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  • 51.
    Axelsson, Magnus
    et al.
    Department of Astronomy, Stockholm University.
    Ryde, FelixDepartment of Astronomy, Stockholm University.
    Gamma-Ray Bursts: Prospects for Glast2007Konferanseproceedings (Annet vitenskapelig)
  • 52.
    Axelsson, Magnus
    et al.
    Department of Astronomy, Stockholm University.
    Ryde, Felix
    Department of Astronomy, Stockholm University.
    Gamma-Ray Bursts: Prospects for GLAST: Preface2007Inngår i: AIP Conference Proceedings, Stockholm, 2007, Vol. 906, s. vii-Konferansepaper (Annet vitenskapelig)
  • 53. Band, D. L.
    et al.
    Axelsson, Magnus
    Ist Nazl Fis Nucl, Sez Pisa, Pisa, Italy .
    Battelino, Milan
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    McGlynn, Sinéad
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Moretti, Elena
    University and INFN of Trieste.
    Ryde, Felix
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Yamazaki, R.
    et al.,
    PROSPECTS FOR GRB SCIENCE WITH THE FERMI LARGE AREA TELESCOPE2009Inngår i: Astrophysical Journal, ISSN 0004-637X, E-ISSN 1538-4357, Vol. 701, nr 2, s. 1673-1694Artikkel, forskningsoversikt (Fagfellevurdert)
    Abstract [en]

    The Large Area Telescope (LAT) instrument on the Fermi mission will reveal the rich spectral and temporal gamma-ray burst (GRB) phenomena in the > 100 MeV band. The synergy with Fermi's Gamma-ray Burst Monitor detectors will link these observations to those in the well explored 10-1000 keV range; the addition of the > 100 MeV band observations will resolve theoretical uncertainties about burst emission in both the prompt and afterglow phases. Trigger algorithms will be applied to the LAT data both onboard the spacecraft and on the ground. The sensitivity of these triggers will differ because of the available computing resources onboard and on the ground. Here we present the LAT's burst detection methodologies and the instrument's GRB capabilities.

  • 54. Burgess, J. M.
    et al.
    Preece, R. D.
    Connaughton, V.
    Briggs, M. S.
    Goldstein, A.
    Bhat, P. N.
    Greiner, J.
    Gruber, D.
    Kienlin, A.
    Kouveliotou, C.
    McGlynn, S.
    Meegan, C. A.
    Paciesas, W. S.
    Rau, A.
    Xiong, S.
    Axelsson, Magnus
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Baring, M. G.
    Dermer, C. D.
    Iyyani, S.
    Kocevski, D.
    Omodei, N.
    Ryde, Felix
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Vianello, G.
    Time-resolved analysis of fermi gamma-ray bursts with fast- and slow-cooled synchrotron photon models2014Inngår i: Astrophysical Journal, ISSN 0004-637X, E-ISSN 1538-4357, Vol. 784, nr 1, s. 17-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Time-resolved spectroscopy is performed on eight bright, long gamma-ray bursts (GRBs) dominated by single emission pulses that were observed with the Fermi Gamma-Ray Space Telescope. Fitting the prompt radiation of GRBs by empirical spectral forms such as the Band function leads to ambiguous conclusions about the physical model for the prompt radiation. Moreover, the Band function is often inadequate to fit the data. The GRB spectrum is therefore modeled with two emission components consisting of optically thin non-thermal synchrotron radiation from relativistic electrons and, when significant, thermal emission from a jet photosphere, which is represented by a blackbody spectrum. To produce an acceptable fit, the addition of a blackbody component is required in five out of the eight cases. We also find that the low-energy spectral index a is consistent with a synchrotron component with a = -0.81 +/- 0.1. This value lies between the limiting values of a = -2/3 and a = -3/2 for electrons in the slow-and fast-cooling regimes, respectively, suggesting ongoing acceleration at the emission site. The blackbody component can be more significant when using a physical synchrotron model instead of the Band function, illustrating that the Band function does not serve as a good proxy for a non-thermal synchrotron emission component. The temperature and characteristic emission-region size of the blackbody component are found to, respectively, decrease and increase as power laws with time during the prompt phase. In addition, we find that the blackbody and non-thermal components have separate temporal behaviors as far as their respective flux and spectral evolutions.

  • 55. Burgess, J. Michael
    et al.
    Preece, Robert D.
    Ryde, Felix
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Veres, Peter
    Meszaros, Peter
    Connaughton, Valerie
    Briggs, Michael
    Pe'er, Asaf
    Iyyani, Shabnam
    Goldstein, Adam
    Axelsson, Magnus
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Baring, Matthew G.
    Bhat, P. N.
    Byrne, David
    Fitzpatrick, Gerard
    Foley, Suzanne
    Kocevski, Daniel
    Omodei, Nicola
    Paciesas, William S.
    Pelassa, Veronique
    Kouveliotou, Chryssa
    Xiong, Shaolin
    Yu, Hoi-Fung
    Zhang, Binbin
    Zhu, Sylvia
    An observed correlation between thermal and non-thermal emission in gamma-ray bursts2014Inngår i: Astrophysical Journal Letters, ISSN 2041-8205, Vol. 784, nr 2, s. L43-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Recent observations by the Fermi Gamma-ray Space Telescope have confirmed the existence of thermal and non-thermal components in the prompt photon spectra of some gamma-ray bursts (GRBs). Through an analysis of six bright Fermi GRBs, we have discovered a correlation between the observed photospheric and non-thermal gamma-ray emission components of several GRBs using a physical model that has previously been shown to be a good fit to the Fermi data. From the spectral parameters of these fits we find that the characteristic energies, E-p and kT, of these two components are correlated via the relation E-p proportional to T-alpha which varies from GRB to GRB. We present an interpretation in which the value of the index alpha indicates whether the jet is dominated by kinetic or magnetic energy. To date, this jet composition parameter has been assumed in the modeling of GRB outflows rather than derived from the data.

  • 56. Iyudin, Anatoli F.
    et al.
    Pakhomov, Y. V.
    Chugai, N. N.
    Greiner, J.
    Axelsson, Magnus
    Department of Astronomy, Stockholm University.
    Larsson, S.
    Ryabchikova, T. A.
    Search for broad absorption lines in spectra of stars in the field of supernova remnant RX J0852.0-4622 (Vela Jr.)2010Inngår i: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, ISSN 0004-6361, Vol. 519, nr 9, s. A86-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Aims. Supernova remnant (SNR) RX J0852.0-4622 is one of the youngest and is most likely the closest among known Galactic SNRs. It was detected in X-rays, the (44)Ti gamma-line, and radio. We obtain and analyze medium-resolution spectra of 14 stars in the direction towards the SNR RX J0852.0-4622 in an attempt to detect broad absorption lines of unshocked ejecta against background stars. Methods. Spectral synthesis is performed for all the stars in the wavelength range of 3740-4020 angstrom to extract the broad absorption lines of Ca II related to the SNR RX J0852.0-4622. Results. We do not detect any broad absorption line and place a 3 sigma upper limit on the relative depths of <0.04 for the broad Ca II absorption produced by the SNR. We detect narrow low and high velocity absorption components of Ca II. High velocity vertical bar V(LSR)vertical bar similar to 100-140 km s(-1) components are attributed to radiative shocks in clouds engulfed by the old Vela SNR. The upper limit to the absorption line strength combined with the width and flux of the (44)Ti gamma-ray line 1.16 MeV lead us to conclude that SNR RX J0852.0-4622 was probably produced by an energetic SN Ic explosion.

  • 57. Iyyani, S
    et al.
    Ryde, Felix
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Axelsson, Magnus
    KTH, Skolan för teknikvetenskap (SCI), Fysik.
    Burgess, J. M.
    Guiriec, S.
    Larsson, Josefin
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Lundman, Christoffer
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Moretti, Elena
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    McGlynn, S.
    Nymark, Tanja
    KTH, Skolan för teknikvetenskap (SCI), Fysik.
    Rosquist, K.
    Variable jet properties in GRB 110721A: time resolved observations of the jet photosphere2013Inngår i: Monthly notices of the Royal Astronomical Society, ISSN 0035-8711, E-ISSN 1365-2966, Vol. 433, nr 4, s. 2739-2748Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Fermi Gamma-ray Space Telescope observations of GRB 110721A have revealed two emission components from the relativistic jet: emission from the photosphere, peaking at similar to 100 keV, and a non-thermal component, which peaks at similar to 1000 keV. We use the photospheric component to calculate the properties of the relativistic outflow. We find a strong evolution in the flow properties: the Lorentz factor decreases with time during the bursts from G similar to 1000 to similar to 150 (assuming a redshift z = 2; the values are only weakly dependent on unknown efficiency parameters). Such a decrease is contrary to the expectations from the internal shocks and the isolated magnetar birth models. Moreover, the position of the flow nozzle measured from the central engine, r(0), increases by more than two orders of magnitude. Assuming a moderately magnetized outflow we estimate that r(0) varies from 10(6) to similar to 10(9) cm during the burst. We suggest that the maximal value reflects the size of the progenitor core. Finally, we show that these jet properties naturally explain the observed broken power-law decay of the temperature which has been reported as a characteristic for gamma-ray burst pulses.

  • 58. Kamae, Tuneyoshi
    et al.
    Andersson, Viktor
    KTH, Skolan för teknikvetenskap (SCI), Fysik.
    Arimoto, Makoto
    Axelsson, Magnus
    Bettolo, Cecilia Marini
    KTH, Skolan för teknikvetenskap (SCI), Fysik.
    Björnsson, Claes-Ingvar
    Bogaert, Gilles
    Carlson, Per
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Craig, William
    Ekeberg, Tomas
    KTH, Skolan för teknikvetenskap (SCI), Fysik.
    Engdegård, Olle
    KTH, Skolan för teknikvetenskap (SCI), Fysik.
    Fukazawa, Yasushi
    Gunji, Shuichi
    Hjalmarsdotter, Linnea
    Iwan, Bianca
    KTH, Skolan för teknikvetenskap (SCI), Fysik.
    Kanai, Yoshikazu
    Kataoka, Jun
    Kawai, Nobuyuki
    Kazejev, Jaroslav
    KTH, Skolan för teknikvetenskap (SCI), Fysik.
    Kiss, Mozsi
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Klamra, Wlodzimierz
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Larsson, Stefan
    KTH, Skolan för teknikvetenskap (SCI), Fysik.
    Madejski, Grzegorz
    Mizuno, Tsunefumi
    Ng, Johnny
    Pearce, Mark
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Rydé, Felix
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Suhonen, Markus
    KTH, Skolan för teknikvetenskap (SCI), Fysik.
    TaJima, Hiroyasu
    Takahashi, Hiromitsu
    Takahashi, Tadayuki
    Tanaka, Takuya
    Thurston, Timothy
    Ueno, Masaru
    Varneri, Gary
    Yamamoto, Kazuhide
    Yamashita, Yuichiro
    Ylinen, Tomi
    KTH, Skolan för teknikvetenskap (SCI), Fysik.
    Yoshida, Hiroaki
    PoGOLite - A high sensitivity balloon-borne soft gamma-ray polarimeter2008Inngår i: Astroparticle physics, ISSN 0927-6505, E-ISSN 1873-2852, Vol. 30, nr 2, s. 72-84Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We describe a new balloon-borne instrument (PoGOLite) capable of detecting 10% polarisation from 200 mCrab point-like sources between 25 and 80 keV in one 6-h flight. Polarisation measurements in the soft gamma-ray band are expected to provide a powerful probe into high energy emission mechanisms as well as the distribution of magnetic fields, radiation fields and interstellar matter. Synchrotron radiation, inverse Compton scattering and propagation through high magnetic fields are likely to produce high degrees of polarisation in the energy band of the instrument. We demonstrate, through tests at accelerators, with radioactive sources and through computer simulations, that PoGOLite will be able to detect degrees of polarisation as predicted by models for several classes of high energy sources. At present, only exploratory polarisation measurements have been carried out in the soft gamma-ray band. Reduction of the large background produced by cosmic-ray particles while securing a large effective area has been the greatest challenge. PoGOLite uses Compton scattering and photo-absorption in an array of 217 well-type phoswich detector cells made of plastic and BGO scintillators surrounded by a BGO anticoincidence shield and a thick polyethylene neutron shield. The narrow Held of view (FWHM = 1.25 msr, 2.0 deg x 2.0 deg) obtained with detector cells and the use of thick background shields warrant a large effective area for polarisation measurements (similar to 228 cm(2) at E = 40 keV) without sacrificing the signal-to-noise ratio. Simulation studies for an atmospheric overburden of 3-4 g/cm(2) indicate that neutrons and gamma-rays entering the PDC assembly through the shields are dominant backgrounds. Off-line event selection based on recorded phototube waveforms and Compton kinematics reduce the background to that expected for a similar to 100 mCrab source between 25 and 50 keV. A 6-h observation of the Crab pulsar will differentiate between the Polar Cap/Slot Gap, Outer Gap, and Caustic models with greater than 5 sigma significance; and also cleanly identify the Compton reflection component in the Cygnus X-1 hard state. Long-duration flights will measure the dependence of the polarisation across the cyclotron absorption line in Hercules X-1. A scaled-down instrument will be flown as a pathfinder mission from the north of Sweden in 2010. The first science flight is planned to take place shortly thereafter.

