Recent Gamma-Ray Burst continuum observations and their implications for line features in Gamma-Ray Bursts

Abstract

In the pre-CGRO era, most apparent features in Gamma-Ray Burst (GRB) spectra were commonly interpreted as cyclotron absorption lines produced near strongly magnetized neutron stars distributed in the Galactic disk. Since the advent of the BATSE observations, resulting in the abandonment of the Galactic disk model, the significance and implications of spectral features in bursts are being reexamined. Recent observations of Gamma-Ray Burst spectra indicate that even narrow absorption line-like features in burst spectra can be produced as a natural consequence of continuum superposition. Since the overlapping of distinct continuua can be shown to produce apparent features in bursts, and the flux histories of bursts clearly support burst pulses overlapping, the conventional single continuum model may not be adequate for calculating the statistical significance of apparent line features in burst spectra.