Gamma-ray burst afterglow observations using AXAF and ACIS

Pennsylvania State University, 525 Davey Lab, University Park, PA 16802, U.S.A.

Received: 18 December 1998
Accepted: 10 March 1999

Abstract

With the successful launch of AXAF next summer, it will be possible to observe the X-ray afterglow from gamma-ray bursts with much improved positional accuracy ( arcsec) and sensitivity (2-10 keV, in 10 ksec). A typical burst afterglow should be observable within about 10 hours after the position has been determined by BeppoSAX or any other satellite capable of determining the position to within about 5 arcmin and provide about 1000 counts in a 10 ksec integration using the ACIS on AXAF. To constrain the decrease of intensity with time, using existing data from BeppoSAX and ASCA, the burst should produce a measurable flux for up to about 4 months after the gamma-ray event for an observing time of about 40 ksec, if a simple extrapolation of the observed fall-off with time is assumed. Depending upon a number of assumptions, there is a slight possibility of observing iron lines from the gas immediately surrounding the gamma-ray burst source using a long exposure ( ksec).