On the jets associated with galactic superluminal sources

Recent observations of GRS 1915+105 and GRO J1655+40 reveal superluminal motions in Galactic sources. This Letter examines the physical conditions within these Galactic sources, their interaction with their environment, and their possible formation, and contrasts them with their extragalactic counterparts. In particular, e(+)-e(-) and e-p jets are contrasted; constraints on particle acceleration in the jets are imposed using X-ray and radio observations; and the gamma-ray flux from e(+)-e(-) jets expected at EGRET energies and the flux in infrared lines from an e-p jet are estimated. It is also suggested that these sources may exhibit low-frequency radio lobes extending up to several hundred parsecs in size, strong, soft X-ray absorption during the birth of the radio components, and emission-line strengths anticorrelated with the X-ray flux. The implications for other X-ray transients are briefly discussed.