Multiwavelength observations of GX 339−4

We discuss our recent observations of the Galactic black hole candidate GX 339−4. The source was in a “soft X-ray off” state, and we found that this was similar to previous very hard states. A possible radio jet was found 1996 July 11–14. During this time, there were no dramatic changes in the X-ray or gamma-ray flux or hardness. Our 1996 May 12 Keck observations found that the optical emission was surprisingly bright and still dominated by the highly variable accretion disk, in spite of the fact that RXTE did not see a detectable flux. RXTE observations on 1996 July 26 revealed a 0.35 Hz QPO.