Rest-frame properties of 32 gamma-ray bursts observed by theFermiGamma-ray Burst Monitor
Open Access
- 1 June 2011
- journal article
- research article
- Published by EDP Sciences in Astronomy & Astrophysics
- Vol. 531, A20
- https://doi.org/10.1051/0004-6361/201116953
Abstract
Aims. In this paper we study the main spectral and temporal properties of gamma-ray bursts (GRBs) observed by Fermi/GBM. We investigate these key properties of GRBs in the rest-frame of the progenitor and test for possible intra-parameter correlations to better understand the intrinsic nature of these events.Methods. Our sample comprises 32 GRBs with measured redshift that were observed by GBM until August 2010. 28 of them belong to the long-duration population and 4 events were classified as short/hard bursts. For all of these events we derive, where possible, the intrinsic peak energy in the ν F ν spectrum (E p,rest), the duration in the rest-frame, defined as the time in which 90% of the burst fluence was observed (T 90,rest) and the isotropic equivalent bolometric energy (E iso).Results. The distribution of E p,rest has mean and median values of 1.1 MeV and 750 keV, respectively. A log-normal fit to the sample of long bursts peaks at ~800 keV. No high-E p population is found but the distribution is biased against low E p values. We find the lowest possible E p that GBM can recover to be ≈ 15 keV. The T 90,rest distribution of long GRBs peaks at ~10 s. The distribution of E iso has mean and median values of 8.9 × 1052 erg and 8.2 × 1052 erg, respectively. We confirm the tight correlation between E p,rest and E iso (Amati relation) and the one between E p,rest and the 1-s peak luminosity (L p) (Yonetoku relation). Additionally, we observe a parameter reconstruction effect, i.e. the low-energy power law index α gets softer when E p is located at the lower end of the detector energy range. Moreover, we do not find any significant cosmic evolution of neither E p,rest nor T 90,rest.Keywords
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This publication has 38 references indexed in Scilit:
- FIRST-YEAR RESULTS OF BROADBAND SPECTROSCOPY OF THE BRIGHTESTFERMI-GBM GAMMA-RAY BURSTSThe Astrophysical Journal, 2011
- A SHORT GAMMA-RAY BURST “NO-HOST” PROBLEM? INVESTIGATING LARGE PROGENITOR OFFSETS FOR SHORT GRBs WITH OPTICAL AFTERGLOWSThe Astrophysical Journal, 2010
- THE COSMIC RATE, LUMINOSITY FUNCTION, AND INTRINSIC CORRELATIONS OF LONG GAMMA-RAY BURSTSThe Astrophysical Journal, 2010
- THE LARGE AREA TELESCOPE ON THEFERMI GAMMA-RAY SPACE TELESCOPEMISSIONThe Astrophysical Journal, 2009
- Measuring the cosmological parameters with theEp,i-Eisocorrelation of gamma-ray burstsMonthly Notices of the Royal Astronomical Society, 2008
- A Complete Catalog ofSwiftGamma‐Ray Burst Spectra and Durations: Demise of a Physical Origin for Pre‐SwiftHigh‐Energy CorrelationsThe Astrophysical Journal, 2007
- Spectral analysis of 35 GRBs/XRFs observed with HETE-2/FREGATEAstronomy & Astrophysics, 2003
- Intrinsic spectra and energetics of BeppoSAX Gamma–Ray Bursts with known redshiftsAstronomy & Astrophysics, 2002
- BeppoSAX, the wide band mission for X-ray astronomyAstronomy and Astrophysics Supplement Series, 1997
- BATSE observations of gamma-ray burst spectra. I - Spectral diversityThe Astrophysical Journal, 1993