Change search
Refine search result
1 - 7 of 7
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 1. Bagoly, Z.
    et al.
    Horvath, I.
    Balazs, L. G.
    Borgonovo, L.
    Larsson, S.
    Meszaros, A.
    Ryde, Felix
    Principal-component analysis of gamma-ray bursts' spectra2005In: Nuovo cimento della societa italiana de fisica. C, Geophysics and space physics, ISSN 1124-1896, E-ISSN 1826-9885, Vol. 28, no 3, p. 295-298Article in journal (Refereed)
    Abstract [en]

    The principal-component analysis is a statistical method, which lowers the number of important variables in a data set. The use of this method for the bursts' spectra and afterglows is discussed in this paper. The analysis indicates that three principal components are enough among the eight ones to describe the variablity of the data. The correlation between the spectral index a and the redshift suggests that the thermal emission component becomes more dominant at larger redshifts.

  • 2. De Simone, N.
    et al.
    Jerse, G.
    Mocchiutti, E.
    Adriani, O.
    Barbarino, G. C.
    Bazilevskaya, G. A.
    Bellotti, R.
    Boezio, M.
    Bogomolov, E. A.
    Bonechi, L.
    Bongi, M.
    Bonvicini, V.
    Borisov, S.
    Bottai, S.
    Bruno, A.
    Cafagna, F.
    Campana, D.
    Carbone, R.
    Carlson, Per
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Casolino, M.
    Castellini, G.
    Consiglio, L.
    DePascale, M. P.
    De Santis, C.
    Di Felice, V.
    Galper, A. M.
    Gillard, William
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Grishantseva, L.
    Karelin, A. V.
    Koldashov, S. V.
    Krutkov, S. Y.
    Kvashnin, A. N.
    Leonov, A.
    Maksumov, O.
    Malakhov, V.
    Malvezzi, V.
    Marcelli, L.
    Mayorov, A. G.
    Menn, W.
    Monaco, A.
    Mikhailov, V. V.
    Mori, N.
    Nikonov, N. N.
    Osteria, G.
    Palma, F.
    Papini, P.
    Pearce, Mark
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Picozza, P.
    Pizzolotto, C.
    Ricci, M.
    Ricciarini, S. B.
    Rossetto, Laura
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Runtso, M.
    Sarkar, R.
    Simon, M.
    Sparvoli, R.
    Spillantini, P.
    Stozhkov, Y. I.
    Vacchi, A.
    Vannuccini, E.
    Vasilyev, G.
    Voronov, S. A.
    Wu, Juan
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Yurkin, Y. T.
    Zampa, G.
    Zampa, N.
    Zverev, V. G.
    PAMELA: Measurements of matter and antimatter in space2011In: Nuovo cimento della societa italiana de fisica. C, Geophysics and space physics, ISSN 1124-1896, E-ISSN 1826-9885, Vol. 34, no 3, p. 79-87Article in journal (Refereed)
    Abstract [en]

    On the 15th of June 2006, the PAMELA satellite-borne experiment was launched from the Baikonur cosmodrome and it has been collecting data since July 2006. The apparatus comprises a time-of-flight system, a silicon-microstrip magnetic spectrometer, a silicon-tungsten electromagnetic calorimeter, an anticoincidence system, a shower tail counter scintillator and a neutron detector. The combination of these devices allows precision studies of the charged cosmic radiation to be conducted over a wide energy range (100 MeV-100's GeV) with high statistics. The primary scientific goal is the measurement of the antiproton and positron energy spectra in order to search for exotic sources, such as dark matter particle annihilations. PAMELA is also searching for primordial antinuclei (antihelium), and testing cosmic-ray propagation models through precise measurements of the antiparticle energy spectrum and precision studies of light nuclei and their isotopes. Moreover, PAMELA investigates phenomena connected with solar and earth physics. The main results and updated data will be presented.

  • 3.
    Jovicevic, Jelena
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Performance of b-jet identification in ATLAS2014In: Nuovo cimento della societa italiana de fisica. C, Geophysics and space physics, ISSN 1124-1896, E-ISSN 1826-9885, Vol. 37, no 6, p. 123-128Article in journal (Refereed)
    Abstract [en]

    A performant identification of the jets originating from b-quarks is one of the key ingredients which allows for the diverse physics program of the ATLAS experiment. Algorithms for the b-jet identification in ATLAS are exploiting the long lifetime and the high mass of the b-hadrons, as well as the information on the tracks associated with jets. The performance of these algorithms is measured in data to enable reliable usage in the physics analyses. In this article, the performance of the multivariate technique MV1 for b-jet identification, which as its inputs takes information from the other b-jet identification algorithms in ATLAS, is presented. The efficiency of the MV1 algorithm is measured using dileptonic top pair events and is based on a likelihood approach. This approach allows to exploit per-event flavour and momentum correlations between the two jets. Correction factors which take into account differences in the b-jet identification efficiencies in simulation and data are derived as a function of jet transverse momentum and pseudo-rapidity. All the results are derived using the proton-proton collision dataset at centre of mass energy of √s = 8TeV corresponding to an integrated luminosity of L ≈ 20.3 fb-1.