  • 59. Mizuno, T.
    et al.
    Arimoto, M.
    Axelsson, Magnus
    Stockholm University.
    Björnsson, C. -I
    Bogaert, G.
    Carlson, Per
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Craig, W.
    Fukazawa, Y.
    Gunji, S.
    Hjalmarsdotter, L.
    Kamae, T.
    Kanai, Y.
    Kataoka, J.
    Katsuta, J.
    Kawai, N.
    Kiss, Mózsi Bank
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Klamra, Wlodzimierz
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Larsson, S.
    Madejski, G.
    Bettolo, Cecilia M.
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Ng, J.
    Pearce, Mark
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Ryde, Felix
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Tajima, H.
    Takahash, H.
    Takahashi, T.
    Tanaka, T.
    Thurston, T.
    Ueno, M.
    Varner, G.
    Yoshida, H.
    High sensitivity balloon-borne hard X-ray/soft Gamma-Ray Polarimeter PoGOLite2007Inngår i: Nuclear Science Symposium Conference Record, 2007. NSS ’07. IEEE, IEEE , 2007, Vol. 4, s. 2538-2544Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The Polarized Gamma-ray Observer - Lightweight version (PoGOLite) is a new balloon experiment capable of detecting 10% polarization from a 200 mCrab source in the 25-80 keV energy range in a single 6-hour flight for the first time. Polarization measurements of hard X-rays and soft gamma-rays are expected to provide a powerful probe into high-energy emission mechanisms as well as source geometries. PoGOLite uses Compton scattering and photo-absorption to measure polarization in an array of 217 well-type phoswich detector cells made of plastic and BGO scintillators. The adoption of a well-type phoswich counter concept and a thick polyethylene neutron shield provides a narrow field-of-view (1.25 msr), a large effective area ( gt; 250 cm2 at 40-50 keV), a high modulation factor (more than 25%) and the low background ( 100 mCrab) required to conduct high-sensitivity polarization measurements. Through tests in laboratories and accelerator facilities of a scaled-down prototype with the front-end electronics of flight design and an extensive study by Monte Carlo simulation, we have demonstrated high instrument performance. PoGOLite will be ready for a first engineering flight in 2009 and a science flight in 2010, during which polarization signals from the Crab Nebula/pulsar, Cygnus X-1 and other objects will be observed.

  • 60.
    Moretti, Elena
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik. Max-Planck-Institut für Physik, Germany.
    Axelsson, Magnus
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik. Department of Physics, Tokyo Metropolitan University, Japan.
    Signs of magnetic acceleration and multizone emission in GRB 080825C2016Inngår i: Monthly notices of the Royal Astronomical Society, ISSN 0035-8711, E-ISSN 1365-2966, Vol. 458, nr 2, s. 1728-1732Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    One of the major results from the study of gamma-ray bursts with the Fermi Gamma-ray Space Telescope has been the confirmation that several emission components can be present in the energy spectrum. Here, we reanalyse the spectrum of GRB 080825C using data from the Fermi-Large Area Telescope (LAT) and Gamma-ray Burst Monitor instruments. Although fairly weak, it is the first gamma-ray burst detected by the Fermi-LAT. We improve on the original analysis by using the LAT Low Energy events covering the 30–100 MeV band. We find evidence of an additional component above the main emission peak (modelled using a Band function) with a significance of 3.5σ in two out of the four time bins. The component is well fitted by a Planck function, but shows unusual behaviour: the peak energy increases in the prompt emission phase, reaching energies of several MeV. This is the first time such a trend has been seen, and implies that the origin of this component is different from those previously detected. We suggest that the two spectral components likely arise in different regions of the outflow, and that strong constraints can be achieved by assuming one of them originates from the photosphere. The most promising model appears to be that the high-energy peak is the result of photospheric emission in a Poynting flux dominated outflow where the magnetization increases with time.

  • 61. Nolan, P. L.
    et al.
    Abdo, A. A.
    Ackermann, M.
    Ajello, M.
    Allafort, A.
    Antolini, E.
    Atwood, W. B.
    Axelsson, Magnus
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Baldini, L.
    Ballet, J.
    Barbiellini, G.
    Bastieri, D.
    Bechtol, K.
    Belfiore, A.
    Bellazzini, R.
    Berenji, B.
    Bignami, G. F.
    Blandford, R. D.
    Bloom, E. D.
    Bonamente, E.
    Bonnell, J.
    Borgland, A. W.
    Bottacini, E.
    Bouvier, A.
    Brandt, T. J.
    Bregeon, J.
    Brigida, M.
    Bruel, P.
    Buehler, R.
    Burnett, T. H.
    Buson, S.
    Caliandro, G. A.
    Cameron, R. A.
    Campana, R.
    Canadas, B.
    Cannon, A.
    Caraveo, P. A.
    Casandjian, J. M.
    Cavazzuti, E.
    Ceccanti, M.
    Cecchi, C.
    Celik, Oe
    Charles, E.
    Chekhtman, A.
    Cheung, C. C.
    Chiang, J.
    Chipaux, R.
    Ciprini, S.
    Claus, R.
    Cohen-Tanugi, J.
    Cominsky, L. R.
    Conrad, J.
    Corbet, R.
    Cutini, S.
    D'Ammando, F.
    Davis, D. S.
    de Angelis, A.
    DeCesar, M. E.
    DeKlotz, M.
    De Luca, A.
    den Hartog, P. R.
    de Palma, F.
    Dermer, C. D.
    Digel, S. W.
    Do Couto E Silva, E.
    Drell, P. S.
    Drlica-Wagner, A.
    Dubois, R.
    Dumora, D.
    Enoto, T.
    Escande, L.
    Fabiani, D.
    Falletti, L.
    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.
    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.
    Hill, A. B.
    Horan, D.
    Hou, X.
    Hughes, R. E.
    Iafrate, G.
    Itoh, R.
    Johannesson, G.
    Johnson, R. P.
    Johnson, T. E.
    Johnson, A. S.
    Johnson, T. J.
    Kamae, T.
    Katagiri, H.
    Kataoka, J.
    Katsuta, J.
    Kawai, N.
    Kerr, M.
    Knoedlseder, J.
    Kocevski, D.
    Kuss, M.
    Lande, J.
    Landriu, D.
    Latronico, L.
    Lemoine-Goumard, M.
    Lionetto, A. M.
    Garde, M. Llena
    Longo, F.
    Loparco, F.
    Lott, B.
    Lovellette, M. N.
    Lubrano, P.
    Madejski, G. M.
    Marelli, M.
    Massaro, E.
    Mazziotta, M. N.
    McConville, W.
    McEnery, J. E.
    Mehault, J.
    Michelson, P. F.
    Minuti, M.
    Mitthumsiri, W.
    Mizuno, T.
    Moiseev, A. A.
    Mongelli, M.
    Monte, C.
    Monzani, M. E.
    Morselli, A.
    Moskalenko, I. V.
    Murgia, S.
    Nakamori, T.
    Naumann-Godo, M.
    Norris, J. P.
    Nuss, E.
    Nymark, Tanja
    KTH, Skolan för teknikvetenskap (SCI), Fysik.
    Ohno, M.
    Ohsugi, T.
    Okumura, A.
    Omodei, N.
    Orlando, E.
    Ormes, J. F.
    Ozaki, M.
    Paneque, D.
    Panetta, J. H.
    Parent, D.
    Perkins, J. S.
    Pesce-Rollins, M.
    Pierbattista, M.
    Pinchera, M.
    Piron, F.
    Pivato, G.
    Porter, T. A.
    Racusin, J. L.
    Raino, S.
    Rando, R.
    Razzano, M.
    Razzaque, S.
    Reimer, A.
    Reimer, O.
    Reposeur, T.
    Ritz, S.
    Rochester, L. S.
    Romani, R. W.
    Roth, M.
    Rousseau, R.
    Ryde, Felix
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Sadrozinski, H. F. -W
    Salvetti, D.
    Sanchez, D. A.
    Parkinson, P. M. Saz
    Sbarra, C.
    Scargle, J. D.
    Schalk, T. L.
    Sgro, C.
    Shaw, M. S.
    Shrader, C.
    Siskind, E. J.
    Smith, D. A.
    Spandre, G.
    Spinelli, P.
    Stephens, T. E.
    Strickman, M. S.
    Suson, D. J.
    Tajima, H.
    Takahashi, H.
    Takahashi, T.
    Tanaka, T.
    Thayer, J. G.
    Thayer, J. B.
    Thompson, D. J.
    Tibaldo, L.
    Tibolla, O.
    Tinebra, F.
    Tinivella, M.
    Torres, D. F.
    Tosti, G.
    Troja, E.
    Uchiyama, Y.
    Vandenbroucke, J.
    Van Etten, A.
    Van Klaveren, B.
    Vasileiou, V.
    Vianello, G.
    Vitale, V.
    Waite, A. P.
    Wallace, E.
    Wang, P.
    Werner, M.
    Winer, B. L.
    Wood, D. L.
    Wood, K. S.
    Wood, M.
    Yang, Z.
    Zimmer, S.
    Fermi large area telescope second source catalog2012Inngår i: Astrophysical Journal Supplement Series, ISSN 0067-0049, E-ISSN 1538-4365, Vol. 199, nr 2, s. 31-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We present the second 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), derived from data taken during the first 24 months of the science phase of the mission, which began on 2008 August 4. Source detection is based on the average flux over the 24 month period. The second Fermi-LAT catalog (2FGL) includes source location regions, defined in terms of elliptical fits to the 95% confidence regions and spectral fits in terms of power-law, exponentially cutoff power-law, or log-normal forms. Also included are flux measurements in five energy bands and light curves on monthly intervals for each source. Twelve sources in the catalog are modeled as spatially extended. We provide a detailed comparison of the results from this catalog with those from the first Fermi-LAT catalog (1FGL). Although the diffuse Galactic and isotropic models used in the 2FGL analysis are improved compared to the 1FGL catalog, we attach caution flags to 162 of the sources to indicate possible confusion with residual imperfections in the diffuse model. The 2FGL catalog contains 1873 sources detected and characterized in the 100 MeV to 100 GeV range of which we consider 127 as being firmly identified and 1171 as being reliably associated with counterparts of known or likely gamma-ray-producing source classes.

  • 62.
    Nymark, Tanja
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Fysik.
    Axelsson, Magnus
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Lundman, Christoffer
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Moretti, Elena
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Ryde, Felix
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Pe’er, A.
    Subphotospheric heating in GRBs: analysis and modeling of GRB090902B as observed by Fermi2011Inngår i: 2011 Fermi Symposium proceedings: eConf C110509, 2011Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    We analyze the spectral evolution of GRB 090902B and show that subphotospheric dissipation can explain both the spectra and the spectral evolution. The emission from a GRB photosphere can give rise to a variety of spectral shapes. The spectrum can have a shape close to that of a Planck function (as is observed during the first half of GRB090902B) or be broadened, resembling a typical Band function (as is observed during the second half of GRB090902B). The shape mainly depends on the strength and location of the dissipation in the jet, the ratio of the energy densities of thermal photons and of the electrons at the dissipation site, as well as on the strength of the magnetic field. We further discuss numerical models of the dissipation and relate these to the observed spectra.

  • 63.
    Pearce, Mark
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Arimoto, M.
    Axelsson, M.
    PoGOLite: a balloon-borne soft gamma-ray polarimeter2008Inngår i: International Cosmic Ray Conference, 2008, Vol. 2, s. 479-482Konferansepaper (Annet vitenskapelig)
  • 64.
    Pearce, Mark
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Fysik.
    Arimoto, M.
    Axelsson, Magnus
    Stockholm University, Sweden.
    Björnsson, C. -I
    Bogaert, G.
    Carlson, Per
    KTH, Skolan för teknikvetenskap (SCI), Fysik.
    Craig, W.
    Fukazawa, Y.
    Gunji, S.
    Hjalmarsdotter, L.
    Kamae, T.
    Kanai, Y.
    Kataoka, J.
    Katsuta, J.
    Kawai, N.
    Kazejev, Jaroslav
    KTH, Skolan för teknikvetenskap (SCI), Fysik.
    Kiss, Mózsi
    KTH, Skolan för teknikvetenskap (SCI), Fysik.
    Klamra, Wlodzimierz
    KTH, Skolan för teknikvetenskap (SCI), Fysik.
    Larsson, S.
    Madejski, G.
    Marini Bettolo, C.
    Mizuno, T.
    Ng, J.
    Nomachi, M.
    Odaka, H.
    Ryde, Felix
    KTH, Skolan för teknikvetenskap (SCI), Fysik.
    Tajima, H.
    Takahashi, H.
    Takahashi, T.
    Tanaka, T.
    Thurston, T.
    Ueno, M.
    Varner, G.
    Yoshida, H.
    Yuasa, T.
    PoGOLite: A balloon-borne soft gamma-ray polarimeter2007Inngår i: Proceedings of the 30th International Cosmic Ray Conference, ICRC 2007, Universidad Nacional Autonoma de Mexico , 2007, Vol. 2, nr OG PART 1, s. 479-482Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Polarized gamma-rays are expected from a wide variety of sources including rotationpowered pulsars, accreting black holes and neutron stars, and jet-dominated active galaxies. Polarization measurements provide a powerful probe of the gamma-ray emission mechanism and the distribution of magnetic and radiation fields around the source. No measurements have been performed in the soft gamma-ray band where non-thermal processes are expected to produce high degrees of polarization. The PoGOLite experiment applies well-type phoswich detector technology to polarization measurements in the 25 - 80 keV energy range. The instrument uses Compton scattering and photoabsorption in an array of 217 phoswich detector cells made of plastic and BGO scintillators, and surrounded by active BGO shields. A prototype of the flight instrument has been tested with polarized gammarays and background generated with radioactive sources. The test results and computer simulations confirm that the instrument can detect 10% polarization of a 200 mCrab source in one 6 hour balloon observation. In flight, targets are constrained to within better than 5% of the field-of-view (~5 degrees squared) in order to maximize the effective detection area during observations. The pointing direction on the sky is determined by an attitude control system comprising star trackers, differential GPS receiver system, gyroscopes, accelerometers and magnetometers which provide correction signals to a reaction wheel and torque motor system. Additionally, the entire polarimeter assembly rotates around its viewing axis to minimize systematic bias during observations. Flights are foreseen to start in 2009- 2010 and will target northern sky sources including the Crab pulsar/nebula, Cygnus X-1, and Hercules X-1. These observations will provide valuable information about the pulsar emission mechanism, the geometry around the black hole, and photon transportation in the strongly magnetized neutron star surface, respectively. Future goals include a long duration balloon flight from the Esrange facility in Northern Sweden to Canada.

