Article Dans Une Revue Monthly Notices of the Royal Astronomical Society Année : 2007

Blackbody components in gamma-ray bursts spectra?

G. Ghirlanda
  • Fonction : Auteur
G. Ghisellini
F. Tavecchio
C. Firmani
  • Fonction : Auteur

Résumé

We study seven gamma-ray bursts (GRBs), detected both by the Burst And Transient Source Experiment (BATSE) instrument, onboard the Compton Gamma-ray Observatory, and by the Wide Field Camera (WFC), onboard BeppoSAX. These bursts have measured spectroscopic redshifts and are a sizeable fraction of the bursts defining the correlation between the peak energy Epeak (i.e. the peak of the νFν spectrum) and the total prompt isotropic energy Eiso (so-called `Amati' relation). Recent theoretical interpretations of this correlation assume that blackbody 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 blackbody 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 cut-off power law plus a blackbody is consistent with the WFC data but the blackbody 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 cut-off power-law model yields an X-ray flux and spectral slope which well matches the WFC spectra.

Fichier principal
Vignette du fichier
mnras0379-0073.pdf (1.4 Mo) Télécharger le fichier
Origine Fichiers éditeurs autorisés sur une archive ouverte
Licence

Dates et versions

hal-03646584 , version 1 (29-04-2022)

Licence

Identifiants

Citer

G. Ghirlanda, Z. Bosnjak, G. Ghisellini, F. Tavecchio, C. Firmani. Blackbody components in gamma-ray bursts spectra?. Monthly Notices of the Royal Astronomical Society, 2007, 379, pp.73-85. ⟨10.1111/j.1365-2966.2007.11890.x⟩. ⟨hal-03646584⟩
29 Consultations
91 Téléchargements

Altmetric

Partager

  • More