GT2318+620, a variable galactic source with a radio jet

A recent galactic survey with the National Radio Astronomy Observatory (NRAO) 91-m telescope revealed a small number of variable radio sources at low galactic latitude. Similar sources within the Galaxy, where they have been identified, are often associated with energetic objects such as X-ray binaries, pulsars, cataclysmic variables and flare stars. One of the new variable sources, GT2318 + 620, is within the error box for the Uhuru X-ray source 4U2316 + 61, and our measurement of the neutral hydrogen absorption towards GT2318 + 620, reported here, indicates that it is a galactic object, at a distance of 3-6 kpc. We also present a high-resolution radio image of the source, which reveals an unresolved core with a jet-like feature extending on either side. GT2318 + 620 is coincident with a star of ∼ 20th magnitude, and we suggest here that it is radio-emitting low-mass X-ray binary. The radio luminosity of GT2318 + 620 is markedly higher than that of Sco X-1, the only other low-mass X-ray binary to show a radio jet; in its radio brightness it resembles SS433, which is remarkable for its relativistic jet motion on arcsecond scales, thought to result from accretion onto a collapsed stellar object. (author)