  • 65. Preece, R.
    et al.
    Burgess, J. Michael
    University of Alabama in Huntsville, United States.
    von Kienlin, A.
    Bhat, P. N.
    Briggs, M. S.
    Byrne, D.
    Chaplin, V.
    Cleveland, W.
    Collazzi, A. C.
    Connaughton, V.
    Diekmann, A.
    Fitzpatrick, G.
    Foley, S.
    Gibby, M.
    Giles, M.
    Goldstein, A.
    Greiner, J.
    Gruber, D.
    Jenke, P.
    Kippen, R. M.
    Kouveliotou, C.
    McBreen, S.
    Meegan, C.
    Paciesas, W. S.
    Pelassa, V.
    Tierney, D.
    van der Horst, A. J.
    Wilson-Hodge, C.
    Xiong, S.
    Younes, G.
    Yu, H. -F
    Ackermann, M.
    Ajello, M.
    Axelsson, Magnus
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Baldini, L.
    Barbiellini, G.
    Baring, M. G.
    Bastieri, D.
    Bellazzini, R.
    Bissaldi, E.
    Bonamente, E.
    Bregeon, J.
    Brigida, M.
    Bruel, P.
    Buehler, R.
    Buson, S.
    Caliandro, G. A.
    Cameron, R. A.
    Caraveo, P. A.
    Cecchi, C.
    Charles, E.
    Chekhtman, A.
    Chiang, J.
    Chiaro, G.
    Ciprini, S.
    Claus, R.
    Cohen-Tanugi, J.
    Cominsky, L. R.
    Conrad, J.
    D'Ammando, F.
    de Angelis, A.
    de Palma, F.
    Dermer, C. D.
    Desiante, R.
    Digel, S. W.
    Di Venere, L.
    Drell, P. S.
    Drlica-Wagner, A.
    Favuzzi, C.
    Franckowiak, A.
    Fukazawa, Y.
    Fusco, P.
    Gargano, F.
    Gehrels, N.
    Germani, S.
    Giglietto, N.
    Giordano, F.
    Giroletti, M.
    Godfrey, G.
    Granot, J.
    Grenier, I. A.
    Guiriec, S.
    Hadasch, D.
    Hanabata, Y.
    Harding, A. K.
    Hayashida, M.
    Iyyani, S.
    Jogler, T.
    Joannesson, G.
    Kawano, T.
    Knoedlseder, J.
    Kocevski, D.
    Kuss, M.
    Lande, J.
    Larsson, Josefin
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Larsson, S.
    Latronico, L.
    Longo, F.
    Loparco, F.
    Lovellette, M. N.
    Lubrano, P.
    Mayer, M.
    Mazziotta, M. N.
    Michelson, P. F.
    Mizuno, T.
    Monzani, M. E.
    Moretti, Elena
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Morselli, A.
    Murgia, S.
    Nemmen, R.
    Nuss, E.
    Nymark, Tanja
    KTH, Skolan för teknikvetenskap (SCI), Fysik.
    Ohno, M.
    Ohsugi, T.
    Okumura, A.
    Omodei, N.
    Orienti, M.
    Paneque, D.
    Perkins, J. S.
    Pesce-Rollins, M.
    Piron, F.
    Pivato, G.
    Porter, T. A.
    Racusin, J. L.
    Raino, S.
    Rando, R.
    Razzano, M.
    Razzaque, S.
    Reimer, A.
    Reimer, O.
    Ritz, S.
    Roth, M.
    Ryde, Felix
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Sartori, A.
    Scargle, J. D.
    Schulz, A.
    Sgro, C.
    Siskind, E. J.
    Spandre, G.
    Spinelli, P.
    Suson, D. J.
    Tajima, H.
    Takahashi, H.
    Thayer, J. G.
    Thayer, J. B.
    Tibaldo, L.
    Tinivella, M.
    Torres, D. F.
    Tosti, G.
    Troja, E.
    Usher, T. L.
    Vandenbroucke, J.
    Vasileiou, V.
    Vianello, G.
    Vitale, V.
    Werner, M.
    Winer, B. L.
    Wood, K. S.
    Zhu, S.
    The First Pulse of the Extremely Bright GRB 130427A: A Test Lab for Synchrotron Shocks2014Inngår i: Science, ISSN 0036-8075, E-ISSN 1095-9203, Vol. 343, nr 6166, s. 51-54Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Gamma-ray burst (GRB) 130427A is one of the most energetic GRBs ever observed. The initial pulse up to 2.5 seconds is possibly the brightest well-isolated pulse observed to date. A fine time resolution spectral analysis shows power-law decays of the peak energy from the onset of the pulse, consistent with models of internal synchrotron shock pulses. However, a strongly correlated power-law behavior is observed between the luminosity and the spectral peak energy that is inconsistent with curvature effects arising in the relativistic outflow. It is difficult for any of the existing models to account for all of the observed spectral and temporal behaviors simultaneously.

  • 66. Racusin, J. L.
    et al.
    Burns, E.
    Goldstein, A.
    Connaughton, V.
    Wilson-Hodge, C. A.
    Jenke, P.
    Blackburn, L.
    Briggs, M. S.
    Broida, J.
    Camp, J.
    Christensen, N.
    Hui, C. M.
    Littenberg, T.
    Shawhan, P.
    Singer, L.
    Veitch, J.
    Bhat, P. N.
    Cleveland, W.
    Fitzpatrick, G.
    Gibby, M. H.
    von Kienlin, A.
    McBreen, S.
    Mailyan, B.
    Meegan, C. A.
    Paciesas, W. S.
    Preece, R. D.
    Roberts, O. J.
    Stanbro, M.
    Veres, P.
    Zhang, B. -B
    Ackermann, M.
    Albert, A.
    Atwood, W. B.
    Axelsson, M.
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Baldini, L.
    Ballet, J.
    Barbiellini, G.
    Baring, M. G.
    Bastieri, D.
    Bellazzini, R.
    Bissaldi, E.
    Blandford, R. D.
    Bloom, E. D.
    Bonino, R.
    Bregeon, J.
    Bruel, P.
    Buson, S.
    Caliandro, G. A.
    Cameron, R. A.
    Caputo, R.
    Caragiulo, M.
    Caraveo, P. A.
    Cavazzuti, E.
    Charles, E.
    Chiang, J.
    Ciprini, S.
    Costanza, F.
    Cuoco, A.
    Cutini, S.
    D'Ammando, F.
    de Palma, F.
    Desiante, R.
    Digel, S. W.
    Di Lalla, N.
    Di Mauro, M.
    Di Venere, L.
    Drell, P. S.
    Favuzzi, C.
    Ferrara, E. C.
    Focke, W. B.
    Fukazawa, Y.
    Funk, S.
    Fusco, P.
    Gargano, F.
    Gasparrini, D.
    Giglietto, N.
    Gill, R.
    Giroletti, M.
    Glanzman, T.
    Granot, J.
    Green, D.
    Grove, J. E.
    Guillemot, L.
    Guiriec, S.
    Harding, A. K.
    Jogler, T.
    Johannesson, G.
    Kamae, T.
    Kensei, S.
    Kocevski, D.
    Kuss, M.
    Larsson, Stefan
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Latronico, L.
    Li, J.
    Longo, F.
    Loparco, F.
    Lubrano, P.
    Magill, J. D.
    Maldera, S.
    Malyshev, D.
    Mazziotta, M. N.
    McEnery, J. E.
    Michelson, P. F.
    Mizuno, T.
    Monzani, M. E.
    Morselli, A.
    Moskalenko, I. V.
    Negro, M.
    Nuss, E.
    Omodei, N.
    Orienti, M.
    Orlando, E.
    Ormes, J. F.
    Paneque, D.
    Perkins, J. S.
    Pesce-Rollins, M.
    Piron, F.
    Pivato, G.
    Porter, T. A.
    Principe, G.
    Raino, S.
    Rando, R.
    Razzano, M.
    Razzaque, S.
    Reimer, A.
    Reimer, O.
    Parkinson, P. M. Saz
    Scargle, J. D.
    Sgro, C.
    Simone, D.
    Siskind, E. J.
    Smith, D. A.
    Spada, F.
    Spinelli, P.
    Suson, D. J.
    Tajima, H.
    Thayer, J. B.
    Torres, D. F.
    Troja, E.
    Uchiyama, Y.
    Vianello, G.
    Wood, K. S.
    Wood, M.
    SEARCHING THE GAMMA-RAY SKY FOR COUNTERPARTS TO GRAVITATIONAL WAVE SOURCES: FERMI GAMMA-RAY BURST MONITOR. AND LARGE AREA TELESCOPE OBSERVATIONS OF LVT151012 AND GW1512262017Inngår i: Astrophysical Journal, ISSN 0004-637X, E-ISSN 1538-4357, Vol. 835, nr 1, artikkel-id 82Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We present the Fermi Gamma-ray Burst Monitor (GBM) and Large Area Telescope (LAT) observations of the LIGO binary black hole merger event GW151226 and candidate LVT151012. At the time of the LIGO triggers on LVT151012 and GW151226, GBM was observing 68% and 83% of the localization regions, and LAT was observing 47% and 32%, respectively. No candidate electromagnetic counterparts were detected by either the GBM or LAT. We present a detailed analysis of the GBM and LAT data over a range of timescales from seconds to years, using automated pipelines and new techniques for characterizing the flux upper bounds across large areas of the sky. Due to the partial GBM and LAT coverage of the large LIGO localization regions at the trigger times for both events, differences in source distances and masses, as well as the uncertain degree to which emission from these sources could be beamed, these non-detections cannot be used to constrain the variety of theoretical models recently applied to explain the candidate GBM counterpart to GW150914.

  • 67.
    Ryde, Felix
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Axelsson, M.
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Zhang, B. B.
    McGlynn, S.
    Pe'er, A.
    Lundman, Christoffer
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Larsson, S.
    Battelino, Milan
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Zhang, B.
    Bissaldi, E.
    Bregeon, J.
    Briggs, M. S.
    Chiang, J.
    de Palma, F.
    Guiriec, S.
    Larsson, J.
    Longo, F.
    McBreen, S.
    Omodei, N.
    Petrosian, V.
    Preece, R.
    van der Horst, A. J.
    IDENTIFICATION AND PROPERTIES OF THE PHOTOSPHERIC EMISSION IN GRB090902B2010Inngår i: ASTROPHYSICAL JOURNAL LETTERS, ISSN 2041-8213, Vol. 709, nr 2, s. L172-L177Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The Fermi Gamma-ray Space Telescope observed the bright and long GRB090902B, lying at a redshift of z = 1.822. Together the Large Area Telescope (LAT) and the Gamma-ray Burst Monitor (GBM) cover the spectral range from 8 keV to >300 GeV. Here we show that the prompt burst spectrum is consistent with emission from the jet photosphere combined with nonthermal emission described by a single power law with photon index -1.9. The photosphere gives rise to a strong quasi-blackbody spectrum which is somewhat broader than a single Planck function and has a characteristic temperature of similar to 290 keV. We model the photospheric emission with a multicolor blackbody, and its shape indicates that the photospheric radius increases at higher latitudes. We derive the averaged photospheric radius R-ph = (1.1 +/- 0.3) x 10(12) Y-1/4 cm and the bulk Lorentz factor of the flow, which is found to vary by a factor of 2 and has a maximal value of Gamma = 750 Y-1/4. Here, Y is the ratio between the total fireball energy and the energy emitted in the gamma rays. We find that during the first quarter of the prompt phase the photospheric emission dominates, which explains the delayed onset of the observed flux in the LAT compared to the GBM. We interpret the broadband emission as synchrotron emission at R similar to 4 x 10(15) cm. Our analysis emphasizes the importance of having high temporal resolution when performing spectral analysis on gamma-ray bursts, since there is strong spectral evolution.

  • 68.
    Ryde, Felix
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik. The Oskar Klein Centre for Cosmoparticle Physics, Sweden.
    Pe'er, Asaf
    Harvard-Smithsonian Center for Astrophysics, United States.
    Nymark, Tanja
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik. The Oskar Klein Centre for Cosmoparticle Physics, Sweden.
    Axelsson, Magnus
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik. The Oskar Klein Centre for Cosmoparticle Physics, Sweden.
    Moretti, Elena
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik. The Oskar Klein Centre for Cosmoparticle Physics, Sweden.
    Lundman, Christoffer
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik. The Oskar Klein Centre for Cosmoparticle Physics, Sweden.
    Battelino, Milan
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik. The Oskar Klein Centre for Cosmoparticle Physics, Sweden.
    Bissaldi, Elisabetta
    Leopold-Franzens-Universität Innsbruck, Austria.
    Chiang, James
    Stanford University, United States.
    Jackson, Miranda S.
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik. The Oskar Klein Centre for Cosmoparticle Physics, Sweden.
    Larsson, Stefan
    Stockholm University, Sweden.
    Longo, Francesco
    Sezione di Trieste, Italy; Università di Trieste, Italy.
    McGlynn, Sinead
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik. Technische Universität München, Germany.
    Omodei, Nicola
    Stanford University, United States.
    Observational evidence of dissipative photospheres in gamma-ray bursts2011Inngår i: Monthly notices of the Royal Astronomical Society, ISSN 0035-8711, E-ISSN 1365-2966, Vol. 415, nr 4, s. 3693-3705Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The emission from a gamma-ray burst (GRB) photosphere can give rise to a variety of spectral shapes. The spectrum can retain the shape of a Planck function or it can be broadened and have the shape of a Band function. This fact is best illustrated by studying GRB090902B. The main gamma-ray spectral component is initially close to a Planck function, which can only be explained by emission from the jet photosphere. Later, the same component evolves into a broader Band function. This burst thus provides observational evidence that the photosphere can give rise to a non-thermal spectrum. We show that such a broadening is most naturally explained by subphotospheric dissipation in the jet. The broadening mainly depends on the strength and location of the dissipation, the magnetic field strength and the relation between the energy densities of thermal photons and electrons. We suggest that the evolution in spectral shape observed in GRB090902B is due to a decrease in the bulk Lorentz factor of the flow, leading to the main dissipation becoming subphotospheric. Such a change in the flow parameters can also explain the correlation observed between the peak energy of the spectrum and low-energy power-law slope, a, a correlation commonly observed in GRBs. We conclude that photospheric emission could indeed be a ubiquitous feature during the prompt phase in GRBs and play a decisive role in creating the diverse spectral shapes and spectral evolutions that are observed.

  • 69. Soffitta, Paolo
    et al.
    Barcons, Xavier
    Bellazzini, Ronaldo
    Braga, Joao
    Costa, Enrico
    Fraser, George W.
    Gburek, Szymon
    Huovelin, Juhani
    Matt, Giorgio
    Pearce, Mark
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Poutanen, Juri
    Reglero, Victor
    Santangelo, Andrea
    Sunyaev, Rashid A.
    Tagliaferri, Gianpiero
    Weisskopf, Martin
    Aloisio, Roberto
    Amato, Elena
    Attina, Primo
    Axelsson, Magnus
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Baldini, Luca
    Basso, Stefano
    Bianchi, Stefano
    Blasi, Pasquale
    Bregeon, Johan
    Brez, Alessandro
    Bucciantini, Niccolo
    Burderi, Luciano
    Burwitz, Vadim
    Casella, Piergiorgio
    Churazov, Eugene
    Civitani, Marta
    Covino, Stefano
    Curado da Silva, Rui Miguel
    Cusumano, Giancarlo
    Dadina, Mauro
    D'Amico, Flavio
    De Rosa, Alessandra
    Di Cosimo, Sergio
    Di Persio, Giuseppe
    Di Salvo, Tiziana
    Dovciak, Michal
    Elsner, Ronald
    Eyles, Chris J.
    Fabian, Andrew C.
    Fabiani, Sergio
    Feng, Hua
    Giarrusso, Salvatore
    Goosmann, Rene W.
    Grandi, Paola
    Grosso, Nicolas
    Israel, Gianluca
    Jackson, Miranda
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Kaaret, Philip
    Karas, Vladimir
    Kuss, Michael
    Lai, Dong
    La Rosa, Giovanni
    Larsson, Josefin
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Larsson, Stefan
    Latronico, Luca
    Maggio, Antonio
    Maia, Jorge
    Marin, Frederic
    Massai, Marco Maria
    Mineo, Teresa
    Minuti, Massimo
    Moretti, Elena
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Muleri, Fabio
    O'Dell, Stephen L.
    Pareschi, Giovanni
    Peres, Giovanni
    Pesce, Melissa
    Petrucci, Pierre-Olivier
    Pinchera, Michele
    Porquet, Delphine
    Ramsey, Brian
    Rea, Nanda
    Reale, Fabio
    Rodrigo, Juana Maria
    Rozanska, Agata
    Rubini, Alda
    Rudawy, Pawel
    Ryde, Felix
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Salvati, Marco
    de Santiago, Valdivino Alexandre, Jr.
    Sazonov, Sergey
    Sgro, Carmelo
    Silver, Eric
    Spandre, Gloria
    Spiga, Daniele
    Stella, Luigi
    Tamagawa, Toru
    Tamborra, Francesco
    Tavecchio, Fabrizio
    Dias, Teresa Teixeira
    van Adelsberg, Matthew
    Wu, Kinwah
    Zane, Silvia
    XIPE: the X-ray imaging polarimetry explorer2013Inngår i: Experimental astronomy (Print), ISSN 0922-6435, E-ISSN 1572-9508, Vol. 36, nr 3, s. 523-567Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    X-ray polarimetry, sometimes alone, and sometimes coupled to spectral and temporal variability measurements and to imaging, allows a wealth of physical phenomena in astrophysics to be studied. X-ray polarimetry investigates the acceleration process, for example, including those typical of magnetic reconnection in solar flares, but also emission in the strong magnetic fields of neutron stars and white dwarfs. It detects scattering in asymmetric structures such as accretion disks and columns, and in the so-called molecular torus and ionization cones. In addition, it allows fundamental physics in regimes of gravity and of magnetic field intensity not accessible to experiments on the Earth to be probed. Finally, models that describe fundamental interactions (e.g. quantum gravity and the extension of the Standard Model) can be tested. We describe in this paper the X-ray Imaging Polarimetry Explorer (XIPE), proposed in June 2012 to the first ESA call for a small mission with a launch in 2017. The proposal was, unfortunately, not selected. To be compliant with this schedule, we designed the payload mostly with existing items. The XIPE proposal takes advantage of the completed phase A of POLARIX for an ASI small mission program that was cancelled, but is different in many aspects: the detectors, the presence of a solar flare polarimeter and photometer and the use of a light platform derived by a mass production for a cluster of satellites. XIPE is composed of two out of the three existing JET-X telescopes with two Gas Pixel Detectors (GPD) filled with a He-DME mixture at their focus. Two additional GPDs filled with a 3-bar Ar-DME mixture always face the Sun to detect polarization from solar flares. The Minimum Detectable Polarization of a 1 mCrab source reaches 14 % in the 2-10 keV band in 10(5) s for pointed observations, and 0.6 % for an X10 class solar flare in the 15-35 keV energy band. The imaging capability is 24 arcsec Half Energy Width (HEW) in a Field of View of 14.7 arcmin x 14.7 arcmin. The spectral resolution is 20 % at 6 keV and the time resolution is 8 mu s. The imaging capabilities of the JET-X optics and of the GPD have been demonstrated by a recent calibration campaign at PANTER X-ray test facility of the Max-Planck-Institut fur extraterrestrische Physik (MPE, Germany). XIPE takes advantage of a low-earth equatorial orbit with Malindi as down-link station and of a Mission Operation Center (MOC) at INPE (Brazil). The data policy is organized with a Core Program that comprises three months of Science Verification Phase and 25 % of net observing time in the following 2 years. A competitive Guest Observer program covers the remaining 75 % of the net observing time.

  • 70. Sofitta, P
    et al.
    Pearce, Mark
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Axelsson, M.
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Chauvin, Maxime
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Burgess, Michael
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Kiss, Moszi
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Larsson, Josefin
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Ryde, Felix
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Xie, F
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Zoghbi, A.
    et al.,
    XIPE the X-ray Imaging Polarimetry Explorer2016Inngår i: Proceedings of SPIE, SPIE - International Society for Optical Engineering, 2016, Vol. 9905, artikkel-id UNSP 990515Konferansepaper (Fagfellevurdert)
    Abstract [en]

    XIPE, the X-ray Imaging Polarimetry Explorer, is a mission dedicated to X-ray Astronomy. At the time of writing XIPE is in a competitive phase A as fourth medium size mission of ESA (M4). It promises to reopen the polarimetry window in high energy Astrophysics after more than 4 decades thanks to a detector that efficiently exploits the photoelectric effect and to X-ray optics with large effective area. XIPE uniqueness is time-spectrally-spatially- resolved X-ray polarimetry as a breakthrough in high energy astrophysics and fundamental physics. Indeed the payload consists of three Gas Pixel Detectors at the focus of three X-ray optics with a total effective area larger than one XMM mirror but with a low weight. The payload is compatible with the fairing of the Vega launcher. XIPE is designed as an observatory for X- ray astronomers with 75% of the time dedicated to a Guest Observer competitive program and it is organized as a consortium across Europe with main contributions from Italy, Germany, Spain, United Kingdom, Poland, Sweden.

  • 71. Takahashi, H.
    et al.
    Matsuoka, M.
    Umeki, Y.
    Yoshida, H.
    Tanaka, T.
    Mizuno, T.
    Fukazawa, Y.
    Kamae, T.
    Madejski, G.
    Tajima, H.
    Kiss, Mózsi Bank
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Klamra, Wlodzimierz
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Larsson, Stefan
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Bettolo, Cecilia Marini
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Pearce, Mark
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Ryde, Felix
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Rydström, Stefan
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Kurita, K.
    Kanai, Y.
    Arimoto, M.
    Ueno, M.
    Kataoka, J.
    Kawai, N.
    Axelsson, Magnus
    Stockholm University.
    Hjalmarsdotter, L.
    Bogaert, G.
    Gunji, S.
    Katsuta, J.
    Takahashi, T.
    Varner, G.
    Yuasa, T.
    The Polarized Gamma-Ray Observer, PoGOLite2010Inngår i: Transactions of the Japanese Society for Artificial Intelligence, Aerospace Technology Japan, Vol. 8Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The Polarized Gamma-ray Observer, PoGOLite, is a balloon experiment with the capability of detecting 10% polarization from a 200 mCrab celestial object in the energy-range 25–80 keV. During a beam test at KEK-PF in 2008, 19 detector units and one anti-coincidence detector were assembled, and a 50 keV X-ray beam with a polarization degree of ∼90% was irradiated at the center unit. Signals from all 20 units were fed into flight-version electronics consisting of six circuit boards (four waveform digitizer boards, one digital I/O board and one router board) and one microprocessor (SpaceCube), which communicate using a SpaceWire interface. One digitizer board, which can associate up to 8 detectors, outputs a trigger signal. The digital I/O board handles the trigger and returns a data acquisition request if there is no veto signal (upper or pulse-shape discriminators) from any detector unit. This data acquisition system worked well, and the modulation factor was successfully measured to be ∼34%. These results confirmed the capabilities of the data-acquisition system for a “pathfinder” flight planned in 2010.

  • 72. Takahashi, H.
    et al.
    Matsuoka, M.
    Umeki, Y.
    Yoshida, H.
    Tanaka, T.
    Mizuno, T.
    Fukazawa, Y.
    Kamae, T.
    Madejski, G.
    Tajima, H.
    Kiss, Mózsi Bank
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Klamra, Wlodzimierz
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Larsson, Stefan
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Marini Bettolo, Cecilia
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Pearce, Mark
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Ryde, Felix
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Rydstrom, Stefan
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Kurita, K.
    Kanai, Y.
    Arimoto, M.
    Ueno, M.
    Kataoka, J.
    Kawai, N.
    Axelsson, M.
    Hjalmarsdotter, L.
    Bogaert, G.
    Gunji, S.
    Takahashi, T.
    Varner, G.
    Yuasa, T.
    Beam test results of the polarized gamma-ray observer, PoGOLite2008Inngår i: 2008 IEEE NUCLEAR SCIENCE SYMPOSIUM AND MEDICAL IMAGING CONFERENCE (2008 NSS/MIC), VOLS 1-9, 2008, s. 732-736Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The Polarized Gamma-ray Observer, PoGOLite, is a balloon experiment with the capability of detecting 10% polarization from a 200 mCrab celestial object in the energy range 25 #x2013;80 keV. During a beam test at KEK-PF in February 2008, 20 detector units were assembled, and a 50 keV X-ray beam with a polarization degree of #x223C;90% was irradiated at the center unit. Signals from all 20 units were fed into flightversion electronics consisting of six circuit boards (four waveform digitizer boards, one digital I/O board and one router board) and one microprocessor (SpaceCube), which communicate using a SpaceWire interface. One digitizer board, which can associate up to 8 PDCs, outputs a trigger signal. The digital I/O board handles the trigger and returns a data acquisition request if there is no veto signal (upper or pulse-shape discriminators) from any detector unit. This data acquisition system worked well, and the modulation factor was successfully measured to be #x223C;34%. These results confirmed the capabilities of both detector and data-acquisition system for a pathfinder flight planned in 2010.

