Neronov, A.
    Nomoto, K.
    Nonaka, T.
    Ogawa, T.
    Ogio, S.
    Ohmori, H.
    Olinto, A. V.
    Orleariski, P.
    Osteria, G.
    Painter, W.
    Panasyuk, M. I.
    Panico, B.
    Parizot, E.
    Park, I. H.
    Park, H. W.
    Pastircak, B.
    Patzak, T.
    Paul, T.
    Pennypacker, C.
    Perdichizzi, M.
    Perez-Grande, I.
    Perfetto, F.
    Peter, T.
    Picozza, P.
    Pierog, T.
    Pindado, S.
    Piotrowski, L. W.
    Pirainou, S.
    Placidis, L.
    Plebaniak, Z.
    Pliego, S.
    Pollini, A.
    Popescu, E. M.
    Prat, P.
    Prevot, G.
    Prieto, H.
    Putis, M.
    Rabanal, J.
    Radu, A. A.
    Rahmani, M.
    Reardon, P.
    Reyes, M.
    Rezazadeh, M.
    Ricci, M.
    Frias, M. D. Rodriguez
    Ronga, F.
    Roth, M.
    Rothkaehl, H.
    Roudil, G.
    Rusinov, I.
    Rybczynski, M.
    Sabau, M. D.
    Cano, G. Saez
    Sagawa, H.
    Sahnoune, Z.
    Saito, A.
    Sakaki, N.
    Sakata, M.
    Salazar, H.
    Sanchez, J. C.
    Sanchez, J. L.
    Santangelo, A.
    Cruz, L. Santiago
    Sanz-Andres, A.
    Palomino, M. Sanz
    Saprykin, O.
    Sarazin, F.
    Sato, H.
    Sato, M.
    Schanz, T.
    Schieler, H.
    Scotti, V.
    Segreto, A.
    Selmane, S.
    Semikoz, D.
    Serra, M.
    Sharakin, S.
    Shibata, T.
    Shimizu, H. M.
    Shinozaki, K.
    Shirahama, T.
    Siemieniec-Ozieblo, G.
    Sledd, J.
    Slomiriska, K.
    Sobey, A.
    Stan, I.
    Sugiyama, T.
    Supanitsky, D.
    Suzuki, M.
    Szabelska, B.
    Szabelski, J.
    Tahi, H.
    Tajima, F.
    Tajima, N.
    Tajima, T.
    Takahashi, Y.
    Takami, H.
    Takeda, M.
    Takizawa, Y.
    Talai, M. C.
    Tenzer, C.
    Tibolla, O.
    Tkachev, L.
    Tokuno, H.
    Tomida, T.
    Tone, N.
    Toscano, S.
    Traiche, M.
    Tsenov, R.
    Tsunesada, Y.
    Tsuno, K.
    Tymieniecka, T.
    Uchihori, Y.
    Unger, M.
    Vaduvescu, O.
    Valdes-Galicia, J. F.
    Vallania, P.
    Vankova, G.
    Vigorito, C.
    Villasenor, L.
    Vicek, B.
    von Ballmoos, P.
    Vrabel, M.
    Wada, S.
    Watanabe, J.
    Watanabe, S.
    Watts, J., Jr.
    Weber, M.
    Munoz, R. Weigand
    Weindl, A.
    Weiler, T. J.
    Wibig, T.
    Wiencke, L.
    Wille, M.
    Wilms, J.
    Wlodarczyk, Z.
    Yamamoto, T.
    Yamamoto, Y.
    Yang, J.
    Yano, H.
    Yashin, I. V.
    Yonetoku, D.
    Yoshida, S.
    Young, R.
    Zgura, I. S.
    Zotov, M. Yu.
    Marchi, A. Zuccaro
    Meteor studies in the framework of the JEM-EUSO program2017Ingår i: Planetary and Space Science, ISSN 0032-0633, E-ISSN 1873-5088, Vol. 143, s. 245-255Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We summarize the state of the art of a program of UV observations from space of meteor phenomena, a secondary objective of the JEM-EUSO international collaboration. Our preliminary analysis indicates that JEM-EUSO, taking advantage of its large FOV and good sensitivity, should be able to detect meteors down to absolute magnitude close to 7. This means that JEM-EUSO should be able to record a statistically significant flux of meteors, including both sporadic ones, and events produced by different meteor streams. Being unaffected by adverse weather conditions, JEM-EUSO can also be a very important facility for the detection of bright meteors and fireballs, as these events can be detected even in conditions of very high sky background. In the case of bright events, moreover, exhibiting some persistence of the meteor train, preliminary simulations show that it should be possible to exploit the motion of the ISS itself and derive at least a rough 3D reconstruction of the meteor trajectory. Moreover, the observing strategy developed to detect meteors may also be applied to the detection of nuclearites, exotic particles whose existence has been suggested by some theoretical investigations. Nuclearites are expected to move at higher velocities than meteoroids, and to exhibit a wider range of possible trajectories, including particles moving upward after crossing the Earth. Some pilot studies, including the approved Mini-EUSO mission, a precursor of JEM-EUSO, are currently operational or in preparation. We are doing simulations to assess the performance of Mini-EUSO for meteor studies, while a few meteor events have been already detected using the ground-based facility EUSO-TA.

  • 79.
    Abdellaoui, G.
    et al.
    Telecom Lab., Faculty of Technology, University Abou Bekr Belkaid, Tlemcen, Algeria.
    Bolmgren, Karl
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Carlson, Per
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Fuglesang, Christer
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Zuccaro Marchi, A.
    RIKEN, Wako, Japan.
    An overview of the JEM-EUSO program and results2022Ingår i: 37th International Cosmic Ray Conference, ICRC 2021, Sissa Medialab Srl , 2022, artikel-id 406Konferensbidrag (Refereegranskat)
    Abstract [en]

    The field of UHECRs (Ultra-High energy cosmic Rays) and the understanding of particle acceleration in the cosmos, as a key ingredient to the behaviour of the most powerful sources in the universe, is of outmost importance for astroparticle physics as well as for fundamental physics and will improve our general understanding of the universe. The current main goals are to identify sources of UHECRs and their composition. For this, increased statistics is required. A space-based detector for UHECR research has the advantage of a very large exposure and a uniform coverage of the celestial sphere. The aim of the JEM-EUSO program [1] is to bring the study of UHECRs to space. The principle of observation is based on the detection of UV light emitted by isotropic fluorescence of atmospheric nitrogen excited by the Extensive Air Showers (EAS) in the Earth's atmosphere and forward-beamed Cherenkov radiation reflected from the Earth's surface or dense cloud tops. In addition to the prime objective of UHECR studies, JEM-EUSO will do several secondary studies due to the instruments' unique capacity of detecting very weak UV-signals with extreme time-resolution around 1 μs: meteors, Transient Luminous Events (TLE), bioluminescence, maps of human generated UV-light, searches for Strange Quark Matter (SQM) and high-energy neutrinos, and more. The JEM-EUSO program includes several missions from ground (EUSO-TA [2]), from stratospheric balloons (EUSO-Balloon [3], EUSO-SPB1 [4], EUSO-SPB2 [5]), and from space (TUS [6], Mini-EUSO [7]) employing fluorescence detectors to demonstrate the UHECR observation from space and prepare the large size missions K-EUSO [8] and POEMMA [9]. A review of the current status of the program, the key results obtained so far by the different projects, and the perspectives for the near future are presented.

  • 80.
    Abdellaoui, G.
    et al.
    Telecom Lab., Faculty of Technology, University Abou Bekr Belkaid, Tlemcen, Algeria.
    Bolmgren, Karl
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Carlson, Per
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Fuglesang, Christer
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Zuccaro Marchi, A.
    RIKEN, Wako, Japan.
    et al.,
    Towards observations of nuclearites in Mini-EUSO2022Ingår i: 37th International Cosmic Ray Conference, ICRC 2021, Sissa Medialab Srl , 2022, artikel-id 503Konferensbidrag (Refereegranskat)
    Abstract [en]

    Mini-EUSO is a small orbital telescope with a field of view of 44◦ × 44◦, observing the night-time Earth mostly in 320-420 nm band. Its time resolution spanning from microseconds (triggered) to milliseconds (untriggered) and more than 300 × 300 km of the ground covered, already allowed it to register thousands of meteors. Such detections make the telescope a suitable tool in the search for hypothetical heavy compact objects, which would leave trails of light in the atmosphere due to their high density and speed. The most prominent example are the nuclearites – hypothetical lumps of strange quark matter that could be stabler and denser than the nuclear matter. In this paper, we show potential limits on the flux of nuclearites after collecting 42 hours of observations data.

  • 81.
    Abdellaoui, G.
    et al.
    Telecom Laboratory, Faculty of Technology, University Abou Bekr Belkaid, Tlemcen, Algeria.
    Bolmgren, Karl
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Fuglesang, Christer
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Marchi, A. Zuccaro
    RIKEN, Wako, Japan.
    EUSO-SPB1 mission and science2024Ingår i: Astroparticle physics, ISSN 0927-6505, E-ISSN 1873-2852, Vol. 154, s. 102891-, artikel-id 102891Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The Extreme Universe Space Observatory on a Super Pressure Balloon 1 (EUSO-SPB1) was launched in 2017 April from Wanaka, New Zealand. The plan of this mission of opportunity on a NASA super pressure balloon test flight was to circle the southern hemisphere. The primary scientific goal was to make the first observations of ultra-high-energy cosmic-ray extensive air showers (EASs) by looking down on the atmosphere with an ultraviolet (UV) fluorescence telescope from suborbital altitude (33 km). After 12 days and 4 h aloft, the flight was terminated prematurely in the Pacific Ocean. Before the flight, the instrument was tested extensively in the West Desert of Utah, USA, with UV point sources and lasers. The test results indicated that the instrument had sensitivity to EASs of ⪆3 EeV. Simulations of the telescope system, telescope on time, and realized flight trajectory predicted an observation of about 1 event assuming clear sky conditions. The effects of high clouds were estimated to reduce this value by approximately a factor of 2. A manual search and a machine-learning-based search did not find any EAS signals in these data. Here we review the EUSO-SPB1 instrument and flight and the EAS search.

  • 82.
    Abdellaoui, G.
    et al.
    Telecom Lab., Faculty of Technology, University Abou Bekr Belkaid, Tlemcen, Algeria.
    Carlson, Per
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Eliasson, Linda
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Fuglesang, Christer
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Zuccaro Marchi, A.
    RIKEN, Wako, Japan.
    Science and mission status of EUSO-SPB22022Ingår i: 37th International Cosmic Ray Conference, ICRC 2021, Sissa Medialab Srl , 2022, artikel-id 404Konferensbidrag (Refereegranskat)
    Abstract [en]

    The Extreme Universe Space Observatory on a Super Pressure Balloon II (EUSO-SPB2) is a second generation stratospheric balloon instrument for the detection of Ultra High Energy Cosmic Rays (UHECRs, E > 1 EeV) via the fluorescence technique and of Very High Energy (VHE, E > 10 PeV) neutrinos via Cherenkov emission. EUSO-SPB2 is a pathfinder mission for instruments like the proposed Probe Of Extreme Multi-Messenger Astrophysics (POEMMA). The purpose of such a space-based observatory is to measure UHECRs and UHE neutrinos with high statistics and uniform exposure. EUSO-SPB2 is designed with two Schmidt telescopes, each optimized for their respective observational goals. The Fluorescence Telescope looks at the nadir to measure the fluorescence emission from UHECR-induced extensive air shower (EAS), while the Cherenkov Telescope is optimized for fast signals (∼10 ns) and points near the Earth's limb. This allows for the measurement of Cherenkov light from EAS caused by Earth skimming VHE neutrinos if pointed slightly below the limb or from UHECRs if observing slightly above. The expected launch date of EUSO-SPB2 is Spring 2023 from Wanaka, NZ with target duration of up to 100 days. Such a flight would provide thousands of VHECR Cherenkov signals in addition to tens of UHECR fluorescence tracks. Neither of these kinds of events have been observed from either orbital or suborbital altitudes before, making EUSO-SPB2 crucial to move forward towards a space-based instrument. It will also enhance the understanding of potential background signals for both detection techniques. This contribution will provide a short overview of the detector and the current status of the mission as well as its scientific goals.

