主要内容:
由于GBM和BATSE差不多,观测到的暴的性质也差不多,峰值能量在800keV,不想Swift的BAT。
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文章信息:
- · arXiv e-print (arXiv:1104.5495)
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Title: |
| Rest-frame properties of 32 gamma-ray bursts observed by the Fermi Gamma-Ray Burst Monitor |
Authors: |
| Gruber, D.; Greiner, J.; von Kienlin, A.; Rau, A.; Briggs, M. S.; Connaughton, V.; Goldstein, A.; van der Horst, A. J.; Nardini, M.; Bhat, P. N.; Bissaldi, E.; Burgess, J. M.; Chaplin, V. L.; Diehl, R.; Fishman, G. J.; Fitzpatrick, G.; Foley, S.; Gibby, M. H.; Giles, M. M.; Guiriec, S.; Kippen, R. M.; Kouveliotou, C.; Lin, L.; McBreen, S.; Meegan, C. A.; Olivares E., F.; Paciesas, W. S.; Preece, R. D.; Tierney, D.; Wilson-Hodge, C. |
Publication: |
| eprint arXiv:1104.5495 |
Publication Date: |
| 04/2011 |
Origin: |
| ARXIV |
Keywords: |
| Astrophysics - High Energy Astrophysical Phenomena |
Comment: |
| accepted by A&A |
Bibliographic Code: |
| 2011arXiv1104.5495G |
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 $\nu F_{\nu}$ spectrum (\eprest), the duration in the rest-frame, defined as the time in which 90% of the burst fluence was observed (\tninetyrest) and the isotropic equivalent bolometric energy (\eiso). Results: The distribution of \eprest 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-\ep population is found but the distribution is biased against low \ep values. We find the lowest possible \ep that GBM can recover to be ~ 15 keV. The \tninetyrest distribution of long GRBs peaks at ~10 s. The distribution of \eiso has mean and median values of $8.9\times 10^{52}$ erg and $8.2 \times 10^{52}$ erg, respectively. We confirm the tight correlation between \eprest and \eiso (Amati relation) and the one between \eprest 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 $\alpha$ gets softer when \ep is located at the lower end of the detector energy range. Moreover, we do not find any significant cosmic evolution of neither \eprest nor \tninetyrest.
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