  • 73. Takahashi, H.
    et al.
    Yonetani, M.
    Matsuoka, M.
    Mizuno, T.
    Fukazawa, Y.
    Yanagida, T.
    Fujimoto, Y.
    Yokota, Y.
    Yoshikawa, A.
    Kawaguchi, N.
    Ishizu, S.
    Fukuda, K.
    Suyama, T.
    Watanabe, K.
    Tajima, H.
    Kanai, Y.
    Kawai, N.
    Kataoka, J.
    Katsuta, J.
    Takahashi, T.
    Gunji, S.
    Axelsson, Magnus
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Jackson, Miranda
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Kiss, Mózsi Bank
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Klamra, Wlodzimierz
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Kole, Merlin
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Larsson, Stefan
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Mallol, Parera Pau
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Pearce, Mark
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Ryde, Felix
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Rydström, Stefan
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Olofsson, G.
    Floren, H.
    Kamae, T.
    Madejski, G.
    Varner, G.
    A thermal-neutron detector with a phoswich system of LiCaAlF6 and BGO crystal scintillators onboard PoGOLite2010Inngår i: 2010 IEEE Nuclear Science Symposium, Medical Imaging Conference, NSS/MIC 2010 and 17th International Workshop on Room-Temperature Semiconductor X-ray and Gamma-ray Detectors, RTSD 2010, 2010, s. 32-37Konferansepaper (Fagfellevurdert)
    Abstract [en]

    To measure the flux of atmospheric neutrons and study the neutron contribution to the background of the main detector of the PoGOLite (Polarized Gamma-ray Observer) balloon-borne experiment, a thermal-neutron detector with a phoswich system of LiCaAlF6 (Eu) and BGO crystal scintillators is developed. The performance to separate thermal-neutron events from those of gamma-rays and charged particles is validated with 252Cf on ground. The detector is attached to the PoGOLite instrument and is launched in 2011 from the Esrange facility in the North of Sweden. Although the emission wavelength of the LiCaAlF6 (Ce) is 300 nm and overlaps with the absorption wavelength of the BGO, the phoswich capability of the LiCaAlF6 (Ce) with the BGO is also confirmed with installing a waveform shifter.

  • 74. Tanaka, T.
    et al.
    Arimoto, M.
    Axelsson, Magnus
    Stockholm University.
    Bjornsson, C. -I
    Bogaert, G.
    Carlson, Per
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Cooney, M.
    Craig, W.
    Engdegård, Olle
    KTH, Skolan för teknikvetenskap (SCI), Fysik.
    Fukazawa, Y.
    Gunji, S.
    Hjalmarsdotter, L.
    Kamae, T.
    Kanai, Y.
    Kataoka, J.
    Katsuta, J.
    Kawai, N.
    Kazejev, Jaroslav
    KTH, Skolan för teknikvetenskap (SCI), Fysik.
    Kiss, Mozsi
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Klamra, Wlodzimierz
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Larsson, Stefan
    Madejski, G.
    Bettolo, Cecilia Marini
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Mizuno, T.
    Ng, J.
    Nomachi, M.
    Odaka, H.
    Pearce, Mark
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Ruckman, L.
    Ryde, F.
    Tajima, H.
    Takahashi, H.
    Takahashi, T.
    Thurston, T.
    Ueno, M.
    Varner, G.
    Ylinen, T.
    Yoshida, H.
    Yuasa, T.
    Data acquisition system for the PoGOLite astronomical hard X-ray polarimeter2007Inngår i: 2007 IEEE NUCLEAR SCIENCE SYMPOSIUM CONFERENCE RECORD, VOLS 1-11, 2007, Vol. 1, s. 445-449Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The PoGOLite is a new balloon-borne instrument to measure the polarization of hard X-rays / soft gamma-rays in the 25-80 keV energy range for the first time. In order to detect the polarization, PoGOLite measures the azimuthal angle asymmetry of Compton scattering and the subsequent photo- absorption in an array of detectors. This array consists of 217 well-type phoswich detector cells (PDCs) surrounded by a side anti-coincidence shield (SAS) composed of 54 segments of BGO crystals. At balloon altitude, the intensity of backgrounds due to cosmic-ray charged particles, atmospheric gamma-rays and neutrons is extremely high, typically a few hundred Hz per unit. Hence the data acquisition (DAQ) system of PoGOLite is required to handle more than 270 signals simultaneously, and detect weak signals from astrophysical objects (lOOmCrab, 1.5 cs-1 in 25-80 keV ) under such a severe environment. We have developed a new DAQ system consisting of front-end electronics, waveform digitizer, field programmable gate array (FPGA) and a microprocessor. In this system, all output signals of PDC / SAS are fed into individual charge-sensitive amplifier and then digitized to 12 bit accuracy at 24MSa/s by pipelined analog to digital converters. A DAQ board for the PDC records waveforms which will be examined in an off-line analysis to distinguish signals from the background events and measure the energy spectrum and polarization of targets. A board for the SAS records hit pattern to be used for background rejection. It also continuously records a pulse-height analysis (PHA) histogram to monitor incident background flux. These basic functions of the DAQ system were verified in a series of beam tests.

