  The observed lightcurves and estimated sky rate of fast extragalactic x-ray
transients (XRTs) discovered in archival Chandra data indicate that they belong
to two distinct XRT populations. The first population of relatively short
duration pulses, which typically last less than few minutes seems to be pulses
of x-ray flashes (XRFs), which are nearby long duration gamma ray bursts viewed
from far off axis. The second population of much longer pulses, which typically
last hours, seems to be the early time afterglows of short gamma ray bursts
(SGRBs) which are beamed away from Earth, as was shown in a previous paper.
