Imaging and spectroscopy with FORS1 in the field of Q 0307-0015

We present VLT-observations of a recently detected galaxy cluster candidate in the field of the radio-quiet quasar Q 0307-0015. R-band images and mult i-object spectra (MOS) have been obtained during the commissioning phase II of FORS I in December 1998. The presumed central cluster galaxy shows the typical spectrum and surface brightness profile of an early-type galaxy and has a redshift of z=0.396. We measured the redshift of 20 galaxies in the 6.'8 x 6.'8 field and found further 11 galaxies with similar redshift imply ing that we see a galaxy cluster at intermediate z. We estimate the cluster richness to be comparable with Abell class 0-1. The cluster is not physica lly associated with Q 0307-0015 having a redshift of z=0.770. This was to b e expected considering the projected distance of approximate to 5' on the s ky. A closer look at the immediate sourrounding of the QSO shows that Q 0307-00 15 seems to reside in an unspectacular environment. Neither a definite clos e companion candidate nor any excess population of faint galaxies can be se en. This is consistent with the finding at low redshift that most radio-qui et QSOs reside in poorer environments than their radio-loud counterparts.