A Slower Superluminal Velocity for the Quasar 1156+295

Abstract

As part of an ongoing effort to observe high energy gamma-ray blazars with VLBI, we have produced 8 and 2 GHz VLBI images, at ten epochs spanning the years 1988 to 1996, of the quasar 1156+295. The VLBI data have been taken from the Washington VLBI correlator's geodetic database. We have detected detected four components and have measured their apparent speeds to be 8.8 +/- 2.3, 5.3 +/- 1.1, 5.5 +/- 0.9, and 3.5 +/- 1.2 h^{-1}c from the outermost component inwards. (H_{0}=100h km/(s Mpc), q_{0}=0.5 throughout paper). These velocities contradict a previously published very high superluminal velocity of 26 h^{-1}c for this source.