Consistency analysis of a candidate line feature in GRB930506

Abstract

A highly significant candidate absorption‐type line feature has been observed in several spectra obtained by one BATSE spectroscopy detector (SD) for GRB930506. The ability of the BATSE large area detectors (LADs) to detect Ginga‐like absorption features has been demonstrated previously to be quite good at the fit energy (55 keV) of the candidate line feature. We present an analysis of the consistency between a model derived from a fit to the SD data and spectra from the two brightest LADs. The low‐end of the current channel‐to‐energy conversion routine for the LADs is known to be inadequate. A new determination of the LAD calibration was made by relaxing the energy edges of 16 channel occultation data for the Crab Nebula spectrum until a good fit was obtained. We show that the re‐calibration of the LAD channel‐to‐energy conversion function at the low end produces spectral fits inconsistent with the presence of an absorption feature.