  • 4. Meszaros, A.
    et al.
    Bagoly, Z.
    Klose, S.
    Ryde, Felix
    Larsson, S.
    Balazs, L. G.
    Horvath, I.
    Borgonovo, L.
    On the origin of the dark gamma-ray bursts2005In: Nuovo cimento della societa italiana de fisica. C, Geophysics and space physics, ISSN 1124-1896, E-ISSN 1826-9885, Vol. 28, no 3, p. 311-314Article in journal (Refereed)
    Abstract [en]

    The origin of dark bursts-i.e. that have no observed afterglows in X-ray, optical/NIR and radio ranges-is unclear yet. Different possibilities-instrumental biases, very high redshifts, extinction in the host galaxies-are discussed and shown to be important. On the other hand, the dark bursts should not form a new subgroup of long gamma-ray bursts themselves.

  • 5.
    Moretti, Elena
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    Observations of GRBs with the fermi large area telescope2011In: Nuovo cimento della societa italiana de fisica. C, Geophysics and space physics, ISSN 1124-1896, E-ISSN 1826-9885, Vol. 34, no 3, p. 261-265Article in journal (Refereed)
    Abstract [en]

    Fermi Gamma-ray Space Telescope successfully detected high-energy emission from 20 GRBs so far. Thanks to its unprecedented very wide energy coverage of Large Area Telescope (LAT: from 25MeV to < 300GeV) and Gammaray Burst Monitor (GBM: from 8keV to 40MeV), Fermi provided new observational pictures of GRBs. Here we review some of the GRB properties seen by the LAT instrument such as the delayed onset and longer durations of high-energy emission compared with low-energy emission of the GBM. An extra spectral component in high and low energy is detected in some GRBs and moreover for the first time a cut-off in the spectral extra component is seen. These temporal and spectral distinct behaviors inspire many implications on the emission mechanism, including leptonic, hadronic and afterglow origin. Fermi also placed constraints both on the bulk Lorentz factor of the relativistic jet, larger than 1000 for bright LAT GRBs, and on outside-GRB topics such as quantum gravity.

  • 6. Ryde, Felix
    et al.
    Battelino, M.
    The conspicuous gamma-ray burst of 30 May 19962005In: Nuovo cimento della societa italiana de fisica. C, Geophysics and space physics, ISSN 1124-1896, E-ISSN 1826-9885, Vol. 28, no 3, p. 335-338Article in journal (Refereed)
    Abstract [en]

    The spectra of the majority of bursts exhibit a low-energy power law index, a, that is either a constant or becomes softer with time. However, in the burst of 30 May 1996 a becomes harder. Here we show that this behavior can be explained by a hybrid model consisting of a thermal and a non-thermal component. In this burst the power law index of the non-thermal component changes drastically from s similar to -1.5 to s similar to -0.67 at approximately 5 seconds after the trigger, thereby revealing, at low energies, the thermal component with its hard Rayleigh-Jeans tail. This leads to the large alpha-values that are found if the Band function is fitted to the spectra. We suggest that the change in s could be due to a transition from fast to slow cooling of the electrons emitting in the BATSE range. This could be due to the fact that the magnetic field strength becomes weaker.

  • 7. Sparvoli, R.
    et al.
    Adriani, O.
    Barbarino, G. C.
    Bazilevskaya, G. A.
    Bellotti, R.
    Boezio, M.
    Bogomolov, E. A.
    Bonechi, L.
    Bongi, M.
    Bonvicini, V.
    Bottai, S.
    Bruno, A.
    Cafagna, F.
    Campana, D.
    Carlson, Per
    KTH, School of Engineering Sciences (SCI), Physics.
    Casolino, M.
    Castellini, G.
    De Pascale, M. P.
    De Santis, C.
    De Simone, N.
    Di Felice, V.
    Galper, A. M.
    Grishantseva, L.
    Hofverberg, Petter
    KTH, School of Engineering Sciences (SCI), Physics.
    Koldashov, S. V.
    Krutkov, S. Y.
    Kvashnin, A. N.
    Leonov, A.
    Malvezzi, V.
    Marcelli, L.
    Menn, W.
    Mikhailov, V. V.
    Mocchiutti, E.
    Osteria, G.
    Papini, P.
    Pearce, Mark
    KTH, School of Engineering Sciences (SCI), Physics.
    Picozza, P.
    Ricci, M.
    Ricciarini, S. B.
    Simon, M.
    Spillantini, P.
    Stozhkov, Y. I.
    Vacchi, A.
    Vannuccini, E.
    Vasilyev, G.
    Voronov, S. A.
    Yurkin, Y. T.
    Zampa, G.
    Zampa, N.
    Zverev, V. G.
    Cosmic rays studies with the PAMELA space experiment2009In: Nuovo cimento della societa italiana de fisica. C, Geophysics and space physics, ISSN 1124-1896, E-ISSN 1826-9885, Vol. 32, no 5-6, p. 1-10Article in journal (Refereed)
    Abstract [en]

    The instrument PAMELA, in orbit since June 15th, 2006 on board the Russian satellite Resurs DK1, is delivering to ground 16 Gigabytes of data per day. The apparatus is designed to study charged particles in the cosmic radiation, with a particular focus on antiparticles as a possible signature of dark matter annihilation in the galactic halo; the combination of a magnetic spectrometer and different detectors-indeed- allows antiparticles to be reliably identified from a large background of other charged particles. New results on the antiproton-to-proton and positron-to-all-electron ratios over a wide energy range (1-100GeV) have been recently released by the PAMELA Collaboration, and will be summarized in this paper. While the antiproton-to-proton ratio does not show particular differences from an antiparticle standard secondary production, in the positron-to-all-electron ratio an enhancement is clearly seen at energies above 10 GeV. Possible interpretations of this effect will be briefly discussed.

1 - 7 of 7
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf