Observations of GX 339-4 in 1996

GX 339-4 is an unusual black hole candidate in that it is a persistent source, being detected by X-ray telescopes most of the time, but it also has nova-like flaring states. In 1996 we performed radio, optical, X-ray, and gamma-ray observations of GX 339-4 when it was in a hard state (= soft X-ray low state). Here we present a brief summary of some of the results. © 1999 OPA (Overseas Publishers Association) N.V. Published by license under the Gordon and Breach Science Publishers imprint.