1994A&A...292...45W

The environment of the luminous low-redshift QSO HE 1029-1401 (z=0.086, M_V=-25.1) is investigated within a projected radius of ∼700kpc (H₀=50km/s/Mpc, q₀=0.5) by direct imaging and long-slit spectroscopy. The surface density of galaxies with R<22 is uniform to 350kpc projected radius around the QSO, and shows only minor departures from uniformity at larger radii, revealing no evidence for clustering around the QSO. A spectroscopic survey of 15 galaxies confirms the absence of any rich cluster, but shows four galaxies to have redshifts very similar to that of the QSO. The apparently closest companion however, an elliptical galaxy with 22" separation (51kpc projected distance), is a background object at z=0.162. The group at z=0.086 extends over the whole mapped field. Its kinematic properties are similar to those of `normal' galaxy groups. The two galaxies closest to the QSO in velocity space (±200km/s) have blue spectra with Balmer absorption and strong emission lines, typical for a major burst of star formation in recent times. One galaxy shows a broad emission feature around λ4650, indicating the presence of a large number of Wolf-Rayet stars. The oxygen abundance in both starburst galaxies is sub-solar by a factor 2-5. It is suggested that the starburst activity was triggered by gravitational interaction with the potential of the QSO host galaxy. A causal relation between these interaction events and the nuclear activity in the QSO itself is not probable, because of the large impact parameter and mass ratio involved. This is supported by the the age of no more than a few Myr estimated for the starburst in the Wolf-Rayet galaxy, much less than the commonly assumed evolutionary timescale of active galactic nuclei.