MULTIWAVELENGTH OBSERVATIONS OF THE BRIGHT QSO-HS-0624+6907

We present non-simultaneous multi-wavelength observations of the brigh t radio-quiet QSO HS 0624 + 6907 (V = 14.2, z = 0.37) discovered by th e Hamburg Survey (Groote et al. 1989). HS 0624 + 6907 has a particular ly strong UV-soft X-ray bump which turns over already at the shortest IUE wavelengths, and it has a steep (Photon index Gamma = -2.9) soft X -ray spectral slope. While the spectrum resembles in the optical UV an d soft X-rays that of H 1821 + 643, its ''twin'' in the sky in brightn ess and redshift, its energy distribution lacks the components in the IR and at hard X-rays seen in H 1821 + 641. A unique feature of the em ission line spectrum seen at high spectral resolution is a narrow [O I II] and H-beta component (FWHM = 140 km s(-1)) redshifted by 360 km s( -1) relative to broad allowed lines. The QSO has been found to be slig htly variable in the optical and at soft X-rays (factor 2). The host g alaxy of HS 0624 + 6907 obeys a de Vaucouleurs-type radial brightness distribution and appears to be a giant elliptical galaxy, probably loc ated in a cluster.