  • 83. Abdellaoui, G.
    et al.
    Fuglesang, Christer
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Zuccaro Marchi, Alessandro
    et al,
    EUSO-TA - First results from a ground-based EUSO telescope2018Ingår i: Astroparticle physics, ISSN 0927-6505, E-ISSN 1873-2852, Vol. 102, s. 98-111Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    EUSO-TA is a ground-based telescope, installed at the Telescope Array (TA) site in Black Rock Mesa, Utah, USA. This is the first detector to successfully use a Fresnel lens based optical system and multi-anode photomultipliers (64 channels per tube, 2304 channels encompassing a 10.6° × 10.6° field of view) for detection of Ultra High Energy Cosmic Rays (UHECR). The telescope is located in front of one of the fluorescence detectors of the TA experiment. Since its installation in 2013, the detector has observed several ultra-high energy cosmic ray events and, in addition, meteors. The limiting magnitude of 5.5 on summed frames (∼ 3 ms) has been established. Measurements of the UV night sky emission in different conditions and moon phases and positions have been completed. The performed observations serve as a proof of concept for the future application of this detector technology.

  • 84. Abdin, A.
    et al.
    Amberger, S.
    Apollonio, E.
    De Fourtou, G. B.
    Bolmgren, Karl
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Ciocca, G.
    Ekal, M.
    Garcia, A.
    Godeanu, A.
    Irrera, D.
    Lidgard, L. C. L.
    Lorini, G.
    Monat, S.
    Montenegro, J.
    Oleary, A.
    Onn, O.
    Pauzie, L.
    Pouwels, C.
    Sokolowski, A.
    Tian, Z.
    Za, A.
    Solutions for construction of a lunar base: A proposal to use the spacex starship as a permanent habitat2021Ingår i: Proceedings of the International Astronautical Congress, IAC, International Astronautical Federation, IAF , 2021Konferensbidrag (Refereegranskat)
    Abstract [en]

    Returning to the Moon and establishing a permanent human presence is the next step in human space exploration. This necessitates the development of lunar infrastructure up to this task. This contribution presents a framework for rapid, cost-efficient, and supporting construction of a permanent and modular lunar base within the scope of what will be technically and legally feasible today. The proposed concept uses the SpaceX Starship Human Landing System as the foundation for a lunar base. The Starship will be placed horizontally on the lunar surface and transformed into a habitable volume. A workforce of modular rovers will aid astronauts in the construction process, and an array of countermeasures are presented to protect the astronauts from the effects of exposure to radiation, lunar dust, and extended hypogravity. Psychological and psychosocial factors are included to enhance individual well-being and crew dynamics. Physical and cognitive workloads are defined and evaluated to identify effective countermeasures, including specific spacesuit requirements. The proposed construction activities are to be organized as a multi-national public-private partnership to establish an international authority, a concept that has been successful on Earth but has yet to be applied to space activities on a multi-national level. A roadmap incorporating each part of the construction from human and technical perspectives is outlined. Other aspects that are critical to mission success include the cultural significance of the project, legal aspects, budget, financing, and potential future uses of the base. These solutions rely mainly on existing technologies and limited modifications to the lunar lander vehicle, making it a viable solution for the construction of a lunar base in the near future.

  • 85. Abdo, A. A.
    et al.
    Ackermann, M.
    Agudo, I.
    Ajello, M.
    Allafort, A.
    Aller, H. D.
    Aller, M. F.
    Antolini, E.
    Arkharov, A. A.
    Axelsson, Magnus
    Bach, U.
    Baldini, L.
    Ballet, J.
    Barbiellini, G.
    Bastieri, D.
    Bechtol, K.
    Bellazzini, R.
    Berdyugin, A.
    Berenji, B.
    Blandford, R. D.
    Blinov, D. A.
    Bloom, E. D.
    Boettcher, M.
    Bonamente, E.
    Borgland, A. W.
    Bouvier, A.
    Bregeon, J.
    Brez, A.
    Brigida, M.
    Bruel, P.
    Buehler, R.
    Buemi, C. S.
    Burnett, T. H.
    Buson, S.
    Caliandro, G. A.
    Cameron, R. A.
    Caraveo, P. A.
    Carosati, D.
    Carrigan, S.
    Casandjian, J. M.
    Cavazzuti, E.
    Cecchi, C.
    Celik, Oe
    Chekhtman, A.
    Chen, W. P.
    Cheung, C. C.
    Chiang, J.
    Ciprini, S.
    Claus, R.
    Cohen-Tanugi, J.
    Conrad, J.
    Corbel, S.
    Costamante, L.
    Dermer, C. D.
    de Angelis, A.
    de Palma, F.
    Donato, D.
    do Couto e Silva, E.
    Drell, P. S.
    Dubois, R.
    Dumora, D.
    Farnier, C.
    Favuzzi, C.
    Fegan, S. J.
    Ferrara, E. C.
    Focke, W. B.
    Forne, E.
    Fortin, P.
    Fukazawa, Y.
    Funk, S.
    Fusco, P.
    Gargano, F.
    Gasparrini, D.
    Gehrels, N.
    Germani, S.
    Giebels, B.
    Giglietto, N.
    Giordano, F.
    Giroletti, M.
    Glanzman, T.
    Godfrey, G.
    Grenier, I. A.
    Grove, J. E.
    Guiriec, S.
    Gurwell, M. A.
    Gusbar, C.
    Gomez, J. L.
    Hadasch, D.
    Hagen-Thorn, V. A.
    Hayashida, M.
    Hays, E.
    Horan, D.
    Hughes, R. E.
    Johannesson, G.
    Johnson, A. S.
    Johnson, W. N.
    Kamae, T.
    Katagiri, H.
    Kataoka, J.
    Kawai, N.
    Kimeridze, G.
    Knoedlseder, J.
    Konstantinova, T. S.
    Kopatskaya, E. N.
    Koptelova, E.
    Kovalev, Y. Y.
    Kurtanidze, O. M.
    Kuss, M.
    Lahteenmaki, A.
    Lande, J.
    Larionov, V. M.
    Larionova, E. G.
    Larionova, L. V.
    Larsson, S.
    Latronico, L.
    Lee, S. -H
    Leto, P.
    Lister, M. L.
    Longo, F.
    Loparco, F.
    Lott, B.
    Lovellette, M. N.
    Lubrano, P.
    Madejski, G. M.
    Makeev, A.
    Massaro, E.
    Mazziotta, M. N.
    McConville, W.
    McEnery, J. E.
    McHardy, I. M.
    Michelson, P. F.
    Mitthumsiri, W.
    Mizuno, T.
    Moiseev, A. A.
    Monte, C.
    Monzani, M. E.
    Morozova, D. A.
    Morselli, A.
    Moskalenko, I. V.
    Murgia, S.
    Naumann-Godo, M.
    Nikolashvili, M. G.
    Nolan, P. L.
    Norris, J. P.
    Nuss, E.
    Ohno, M.
    Ohsugi, T.
    Okumura, A.
    Omodei, N.
    Orlando, E.
    Ormes, J. F.
    Ozaki, M.
    Paneque, D.
    Panetta, J. H.
    Parent, D.
    Pasanen, M.
    Pelassa, V.
    Pepe, M.
    Pesce-Rollins, M.
    Piron, F.
    Porter, T. A.
    Pushkarev, A. B.
    Raino, S.
    Raiteri, C. M.
    Rando, R.
    Razzano, M.
    Reimer, A.
    Reimer, O.
    Reinthal, R.
    Ripken, J.
    Ritz, S.
    Roca-Sogorb, M.
    Rodriguez, A. Y.
    Roth, M.
    Roustazadeh, P.
    Ryde, Felix
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Sadrozinski, H. F. -W
    Sander, A.
    Scargle, J. D.
    Sgro, C.
    Sigua, L. A.
    Smith, P. D.
    Sokolovsky, K.
    Spandre, G.
    Spinelli, P.
    Starck, J. -L
    Strickman, M. S.
    Suson, D. J.
    Takahashi, H.
    Takahashi, T.
    Takalo, L. O.
    Tanaka, T.
    Taylor, B.
    Thayer, J. B.
    Thayer, J. G.
    Thompson, D. J.
    Tibaldo, L.
    Tornikoski, M.
    Torres, D. F.
    Tosti, G.
    Tramacere, A.
    Trigilio, C.
    Troitsky, I. S.
    Umana, G.
    Usher, T. L.
    Vandenbroucke, J.
    Vasileiou, V.
    Vilchez, N.
    Villata, M.
    Vitale, V.
    Waite, A. P.
    Wang, P.
    Winer, B. L.
    Wood, K. S.
    Yang, Z.
    Ylinen, Tomi
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Ziegler, M.
    FERMI Large Area Telescope and multi-wavelength observations of the flaring activity of PKS 1510-089 between 2008 september and 2009 june2010Ingår i: Astrophysical Journal, ISSN 0004-637X, E-ISSN 1538-4357, Vol. 721, nr 2, s. 1425-1447Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We report on the multi-wavelength observations of PKS 1510-089 (a flat spectrum radio quasar (FSRQ) at z = 0.361) during its high activity period between 2008 September and 2009 June. During this 11 month period, the source was characterized by a complex variability at optical, UV, and gamma-ray bands, on timescales down to 6-12 hr. The brightest gamma-ray isotropic luminosity, recorded on 2009 March 26, was similar or equal to 2 x 1048 erg s-1. The spectrum in the Fermi Large Area Telescope energy range shows a mild curvature described well by a log-parabolic law, and can be understood as due to the Klein-Nishina effect. The. -ray flux has a complex correlation with the other wavelengths. There is no correlation at all with the X-ray band, a weak correlation with the UV, and a significant correlation with the optical flux. The. -ray flux seems to lead the optical one by about 13 days. From the UV photometry, we estimated a black hole mass of similar or equal to 5.4 x 10(8)M(circle dot) and an accretion rate of similar or equal to 0.5M(circle dot) yr(-1). Although the power in the thermal and non-thermal outputs is smaller compared to the very luminous and distant FSRQs, PKS 1510-089 exhibits a quite large Compton dominance and a prominent big blue bump (BBB) as observed in the most powerful gamma-ray quasars. The BBB was still prominent during the historical maximum optical state in 2009 May, but the optical/ UV spectral index was softer than in the quiescent state. This seems to indicate that the BBB was not completely dominated by the synchrotron emission during the highest optical state. We model the broadband spectrum assuming a leptonic scenario in which the inverse Compton emission is dominated by the scattering of soft photons produced externally to the jet. The resulting model-dependent jet energetic content is compatible with a scenario in which the jet is powered by the accretion disk, with a total efficiency within the Kerr black hole limit.

