scholarly journals Spectral properties of INTEGRAL Gamma-Ray Bursts

2009 ◽  
Author(s):  
Giacomo Vianello
2019 ◽  
Vol 71 (4) ◽  
Author(s):  
Norisuke Ohmori ◽  
Kazutaka Yamaoka ◽  
Makoto Yamauchi ◽  
Yuji Urata ◽  
Masanori Ohno ◽  
...  

Abstract We have systematically studied the spectral properties of 302 localized gamma-ray bursts (GRBs) observed by the Suzaku wide-band all-sky monitor (WAM) from 2005 August to 2010 December. The energy spectra in the 100–5000 keV range integrated over the entire emission and the 1 s peak were fitted by three models: a single power law, a power law with an exponential cutoff (CPL), and the GRB Band function (GRB). Most of the burst spectra were well fitted by a single power law. The average photon index α was −2.11 and −1.73 for long and short bursts, respectively. For the CPL and GRB models, the low-energy and high-energy photon indices (α and β) for the entire emission spectra were consistent with previous measurements. The averages of the α and β were −0.90 and −2.65 for long-duration GRBs, while the average α was −0.55 and the β was not well constrained for short-duration GRBs. However, the average peak energy Epeak was 645 and 1286 keV for long- and short-duration GRBs respectively, which are higher than previous Fermi/GBM measurements (285 keV and 736 keV). The α and Epeak of the 1 s peak spectra were larger, i.e., the spectra were harder, than the total fluence spectra. Spectral simulations based on Fermi-GBM results suggest that the higher Epeaks measured by the Suzaku WAM could be due to detector selection bias, mainly caused by the limited energy range above 100 keV.


2008 ◽  
Vol 60 (sp1) ◽  
pp. S361-S373 ◽  
Author(s):  
Masanori Ohno ◽  
Yasushi Fukazawa ◽  
Takuya Takahashi ◽  
Kazutaka Yamaoka ◽  
Satoshi Sugita ◽  
...  

2012 ◽  
Vol 12 ◽  
pp. 385-389
Author(s):  
B. PATRICELLI ◽  
M.G. BERNARDINI ◽  
C.L. BIANCO ◽  
L. CAITO ◽  
G. DE BARROS ◽  
...  

The analysis of various Gamma Ray Bursts (GRBs) characterized by an isotropic energy Eiso ≲ 1053 ergs within the fireshell model has shown how that the observed N(E) spectrum of their prompt emission can be reproduced in a satisfactory way by assuming a thermal spectrum in the comoving frame of the fireshell. Nevertheless, from the study of higher energetic bursts (Eiso ≳ 1054 ergs ) such as, for example, GRB 080319B, some discrepancies between the numerical simulations and the observational data have been observed. We investigate a different spectrum of photons in the comoving frame of the fireshell in order to better reproduce the spectral properties of GRB prompt emission within the fireshell model. We introduce a phenomenologically modified comoving thermal spectrum: a spectrum characterized by a different asymptotic low energy slope with respect to the thermal one. We test this spectrum by comparing the numerical simulations with the observed prompt emission spectra of various GRBs; we present, as an exaple, the case of GRB 080319B.


Author(s):  
W. S. Paciesas ◽  
R. D. Preece ◽  
M. S. Briggs ◽  
R. S. Mallozzi

1987 ◽  
Vol 125 ◽  
pp. 477-487
Author(s):  
W. Doyle Evans ◽  
John G. Laros

Gamma-ray bursts are generally believed to originate in the vicinity of neutron stars, but the phenomenology is still not understood. In this paper we review the known characteristics of gamma bursts and give new observational results on temporal and spectral properties. We suggest that a class of repeating bursters exists that are spectrally harder than x-ray bursters but significantly softer than “classical” gamma bursts. The March 5, 1979, burst may be the prototype of this class of bursters.


2011 ◽  
Vol 415 (4) ◽  
pp. 3153-3162 ◽  
Author(s):  
L. Nava ◽  
G. Ghirlanda ◽  
G. Ghisellini ◽  
A. Celotti

2007 ◽  
Vol 671 (2) ◽  
pp. 1921-1938 ◽  
Author(s):  
A. D. Falcone ◽  
D. Morris ◽  
J. Racusin ◽  
G. Chincarini ◽  
A. Moretti ◽  
...  

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