THE IDENTIFICATION OF 2 DIFFERENT SPECTRAL TYPES OF PULSES IN GAMMA-RAY BURSTS

It is shown in this study that two different types of spectral emissio n are generally produced in gamma-ray bursts. A subset of bursts is id entified that exhibits a marked lack of fluence above 300 keV, and the se bursts are shown to have luminosities about an order of magnitude l ower than bursts with significant fluence above 300 keV. The bursts la cking emission above 300 keV exhibit an effectively homogeneous intens ity distribution. In addition, it is shown that both types of emission are common in many bursts, demonstrating that a single source object is capable of generating both of them. These results strongly favor a gamma-ray burst source object that produces two different types of emi ssion with varying degrees of superposition The impact of this behavio r is strong enough that it affects the properties of the burst intensi ty distribution, as well as the burst spectral characteristics.