Burst spectra over a wide energy range

Abstract

Burst spectra over a restricted energy range look like a power law plus some curvature. Such spectra can be well fit by most models or mechanisms, and hence reveal little of the underlying physics. With the launch of the Compton Gamma Ray Observatory, we can construct composite spectra from tens of keV to tens of GeV. This wide spectral range yields burst spectra that can sharply confront models. We have constructed wide-range composite spectra for several bursts, two of which are presented here: GRB910601 and GRB910814. The energy ranges are 28 keV to 10 MeV and 100 keV to 200 MeV. These spectra were constructed from spectra by BATSE, EGRET, COMPTEL, and OSSE. The spectral shape of GRB910601 shows a continuous turnover between 100 keV and 1 MeV, with peak νFν at 500 keV. The spectral shape of GRB910814 is dominated by a sharp and strong spectral break near 2 MeV. In addition to these two broad spectra, we have derived an ‘average’ spectral shape for 20 bright bursts from 40 keV to 1500 keV. This average spectra will be useful for studies of the red shifting of average spectra.Burst spectra over a restricted energy range look like a power law plus some curvature. Such spectra can be well fit by most models or mechanisms, and hence reveal little of the underlying physics. With the launch of the Compton Gamma Ray Observatory, we can construct composite spectra from tens of keV to tens of GeV. This wide spectral range yields burst spectra that can sharply confront models. We have constructed wide-range composite spectra for several bursts, two of which are presented here: GRB910601 and GRB910814. The energy ranges are 28 keV to 10 MeV and 100 keV to 200 MeV. These spectra were constructed from spectra by BATSE, EGRET, COMPTEL, and OSSE. The spectral shape of GRB910601 shows a continuous turnover between 100 keV and 1 MeV, with peak νFν at 500 keV. The spectral shape of GRB910814 is dominated by a sharp and strong spectral break near 2 MeV. In addition to these two broad spectra, we have derived an ‘average’ spectral shape for 20 bright bursts from 40 keV to 1500 keV. This average ...