1928 + 738 - A superluminal source with large-scale structure

Abstract

The quasar 1928+738 has been mapped with resolution of 1arcsec.2 and 30arcsec at 20 and 49 cm wavelengths, respectively, and displays two-sided radio structure which extends up to 40arcsec on either side of the compact core along a position angle close to 0°. The redshift of this object (0.3) would indicate that the overall linear size of this emission is 235 h<SUP>-1</SUP>kpc. The core of this radio source has been reported to display apparent superluminal motion which suggests that the small-scale structure is aligned within 12°.5 of the line of sight to the source. If the large-scale structure is also aligned at this angle, the deprojected size is approximately 800 h<SUP>-1</SUP>kpc. As this unlikely, the large-scale structure is probably aligned to the line of sight at a considerably different angle (&gt;24°) than that predicted by the superluminal motion of the milliarcsecond structure.