  • 75.
    Veres, P.
    et al.
    Univ Alabama, Ctr Space Plasma & Aeron Res, Huntsville, AL 35899 USA..
    Acciari, V. A.
    Univ La Laguna, Inst Astrofis Canarias, San Cristobal la Laguna, Spain.;Univ La Laguna, Dept Astrofis, San Cristobal la Laguna, Spain..
    Ansoldi, S.
    Chinese Acad Sci, Natl Astron Observ, CAS Key Lab Space Astron & Technol, Beijing 100012, Peoples R China.;Kyoto Univ, Dept Phys, Japanese MAGIC Consortium, Kyoto, Japan..
    Antonelli, L. A.
    Natl Inst Astrophys INAF, Rome, Italy..
    Engels, A. Arbet
    Swiss Fed Inst Technol, Zurich, Switzerland..
    Baack, D.
    Tech Univ Dortmund, Dortmund, Germany..
    Babic, A.
    Univ Zagreb, Croatian Consortium, FER, Zagreb, Croatia..
    Banerjee, B.
    HBNI, Saha Inst Nucl Phys, Kolkata, India..
    de Almeida, U. Barres
    CBPF, Rio De Janeiro, Brazil..
    Barrio, J. A.
    Univ Complutense Madrid, IPARCOS Inst, Madrid, Spain.;Univ Complutense Madrid, EMFTEL Dept, Madrid, Spain..
    Gonzalez, J. Becerra
    Univ La Laguna, Inst Astrofis Canarias, San Cristobal la Laguna, Spain.;Univ La Laguna, Dept Astrofis, San Cristobal la Laguna, Spain..
    Bednarek, W.
    Univ Lodz, Dept Astrophys, Lodz, Poland..
    Bellizzi, L.
    Univ Complutense Madrid, IPARCOS Inst, Madrid, Spain.;Univ Complutense Madrid, EMFTEL Dept, Madrid, Spain..
    Bernardini, E.
    Deutsches Elektronen Synchrotron DESY, Zeuthen, Germany.;Univ Padua, Padua, Italy.;INFN, Padua, Italy..
    Berti, A.
    Ist Nazl Fis Nucl, Frascati, Italy..
    Besenrieder, J.
    Max Planck Inst Phys & Astrophys, Munich, Germany..
    Bhattacharyya, W.
    Deutsches Elektronen Synchrotron DESY, Zeuthen, Germany..
    Bigongiari, C.
    Natl Inst Astrophys INAF, Rome, Italy..
    Biland, A.
    Swiss Fed Inst Technol, Zurich, Switzerland..
    Blanch, O.
    BIST, IFAE, Barcelona, Spain..
    Bonnoli, G.
    Univ Complutense Madrid, IPARCOS Inst, Madrid, Spain.;Univ Complutense Madrid, EMFTEL Dept, Madrid, Spain..
    Bosnjak, Z.
    Univ Zagreb, Croatian Consortium, FER, Zagreb, Croatia..
    Busetto, G.
    Univ Padua, Padua, Italy.;INFN, Padua, Italy..
    Carosi, R.
    Univ Pisa, Pisa, Italy.;INFN Pisa, Pisa, Italy. A Alikhanyan Natl Lab, Armenian Consortium, Yerevan, Armenia..
    Ceribella, G.
    Max Planck Inst Phys & Astrophys, Munich, Germany..
    Chai, Y.
    Max Planck Inst Phys & Astrophys, Munich, Germany..
    Chilingaryan, A.
    Ctr Invest Energet Medioambientales & Tecnol, Madrid, Spain..
    Cikota, S.
    Univ Zagreb, Croatian Consortium, FER, Zagreb, Croatia..
    Colak, S. M.
    BIST, IFAE, Barcelona, Spain..
    Colin, U.
    Max Planck Inst Phys & Astrophys, Munich, Germany..
    Colombo, E.
    Univ Alabama, Ctr Space Plasma & Aeron Res, Huntsville, AL 35899 USA..
    Contreras, J. L.
    Univ Complutense Madrid, IPARCOS Inst, Madrid, Spain.;Univ Complutense Madrid, EMFTEL Dept, Madrid, Spain..
    Cortina, J.
    Ctr Invest Energet Medioambientales & Tecnol, Madrid, Spain..
    Covino, S.
    Natl Inst Astrophys INAF, Rome, Italy..
    D'Elia, V.
    Natl Inst Astrophys INAF, Rome, Italy..
    Da Vela, P.
    Univ Pisa, Pisa, Italy.;INFN Pisa, Pisa, Italy. A Alikhanyan Natl Lab, Armenian Consortium, Yerevan, Armenia..
    Dazzi, F.
    Natl Inst Astrophys INAF, Rome, Italy..
    De Angelis, A.
    Univ Padua, Padua, Italy.;INFN, Padua, Italy..
    De Lotto, B.
    Chinese Acad Sci, Natl Astron Observ, CAS Key Lab Space Astron & Technol, Beijing 100012, Peoples R China..
    Delfino, M.
    BIST, IFAE, Barcelona, Spain.;PIC, Barcelona, Spain..
    Delgado, J.
    BIST, IFAE, Barcelona, Spain.;PIC, Barcelona, Spain..
    Depaoli, D.
    Ist Nazl Fis Nucl, Frascati, Italy..
    Di Pierro, F.
    Ist Nazl Fis Nucl, Frascati, Italy..
    Di Venere, L.
    Ist Nazl Fis Nucl, Frascati, Italy..
    Espineira, E. Do Souto
    Univ Rijeka, Dept Phys, Croatian Consortium, Rijeka, Croatia..
    Prester, D. Dominis
    Ctr Invest Energet Medioambientales & Tecnol, Madrid, Spain..
    Donini, A.
    Chinese Acad Sci, Natl Astron Observ, CAS Key Lab Space Astron & Technol, Beijing 100012, Peoples R China..
    Dorner, D.
    Univ Wurzburg, Wurzburg, Germany..
    Doro, M.
    Univ Padua, Padua, Italy.;INFN, Padua, Italy..
    Elsaesser, D.
    Tech Univ Dortmund, Dortmund, Germany..
    Ramazani, V. Fallah
    Univ Turku, Finnish Ctr Astron ESO FINCA, Finnish MAGIC Consortium, Turku, Finland..
    Fattorini, A.
    Tech Univ Dortmund, Dortmund, Germany..
    Ferrara, G.
    Natl Inst Astrophys INAF, Rome, Italy..
    Fidalgo, D.
    Univ Complutense Madrid, IPARCOS Inst, Madrid, Spain.;Univ Complutense Madrid, EMFTEL Dept, Madrid, Spain..
    Foffano, L.
    Univ Padua, Padua, Italy.;INFN, Padua, Italy..
    Fonseca, M. V.
    Univ Complutense Madrid, IPARCOS Inst, Madrid, Spain.;Univ Complutense Madrid, EMFTEL Dept, Madrid, Spain..
    Font, L.
    Univ Autonoma Barcelona, Dept Fis, Bellaterra, Spain.;Univ Autonoma Barcelona, CERES IEEC, Bellaterra, Spain..
    Fruck, C.
    Max Planck Inst Phys & Astrophys, Munich, Germany..
    Fukami, S.
    Univ Tokyo, ICRR, Japanese MAGIC Consortium, Kashiwa, Chiba, Japan..
    Lopez, R. J. Garcia
    Univ Alabama, Ctr Space Plasma & Aeron Res, Huntsville, AL 35899 USA..
    Garczarczyk, M.
    Deutsches Elektronen Synchrotron DESY, Zeuthen, Germany..
    Gasparyan, S.
    NAS RA, ICRANet Armenia, Armenian Consortium, Yerevan, Armenia..
    Gaug, M.
    Univ Autonoma Barcelona, Dept Fis, Bellaterra, Spain.;Univ Autonoma Barcelona, CERES IEEC, Bellaterra, Spain..
    Giglietto, N.
    Ist Nazl Fis Nucl, Frascati, Italy..
    Giordano, F.
    Ist Nazl Fis Nucl, Frascati, Italy..
    Godinovic, N.
    Univ Split, Croatian Consortium, FESB, Split, Croatia..
    Green, D.
    Max Planck Inst Phys & Astrophys, Munich, Germany..
    Guberman, D.
    BIST, IFAE, Barcelona, Spain..
    Hadasch, D.
    Univ Tokyo, ICRR, Japanese MAGIC Consortium, Kashiwa, Chiba, Japan..
    Hahn, A.
    Max Planck Inst Phys & Astrophys, Munich, Germany..
    Herrera, J.
    Univ Alabama, Ctr Space Plasma & Aeron Res, Huntsville, AL 35899 USA..
    Hoang, J.
    Univ Complutense Madrid, IPARCOS Inst, Madrid, Spain.;Univ Complutense Madrid, EMFTEL Dept, Madrid, Spain..
    Hrupec, D.
    Josip Juraj Strossmayer Univ Osijek, Croatian Consortium, Osijek, Croatia..
    Hutten, M.
    Max Planck Inst Phys & Astrophys, Munich, Germany..
    Inada, T.
    Univ Tokyo, ICRR, Japanese MAGIC Consortium, Kashiwa, Chiba, Japan..
    Inoue, S.
    RIKEN, Japanese MAGIC Consortium, Wako, Saitama, Japan..
    Ishio, K.
    Max Planck Inst Phys & Astrophys, Munich, Germany..
    Iwamura, Y.
    Univ Tokyo, ICRR, Japanese MAGIC Consortium, Kashiwa, Chiba, Japan..
    Jouvin, L.
    BIST, IFAE, Barcelona, Spain..
    Kerszberg, D.
    BIST, IFAE, Barcelona, Spain..
    Kubo, H.
    Kyoto Univ, Dept Phys, Japanese MAGIC Consortium, Kyoto, Japan..
    Kushida, J.
    Tokai Univ, Japanese MAGIC Consortium, Hiratsuka, Kanagawa, Japan..
    Lamastra, A.
    Natl Inst Astrophys INAF, Rome, Italy..
    Lelas, D.
    Univ Split, Croatian Consortium, FESB, Split, Croatia..
    Leone, F.
    Natl Inst Astrophys INAF, Rome, Italy..
    Lindfors, E.
    Univ Turku, Finnish Ctr Astron ESO FINCA, Finnish MAGIC Consortium, Turku, Finland..
    Lombardi, S.
    Natl Inst Astrophys INAF, Rome, Italy..
    Longo, F.
    Univ Udine, Udine, Italy.;INFN Trieste, Udine, Italy.;Univ Trieste, Dipartimento Fis, Trieste, Italy.;IFPU, Trieste, Italy..
    Lopez, M.
    Univ Complutense Madrid, IPARCOS Inst, Madrid, Spain.;Univ Complutense Madrid, EMFTEL Dept, Madrid, Spain..
    Lopez-Coto, R.
    Univ Padua, Padua, Italy.;INFN, Padua, Italy..
    Lopez-Oramas, A.
    Univ Alabama, Ctr Space Plasma & Aeron Res, Huntsville, AL 35899 USA..
    Loporchio, S.
    Ist Nazl Fis Nucl, Frascati, Italy..
    Fraga, B. Machado de Oliveira
    CBPF, Rio De Janeiro, Brazil..
    Maggio, C.
    Univ Autonoma Barcelona, Dept Fis, Bellaterra, Spain.;Univ Autonoma Barcelona, CERES IEEC, Bellaterra, Spain..
    Majumdar, P.
    HBNI, Saha Inst Nucl Phys, Kolkata, India..
    Makariev, M.
    Bulgarian Acad Sci, Inst Nucl Res & Nucl Energy, Sofia, Bulgaria..
    Mallamaci, M.
    Univ Padua, Padua, Italy.;INFN, Padua, Italy..
    Maneva, G.
    Bulgarian Acad Sci, Inst Nucl Res & Nucl Energy, Sofia, Bulgaria..
    Manganaro, M.
    Univ Rijeka, Dept Phys, Croatian Consortium, Rijeka, Croatia..
    Mannheim, K.
    Univ Wurzburg, Wurzburg, Germany..
    Maraschi, L.
    Natl Inst Astrophys INAF, Rome, Italy..
    Mariotti, M.
    Univ Padua, Padua, Italy.;INFN, Padua, Italy..
    Martinez, M.
    BIST, IFAE, Barcelona, Spain..
    Mazin, D.
    Max Planck Inst Phys & Astrophys, Munich, Germany.;Univ Tokyo, ICRR, Japanese MAGIC Consortium, Kashiwa, Chiba, Japan..
    Micanovic, S.
    Univ Rijeka, Dept Phys, Croatian Consortium, Rijeka, Croatia..
    Miceli, D.
    Univ Udine, Udine, Italy.;INFN Trieste, Udine, Italy..
    Minev, M.
    Bulgarian Acad Sci, Inst Nucl Res & Nucl Energy, Sofia, Bulgaria..
    Miranda, J. M.
    Univ Siena, Siena, Italy.;INFN Pisa, Siena, Italy..
    Mirzoyan, R.
    Max Planck Inst Phys & Astrophys, Munich, Germany..
    Molina, E.
    Univ Barcelona, ICCUB, IEEC UB, Barcelona, Spain..
    Moralejo, A.
    BIST, IFAE, Barcelona, Spain..
    Morcuende, D.
    Univ Complutense Madrid, IPARCOS Inst, Madrid, Spain.;Univ Complutense Madrid, EMFTEL Dept, Madrid, Spain..
    Moreno, V.
    Univ Autonoma Barcelona, Dept Fis, Bellaterra, Spain.;Univ Autonoma Barcelona, CERES IEEC, Bellaterra, Spain..
    Moretti, E.
    BIST, IFAE, Barcelona, Spain..
    Munar-Adrover, P.
    Univ Autonoma Barcelona, Dept Fis, Bellaterra, Spain.;Univ Autonoma Barcelona, CERES IEEC, Bellaterra, Spain..
    Neustroev, V.
    Univ Oulu, Astron Res Unit, Finnish MAGIC Consortium, Oulu, Finland..
    Nigro, C.
    Deutsches Elektronen Synchrotron DESY, Zeuthen, Germany..
    Nilsson, K.
    Univ Turku, Finnish Ctr Astron ESO FINCA, Finnish MAGIC Consortium, Turku, Finland..
    Ninci, D.
    BIST, IFAE, Barcelona, Spain..
    Nishijima, K.
    Tokai Univ, Japanese MAGIC Consortium, Hiratsuka, Kanagawa, Japan..
    Noda, K.
    Univ Tokyo, ICRR, Japanese MAGIC Consortium, Kashiwa, Chiba, Japan..
    Nogues, L.
    BIST, IFAE, Barcelona, Spain..
    Nozaki, S.
    Kyoto Univ, Dept Phys, Japanese MAGIC Consortium, Kyoto, Japan..
    Paiano, S.
    Univ Padua, Padua, Italy.;INFN, Padua, Italy..
    Palatiello, M.
    Chinese Acad Sci, Natl Astron Observ, CAS Key Lab Space Astron & Technol, Beijing 100012, Peoples R China..
    Paneque, D.
    Max Planck Inst Phys & Astrophys, Munich, Germany..
    Paoletti, R.
    Univ Complutense Madrid, IPARCOS Inst, Madrid, Spain.;Univ Complutense Madrid, EMFTEL Dept, Madrid, Spain..
    Paredes, J. M.
    Univ Barcelona, ICCUB, IEEC UB, Barcelona, Spain..
    Penil, P.
    Univ Complutense Madrid, IPARCOS Inst, Madrid, Spain.;Univ Complutense Madrid, EMFTEL Dept, Madrid, Spain..
    Peresano, M.
    Chinese Acad Sci, Natl Astron Observ, CAS Key Lab Space Astron & Technol, Beijing 100012, Peoples R China..
    Persic, M.
    Chinese Acad Sci, Natl Astron Observ, CAS Key Lab Space Astron & Technol, Beijing 100012, Peoples R China..
    Moroni, P. G. Prada
    Univ Pisa, Pisa, Italy.;INFN Pisa, Pisa, Italy. A Alikhanyan Natl Lab, Armenian Consortium, Yerevan, Armenia..
    Prandini, E.
    Univ Padua, Padua, Italy.;INFN, Padua, Italy..
    Puljak, I.
    Univ Split, Croatian Consortium, FESB, Split, Croatia..
    Rhode, W.
    Tech Univ Dortmund, Dortmund, Germany..
    Ribo, M.
    Univ Barcelona, ICCUB, IEEC UB, Barcelona, Spain..
    Rico, J.
    BIST, IFAE, Barcelona, Spain..
    Righi, C.
    Natl Inst Astrophys INAF, Rome, Italy..
    Rugliancich, A.
    Univ Pisa, Pisa, Italy.;INFN Pisa, Pisa, Italy. A Alikhanyan Natl Lab, Armenian Consortium, Yerevan, Armenia..
    Saha, L.
    Univ Complutense Madrid, IPARCOS Inst, Madrid, Spain.;Univ Complutense Madrid, EMFTEL Dept, Madrid, Spain..
    Sahakyan, N.
    NAS RA, ICRANet Armenia, Armenian Consortium, Yerevan, Armenia..
    Saito, T.
    Univ Tokyo, ICRR, Japanese MAGIC Consortium, Kashiwa, Chiba, Japan..
    Sakurai, S.
    Univ Tokyo, ICRR, Japanese MAGIC Consortium, Kashiwa, Chiba, Japan..
    Satalecka, K.
    Deutsches Elektronen Synchrotron DESY, Zeuthen, Germany..
    Schmidt, K.
    Tech Univ Dortmund, Dortmund, Germany..
    Schweizer, T.
    Max Planck Inst Phys & Astrophys, Munich, Germany..
    Sitarek, J.
    Univ Lodz, Dept Astrophys, Lodz, Poland..
    Snidaric, I.
    Rudjer Boskovic Inst, Croatian Consortium, Zagreb, Croatia..
    Sobczynska, D.
    Univ Lodz, Dept Astrophys, Lodz, Poland..
    Somero, A.
    Univ Alabama, Ctr Space Plasma & Aeron Res, Huntsville, AL 35899 USA..
    Stamerra, A.
    NASA, Astrophys Branch, ST12, Marshall Space Flight Ctr, Huntsville, AL USA..
    Strom, D.
    Max Planck Inst Phys & Astrophys, Munich, Germany..
    Strzys, M.
    Max Planck Inst Phys & Astrophys, Munich, Germany..
    Suda, Y.
    Max Planck Inst Phys & Astrophys, Munich, Germany..
    Suric, T.
    Rudjer Boskovic Inst, Croatian Consortium, Zagreb, Croatia..
    Takahashi, M.
    Univ Tokyo, ICRR, Japanese MAGIC Consortium, Kashiwa, Chiba, Japan..
    Tavecchio, F.
    NASA, Astrophys Branch, ST12, Marshall Space Flight Ctr, Huntsville, AL USA..
    Temnikov, P.
    Bulgarian Acad Sci, Inst Nucl Res & Nucl Energy, Sofia, Bulgaria..
    Terzic, T.
    Ctr Invest Energet Medioambientales & Tecnol, Madrid, Spain.;Rudjer Boskovic Inst, Croatian Consortium, Zagreb, Croatia..
    Teshima, M.
    Max Planck Inst Phys & Astrophys, Munich, Germany.;Univ Tokyo, ICRR, Japanese MAGIC Consortium, Kashiwa, Chiba, Japan..
    Torres-Alba, N.
    Univ Barcelona, ICCUB, IEEC UB, Barcelona, Spain..
    Tosti, L.
    Ist Nazl Fis Nucl, Frascati, Italy..
    Vagelli, V.
    Ist Nazl Fis Nucl, Frascati, Italy..
    van Scherpenberg, J.
    Max Planck Inst Phys & Astrophys, Munich, Germany..
    Vanzo, G.
    Univ Alabama, Ctr Space Plasma & Aeron Res, Huntsville, AL 35899 USA..
    Acosta, M. Vazquez
    Univ Alabama, Ctr Space Plasma & Aeron Res, Huntsville, AL 35899 USA..
    Vigorito, C. F.
    Ist Nazl Fis Nucl, Frascati, Italy..
    Vitale, V.
    Ist Nazl Fis Nucl, Frascati, Italy..
    Vovk, I.
    Max Planck Inst Phys & Astrophys, Munich, Germany..
    Will, M.
    Max Planck Inst Phys & Astrophys, Munich, Germany..
    Zaric, D.
    Univ Split, Croatian Consortium, FESB, Split, Croatia..
    Nava, L.
    NASA, Astrophys Branch, ST12, Marshall Space Flight Ctr, Huntsville, AL USA.;Ist Nazl Fis Nucl, Trieste, Italy.;IFPU, Trieste, Italy..
    Bhat, P. N.
    Univ Alabama, Ctr Space Plasma & Aeron Res, Huntsville, AL 35899 USA.;Univ Alabama, Space Sci Dept, Huntsville, AL 35899 USA..
    Briggs, M. S.
    Univ Alabama, Ctr Space Plasma & Aeron Res, Huntsville, AL 35899 USA.;Univ Alabama, Space Sci Dept, Huntsville, AL 35899 USA..
    Cleveland, W. H.
    Univ Space Res Assoc, Sci & Technol Inst, Huntsville, AL USA..
    Hamburg, R.
    Univ Alabama, Ctr Space Plasma & Aeron Res, Huntsville, AL 35899 USA.;Univ Alabama, Space Sci Dept, Huntsville, AL 35899 USA..
    Hui, C. M.
    NASA, Astrophys Branch, ST12, Marshall Space Flight Ctr, Huntsville, AL USA..
    Mailyan, B.
    Univ Alabama, Ctr Space Plasma & Aeron Res, Huntsville, AL 35899 USA..
    Preece, R. D.
    Univ Alabama, Ctr Space Plasma & Aeron Res, Huntsville, AL 35899 USA.;Univ Alabama, Space Sci Dept, Huntsville, AL 35899 USA..
    Roberts, O. J.
    Univ Space Res Assoc, Sci & Technol Inst, Huntsville, AL USA..
    von Kienlin, A.
    Max Planck Inst Extraterr Phys, Garching, Germany. Kanazawa Univ, Inst Sci & Engn, Fac Math & Phys, Kanazawa, Ishikawa, Japan..
    Wilson-Hodge, C. A.
    NASA, Astrophys Branch, ST12, Marshall Space Flight Ctr, Huntsville, AL USA..
    Kocevski, D.
    NASA, Astrophys Branch, ST12, Marshall Space Flight Ctr, Huntsville, AL USA..
    Arimoto, M.
    Max Planck Inst Extraterr Phys, Garching, Germany. Kanazawa Univ, Inst Sci & Engn, Fac Math & Phys, Kanazawa, Ishikawa, Japan..
    Tak, D.
    Univ Maryland, Dept Phys, College Pk, MD 20742 USA.;NASA, Astrophys Sci Div, Goddard Space Flight Ctr, Greenbelt, MD USA..
    Asano, K.
    Univ Tokyo, Inst Cosm Ray Res, Kashiwa, Chiba, Japan..
    Axelsson, Magnus
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik. Stockholm Univ, Dept Phys, Stockholm, Sweden..
    Barbiellini, G.
    Ist Nazl Fis Nucl, Trieste, Italy..
    Bissaldi, E.
    Univ Politecn Bari, Dipartimento Fis M Merlin, Bari, Italy.;Ist Nazl Fis Nucl, Sez Bari, Bari, Italy..
    Dirirsa, F. Fana
    Univ Johannesburg, Dept Phys, Auckland Pk, South Africa..
    Gill, R.
    Open Univ Israel, Dept Nat Sci, Raanana, Israel..
    Granot, J.
    Open Univ Israel, Dept Nat Sci, Raanana, Israel..
    McEnery, J.
    Univ Maryland, Dept Phys, College Pk, MD 20742 USA.;NASA, Astrophys Sci Div, Goddard Space Flight Ctr, Greenbelt, MD USA..
    Omodei, N.
    Kavli Inst Particle Astrophys & Cosmol, Dept Phys, WW Hansen Expt Phys Lab, Stanford, CA USA.;Stanford Univ, LAC Natl Accelerator Lab, Stanford, CA 94305 USA..
    Razzaque, S.
    Univ Johannesburg, Dept Phys, Auckland Pk, South Africa..
    Piron, F.
    Univ Montpellier, CNRS, IN2P3, Lab Univers & Particules Montpellier, Montpellier, France..
    Racusin, J. L.
    NASA, Astrophys Sci Div, Goddard Space Flight Ctr, Greenbelt, MD USA..
    Thompson, D. J.
    NASA, Astrophys Sci Div, Goddard Space Flight Ctr, Greenbelt, MD USA..
    Campana, S.
    INAF, Astron Observ Brera, Merate, Italy..
    Bernardini, M. G.
    INAF, Astron Observ Brera, Merate, Italy..
    Kuin, N. P. M.
    Univ Coll London, Mullard Space Sci Lab, Dorking, Surrey, England..
    Siegel, M. H.
    Penn State Univ, Dept Astron & Astrophys, 525 Davey Lab, University Pk, PA 16802 USA..
    Cenko, B.
    NASA, Astrophys Sci Div, Goddard Space Flight Ctr, Greenbelt, MD USA.;Univ Maryland, Joint Space Sci Inst, College Pk, MD 20742 USA..
    O'Brien, P.
    Univ Leicester, Dept Phys & Astron, Leicester, Leics, England..
    Capalbi, M.
    INAF, Ist Astrofis Spaziale & Fis Cosm Palermo, Palermo, Italy..
    Dai, A.
    INAF, Ist Astrofis Spaziale & Fis Cosm Palermo, Palermo, Italy..
    De Pasquale, M.
    Istanbul Univ, Dept Astron & Space Sci, Istanbul, Turkey..
    Gropp, J.
    Penn State Univ, Dept Astron & Astrophys, 525 Davey Lab, University Pk, PA 16802 USA..
    Klingler, N.
    Penn State Univ, Dept Astron & Astrophys, 525 Davey Lab, University Pk, PA 16802 USA..
    Osborne, P.
    Univ Leicester, Dept Phys & Astron, Leicester, Leics, England..
    Perri, M.
    INAF, Osservatorio Astron Roma, Rome, Italy.;ASI, SSDC, Rome, Italy..
    Starling, R. L. C.
    ASI, SSDC, Rome, Italy..
    Tagliaferri, G.
    ASI, SSDC, Rome, Italy..
    Tohuvavohu, A.
    Curtin Univ, Int Ctr Radio Astron Res, Perth, WA, Australia..
    Ursi, A.
    European Southern Observ, Santiago, Chile..
    Tavani, M.
    INAF IAPS, Rome, Italy.;Univ Tor Vergata, Rome, Italy.;Gran Sasso Sci Inst, Laquila, Italy..
    Cardillo, M.
    INAF IAPS, Rome, Italy..
    Casentini, C.
    INAF IAPS, Rome, Italy..
    Piano, G.
    INAF IAPS, Rome, Italy..
    Evangelista, Y.
    INAF IAPS, Rome, Italy..
    Verrecchia, F.
    INAF, Osservatorio Astron Roma, Rome, Italy.;ASI, SSDC, Rome, Italy..
    Pittori, C.
    INAF, Osservatorio Astron Roma, Rome, Italy.;ASI, SSDC, Rome, Italy..
    Lucarelli, F.
    INAF, Osservatorio Astron Roma, Rome, Italy.;ASI, SSDC, Rome, Italy..
    Bulgarelli, A.
    ASI, SSDC, Rome, Italy..
    Parmiggiani, N.
    Anderson, G. E.
    Curtin Univ, Int Ctr Radio Astron Res, Perth, WA, Australia..
    Anderson, J. P.
    European Southern Observ, Santiago, Chile..
    Bernardi, G.
    INAF Ist Radioastron, Bologna, Italy.;Rhodes Univ, Dept Phys & Elect, Grahamstown, South Africa.;South African Radio Astron Observ, Cape Town, South Africa..
    Bolmer, J.
    Max Planck Inst Extraterr Phys, Garching, Germany. Kanazawa Univ, Inst Sci & Engn, Fac Math & Phys, Kanazawa, Ishikawa, Japan..
    Caballero-Garcia, M. D.
    Astron Inst Acad Sci, Prague, Czech Republic..
    Carrasco, I. M.
    Univ Malaga, Fac Ciencias, Dept Fis Aplicada, Malaga, Spain..
    Castellon, A.
    Univ Malaga, Fac Ciencias, Dept Algebra Geometria & Topol, Malaga, Spain..
    Segura, N. Castro
    Univ Southampton, Phys & Astron Dept, Southampton, Hants, England..
    Castro-Tirado, A. J.
    Univ Malaga, Dept Ingn Sistemas & Automat ETS Ingenieros Ind, Unidad Asociada CSIC, Malaga, Spain.;CSIC, IAA, Granada, Spain..
    Cherukuri, S. V.
    Indian Inst Space Sci & Technol, Trivandrum, Kerala, India..
    Cockeram, A. M.
    Liverpool John Moores Univ, Astrophys Res Inst, Liverpool, Merseyside, England..
    D'Avanzo, P.
    INAF, Astron Observ Brera, Merate, Italy..
    Di Dato, A.
    Osservatorio Astron S Di Giacomo Astrocampania, Agerola, Italy.;INAF Astron Observ Naples, Naples, Italy..
    Diretse, R.
    Univ Cape Town, Dept Astron, Interuniv Inst Data Intens Astron, Rondebosch, South Africa..
    Fender, R. P.
    Univ Oxford, Dept Phys, Keble Rd, Oxford, England..
    Fernandez-Garcia, E.
    CSIC, IAA, Granada, Spain..
    Fynbo, J. P. U.
    Cosm Dawn Ctr DAWN, Copenhagen, Denmark.;Univ Copenhagen, Niels Bohr Inst, Copenhagen, Denmark..
    Fruchter, A. S.
    Space Telescope Sci Inst, 3700 San Martin Dr, Baltimore, MD 21218 USA..
    Greiner, J.
    Max Planck Inst Extraterr Phys, Garching, Germany. Kanazawa Univ, Inst Sci & Engn, Fac Math & Phys, Kanazawa, Ishikawa, Japan..
    Gromadzki, M.
    Univ Warsaw, Astron Observ, Warsaw, Poland..
    Heintz, K. E.
    Univ Iceland, Sci Inst, Ctr Astrophys & Cosmol, Reykjavik, Iceland..
    Heywood, I.
    Rhodes Univ, Dept Phys & Elect, Grahamstown, South Africa.;Univ Oxford, Dept Phys, Keble Rd, Oxford, England..
    van der Horst, A. J.
    George Washington Univ, Dept Phys, Washington, DC 20052 USA.;George Washington Univ, APSIS, Washington, DC USA..
    Hu, Y. -D
    Inserra, C.
    Cardiff Univ, Sch Phys & Astron, Cardiff, S Glam, Wales..
    Izzo, L.
    CSIC, IAA, Granada, Spain.;Univ Copenhagen, Niels Bohr Inst, DARK, Copenhagen, Denmark..
    Jaiswal, V.
    Indian Inst Space Sci & Technol, Trivandrum, Kerala, India..
    Jakobsson, P.
    Univ Iceland, Sci Inst, Ctr Astrophys & Cosmol, Reykjavik, Iceland..
    Japelj, J.
    Univ Amsterdam, Anton Pannekoek Inst Astron, Amsterdam, Netherlands..
    Kankare, E.
    Univ Turku, Dept Phys & Astron, Tuorla Observ, Turku, Finland..
    Kann, D. A.
    CSIC, IAA, Granada, Spain..
    Kouveliotou, C.
    George Washington Univ, Dept Phys, Washington, DC 20052 USA.;George Washington Univ, APSIS, Washington, DC USA..
    Klose, S.
    Thuringer Landessternwarte Tautenburg, Tautenburg, Germany..
    Levan, A. J.
    Radboud Univ Nijmegen, Dept Astrophys, IMAPP, Nijmegen, Netherlands..
    Li, X. Y.
    UMA, CSIC, Inst Hortofruticultura Subtrop & Mediterrane La M, Malaga, Spain.;Chinese Acad Sci, Natl Observ, Nanjing Inst Astron Optic & Technol, Nanjing, Jiangsu, Peoples R China..
    Lotti, S.
    INAF IAPS, Rome, Italy..
    Maguire, K.
    Trinity Coll Dublin, Sch Phys, Dublin, Ireland..
    Malesani, D. B.
    Cosm Dawn Ctr DAWN, Copenhagen, Denmark.;Univ Copenhagen, Niels Bohr Inst, Copenhagen, Denmark.;Univ Copenhagen, Niels Bohr Inst, DARK, Copenhagen, Denmark.;Tech Univ Denmark, Natl Space Inst, DTU Space, Lyngby, Denmark..
    Manulis, I.
    Weizmann Inst Sci, Benoziyo Ctr Astrophys, Rehovot, Israel..
    Marongiu, M.
    Univ Ferrara, Dept Phys & Earth Sci, Ferrara, Italy.;Int Ctr Relativist Astrophys Network ICRANet, Pescara, Italy..
    Martin, S.
    European Southern Observ, Santiago, Chile.;Joint ALMA Observ, Santiago, Chile..
    Melandri, A.
    INAF, Astron Observ Brera, Merate, Italy..
    Michalowski, M. J.
    Adam Mickiewicz Univ, Fac Phys, Astron Observ Inst, Poznan, Poland..
    Miller-Jones, J. C. A.
    Curtin Univ, Int Ctr Radio Astron Res, Perth, WA, Australia..
    Misra, K.
    Aryabhatta Res Inst Observat Sci, Naini Tal, India.;Univ Calif Davis, Dept Phys, Davis, CA 95616 USA..
    Moin, A.
    United Arab Emirates Univ, Phys Dept, Al Ain, U Arab Emirates..
    Mooley, K. P.
    Natl Radio Astron Observ, Socorro, NM 87801 USA.;CALTECH, Pasadena, CA 91125 USA..
    Nasri, S.
    United Arab Emirates Univ, Phys Dept, Al Ain, U Arab Emirates..
    Nicholl, M.
    Univ Edinburgh, Royal Observ, Inst Astron, Edinburgh, Midlothian, Scotland.;Univ Birmingham, Birmingham Inst Gravitat Wave Astron, Birmingham, W Midlands, England.;Univ Birmingham, Sch Phys & Astron, Birmingham, W Midlands, England..
    Noschese, A.
    Natl Radio Astron Observ, Socorro, NM 87801 USA..
    Novara, G.
    Scuola Univ Super IUSS Pavia, Pavia, Italy.;INAF IASF Milano, Milan, Italy..
    Pandey, S. B.
    Aryabhatta Res Inst Observat Sci, Naini Tal, India..
    Peretti, E.
    Univ Ferrara, Dept Phys & Earth Sci, Ferrara, Italy.;INFN, Lab Nazl Gran Sasso, Assergi, Italy..
    del Pulgar, C. J. Perez
    Univ Malaga, Dept Ingn Sistemas & Automat ETS Ingenieros Ind, Unidad Asociada CSIC, Malaga, Spain..
    Perez-Torres, M. A.
    CSIC, IAA, Granada, Spain.;Univ Zaragoza, Dept Fis Teor, Zaragoza, Spain..
    Perley, D. A.
    Liverpool John Moores Univ, Astrophys Res Inst, Liverpool, Merseyside, England..
    Piro, L.
    INAF IAPS, Rome, Italy..
    Ragosta, F.
    INAF Astron Observ Naples, Naples, Italy.;Univ Napoli Federico II, Dipartimento Sci Fis, Naples, Italy.;Complesso Univ Monte S Angelo, INFN, Sez Napoli, Naples, Italy..
    Resmi, L.
    Indian Inst Space Sci & Technol, Trivandrum, Kerala, India..
    Ricci, R.
    INAF Ist Radioastron, Bologna, Italy..
    Rossi, A.
    INAF Osservatorio Astrofis & Sci Spazio, Bologna, Italy..
    Sanchez-Ramirez, R.
    INAF IAPS, Rome, Italy..
    Selsing, J.
    Univ Copenhagen, Niels Bohr Inst, Copenhagen, Denmark..
    Schulze, S.
    Weizmann Inst Sci, Dept Particle Phys & Astrophys, Rehovot, Israel..
    Smartt, S. J.
    Queens Univ Belfast, Sch Math & Phys, Astrophys Res Ctr, Belfast, Antrim, North Ireland..
    Smith, I. A.
    Rice Univ, Dept Phys & Astron, Houston, TX USA..
    Sokolov, V. V.
    RAS, SAO, Nizhniy Arkhyz, Russia..
    Stevens, J.
    CSIRO Australia Telescope Natl Facil, Paul Wild Observ, Narrabri, NSW, Australia..
    Tanvir, N. R.
    Univ Leicester, Dept Phys & Astron, Leicester, Leics, England..
    Thone, C. C.
    CSIC, IAA, Granada, Spain..
    Tiengo, A.
    Scuola Univ Super IUSS Pavia, Pavia, Italy.;INAF IASF Milano, Milan, Italy.;Ist Nazl Fis Nucl, Sez Pavia, Pavia, Italy..
    Tremou, E.
    Univ Paris Saclay, Univ Paris Diderot, Sorbonne Paris Cite, AIM,CEA,CNRS, Gif Sur Yvette, France..
    Troja, E.
    NASA, Astrophys Sci Div, Goddard Space Flight Ctr, Greenbelt, MD USA.;Univ Maryland, Dept Astron, College Pk, MD 20742 USA..
    Postigo, A. de Ugarte
    CSIC, IAA, Granada, Spain..
    Valeev, A. F.
    RAS, SAO, Nizhniy Arkhyz, Russia..
    Vergani, S. D.
    PSL Univ, CNRS, Observ Paris, GEPI, Meudon, France..
    Wieringa, M.
    CSIRO Astron & Space Sci, Australia Telescope Natl Facil, Epping, NSW, Australia..
    Woudt, P. A.
    Univ Cape Town, Dept Astron, Interuniv Inst Data Intens Astron, Rondebosch, South Africa..
    Xu, D.
    Chinese Acad Sci, Natl Astron Observ, CAS Key Lab Space Astron & Technol, Beijing 100012, Peoples R China..
    Yaron, O.
    Weizmann Inst Sci, Benoziyo Ctr Astrophys, Rehovot, Israel..
    Young, D. R.
    Weizmann Inst Sci, Benoziyo Ctr Astrophys, Rehovot, Israel..
    Observation of inverse Compton emission from a long gamma-ray burst2019Inngår i: Nature, ISSN 0028-0836, E-ISSN 1476-4687, Vol. 575, nr 7783, s. 459-+Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Long-duration gamma-ray bursts (GRBs) originate from ultra-relativistic jets launched from the collapsing cores of dying massive stars. They are characterized by an initial phase of bright and highly variable radiation in the kiloelectron volt-to-mega electronvoltband, which is probably produced within the jet and lasts from milliseconds to minutes, known as the prompt emission(1,2). Subsequently, the interaction of the jet with the surrounding medium generates shock waves that are responsible for the afterglow emission, which lasts from days to months and occurs over a broad energy range from the radio to the gigaelectronvolt bands(1-6). The afterglow emission is generally well explained as synchrotron radiation emitted by electrons accelerated by the external shock(7-9). Recently, intense long-lasting emission between 0.2 and 1 teraelectronvolts was observed from GRB 190114C(10,11). Here we report multifrequency observations of GRB 190114C, and study the evolution in time of the GRB emission across 17 orders of magnitude in energy, from 5 x 10(-6) to 10(12) electronvolts. We find that the broadband spectral energy distribution is double-peaked, with the teraelectronvolt emission constituting a distinct spectral component with power comparable to the synchrotron component. This component is associated with the afterglow and is satisfactorily explained by inverse Compton up-scattering of synchrotron photons by high-energy electrons. We find that the conditions required to account for the observed teraelectronvolt component are typical for GRBs, supporting the possibility that inverse Compton emission is commonly produced in GRBs.

