Ghirlanda 2007 伽玛暴谱的黑体成分

主要内容:
通过对7个暴的谱的分析，得出是含有黑体成分的。

精彩摘抄:


文章信息:
Black-body components in Gamma-Ray Bursts spectra?

Authors: G. Ghirlanda (1), Z. Bosnjak (2,1), G. Ghisellini (1), F. Tavecchio (1), C. Firmani (1,3) ((1) INAF-Osservatorio Astronomico di Brera; (2) Institut d'Astrophysique de Paris; (3) U.N.A.M. - Mexico)

(Submitted on 25 Apr 2007)

Abstract: We study 7 Gamma Ray Bursts (GRBs), detected both by the BATSE instrument, on-board the Compton Gamma Ray Observatory, and by the Wide Field Camera (WFC), on-board BeppoSAX. These bursts have measured spectroscopic redshifts and are a sizeable fraction of the bursts defining the correlation between the peak energy E_peak (i.e. the peak of the vFv spectrum) and the total prompt isotropic energy E_iso (the so called "Amati" relation). Recent theoretical interpretations of this correlation assume that black-body emission dominates the time resolved spectra of GRBs, even if, in the time integrated spectrum, its presence may be hidden by the change of its temperature and by the dilution of a possible non-thermal power law component. We perform a time resolved spectral analysis, and show that the sum of a power-law and a black-body gives acceptable fits to the time dependent spectra within the BATSE energy range, but overpredicts the flux in the WFC X-ray range. Moreover, a fit with a cutoff power-law plus a black-body is consistent with the WFC data, but the black-body component contributes a negligible fraction of the total flux. On the contrary, we find that fitting the spectra with a Band model or a simple cutoff power-law model yields an X-ray flux and spectral slope which well matches the WFC spectra.

Comments:

14 pages, 13 figures, accepted for publication in MNRAS

Subjects:

Astrophysics (astro-ph)

Cite as:

arXiv:0704.3438v1 [astro-ph]