Naslov
Blackbody components in gamma-ray bursts spectra?

Autori
Ghirlanda, G. ; BoŠnjak, Željka ; Ghisellini, G. ; Tavecchio, F. ; Firmani, C.

Izvornik
Monthly notices of the Royal Astronomical Society (0035-8711) 379 (2007), 1; 73-85

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
radiation mechanisms: non-thermal, radiation mechanisms: thermal, gamma-rays: bursts

Sažetak
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.

Izvorni jezik
Engleski

Znanstvena područja
Fizika

POVEZANOST RADA