  • 86. Abdo, A. A.
    et al.
    Ackermann, M.
    Agudo, I.
    Ajello, M.
    Aller, H. D.
    Aller, M. F.
    Angelakis, E.
    Arkharov, A. A.
    Axelsson, Magnus
    Bach, U.
    Baldini, L.
    Ballet, J.
    Barbiellini, G.
    Bastieri, D.
    Baughman, B. M.
    Bechtol, K.
    Bellazzini, R.
    Benitez, E.
    Berdyugin, A.
    Berenji, B.
    Blandford, R. D.
    Bloom, E. D.
    Boettcher, M.
    Bonamente, E.
    Borgland, A. W.
    Bregeon, J.
    Brez, A.
    Brigida, M.
    Bruel, P.
    Burnett, T. H.
    Burrows, D.
    Buson, S.
    Caliandro, G. A.
    Calzoletti, L.
    Cameron, R. A.
    Capalbi, M.
    Caraveo, P. A.
    Carosati, D.
    Casandjian, J. M.
    Cavazzuti, E.
    Cecchi, C.
    Celik, Oe.
    Charles, E.
    Chaty, S.
    Chekhtman, A.
    Chen, W. P.
    Chiang, J.
    Chincarini, G.
    Ciprini, S.
    Claus, R.
    Cohen-Tanugi, J.
    Colafrancesco, S.
    Cominsky, L. R.
    Conrad, J.
    Costamante, L.
    Cutini, S.
    D'ammando, F.
    Deitrick, R.
    D'Elia, V.
    Dermer, C. D.
    de Angelis, A.
    de Palma, F.
    Digel, S. W.
    Donnarumma, I.
    do Couto e Silva, E.
    Drell, P. S.
    Dubois, R.
    Dultzin, D.
    Dumora, D.
    Falcone, A.
    Farnier, C.
    Favuzzi, C.
    Fegan, S. J.
    Focke, W. B.
    Forne, E.
    Fortin, P.
    Frailis, M.
    Fuhrmann, L.
    Fukazawa, Y.
    Funk, S.
    Fusco, P.
    Gomez, J. L.
    Gargano, F.
    Gasparrini, D.
    Gehrels, N.
    Germani, S.
    Giebels, B.
    Giglietto, N.
    Giommi, P.
    Giordano, F.
    Giuliani, A.
    Glanzman, T.
    Godfrey, G.
    Grenier, I. A.
    Gronwall, C.
    Grove, J. E.
    Guillemot, L.
    Guiriec, S.
    Gurwell, M. A.
    Hadasch, D.
    Hanabata, Y.
    Harding, A. K.
    Hayashida, M.
    Hays, E.
    Healey, S. E.
    Heidt, J.
    Hiriart, D.
    Horan, D.
    Hoversten, E. A.
    Hughes, R. E.
    Itoh, R.
    Jackson, Miranda
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Johannesson, G.
    Johnson, A. S.
    Johnson, W. N.
    Jorstad, S. G.
    Kadler, M.
    Kamae, T.
    Katagiri, H.
    Kataoka, J.
    Kawai, N.
    Kennea, J.
    Kerr, M.
    Kimeridze, G.
    Knoedlseder, J.
    Kocian, M. L.
    Kopatskaya, E. N.
    Koptelova, E.
    Konstantinova, T. S.
    Kovalev, Y. Y.
    Kovalev, Yu. A.
    Kurtanidze, O. M.
    Kuss, M.
    Lande, J.
    Larionov, V. M.
    Latronico, L.
    Leto, P.
    Lindfors, E.
    Longo, F.
    Loparco, F.
    Lott, B.
    Lovellette, M. N.
    Lubrano, P.
    Madejski, G. M.
    Makeev, A.
    Marchegiani, P.
    Marscher, A. P.
    Marshall, F.
    Max-Moerbeck, W.
    Mazziotta, M. N.
    McConville, W.
    McEnery, J. E.
    Meurer, C.
    Michelson, P. F.
    Mitthumsiri, W.
    Mizuno, T.
    Moiseev, A. A.
    Monte, C.
    Monzani, M. E.
    Morselli, A.
    Moskalenko, I. V.
    Murgia, S.
    Nestoras, I.
    Nilsson, K.
    Nizhelsky, N. A.
    Nolan, P. L.
    Norris, J. P.
    Nuss, E.
    Ohsugi, T.
    Ojha, R.
    Omodei, N.
    Orlando, E.
    Ormes, J. F.
    Osborne, J.
    Ozaki, M.
    Pacciani, L.
    Padovani, P.
    Pagani, C.
    Page, K.
    Paneque, D.
    Panetta, J. H.
    Parent, D.
    Pasanen, M.
    Pavlidou, V.
    Pelassa, V.
    Pepe, M.
    Perri, M.
    Pesce-Rollins, M.
    Piranomonte, S.
    Piron, F.
    Pittori, C.
    Porter, T. A.
    Puccetti, S.
    Rahoui, F.
    Raino, S.
    Raiteri, C.
    Rando, R.
    Razzano, M.
    Reimer, A.
    Reimer, O.
    Reposeur, T.
    Richards, J. L.
    Ritz, S.
    Rochester, L. S.
    Rodriguez, A. Y.
    Romani, R. W.
    Ros, J. A.
    Roth, M.
    Roustazadeh, P.
    Ryde, Felix
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Sadrozinski, H. F. -W
    Sadun, A.
    Sanchez, D.
    Sander, A.
    Parkinson, P. M. Saz
    Scargle, J. D.
    Sellerholm, A.
    Sgro, C.
    Shaw, M. S.
    Sigua, L. A.
    Siskind, E. J.
    Smith, D. A.
    Smith, P. D.
    Spandre, G.
    Spinelli, P.
    Starck, J. -L
    Stevenson, M.
    Stratta, G.
    Strickman, M. S.
    Suson, D. J.
    Tajima, H.
    Takahashi, H.
    Takahashi, T.
    Takalo, L. O.
    Tanaka, T.
    Thayer, J. B.
    Thayer, J. G.
    Thompson, D. J.
    Tibaldo, L.
    Torres, D. F.
    Tosti, G.
    Tramacere, A.
    Uchiyama, Y.
    Usher, T. L.
    Vasileiou, V.
    Verrecchia, F.
    Vilchez, N.
    Villata, M.
    Vitale, V.
    Waite, A. P.
    Wang, P.
    Winer, B. L.
    Wood, K. S.
    Ylinen, Tomi
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Zensus, J. A.
    Zhekanis, G. V.
    Ziegler, M.
    The spectral energy distribution of fermi bright blazars2010Ingår i: Astrophysical Journal, ISSN 0004-637X, E-ISSN 1538-4357, Vol. 716, nr 1, s. 30-70Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We have conducted a detailed investigation of the broadband spectral properties of the gamma-ray selected blazars of the Fermi LAT Bright AGN Sample (LBAS). By combining our accurately estimated Fermi gamma-ray spectra with Swift, radio, infra-red, optical, and other hard X-ray/gamma-ray data, collected within 3 months of the LBAS data taking period, we were able to assemble high-quality and quasi-simultaneous spectral energy distributions (SED) for 48 LBAS blazars. The SED of these gamma-ray sources is similar to that of blazars discovered at other wavelengths, clearly showing, in the usual log nu-log nu F-nu representation, the typical broadband spectral signatures normally attributed to a combination of low-energy synchrotron radiation followed by inverse Compton emission of one or more components. We have used these SED to characterize the peak intensity of both the low-and the high-energy components. The results have been used to derive empirical relationships that estimate the position of the two peaks from the broadband colors (i.e., the radio to optical, alpha(ro), and optical to X-ray, alpha(ox), spectral slopes) and from the gamma-ray spectral index. Our data show that the synchrotron peak frequency (nu(S)(peak)) is positioned between 10(12.5) and 10(14.5) Hz in broad-lined flat spectrum radio quasars (FSRQs) and between 10(13) and 10(17) Hz in featureless BL Lacertae objects. We find that the gamma-ray spectral slope is strongly correlated with the synchrotron peak energy and with the X-ray spectral index, as expected at first order in synchrotron-inverse Compton scenarios. However, simple homogeneous, one-zone, synchrotron self-Compton (SSC) models cannot explain most of our SED, especially in the case of FSRQs and low energy peaked (LBL) BL Lacs. More complex models involving external Compton radiation or multiple SSC components are required to reproduce the overall SED and the observed spectral variability. While more than 50% of known radio bright high energy peaked (HBL) BL Lacs are detected in the LBAS sample, only less than 13% of known bright FSRQs and LBL BL Lacs are included. This suggests that the latter sources, as a class, may be much fainter gamma-ray emitters than LBAS blazars, and could in fact radiate close to the expectations of simple SSC models. We categorized all our sources according to a new physical classification scheme based on the generally accepted paradigm for Active Galactic Nuclei and on the results of this SED study. Since the LAT detector is more sensitive to flat spectrum gamma-ray sources, the correlation between nu(S)(peak) and gamma-ray spectral index strongly favors the detection of high energy peaked blazars, thus explaining the Fermi overabundance of this type of sources compared to radio and EGRET samples. This selection effect is similar to that experienced in the soft X-ray band where HBL BL Lacs are the dominant type of blazars.

  • 87. Abdo, A. A.
    et al.
    Ackermann, M.
    Ajello, M.
    Allafort, A.
    Amin, M. A.
    Baldini, L.
    Barbiellini, G.
    Bastieri, D.
    Bechtol, K.
    Bellazzini, R.
    Blandford, R. D.
    Bonamente, E.
    Borgland, A. W.
    Bregeon, J.
    Brigida, M.
    Buehler, R.
    Bulmash, D.
    Buson, S.
    Caliandro, G. A.
    Cameron, R. A.
    Caraveo, P. A.
    Cavazzuti, E.
    Cecchi, C.
    Charles, E.
    Cheung, C. C.
    Chiang, J.
    Chiaro, G.
    Ciprini, S.
    Claus, R.
    Cohen-Tanugi, J.
    Conrad, J.
    Corbet, R. H. D.
    Cutini, S.
    D'Ammando, F.
    de Angelis, A.
    de Palma, F.
    Dermer, C. D.
    Drell, P. S.
    Drlica-Wagner, A.
    Favuzzi, C.
    Finke, J.
    Focke, W. B.
    Fukazawa, Y.
    Fusco, P.
    Gargano, F.
    Gasparrini, D.
    Gehrels, N.
    Giglietto, N.
    Giordano, F.
    Giroletti, M.
    Glanzman, T.
    Grenier, I. A.
    Grove, J. E.
    Guiriec, S.
    Hadasch, D.
    Hayashida, M.
    Hays, E.
    Hughes, R. E.
    Inoue, Y.
    Jackson, Miranda S.
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik. Oskar Klein Centre for Cosmoparticle Physics, Sweden.
    Jogler, T.
    Johannesson, G.
    Johnson, A. S.
    Kamae, T.
    Knoedlseder, J.
    Kuss, M.
    Lande, J.
    Larsson, S.
    Latronico, L.
    Longo, F.
    Loparco, F.
    Lott, B.
    Lovellette, M. N.
    Lubrano, P.
    Madejski, G. M.
    Mazziotta, M. N.
    Mehault, J.
    Michelson, P. F.
    Mizuno, T.
    Monzani, M. E.
    Morselli, A.
    Moskalenko, I. V.
    Murgia, S.
    Nemmen, R.
    Nuss, E.
    Ohno, M.
    Ohsugi, T.
    Paneque, D.
    Perkins, J. S.
    Pesce-Rollins, M.
    Piron, F.
    Pivato, G.
    Porter, T. A.
    Raino, S.
    Rando, R.
    Razzano, M.
    Reimer, A.
    Reimer, O.
    Reyes, L. C.
    Ritz, S.
    Romoli, C.
    Roth, M.
    Parkinson, P. M. Saz
    Sgro, C.
    Siskind, E. J.
    Spandre, G.
    Spinelli, P.
    Takahashi, H.
    Takeuchi, Y.
    Tanaka, T.
    Thayer, J. G.
    Thayer, J. B.
    Thompson, D. J.
    Tibaldo, L.
    Tinivella, M.
    Torres, D. F.
    Tosti, G.
    Troja, E.
    Tronconi, V.
    Usher, T. L.
    Vandenbroucke, J.
    Vasileiou, V.
    Vianello, G.
    Vitale, V.
    Waite, A. P.
    Werner, M.
    Winer, B. L.
    Wood, K. S.
    Gamma-ray flaring activity from the gravitationally lensed blazar PKS 1830-211 observed by Fermi LAT2015Ingår i: Astrophysical Journal, ISSN 0004-637X, E-ISSN 1538-4357, Vol. 799, nr 2, artikel-id 143Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The Large Area Telescope ( LAT) on board the FermiGamma- ray Space Telescope routinely detects the MeV- peaked flat- spectrum radio quasar PKS 1830- 211 ( z = 2.507). Its apparent isotropic. - ray luminosity ( E > 100 MeV), averaged over 3 years of observations and peaking on 2010 October 14/ 15 at 2.9 x 1050 erg s- 1, makes it among the brightest high- redshift Fermi blazars. No published model with a single lens can account for all of the observed characteristics of this complex system. Based on radio observations, one expects time- delayed variability to follow about 25 days after a primary flare, with flux about a factor of 1.5 less. Two large. - ray flares of PKS 1830- 211 have been detected by the LAT in the considered period, and no substantial evidence for such a delayed activity was found. This allows us to place a lower limit of about 6 on the. - ray flux ratio between the two lensed images. Swift XRT observations from a dedicated Target of Opportunity program indicate a hard spectrum with no significant correlation of X- ray flux with the. - ray variability. The spectral energy distribution can be modeled with inverse Compton scattering of thermal photons from the dusty torus. The implications of the LAT data in terms of variability, the lack of evident delayed flare events, and different radio and. - ray flux ratios are discussed. Microlensing effects, absorption, size and location of the emitting regions, the complex mass distribution of the system, an energy- dependent inner structure of the source, and flux suppression by the lens galaxy for one image path may be considered as hypotheses for understanding our results.