  • 76. Weltevrede, P.
    et al.
    Abdo, A. A.
    Ackermann, M.
    Ajello, M.
    Axelsson, M.
    Baldini, L.
    Ballet, J.
    Barbiellini, G.
    Bastieri, D.
    Baughman, B. M.
    Bechtol, K.
    Bellazzini, R.
    Berenji, B.
    Bloom, E. D.
    Bonamente, E.
    Borgland, A. W.
    Bregeon, J.
    Brez, A.
    Brigida, M.
    Bruel, P.
    Burnett, T. H.
    Buson, S.
    Caliandro, G. A.
    Cameron, R. A.
    Camilo, F.
    Caraveo, P. A.
    Casandjian, J. M.
    Cecchi, C.
    Celik, Oe.
    Charles, E.
    Chekhtman, A.
    Cheung, C. C.
    Chiang, J.
    Ciprini, S.
    Claus, R.
    Cognard, I.
    Cohen-Tanugi, J.
    Cominsky, L. R.
    Conrad, J.
    Cutini, S.
    Dermer, C. D.
    Desvignes, G.
    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.
    Farnier, C.
    Favuzzi, C.
    Fegan, S. J.
    Focke, W. B.
    Fortin, P.
    Frailis, M.
    Freire, P. C. C.
    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.
    Hanabata, Y.
    Harding, A. K.
    Hays, E.
    Hobbs, G.
    Hughes, R. E.
    Jackson, Miranda
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Johannesson, G.
    Johnson, A. S.
    Johnson, T. J.
    Johnson, W. N.
    Johnston, S.
    Kamae, T.
    Katagiri, H.
    Kataoka, J.
    Kawai, N.
    Keith, M.
    Kerr, M.
    Knoedlseder, J.
    Kocian, M. L.
    Kramer, M.
    Kuss, M.
    Lande, J.
    Latronico, L.
    Lemoine-Goumard, M.
    Longo, F.
    Loparco, F.
    Lott, B.
    Lovellette, M. N.
    Lubrano, P.
    Lyne, A. G.
    Makeev, A.
    Manchester, R. N.
    Mazziotta, M. N.
    McEnery, J. E.
    McGlynn, Sinéad
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Meurer, C.
    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.
    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.
    Ransom, S. M.
    Razzano, M.
    Rea, N.
    Reimer, A.
    Reimer, O.
    Reposeur, T.
    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
    Sanchez, D.
    Sander, A.
    Parkinson, P. M. Saz
    Sgro, C.
    Siskind, E. J.
    Smith, D. A.
    Smith, P. D.
    Spandre, G.
    Spinelli, P.
    Stappers, B. W.
    Strickman, M. S.
    Suson, D. J.
    Tajima, H.
    Takahashi, H.
    Tanaka, T.
    Thayer, J. B.
    Thayer, J. G.
    Theureau, G.
    Thompson, D. J.
    Thorsett, S. E.
    Tibaldo, L.
    Torres, D. F.
    Tosti, G.
    Tramacere, A.
    Uchiyama, Y.
    Usher, T. L.
    Van Etten, A.
    Vasileiou, V.
    Venter, C.
    Vilchez, N.
    Vitale, V.
    Waite, A. P.
    Wang, P.
    Wang, N.
    Watters, K.
    Winer, B. L.
    Wood, K. S.
    Ylinen, Tomi
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik.
    Ziegler, M.
    Gamma-ray and radio properties of six pulsars detected by the Fermi large area telescope2010Inngår i: Astrophysical Journal, ISSN 0004-637X, E-ISSN 1538-4357, Vol. 708, nr 2, s. 1426-1441Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We report the detection of pulsed gamma-rays for PSRs J0631+1036, J0659+1414, J0742-2822, J1420-6048, J1509-5850, and J1718-3825 using the Large Area Telescope on board the Fermi Gamma-ray Space Telescope (formerly known as GLAST). Although these six pulsars are diverse in terms of their spin parameters, they share an important feature: their gamma-ray light curves are (at least given the current count statistics) single peaked. For two pulsars, there are hints for a double-peaked structure in the light curves. The shapes of the observed light curves of this group of pulsars are discussed in the light of models for which the emission originates from high up in the magnetosphere. The observed phases of the gamma-ray light curves are, in general, consistent with those predicted by high-altitude models, although we speculate that the gamma-ray emission of PSR J0659+1414, possibly featuring the softest spectrum of all Fermi pulsars coupled with a very low efficiency, arises from relatively low down in the magnetosphere. High-quality radio polarization data are available showing that all but one have a high degree of linear polarization. This allows us to place some constraints on the viewing geometry and aids the comparison of the gamma-ray light curves with high-energy beam models.

