Absorption spectrum of the quasar HS1603+3820

Context.We present multi-wavelength observations of the bright quasar HS1603+3820: the optical data taken with the MMT and Keck telescopes, with the 40-50 km^-1 resolution, and X-ray data taken by the Chandra X-ray Observatory satellite.Aims.The optical spectra contain a very large number of absorption lines from numerous heavy elements. Our goal is to analyze these features to obtain constraints on the properties of associated absorbers, to be used in modeling of the quasar intrinsic flux and properties of the clouds.Methods.We have determined the properties - column densities and redshifts - of the individual components. We derived the X-ray properties of HS1603+3820 and the optical-to-X-ray slope index .Results.We found alpha;_ox of 1.70, which is at the high end of the typical range for a radio quiet quasar. We found 49 individual heavy element absorption clouds, which can be grouped into eleven distinct systems. Absorbers from the associated system, which likely is the one spatially closest to the quasar, show large CIV to HI column density ratio, reaching ∼20.Conclusions.Intrinsic X-ray properties of the quasar are typical. Determination of column densities of ions (including hydrogen) gives a strong foundation for modeling of the quasar ionising flux.