Radio Emission from the Region of GX 1+4

R. K. Manchanda, University College, Australian Defence Force Academy, University of New South Wales, Canberra, writes: "I have discovered two weak radio sources close to the position of the optical candidate of GX 1+4. The observations were made on Aug. 26 using the Molonglo Observatory Synthesis Telescope operating at 843 MHz. The two sources have the following approximate centroid positions (equinox 1950.0) and radio fluxes: (1) R.A. = 17h28m44.6, Decl. = -24 44'05", about 70 mJy; (2) R.A. = 17h29m15s, Decl. = -24 40.9, about 12 mJy. Source (1) is only about 3' away from the optical candidate and lies within the position error box of the x-ray source from UHURU and OSO-7 satellite surveys, but is inconsistent with the Copernicus position error circle. The radio sources are not seen in any previous surveys; this is probably due to the higher threshold sensitivity (about 1 Jy) of these surveys. Close to the position of source (1), a star is present only on the blue Palomar survey plates. In view of the anomalous behavior of GX 1+4 in the past decade, further spectral and temporal investigations --- both in the radio and the optical bands --- are urgently required for source (1), to establish a possible association. I thank J. G. Robertson and the Molonglo Observatory staff for making the observation and synthesis map."