Chandra High Resolution Camera Imaging of GRS 1758-258

Abstract

We observed the "micro-quasar" GRS 1758-258 four times with Chandra. Two HRC-I observations were made in 2000 September-October spanning an intermediate-to-hard spectral transition (identified with RXTE). Another HRC-I and an ACIS/HETG observation were made in 2001 March following a hard-to-soft transition to a very low flux state. Based on the three HRC images and the HETG zero order image, the accurate position (J2000) of the X-ray source is RA = 18h 01m 12.39s, Dec = -25d 44m 36.1s (90% confidence radius = 0".45), consistent with the purported variable radio counterpart. All three HRC images are consistent with GRS 1758-258 being a point source, indicating that any bright jet is less than ~1 light-month in projected length, assuming a distance of 8.5 kpc.