  • 88. Abdo, A. A.
    et al.
    Ackermann, M.
    Ajello, M.
    Allafort, A.
    Antolini, E.
    Atwood, W. B.
    Axelsson, Magnus
    Baldini, L.
    Ballet, J.
    Barbiellini, G.
    Bastieri, D.
    Baughman, B. M.
    Bechtol, K.
    Bellazzini, R.
    Belli, F.
    Berenji, B.
    Bisello, D.
    Blandford, R. D.
    Bloom, E. D.
    Bonamente, E.
    Bonnell, J.
    Borgland, A. W.
    Bouvier, A.
    Bregeon, J.
    Brez, A.
    Brigida, M.
    Bruel, P.
    Burnett, T. H.
    Busetto, G.
    Buson, S.
    Caliandro, G. A.
    Cameron, R. A.
    Campana, R.
    Canadas, B.
    Caraveo, P. A.
    Carrigan, S.
    Casandjian, J. M.
    Cavazzuti, E.
    Ceccanti, M.
    Cecchi, C.
    Celik, Oe.
    Charles, E.
    Chekhtman, A.
    Cheung, C. C.
    Chiang, J.
    Cillis, A. N.
    Ciprini, S.
    Claus, R.
    Cohen-Tanugi, J.
    Conrad, J.
    Corbet, R.
    Davis, D. S.
    DeKlotz, M.
    den Hartog, P. R.
    Dermer, C. D.
    de Angelis, A.
    de Luca, A.
    de Palma, F.
    Digel, S. W.
    Dormody, M.
    do Couto E Silva, E.
    Drell, P. S.
    Dubois, R.
    Dumora, D.
    Fabiani, D.
    Farnier, C.
    Favuzzi, C.
    Fegan, S. J.
    Ferrara, E. C.
    Focke, W. B.
    Fortin, P.
    Frailis, M.
    Fukazawa, Y.
    Funk, S.
    Fusco, P.
    Gargano, F.
    Gasparrini, D.
    Gehrels, N.
    Germani, S.
    Giavitto, G.
    Giebels, B.
    Giglietto, N.
    Giommi, P.
    Giordano, F.
    Giroletti, M.
    Glanzman, T.
    Godfrey, G.
    Grenier, I. A.
    Grondin, M. -H
    Grove, J. E.
    Guillemot, L.
    Guiriec, S.
    Gustafsson, M.
    Hadasch, D.
    Hanabata, Y.
    Harding, A. K.
    Hayashida, M.
    Hays, E.
    Healey, S. E.
    Hill, A. B.
    Horan, D.
    Hughes, R. E.
    Iafrate, G.
    Johannesson, G.
    Johnson, A. S.
    Johnson, R. P.
    Johnson, T. J.
    Johnson, W. N.
    Kamae, T.
    Katagiri, H.
    Kataoka, J.
    Kawai, N.
    Kerr, M.
    Knoedlseder, J.
    Kocevski, D.
    Kuss, M.
    Lande, J.
    Landriu, D.
    Latronico, L.
    Lee, S. -H
    Lemoine-Goumard, M.
    Lionetto, A. M.
    Garde, M. Llena
    Longo, F.
    Loparco, F.
    Lott, B.
    Lovellette, M. N.
    Lubrano, P.
    Madejski, G. M.
    Makeev, A.
    Marangelli, B.
    Marelli, M.
    Massaro, E.
    Mazziotta, M. N.
    McConville, W.
    McEnery, J. E.
    Michelson, P. F.
    Minuti, M.
    Mitthumsiri, W.
    Mizuno, T.
    Moiseev, A. A.
    Mongelli, M.
    Monte, C.
    Monzani, M. E.
    Moretti, Elena
    University and INFN of Trieste.
    Morselli, A.
    Moskalenko, I. V.
    Murgia, S.
    Nakajima, H.
    Nakamori, T.
    Naumann-Godo, M.
    Nolan, P. L.
    Norris, J. P.
    Nuss, E.
    Ohno, M.
    Ohsugi, T.
    Omodei, N.
    Orlando, E.
    Ormes, J. F.
    Ozaki, M.
    Paccagnella, A.
    Paneque, D.
    Panetta, J. H.
    Parent, D.
    Pelassa, V.
    Pepe, M.
    Pesce-Rollins, M.
    Pinchera, M.
    Piron, F.
    Porter, T. A.
    Poupard, L.
    Raino, S.
    Rando, R.
    Ray, P. S.
    Razzano, M.
    Razzaque, S.
    Rea, N.
    Reimer, A.
    Reimer, O.
    Reposeur, T.
    Ripken, J.
    Ritz, S.
    Rochester, L. S.
    Rodriguez, A. Y.
    Romani, R. W.
    Roth, M.
    Sadrozinski, H. F. -W
    Salvetti, D.
    Sanchez, D.
    Sander, A.
    Parkinson, P. M. Saz
    Scargle, J. D.
    Schalk, T. L.
    Scolieri, G.
    Sgro, C.
    Shaw, M. S.
    Siskind, E. J.
    Smith, D. A.
    Smith, P. D.
    Spandre, G.
    Spinelli, P.
    Starck, J. -L
    Stephens, T. E.
    Striani, E.
    Strickman, M. S.
    Strong, A. W.
    Suson, D. J.
    Tajima, H.
    Takahashi, H.
    Takahashi, T.
    Tanaka, T.
    Thayer, J. B.
    Thayer, J. G.
    Thompson, D. J.
    Tibaldo, L.
    Tibolla, O.
    Tinebra, F.
    Torres, D. F.
    Tosti, G.
    Tramacere, A.
    Uchiyama, Y.
    Usher, T. L.
    Van Etten, A.
    Vasileiou, V.
    Vilchez, N.
    Vitale, V.
    Waite, A. P.
    Wallace, E.
    Wang, P.
    Watters, K.
    Winer, B. L.
    Wood, K. S.
    Yang, Z.
    Ylinen, Tomi
    KTH, Skolan för teknikvetenskap (SCI), Fysik.
    Ziegler, M.
    FERMI LARGE AREA TELESCOPE FIRST SOURCE CATALOG2010Ingår i: Astrophysical Journal Supplement Series, ISSN 0067-0049, E-ISSN 1538-4365, Vol. 188, nr 2, s. 405-436Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We present a catalog of high-energy gamma-ray sources detected by the Large Area Telescope (LAT), the primary science instrument on the Fermi Gamma-ray Space Telescope (Fermi), during the first 11 months of the science phase of the mission, which began on 2008 August 4. The First Fermi-LAT catalog (1FGL) contains 1451 sources detected and characterized in the 100 MeV to 100 GeV range. Source detection was based on the average flux over the 11 month period, and the threshold likelihood Test Statistic is 25, corresponding to a significance of just over 4 sigma. The 1FGL catalog includes source location regions, defined in terms of elliptical fits to the 95% confidence regions and power-law spectral fits as well as flux measurements in five energy bands for each source. In addition, monthly light curves are provided. Using a protocol defined before launch we have tested for several populations of gamma-ray sources among the sources in the catalog. For individual LAT-detected sources we provide firm identifications or plausible associations with sources in other astronomical catalogs. Identifications are based on correlated variability with counterparts at other wavelengths, or on spin or orbital periodicity. For the catalogs and association criteria that we have selected, 630 of the sources are unassociated. Care was taken to characterize the sensitivity of the results to the model of interstellar diffuse gamma-ray emission used to model the bright foreground, with the result that 161 sources at low Galactic latitudes and toward bright local interstellar clouds are flagged as having properties that are strongly dependent on the model or as potentially being due to incorrectly modeled structure in the Galactic diffuse emission.

  • 89. Abdo, A. A.
    et al.
    Ackermann, M.
    Ajello, M.
    Allafort, A.
    Antolini, E.
    Atwood, W. B.
    Axelsson, Magnus
    Baldini, L.
    Ballet, J.
    Barbiellini, G.
    Bastieri, D.
    Baughman, B. M.
    Bechtol, K.
    Bellazzini, R.
    Berenji, B.
    Blandford, R. D.
    Bloom, E. D.
    Bogart, J. R.
    Bonamente, E.
    Borgland, A. W.
    Bouvier, A.
    Bregeon, J.
    Brez, A.
    Brigida, M.
    Bruel, P.
    Buehler, R.
    Burnett, T. H.
    Buson, S.
    Caliandro, G. A.
    Cameron, R. A.
    Cannon, A.
    Caraveo, P. A.
    Carrigan, S.
    Casandjian, J. M.
    Cavazzuti, E.
    Cecchi, C.
    Celik, Oe.
    Celotti, A.
    Charles, E.
    Chekhtman, A.
    Chen, A. W.
    Cheung, C. C.
    Chiang, J.
    Ciprini, S.
    Claus, R.
    Cohen-Tanugi, J.
    Conrad, J.
    Costamante, L.
    Cotter, G.
    Cutini, S.
    D'Elia, V.
    Dermer, C. D.
    de Angelis, A.
    de Palma, F.
    De Rosa, A.
    Digel, S. W.
    do Couto e Silva, E.
    Drell, P. S.
    Dubois, R.
    Dumora, D.
    Escande, L.
    Farnier, C.
    Favuzzi, C.
    Fegan, S. J.
    Ferrara, E. C.
    Focke, W. B.
    Fortin, P.
    Frailis, M.
    Fukazawa, Y.
    Funk, S.
    Fusco, P.
    Gargano, F.
    Gasparrini, D.
    Gehrels, N.
    Germani, S.
    Giebels, B.
    Giglietto, N.
    Giommi, P.
    Giordano, F.
    Giroletti, M.
    Glanzman, T.
    Godfrey, G.
    Grandi, P.
    Grenier, I. A.
    Grondin, M. -H
    Grove, J. E.
    Guiriec, S.
    Hadasch, D.
    Harding, A. K.
    Hayashida, M.
    Hays, E.
    Healey, S. E.
    Hill, A. B.
    Horan, D.
    Hughes, R. E.
    Iafrate, G.
    Itoh, R.
    Johannesson, G.
    Johnson, A. S.
    Johnson, R. P.
    Johnson, T. J.
    Johnson, W. N.
    Kamae, T.
    Katagiri, H.
    Kataoka, J.
    Kawai, N.
    Kerr, M.
    Knoedlseder, J.
    Kuss, M.
    Lande, J.
    Latronico, L.
    Lavalley, C.
    Lemoine-Goumard, M.
    Garde, M. Llena
    Longo, F.
    Loparco, F.
    Lott, B.
    Lovellette, M. N.
    Lubrano, P.
    Madejski, G. M.
    Makeev, A.
    Malaguti, G.
    Massaro, E.
    Mazziotta, M. N.
    McConville, W.
    McEnery, J. E.
    McGlynn, Sinéad
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Michelson, P. F.
    Mitthumsiri, W.
    Mizuno, T.
    Moiseev, A. A.
    Monte, C.
    Monzani, M. E.
    Morselli, A.
    Moskalenko, I. V.
    Murgia, S.
    Nolan, P. L.
    Norris, J. P.
    Nuss, E.
    Ohno, M.
    Ohsugi, T.
    Omodei, N.
    Orlando, E.
    Ormes, J. F.
    Ozaki, M.
    Paneque, D.
    Panetta, J. H.
    Parent, D.
    Pelassa, V.
    Pepe, M.
    Pesce-Rollins, M.
    Piranomonte, S.
    Piron, F.
    Porter, T. A.
    Raino, S.
    Rando, R.
    Razzano, M.
    Reimer, A.
    Reimer, O.
    Reposeur, T.
    Ripken, J.
    Ritz, S.
    Rodriguez, A. Y.
    Romani, R. W.
    Roth, M.
    Ryde, Felix
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Sadrozinski, H. F. -W
    Sanchez, D.
    Sander, A.
    Parkinson, P. M. Saz
    Scargle, J. D.
    Sgro, C.
    Shaw, M. S.
    Siskind, E. J.
    Smith, P. D.
    Spandre, G.
    Spinelli, P.
    Starck, J. -L
    Stawarz, L.
    Strickman, M. S.
    Suson, D. J.
    Tajima, H.
    Takahashi, H.
    Takahashi, T.
    Tanaka, T.
    Taylor, G. B.
    Thayer, J. B.
    Thayer, J. G.
    Thompson, D. J.
    Tibaldo, L.
    Torres, D. F.
    Tosti, G.
    Tramacere, A.
    Ubertini, P.
    Uchiyama, Y.
    Usher, T. L.
    Vasileiou, V.
    Vilchez, N.
    Villata, M.
    Vitale, V.
    Waite, A. P.
    Wallace, E.
    Wang, P.
    Winer, B. L.
    Wood, K. S.
    Yang, Z.
    Ylinen, Tomi
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Ziegler, M.
    The first catalog of active galactic nuclei detected by the Fermi large area telescope2010Ingår i: Astrophysical Journal, ISSN 0004-637X, E-ISSN 1538-4357, Vol. 715, nr 1, s. 429-457Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We present the first catalog of active galactic nuclei (AGNs) detected by the Large Area Telescope (LAT), corresponding to 11 months of data collected in scientific operation mode. The First LAT AGN Catalog (1LAC) includes 671 gamma-ray sources located at high Galactic latitudes (|b| > 10 degrees) that are detected with a test statistic greater than 25 and associated statistically with AGNs. Some LAT sources are associated with multiple AGNs, and consequently, the catalog includes 709 AGNs, comprising 300 BL Lacertae objects, 296 flat-spectrum radio quasars, 41 AGNs of other types, and 72 AGNs of unknown type. We also classify the blazars based on their spectral energy distributions as archival radio, optical, and X-ray data permit. In addition to the formal 1LAC sample, we provide AGN associations for 51 low-latitude LAT sources and AGN "affiliations" (unquantified counterpart candidates) for 104 high-latitude LAT sources without AGN associations. The overlap of the 1LAC with existing gamma-ray AGN catalogs (LBAS, EGRET, AGILE, Swift, INTEGRAL, TeVCat) is briefly discussed. Various properties-such as gamma-ray fluxes and photon power-law spectral indices, redshifts, gamma-ray luminosities, variability, and archival radio luminosities-and their correlations are presented and discussed for the different blazar classes. We compare the 1LAC results with predictions regarding the gamma-ray AGN populations, and we comment on the power of the sample to address the question of the blazar sequence.

