Faculty of Science (FNWI) - Anton Pannekoek Institute for Astronomy (API)
Abstract
We have previously reported evidence for a Seyfert-like warm absorber in the stellar-mass Galactic black hole GX 339-4, based on a Chandra/HETGS spectrum obtained during a 75 ksec observation during its 2002-2003 outburst starting on 2003 March 17.8 [1]. The ionized absorption lines detected with this observation were strong, but showed little variability on the timescale of the observation. Variability is perhaps the most important property for ascribing X-ray absorption lines to an accreting source, rather than to absorption in the ISM (which is also a possibility for GX 339-4).