Localization, time histories, and energy spectra of a new type of recurrent high-energy transient source

Abstract

The authors report the detection of a recurrent high-energy transient source which is neither a classical X-ray nor a gamma-ray burster, but whose properties are intermediate between the two. The energy spectra of 12 recurrent events are found to be soft, characterized by kT's of 34 - 56 keV. The time histories are short (≤128 ms) with rise and fall times as fast as ≡10 ms. The source location is a 0.12 deg<SUP>2</SUP> region about 10° from the Galactic center.