  • 90. Abdo, A. A.
    et al.
    Ackermann, M.
    Ajello, M.
    Allafort, A.
    Asano, K.
    Baldini, L.
    Ballet, J.
    Barbiellini, G.
    Baring, M. G.
    Bastieri, D.
    Bechtol, K.
    Bellazzini, R.
    Berenji, B.
    Blandford, R. D.
    Bloom, E. D.
    Bonamente, E.
    Borgland, A. W.
    Bregeon, J.
    Brez, A.
    Brigida, M.
    Bruel, P.
    Buson, S.
    Caliandro, G. A.
    Cameron, R. A.
    Camilo, F.
    Caraveo, P. A.
    Carrigan, S.
    Casandjian, J. M.
    Cecchi, C.
    Celik, Oe
    Chekhtman, A.
    Cheung, C. C.
    Chiang, J.
    Ciprini, S.
    Claus, R.
    Cohen-Tanugi, J.
    Conrad, J.
    den Hartog, P. R.
    Dermer, C. D.
    de Luca, A.
    de Palma, F.
    Dormody, M.
    do Couto e Silva, E.
    Drell, P. S.
    Dubois, R.
    Dumora, D.
    Farnier, C.
    Favuzzi, C.
    Fegan, S. J.
    Ferrara, E. C.
    Focke, W. B.
    Frailis, M.
    Fukazawa, Y.
    Funk, S.
    Fusco, P.
    Gargano, F.
    Gehrels, N.
    Germani, S.
    Giglietto, N.
    Giordano, F.
    Glanzman, T.
    Godfrey, G.
    Gotthelf, E. V.
    Grenier, I. A.
    Grondin, M. -H
    Grove, J. E.
    Guillemot, L.
    Guiriec, S.
    Hanabata, Y.
    Harding, A. K.
    Hays, E.
    Hobbs, G.
    Horan, D.
    Hughes, R. E.
    Johannesson, G.
    Johnson, A. S.
    Johnson, T. J.
    Johnson, W. N.
    Johnston, S.
    Kamae, T.
    Kanai, Y.
    Kanbach, G.
    Katagiri, H.
    Kataoka, J.
    Kawai, N.
    Keith, M.
    Kerr, M.
    Knoedlseder, J.
    Kuss, M.
    Lande, J.
    Latronico, L.
    Lemoine-Goumard, M.
    Garde, M. Llena
    Longo, F.
    Loparco, F.
    Lott, B.
    Lovellette, M. N.
    Lubrano, P.
    Makeev, A.
    Manchester, R. N.
    Marelli, M.
    Mazziotta, M. N.
    McEnery, J. E.
    Michelson, P. F.
    Mitthumsiri, W.
    Mizuno, T.
    Moiseev, A. A.
    Monte, C.
    Monzani, M. E.
    Morselli, A.
    Moskalenko, I. V.
    Murgia, S.
    Nakamori, T.
    Nolan, P. L.
    Norris, J. P.
    Nuss, E.
    Ohno, M.
    Ohsugi, T.
    Omodei, N.
    Orlando, E.
    Ormes, J. F.
    Paneque, D.
    Panetta, J. H.
    Parent, D.
    Pelassa, V.
    Pepe, M.
    Pesce-Rollins, M.
    Piron, F.
    Porter, T. A.
    Raino, S.
    Rando, R.
    Razzano, M.
    Rea, N.
    Reimer, A.
    Reimer, O.
    Reposeur, T.
    Rodriguez, A. Y.
    Romani, R. W.
    Roth, M.
    Ryde, Felix
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Sadrozinski, H. F. -W
    Sander, A.
    Parkinson, P. M. Saz
    Sgro, C.
    Siskind, E. J.
    Smith, D. A.
    Smith, P. D.
    Spandre, G.
    Spinelli, P.
    Starck, J. -L
    Strickman, M. S.
    Suson, D. J.
    Takahashi, H.
    Takahashi, T.
    Tanaka, T.
    Thayer, J. B.
    Thayer, J. G.
    Thompson, D. J.
    Thorsett, S. E.
    Tibaldo, L.
    Torres, D. F.
    Tosti, G.
    Tramacere, A.
    Uchiyama, Y.
    Usher, T. L.
    Vasileiou, V.
    Venter, C.
    Vilchez, N.
    Vitale, V.
    Waite, A. P.
    Wang, P.
    Weltevrede, P.
    Winer, B. L.
    Wood, K. S.
    Yang, Z.
    Ylinen, Tomi
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Ziegler, M.
    Detection of the energetic pulsar PSR B1509-58 and its pulsar wind nebula in MSH 15-52 using the Fermi-large area telescope2010Ingår i: Astrophysical Journal, ISSN 0004-637X, E-ISSN 1538-4357, Vol. 714, nr 1, s. 927-936Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We report the detection of high-energy gamma-ray emission from the young and energetic pulsar PSR B1509-58 and its pulsar wind nebula (PWN) in the composite supernova remnant G320.4-1.2 (aka MSH 15-52). Using 1 yr of survey data with the Fermi-Large Area Telescope (LAT), we detected pulsations from PSR B1509-58 up to 1 GeV and extended gamma-ray emission above 1 GeV spatially coincident with the PWN. The pulsar light curve presents two peaks offset from the radio peak by phases 0.96 +/- 0.01 and 0.33 +/- 0.02. New constraining upper limits on the pulsar emission are derived below 1 GeV and confirm a severe spectral break at a few tens of MeV. The nebular spectrum in the 1-100 GeV energy range is well described by a power law with a spectral index of (1.57 +/- 0.17 +/- 0.13) and a flux above 1 GeV of (2.91 +/- 0.79 +/- 1.35) x 10(-9) cm(-2) s(-1). The first errors represent the statistical errors on the fit parameters, while the second ones are the systematic uncertainties. The LAT spectrum of the nebula connects nicely with Cherenkov observations, and indicates a spectral break between GeV and TeV energies.

  • 91. Abdo, A. A.
    et al.
    Ackermann, M.
    Ajello, M.
    Allafort, A.
    Atwood, W. B.
    Baldini, L.
    Ballet, J.
    Barbiellini, G.
    Baring, M. G.
    Bastieri, D.
    Baughman, B. M.
    Bechtol, K.
    Bellazzini, R.
    Berenji, B.
    Blandford, D.
    Bloom, E. D.
    Bonamente, E.
    Borgland, A. W.
    Bouvier, A.
    Bregeon, J.
    Brez, A.
    Brigida, M.
    Bruel, P.
    Burnett, T. H.
    Buson, S.
    Caliandro, G. A.
    Cameron, R. A.
    Caraveo, P. A.
    Carrigan, S.
    Casandjian, J. M.
    Cecchi, C.
    Celik, Oe
    Chekhtman, A.
    Cheung, C. C.
    Chiang, J.
    Ciprini, S.
    Claus, R.
    Cohen-Tanugi, J.
    Conrad, J.
    Dermer, C. D.
    de Luca, A.
    de Palma, F.
    Dormody, M.
    do Couto e Silva, E.
    Drell, P. S.
    Dubois, R.
    Dumora, D.
    Farnier, C.
    Favuzzi, C.
    Fegan, S. J.
    Focke, W. B.
    Fortin, P.
    Frailis, M.
    Fukazawa, Y.
    Funk, S.
    Fusco, P.
    Gargano, F.
    Gasparrini, D.
    Gehrels, N.
    Germani, S.
    Giavitto, G.
    Giebels, B.
    Giglietto, N.
    Giordano, F.
    Glanzman, T.
    Godfrey, G.
    Grenier, I. A.
    Grondin, M. -H
    Grove, J. E.
    Guillemot, L.
    Guiriec, S.
    Hadasch, D.
    Harding, A. K.
    Hays, E.
    Hobbs, G.
    Horan, D.
    Hughes, R. E.
    Jackson, Miranda S.
    KTH, Skolan för teknikvetenskap (SCI), Fysik.
    Johannesson, G.
    Johnson, A. S.
    Johnson, T. J.
    Johnson, W. N.
    Kamae, T.
    Katagiri, H.
    Kataoka, J.
    Kawai, N.
    Kerr, M.
    Knoedlseder, J.
    Kuss, M.
    Lande, J.
    Latronico, L.
    Lee, S. -H
    Lemoine-Goumard, M.
    Garde, M. Llena
    Longo, F.
    Loparco, F.
    Lott, B.
    Lovellette, M. N.
    Lubrano, P.
    Makeev, A.
    Manchester, R. N.
    Marelli, M.
    Mazziotta, M. N.
    McConville, W.
    McEnery, J. E.
    McGlynn, Sinead
    KTH, Skolan för teknikvetenskap (SCI), Fysik.
    Meurer, C.
    Michelson, P. F.
    Mitthumsiri, W.
    Mizuno, T.
    Moiseev, A. A.
    Monte, C.
    Monzani, M. E.
    Morselli, A.
    Moskalenko, I. V.
    Murgia, S.
    Nakamori, T.
    Nolan, P. L.
    Norris, J. P.
    Noutsos, A.
    Nuss, E.
    Ohsugi, T.
    Omodei, N.
    Orlando, E.
    Ormes, J. F.
    Ozaki, M.
    Paneque, D.
    Panetta, J. H.
    Parent, D.
    Pelassa, V.
    Pepe, M.
    Pesce-Rollins, M.
    Pierbattista, M.
    Piron, F.
    Porter, T. A.
    Raino, S.
    Rando, R.
    Ray, P. S.
    Razzano, M.
    Reimer, A.
    Reimer, O.
    Reposeur, T.
    Ritz, S.
    Rochester, L. S.
    Rodriguez, A. Y.
    Romani, R. W.
    Roth, M.
    Ryde, Felix
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Sadrozinski, H. F. -W
    Sander, A.
    Parkinson, P. M. Saz
    Sgro, C.
    Siskind, E. J.
    Smith, D. A.
    Smith, P. D.
    Spandre, G.
    Spinelli, P.
    Starck, J. -L
    Strickman, M. S.
    Suson, D. J.
    Takahashi, H.
    Takahashi, T.
    Tanaka, T.
    Thayer, J. B.
    Thayer, J. G.
    Thompson, D. J.
    Tibaldo, L.
    Torres, D. F.
    Tosti, G.
    Tramacere, A.
    Usher, T. L.
    Van Etten, A.
    Vasileiou, V.
    Venter, C.
    Vilchez, N.
    Vitale, V.
    Waite, A. P.
    Wang, P.
    Watters, K.
    Weltevrede, P.
    Winer, B. L.
    Wood, K. S.
    Ylinen, Tomi
    KTH, Skolan för teknikvetenskap (SCI), Fysik.
    Ziegler, M.
    THE VELA PULSAR: RESULTS FROM THE FIRST YEAR OF FERMI LAT OBSERVATIONS2010Ingår i: Astrophysical Journal, ISSN 0004-637X, E-ISSN 1538-4357, Vol. 713, nr 1, s. 154-165Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We report on analysis of timing and spectroscopy of the Vela pulsar using 11 months of observations with the Large Area Telescope (LAT) on the Fermi Gamma-ray Space Telescope. The intrinsic brightness of Vela at GeV energies combined with the angular resolution and sensitivity of the LAT allows us to make the most detailed study to date of the energy-dependent light curves and phase-resolved spectra, using a LAT-derived timing model. The light curve consists of two peaks (P1 and P2) connected by bridge emission containing a third peak (P3). We have confirmed the strong decrease of the P1/P2 ratio with increasing energy seen with EGRET and previous Fermi LAT data, and observe that P1 disappears above 20 GeV. The increase with energy of the mean phase of the P3 component can be followed with much greater detail, showing that P3 and P2 are present up to the highest energies of pulsation. We find significant pulsed emission at phases outside the main profile, indicating that magnetospheric emission exists over 80% of the pulsar period. With increased high-energy counts the phase-averaged spectrum is seen to depart from a power law with simple exponential cutoff, and is better fit with a more gradual cutoff. The spectra in fixed-count phase bins are well fit with power laws with exponential cutoffs, revealing a strong and complex phase dependence of the cutoff energy, especially in the peaks. By combining these results with predictions of the outer magnetosphere models that map emission characteristics to phase, it will be possible to probe the particle acceleration and the structure of the pulsar magnetosphere with unprecedented detail.