  • 77.
    Yamada, Shinya
    et al.
    Tokyo Metropolitan Univ, Dept Phys, 1-1 Minami Osawa, Hachioji, Tokyo 1920397, Japan..
    Axelsson, Magnus
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Partikel- och astropartikelfysik. Tokyo Metropolitan Univ, Dept Phys, 1-1 Minami Osawa, Hachioji, Tokyo 1920397, Japan..
    Ishisaki, Yoshitaka
    Tokyo Metropolitan Univ, Dept Phys, 1-1 Minami Osawa, Hachioji, Tokyo 1920397, Japan..
    Konami, Saori
    Tokyo Metropolitan Univ, Dept Phys, 1-1 Minami Osawa, Hachioji, Tokyo 1920397, Japan..
    Takemura, Nozomi
    Tokyo Metropolitan Univ, Dept Phys, 1-1 Minami Osawa, Hachioji, Tokyo 1920397, Japan..
    Kelley, Richard L.
    NASA, Goddard Space Flight Ctr, 8800 Greenbelt Rd, Greenbelt, MD 20771 USA.;Lawrence Livermore Natl Lab, 7000 East Ave, Livermore, CA 94550 USA..
    Kilbourne, Caroline A.
    NASA, Goddard Space Flight Ctr, 8800 Greenbelt Rd, Greenbelt, MD 20771 USA.;Lawrence Livermore Natl Lab, 7000 East Ave, Livermore, CA 94550 USA..
    Leutenegger, Maurice A.
    NASA, Goddard Space Flight Ctr, 8800 Greenbelt Rd, Greenbelt, MD 20771 USA.;Lawrence Livermore Natl Lab, 7000 East Ave, Livermore, CA 94550 USA..
    Porter, F. Scott
    NASA, Goddard Space Flight Ctr, 8800 Greenbelt Rd, Greenbelt, MD 20771 USA.;Lawrence Livermore Natl Lab, 7000 East Ave, Livermore, CA 94550 USA..
    Eckart, Megan E.
    Yale Univ, Dept Phys, POB 208120, New Haven, CT 06520 USA..
    Szymkowiak, Andrew
    Yale Univ, Dept Phys, POB 208120, New Haven, CT 06520 USA..
    Poisson vs. Gaussian statistics for sparse X-ray data: Application to the soft X-ray spectrometer2019Inngår i: Publications of the Astronomical Society of Japan, ISSN 0004-6264, E-ISSN 2053-051X, Vol. 71, nr 4, artikkel-id 75Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Reliable results when fitting X-ray data require proper consideration of the statistics involved. We probe the impact of Gaussian versus Poisson statistics at low count levels using both the standard chi(2) method and maximum likelihood based on Poisson studied and quantified through simulated spectra with known properties. We then test the results through analysis of Mn K alpha calibration data taken with the flight spare microcalorimeter for the Hitomi soft X-ray spectrometer. Through comparison with simulations, our results show that the chi(2) method tends to give overly optimistic estimates of the detector energy resolution, in particular when there are few counts. Given an energy resolution of similar to 5eV and a line with about 100 photons, the line width becomes similar to 10% lower in the chi(2) method than in Poisson statistics. This is a consequence of the uncertainties being dominated by counting statistics, and therefore highlights the need to choose the appropriate fit statistic.

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