  • 92. Abdo, A. A.
    et al.
    Ackermann, M.
    Ajello, M.
    Allafort, A.
    Baldini, L.
    Ballet, J.
    Barbiellini, G.
    Bastieri, D.
    Bechtol, K.
    Bellazzini, R.
    Berenji, B.
    Blandford, R. D.
    Bloom, E. D.
    Bonamente, E.
    Borgland, A. W.
    Bouvier, A.
    Brandt, T. J.
    Bregeon, J.
    Brigida, M.
    Bruel, P.
    Buehler, R.
    Buson, S.
    Caliandro, G. A.
    Cameron, R. A.
    Caraveo, P. A.
    Carrigan, S.
    Casandjian, J. M.
    Cecchi, C.
    Celik, Oe.
    Chekhtman, A.
    Chiang, J.
    Ciprini, S.
    Claus, R.
    Cohen-Tanugi, J.
    Conrad, J.
    Dermer, C. D.
    de Palma, F.
    do Couto e Silva, E.
    Drell, P. S.
    Dubois, R.
    Dumora, D.
    Farnier, C.
    Favuzzi, C.
    Fegan, S. J.
    Fukazawa, Y.
    Fukui, Y.
    Funk, S.
    Fusco, P.
    Gargano, F.
    Gehrels, N.
    Germani, S.
    Giglietto, N.
    Giordano, F.
    Glanzman, T.
    Godfrey, G.
    Grenier, I. A.
    Grove, J. E.
    Guiriec, S.
    Hadasch, D.
    Hanabata, Y.
    Harding, A. K.
    Hays, E.
    Horan, D.
    Hughes, R. E.
    Johannesson, G.
    Johnson, A. S.
    Johnson, W. N.
    Kamae, T.
    Katagiri, H.
    Kataoka, J.
    Knoedlseder, J.
    Kuss, M.
    Lande, J.
    Latronico, L.
    Lee, S. -H
    Lemoine-Goumard, M.
    Garde, M. Llena
    Longo, F.
    Loparco, F.
    Lovellette, M. N.
    Lubrano, P.
    Makeev, A.
    Mazziotta, M. N.
    Michelson, P. F.
    Mitthumsiri, W.
    Mizuno, T.
    Moiseev, A. A.
    Monte, C.
    Monzani, M. E.
    Morselli, A.
    Moskalenko, I. V.
    Murgia, S.
    Nakamori, T.
    Nolan, P. L.
    Norris, J. P.
    Nuss, E.
    Ohno, M.
    Ohsugi, T.
    Omodei, N.
    Orlando, E.
    Ormes, J. F.
    Ozaki, M.
    Panetta, J. H.
    Parent, D.
    Pelassa, V.
    Pepe, M.
    Pesce-Rollins, M.
    Piron, F.
    Porter, T. A.
    Raino, S.
    Rando, R.
    Razzano, M.
    Reimer, A.
    Reimer, O.
    Reposeur, T.
    Rodriguez, Y.
    Roth, M.
    Sadrozinski, H. F. -W
    Sander, A.
    Parkinson, P. M. Saz
    Sgro, C.
    Siskind, E. J.
    Smith, D. A.
    Smith, P. D.
    Spandre, G.
    Spinelli, P.
    Strickman, M. S.
    Suson, D. J.
    Tajima, H.
    Takahashi, H.
    Takahashi, T.
    Tanaka, T.
    Thayer, J. B.
    Thayer, J. G.
    Thompson, D. J.
    Tibaldo, L.
    Tibolla, O.
    Torres, D. F.
    Tosti, G.
    Uchiyama, Y.
    Uehara, T.
    Usher, T. L.
    Vasileiou, V.
    Vilchez, N.
    Vitale, V.
    Waite, A. P.
    Wang, P.
    Winer, B. L.
    Wood, K. S.
    Yamamoto, H.
    Yamazaki, R.
    Yang, Z.
    Ylinen, Tomi
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Ziegler, M.
    FERMI LARGE AREA TELESCOPE OBSERVATIONS OF THE SUPERNOVA REMNANT W28 (G6.4-0.1)2010Ingår i: Astrophysical Journal, ISSN 0004-637X, E-ISSN 1538-4357, Vol. 718, nr 1, s. 348-356Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We present detailed analysis of two gamma-ray sources, 1FGL J1801.3-2322c and 1FGL J1800.5-2359c, that have been found toward the supernova remnant (SNR) W28 with the Large Area Telescope (LAT) on board the Fermi Gamma-ray Space Telescope. 1FGL J1801.3-2322c is found to be an extended source within the boundary of SNR W28, and to extensively overlap with the TeV gamma-ray source HESS J1801-233, which is associated with a dense molecular cloud interacting with the SNR. The gamma-ray spectrum measured with the LAT from 0.2 to 100 GeV can be described by a broken power-law function with a break at similar to 1 GeV and photon indices of 2.09 +/- 0.08 (stat) +/- 0.28 (sys) below the break and 2.74 +/- 0.06 (stat) +/- 0.09 (sys) above the break. Given the clear association between HESS J1801-233 and the shocked molecular cloud and a smoothly connected spectrum in the GeV-TeV band, we consider the origin of the gamma-ray emission in both GeV and TeV ranges to be the interaction between particles accelerated in the SNR and the molecular cloud. The decay of neutral pions produced in interactions between accelerated hadrons and dense molecular gas provides a reasonable explanation for the broadband gamma-ray spectrum. 1FGL J1800.5-2359c, located outside the southern boundary of SNR W28, cannot be resolved. An upper limit on the size of the gamma-ray emission was estimated to be similar to 16' using events above similar to 2 GeV under the assumption of a circular shape with uniform surface brightness. It appears to coincide with the TeV source HESS J1800-240B, which is considered to be associated with a dense molecular cloud that contains the ultra compact H II region W28A2 (G5.89-0.39). We found no significant gamma-ray emission in the LAT energy band at the positions of TeV sources HESS J1800-230A and HESS J1800-230C. The LAT data for HESS J1800-230A combined with the TeV data points indicate a spectral break between 10 GeV and 100 GeV.

  • 93. Abdo, A. A.
    et al.
    Ackermann, M.
    Ajello, M.
    Allafort, A.
    Baldini, L.
    Ballet, J.
    Barbiellini, G.
    Bastieri, D.
    Bechtol, K.
    Bellazzini, R.
    Berenji, B.
    Blandford, R. D.
    Bonamente, E.
    Borgland, A. W.
    Bouvier, A.
    Brandt, T. J.
    Bregeon, J.
    Brez, A.
    Brigida, M.
    Bruel, P.
    Buehler, R.
    Burnett, T. H.
    Caliandro, G. A.
    Cameron, R. A.
    Caraveo, P. A.
    Carrigan, S.
    Casandjian, J. M.
    Cecchi, C.
    Celik, Oe
    Chaty, S.
    Chekhtman, A.
    Cheung, C. C.
    Chiang, J.
    Ciprini, S.
    Claus, R.
    Cohen-Tanugi, J.
    Cominsky, L. R.
    Conrad, J.
    Dermer, C. D.
    de Palma, F.
    Digel, S. W.
    do Couto e Silva, E.
    Drell, P. S.
    Dubois, R.
    Dumora, D.
    Favuzzi, C.
    Fegan, S. J.
    Ferrara, E. C.
    Frailis, M.
    Fukazawa, Y.
    Fusco, P.
    Gargano, F.
    Gehrels, N.
    Germani, S.
    Giglietto, N.
    Giordano, F.
    Godfrey, G.
    Grenier, I. A.
    Grondin, M. -H
    Grove, J. E.
    Guillemot, L.
    Guiriec, S.
    Hadasch, D.
    Hanabata, Y.
    Harding, A. K.
    Hayashida, M.
    Hays, E.
    Hill, A. B.
    Horan, D.
    Hughes, R. E.
    Itoh, R.
    Jackson, Miranda
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Johannesson, G.
    Johnson, A. S.
    Johnson, W. N.
    Kamae, T.
    Katagiri, H.
    Kataoka, J.
    Kerr, M.
    Knoedlseder, J.
    Kuss, M.
    Lande, J.
    Latronico, L.
    Lee, S. -H
    Lemoine-Goumard, M.
    Livingstone, M.
    Garde, M. Llena
    Longo, F.
    Loparco, F.
    Lovellette, M. N.
    Lubrano, P.
    Makeev, A.
    Mazziotta, M. N.
    McEnery, J. E.
    Mehault, J.
    Michelson, P. F.
    Mitthumsiri, W.
    Mizuno, T.
    Moiseev, A. A.
    Monte, C.
    Monzani, M. E.
    Morselli, A.
    Moskalenko, I. V.
    Murgia, S.
    Nakamori, T.
    Naumann-Godo, M.
    Nolan, P. L.
    Norris, J. P.
    Nuss, E.
    Ohsugi, T.
    Okumura, A.
    Omodei, N.
    Orlando, E.
    Ormes, J. F.
    Ozaki, M.
    Panetta, J. H.
    Parent, D.
    Pelassa, V.
    Pepe, M.
    Pesce-Rollins, M.
    Piron, F.
    Porter, T. A.
    Raino, S.
    Rando, R.
    Razzano, M.
    Reimer, A.
    Reimer, O.
    Reposeur, T.
    Rodriguez, A. Y.
    Romani, R. W.
    Roth, M.
    Sadrozinski, H. F. -W
    Sander, A.
    Parkinson, P. M. Saz
    Scargle, J. D.
    Sgro, C.
    Siskind, E. J.
    Smith, D. A.
    Smith, P. D.
    Spandre, G.
    Spinelli, P.
    Strickman, M. S.
    Suson, D. J.
    Takahashi, H.
    Takahashi, T.
    Tanaka, T.
    Thayer, J. B.
    Thayer, J. G.
    Thompson, D. J.
    Tibaldo, L.
    Tibolla, O.
    Torres, D. F.
    Tosti, G.
    Tramacere, A.
    Uchiyama, Y.
    Usher, T. L.
    Vandenbroucke, J.
    Vasileiou, V.
    Vilchez, N.
    Vitale, V.
    Waite, A. P.
    Wallace, E.
    Wang, P.
    Winer, B. L.
    Wood, K. S.
    Yang, Z.
    Ylinen, Tomi
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Ziegler, M.
    Fermi large area telescope observation of a gamma-ray source at the position of Eta Carinae2010Ingår i: Astrophysical Journal, ISSN 0004-637X, E-ISSN 1538-4357, Vol. 723, nr 1, s. 649-657Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The Large Area Telescope (LAT) on board the Fermi Gamma-ray Space Telescope detected a gamma-ray source that is spatially consistent with the location of Eta Carinae. This source has been persistently bright since the beginning of the LAT survey observations (from 2008 August to 2009 July, the time interval considered here). The gamma-ray signal is detected significantly throughout the LAT energy band (i.e., up to similar to 100 GeV). The 0.1-100 GeV energy spectrum is well represented by a combination of a cutoff power-law model (<10 GeV) and a hard power-law component (>10 GeV). The total flux (>100 MeV) is 3.7(-0.1)(+0.3) x 10(-7) photons s(-1) cm(-2), with additional systematic uncertainties of 10%, and consistent with the average flux measured by AGILE. The light curve obtained by Fermi is consistent with steady emission. Our observations do not confirm the presence of a gamma-ray flare in 2008 October, as reported by Tavani et al., although we cannot exclude that a flare lasting only a few hours escaped detection by the Fermi LAT. We also do not find any evidence for gamma-ray variability that correlates with the large X-ray variability of Eta Carinae observed during 2008 December and 2009 January. We are thus not able to establish an unambiguous identification of the LAT source with Eta Carinae.

  • 94. Abdo, A. A.
    et al.
    Ackermann, M.
    Ajello, M.
    Allafort, A.
    Johannesson, G.
    Johnson, A. S.
    Ryde, Felix
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Ylinen, Tomi
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    et al,
    FERMI LARGE AREA TELESCOPE OBSERVATIONS OF THE VELA-X PULSAR WIND NEBULA2010Ingår i: Astrophysical Journal, ISSN 0004-637X, E-ISSN 1538-4357, Vol. 713, nr 1, s. 146-153Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We report on gamma-ray observations in the off-pulse window of the Vela pulsar PSR B0833-45 using 11 months of survey data from the Fermi Large Area Telescope (LAT). This pulsar is located in the 8 degrees diameter Vela supernova remnant, which contains several regions of non-thermal emission detected in the radio, X-ray, and gamma-ray bands. The gamma-ray emission detected by the LAT lies within one of these regions, the 2 degrees x 3 degrees area south of the pulsar known as Vela-X. The LAT flux is significantly spatially extended with a best-fit radius of 0.degrees 88 +/- 0.degrees 12 for an assumed radially symmetric uniform disk. The 200 MeV to 20 GeV LAT spectrum of this source is well described by a power law with a spectral index of 2.41 +/- 0.09 +/- 0.15 and integral flux above 100 MeV of (4.73 +/- 0.63 +/- 1.32) x 10(-7) cm(-2) s(-1). The first errors represent the statistical error on the fit parameters, while the second ones are the systematic uncertainties. Detailed morphological and spectral analyses give strong constraints on the energetics and magnetic field of the pulsar wind nebula system and favor a scenario with two distinct electron populations.

  • 95. Abdo, A. A.
    et al.
    Ackermann, M.
    Ajello, M.
    Allafort, A.
    McGlynn, Sinéad
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Ryde, Felix
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Ylinen, Tomi
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    et al.,
    DISCOVERY OF PULSED gamma-RAYS FROM PSR J0034-0534 WITH THE FERMI LARGE AREA TELESCOPE: A CASE FOR CO-LOCATED RADIO AND gamma-RAY EMISSION REGIONS2010Ingår i: Astrophysical Journal, ISSN 0004-637X, E-ISSN 1538-4357, Vol. 712, nr 2, s. 957-963Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Millisecond pulsars (MSPs) have been firmly established as a class of gamma-ray emitters via the detection of pulsations above 0.1 GeV from eight MSPs by the Fermi Large Area Telescope (LAT). Using 13 months of LAT data, significant gamma-ray pulsations at the radio period have been detected from the MSP PSR J0034-0534, making it the ninth clear MSP detection by the LAT. The gamma-ray light curve shows two peaks separated by 0.274 +/- 0.015 in phase which are very nearly aligned with the radio peaks, a phenomenon seen only in the Crab pulsar until now. The >= 0.1 GeV spectrum of this pulsar is well fit by an exponentially cutoff power law with a cutoff energy of 1.8 +/- 0.6 +/- 0.1 GeV and a photon index of 1.5 +/- 0.2 +/- 0.1, first errors are statistical and second are systematic. The near-alignment of the radio and gamma-ray peaks strongly suggests that the radio and gamma-ray emission regions are co-located and both are the result of caustic formation.

  • 96. Abdo, A. A.
    et al.
    Ackermann, M.
    Ajello, M.
    Ampe, J.
    Anderson, B.
    Johannesson, G.
    Johnson, A. S.
    Klamra, Wlodzimierz
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Ryde, Felix
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Ziegler, M.
    McGlynn, Sinéad
    University College Dublin, Ireland.
    Ylinen, Tomi
    Hogskolan i Kalmar.
    Moretti, Elena
    Max-Planck-Institut-fur-Physik, Germany.
    The on-orbit calibration of the Fermi Large Area Telescope2009Ingår i: Astroparticle physics, ISSN 0927-6505, E-ISSN 1873-2852, Vol. 32, nr 3-4, s. 193-219Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The Large Area Telescope (LAT) on-board the Fermi Gamma-ray Space Telescope began its on-orbit operations on June 23, 2008. Calibrations, defined in a generic sense, correspond to synchronization of trigger signals, optimization of delays for latching data, determination of detector thresholds, gains and responses, evaluation of the perimeter of the South Atlantic Anomaly (SAA), measurements of live time, of absolute time, and internal and spacecraft boresight alignments. Here we describe on-orbit calibration results obtained using known astrophysical sources, galactic cosmic rays, and charge injection into the front-end electronics of each detector. Instrument response functions will be described in a separate publication. This paper demonstrates the stability of calibrations and describes minor changes observed since launch. These results have been used to calibrate the LAT datasets to be publicly released in August 2009.

  • 97. Abdo, A. A.
    et al.
    Ackermann, M.
    Ajello, M.
    Antolini, E.
    Baldini, L.
    Ballet, J.
    Barbiellini, G.
    Baring, M. G.
    Bastieri, D.
    Bechtol, K.
    Bellazzini, R.
    Berenji, B.
    Blandford, R. D.
    Bloom, E. D.
    Bonamente, E.
    Borgland, A. W.
    Bregeon, J.
    Brez, A.
    Brigida, M.
    Bruel, P.
    Buehler, R.
    Buson, S.
    Caliandro, G. A.
    Cameron, R. A.
    Carrigan, S.
    Casandjian, J. M.
    Cavazzuti, E.
    Cecchi, C.
    Celik, Oe.
    Chekhtman, A.
    Chen, A. W.
    Chiang, J.
    Ciprini, S.
    Claus, R.
    Cohen-Tanugi, J.
    Colafrancesco, S.
    Conrad, J.
    Cutini, S.
    Dermer, C. D.
    de Palma, F.
    Digel, S. W.
    do Couto e Silva, E.
    Drell, P. S.
    Dubois, R.
    Dumora, D.
    Farnier, C.
    Favuzzi, C.
    Fegan, S. J.
    Ferrara, E. C.
    Focke, W. B.
    Frailis, M.
    Fukazawa, Y.
    Fusco, P.
    Gargano, F.
    Gasparrini, D.
    Gehrels, N.
    Giebels, B.
    Giglietto, N.
    Giommi, P.
    Giordano, F.
    Giroletti, M.
    Glanzman, T.
    Godfrey, G.
    Grandi, P.
    Grenier, I. A.
    Guillemot, L.
    Guiriec, S.
    Hadasch, D.
    Harding, A. K.
    Hayashida, M.
    Horan, D.
    Hughes, R. E.
    Itoh, R.
    Jackson, Miranda S.
    KTH, Skolan för teknikvetenskap (SCI), Fysik.
    Johannesson, G.
    Johnson, A. S.
    Johnson, W. N.
    Kamae, T.
    Katagiri, H.
    Kataoka, J.
    Kawai, N.
    Knoedlseder, J.
    Kuss, M.
    Lande, J.
    Latronico, L.
    Longo, F.
    Loparco, F.
    Lott, B.
    Lovellette, M. N.
    Lubrano, P.
    Madejski, G. M.
    Makeev, A.
    Mazziotta, M. N.
    McEnery, J. E.
    McGlynn, Sinead
    KTH, Skolan för teknikvetenskap (SCI), Fysik.
    Meurer, C.
    Michelson, P. F.
    Mitthumsiri, W.
    Mizuno, T.
    Monte, C.
    Monzani, M. E.
    Morselli, A.
    Moskalenko, I. V.
    Murgia, S.
    Nestoras, I.
    Nolan, P. L.
    Norris, J. P.
    Nuss, E.
    Ohsugi, T.
    Okumura, A.
    Orlando, E.
    Ormes, J. F.
    Ozaki, M.
    Paneque, D.
    Panetta, J. H.
    Parent, D.
    Pelassa, V.
    Pepe, M.
    Pesce-Rollins, M.
    Piron, F.
    Porter, T. A.
    Raino, S.
    Rando, R.
    Razzano, M.
    Reimer, A.
    Reimer, O.
    Reyes, L. C.
    Rodriguez, A. Y.
    Roth, M.
    Ryde, Felix
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Sadrozinski, H. F. -W
    Sambruna, R.
    Sander, A.
    Sato, R.
    Sgro, C.
    Shaw, M. S.
    Siskind, E. J.
    Smith, P. D.
    Spandre, G.
    Spinelli, P.
    Stawarz, L.
    Stecker, F. W.
    Strickman, M. S.
    Suson, D. J.
    Takahashi, H.
    Takahashi, T.
    Tanaka, T.
    Thayer, J. B.
    Thayer, J. G.
    Thompson, D. J.
    Tibolla, O.
    Torres, D. F.
    Tosti, G.
    Tramacere, A.
    Uchiyama, Y.
    Usher, T. L.
    Vasileiou, V.
    Vilchez, N.
    Villata, M.
    Vitale, V.
    von Kienlin, A.
    Waite, A. P.
    Wang, P.
    Winer, B. L.
    Wood, K. S.
    Yang, Z.
    Ylinen, Tomi
    KTH, Skolan för teknikvetenskap (SCI), Fysik.
    Ziegler, M.
    Tavecchio, F.
    Sikora, M.
    Schady, P.
    Roming, P.
    Chester, M. M.
    Maraschi, L.
    SUZAKU OBSERVATIONS OF LUMINOUS QUASARS: REVEALING THE NATURE OF HIGH-ENERGY BLAZAR EMISSION IN LOW-LEVEL ACTIVITY STATES2010Ingår i: Astrophysical Journal, ISSN 0004-637X, E-ISSN 1538-4357, Vol. 716, nr 1, s. 835-849Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We present the results from the Suzaku X-ray observations of five flat-spectrum radio quasars (FSRQs), namely PKS 0208-512, Q 0827+243, PKS 1127-145, PKS 1510-089, and 3C 454.3. All these sources were additionally monitored simultaneously or quasi-simultaneously by the Fermi satellite in gamma rays and the Swift UVOT in the UV and optical bands, respectively. We constructed their broadband spectra covering the frequency range from 10(14) Hz up to 10(25) Hz, and those reveal the nature of high-energy emission of luminous blazars in their low-activity states. The analyzed X-ray spectra are well fitted by a power-law model with photoelectric absorption. In the case of PKS 0208-512, PKS 1127-145, and 3C 454.3, the X-ray continuum showed indication of hardening at low energies. Moreover, when compared with the previous X-ray observations, we see a significantly increasing contribution of low-energy photons to the total X-ray fluxes when the sources are getting fainter. The same behavior can be noted in the Suzaku data alone. A likely explanation involves a variable, flat-spectrum component produced via inverse-Compton emission, plus an additional, possibly steady soft X-ray component prominent when the source gets fainter. This soft X-ray excess is represented either by a steep power-law (photon indices Gamma similar to 3-5) or a blackbody-type emission with temperatures kT similar to 0.1-0.2 keV. We model the broadband spectra of the five observed FSRQs using synchrotron self-Compton and/or external-Compton radiation models. Our modeling suggests that the difference between the low-and high-activity states in luminous blazars is due to the different total kinetic power of the jet, most likely related to varying bulk Lorentz factor of the outflow within the blazar emission zone.

  • 98. Abdo, A. A.
    et al.
    Ackermann, M.
    Ajello, M.
    Antolini, E.
    Baldini, L.
    Ballet, J.
    Barbiellini, G.
    Bastieri, D.
    Baughman, B. M.
    Bechtol, K.
    Bellazzini, R.
    Berenji, B.
    Blandford, R. D.
    Bloom, E. D.
    Bonamente, E.
    Borgland, A. W.
    Bouvier, A.
    Bregeon, J.
    Brez, A.
    Brigida, M.
    Bruel, P.
    Burnett, T. H.
    Buson, S.
    Caliandro, G. A.
    Cameron, R. A.
    Caraveo, P. A.
    Carrigan, S.
    Casandjian, J. M.
    Cavazzuti, E.
    Cecchi, C.
    Celik, Oe
    Charles, E.
    Chekhtman, A.
    Cheung, C. C.
    Chiang, J.
    Ciprini, S.
    Claus, R.
    Cohen-Tanugi, J.
    Conrad, J.
    Costamante, L.
    Cutini, S.
    Dermer, C. D.
    de Angelis, A.
    de Palma, F.
    do Couto e Silva, E.
    Drell, P. S.
    Dubois, R.
    Dumora, D.
    Farnier, C.
    Favuzzi, C.
    Fegan, S. J.
    Focke, W. B.
    Fukazawa, Y.
    Funk, S.
    Fusco, P.
    Gargano, F.
    Gasparrini, D.
    Gehrels, N.
    Germani, S.
    Giglietto, N.
    Giommi, P.
    Giordano, F.
    Glanzman, T.
    Godfrey, G.
    Grenier, I. A.
    Grove, J. E.
    Guiriec, S.
    Hadasch, D.
    Hayashida, M.
    Hays, E.
    Healey, S. E.
    Horan, D.
    Hughes, R. E.
    Itoh, R.
    Johannesson, G.
    Johnson, A. S.
    Johnson, T. J.
    Johnson, W. N.
    Kamae, T.
    Katagiri, H.
    Kataoka, J.
    Kawai, N.
    Knoedlseder, J.
    Kuss, M.
    Lande, J.
    Latronico, L.
    Lee, S. -H
    Lemoine-Goumard, M.
    Garde, M. Llena
    Longo, F.
    Loparco, F.
    Lott, B.
    Lovellette, M. N.
    Lurrano, P.
    Madejski, G. M.
    Makeev, A.
    Mazziotta, M. N.
    McConville, W.
    McEnery, J. E.
    Meurer, C.
    Michelson, P. F.
    Mitthumsiri, W.
    Mizuno, T.
    Monte, C.
    Monzani, M. E.
    Morselli, A.
    Moskalenko, I. V.
    Murgia, S.
    Nolan, P. L.
    Norris, J. P.
    Nuss, E.
    Ohsugi, T.
    Omodei, N.
    Orlando, E.
    Ormes, J. F.
    Ozaki, M.
    Paneque, D.
    Panetta, J. H.
    Parent, D.
    Pelassa, V.
    Pepe, M.
    Pesce-Rollins, M.
    Piron, F.
    Porter, T. A.
    Raino, S.
    Rando, R.
    Razzan, M.
    Reimer, A.
    Reimer, O.
    Ritz, S.
    Rochester, L. S.
    Rodriguez, A. Y.
    Romani, R. W.
    Roth, M.
    Sadrozinski, H. F. -W
    Sander, A.
    Parkinson, P. M. Saz
    Scargle, J. D.
    Sgro, C.
    Shaw, M. S.
    Smith, P. D.
    Spandre, G.
    Spinelli, P.
    Starck, J. -L
    Strickman, M. S.
    Strong, A. W.
    Suson, D. J.
    Tajima, H.
    Takahashi, H.
    Takahashi, T.
    Tanaka, T.
    Thayer, J. B.
    Thayer, J. G.
    Thompson, D. J.
    Tibaldo, L.
    Torres, D. F.
    Tosti, G.
    Tramacere, A.
    Uchiyama, Y.
    Usher, T. L.
    Vasileiou, V.
    Vilchez, N.
    Vitale, V.
    Waite, A. P.
    Wang, P.
    Winer, B. L.
    Wood, K. S.
    Yang, Z.
    Ylinen, Tomi
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Ziegler, M.
    The Fermi-LAT high-latitude survey: Source count distributions and the origin of the extragalactic diffuse background2010Ingår i: Astrophysical Journal, ISSN 0004-637X, E-ISSN 1538-4357, Vol. 720, nr 1, s. 435-453Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This is the first of a series of papers aimed at characterizing the populations detected in the high-latitude sky of the Fermi-LAT survey. In this work, we focus on the intrinsic spectral and flux properties of the source sample. We show that when selection effects are properly taken into account, Fermi sources are on average steeper than previously found (e.g., in the bright source list) with an average photon index of 2.40 +/- 0.02 over the entire 0.1-100 GeV energy band. We confirm that flat spectrum radio quasars have steeper spectra than BL Lacertae objects with an average index of 2.48 +/- 0.02 versus 2.18 +/- 0.02. Using several methods, we build the deepest source count distribution at GeV energies, deriving that the intrinsic source (i.e., blazar) surface density at F-100 >= 10(-9) ph cm(2) s(-1) is 0.12(-0.02)(+0.03) deg(-2). The integration of the source count distribution yields that point sources contribute 16(+/- 1.8)% (+/- 7% systematic uncertainty) of the GeV isotropic diffuse background. At the fluxes currently reached by LAT, we can rule out the hypothesis that pointlike sources (i.e., blazars) produce a larger fraction of the diffuse emission.

  • 99. Abdo, A. A.
    et al.
    Ackermann, M.
    Ajello, M.
    Antolini, E.
    Baldini, L.
    Ballet, J.
    Barbiellini, G.
    Bastieri, D.
    Bechtol, K.
    Bellazzini, R.
    Berenji, B.
    Blandford, R. D.
    Bloom, E. D.
    Bonamente, E.
    Borgland, A. W.
    Bouvier, A.
    Bregeon, J.
    Brez, A.
    Brigida, M.
    Bruel, P.
    Buehler, R.
    Burnett, T. H.
    Buson, S.
    Caliandro, G. A.
    Cameron, R. A.
    Caraveo, P. A.
    Carrigan, S.
    Casandjian, J. M.
    Cavazzuti, E.
    Cecchi, C.
    Celik, Oe.
    Chekhtman, A.
    Cheung, C. C.
    Chiang, J.
    Ciprini, S.
    Claus, R.
    Cohen-Tanugi, J.
    Cominsky, L. R.
    Conrad, J.
    Costamante, L.
    Cutini, S.
    Dermer, C. D.
    de Angelis, A.
    de Palma, F.
    do Couto e Silva, E.
    Drell, P. S.
    Dubois, R.
    Dumora, D.
    Farnier, C.
    Favuzzi, C.
    Fegan, S. J.
    Focke, W. B.
    Fortin, P.
    Frailis, M.
    Fukazawa, Y.
    Funk, S.
    Fusco, P.
    Gargano, F.
    Gasparrini, D.
    Gehrels, N.
    Germani, S.
    Giebels, B.
    Giglietto, N.
    Giommi, P.
    Giordano, F.
    Glanzman, T.
    Godfrey, G.
    Grenier, I. A.
    Grondin, M. -H
    Grove, J. E.
    Guiriec, S.
    Hadasch, D.
    Hayashida, M.
    Hays, E.
    Healey, S. E.
    Horan, D.
    Hughes, R. E.
    Itoh, R.
    Johannesson, G.
    Johnson, A. S.
    Johnson, W. N.
    Kamae, T.
    Katagiri, H.
    Kataoka, J.
    Kawai, N.
    Knoedlseder, J.
    Kuss, M.
    Lande, J.
    Larsson, S.
    Latronico, L.
    Lemoine-Goumard, M.
    Longo, F.
    Loparco, F.
    Lott, B.
    Lovellette, M. N.
    Lubrano, P.
    Madejski, G. M.
    Makeev, A.
    Massaro, E.
    Mazziotta, M. N.
    McEnery, J. E.
    Michelson, P. F.
    Mitthumsiri, W.
    Mizuno, T.
    Moiseev, A. A.
    Monte, C.
    Monzani, M. E.
    Morselli, A.
    Moskalenko, I. V.
    Mueller, M.
    Murgia, S.
    Nolan, P. L.
    Norris, J. P.
    Nuss, E.
    Ohno, M.
    Ohsugi, T.
    Omodei, N.
    Orlando, E.
    Ormes, J. F.
    Ozaki, M.
    Panetta, J. H.
    Parent, D.
    Pelassa, V.
    Pepe, M.
    Pesce-Rollins, M.
    Piron, F.
    Porter, T. A.
    Raino, S.
    Rando, R.
    Razzano, M.
    Reimer, A.
    Reimer, O.
    Ritz, S.
    Rodriguez, A. Y.
    Romani, R. W.
    Roth, M.
    Ryde, Felix
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Sadrozinski, H. F. -W
    Sander, A.
    Scargle, J. D.
    Sgro, C.
    Shaw, M. S.
    Smith, P. D.
    Spandre, G.
    Spinelli, P.
    Starck, J. -L
    Strickman, M. S.
    Suson, D. J.
    Takahashi, H.
    Takahashi, T.
    Tanaka, T.
    Thayer, J. B.
    Thayer, J. G.
    Thompson, D. J.
    Tibaldo, L.
    Torres, D. F.
    Tosti, G.
    Tramacere, A.
    Uchiyama, Y.
    Usher, T. L.
    Vasileiou, V.
    Vilchez, N.
    Vitale, V.
    Waite, A. P.
    Wallace, E.
    Wang, P.
    Winer, B. L.
    Wood, K. S.
    Yang, Z.
    Ylinen, Tomi
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Ziegler, M.
    Gamma-ray light curves and variability of bright fermi-detected blazars2010Ingår i: Astrophysical Journal, ISSN 0004-637X, E-ISSN 1538-4357, Vol. 722, nr 1, s. 520-542Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper presents light curves as well as the first systematic characterization of variability of the 106 objects in the high-confidence Fermi Large Area Telescope Bright AGN Sample (LBAS). Weekly light curves of this sample, obtained during the first 11 months of the Fermi survey (2008 August 4-2009 July 4), are tested for variability and their properties are quantified through autocorrelation function and structure function analysis. For the brightest sources, 3 or 4 day binned light curves are extracted in order to determine power density spectra (PDSs) and to fit the temporal structure of major flares. More than 50% of the sources are found to be variable with high significance, where high states do not exceed 1/4 of the total observation range. Variation amplitudes are larger for flat spectrum radio quasars and low/intermediate synchrotron frequency peaked BL Lac objects. Autocorrelation timescales derived from weekly light curves vary from four to a dozen of weeks. Variable sources of the sample have weekly and 3-4 day bin light curves that can be described by 1/f(alpha) PDS, and show two kinds of gamma-ray variability: (1) rather constant baseline with sporadic flaring activity characterized by flatter PDS slopes resembling flickering and red noise with occasional intermittence and (2)-measured for a few blazars showing strong activity-complex and structured temporal profiles characterized by long-term memory and steeper PDS slopes, reflecting a random walk underlying mechanism. The average slope of the PDS of the brightest 22 FSRQs and of the 6 brightest BL Lacs is 1.5 and 1.7, respectively. The study of temporal profiles of well-resolved flares observed in the 10 brightest LBAS sources shows that they generally have symmetric profiles and that their total duration vary between 10 and 100 days. Results presented here can assist in source class recognition for unidentified sources and can serve as reference for more detailed analysis of the brightest gamma-ray blazars.

  • 100. Abdo, A. A.
    et al.
    Ackermann, M.
    Ajello, M.
    Asano, K.
    Atwood, W. B.
    Jackson, Miranda
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Johannesson, G.
    Johnson, A. S.
    McGlynn, Sinéad
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Ryde, Felix
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Ylinen, Tomi
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Ziegler, M.
    et al.,
    Fermi detection of delayed GeV emission from the short gamma-ray burst 081024B2010Ingår i: Astrophysical Journal, ISSN 0004-637X, E-ISSN 1538-4357, Vol. 712, nr 1, s. 558-564Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We report on the detailed analysis of the high-energy extended emission from the short gamma-ray burst (GRB) 081024B detected by the Fermi Gamma-ray Space Telescope. Historically, this represents the first clear detection of temporal extended emission from a short GRB. The light curve observed by the Fermi Gamma-ray Burst Monitor lasts approximately 0.8 s whereas the emission in the Fermi Large Area Telescope lasts for about 3 s. Evidence of longer lasting high-energy emission associated with long bursts has been already reported by previous experiments. Our observations, together with the earlier reported study of the bright short GRB 090510, indicate similarities in the high-energy emission of short and long GRBs and open the path to new interpretations.

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