EXOSAT observations of a broad absorption-line quasar: PHL 5200

Abstract

In our observations of the 45' (FWHM) region centered on a broad absorption-line quasar PHL 5200 perfor- med with the medium energy (ME) and low energy (LE) experiments on board EXOSAT Observatory we have detected X-ray emission in the 2-6 keV energy band. No sources are detected in the 0.05-2.0 keV energy band. These observations have been used to suggest that the quasar rather than a cluster of galaxies or a star in the ME field is the optical counterpart of the 2-6 keV X-ray source. Consistency with the soft X-ray observations made with Einstein Observatory about 5 years prior to the EXOSAT observation requires either a highly variable X-ray source or a higher absorbing column (≈ 10²² cm^-2) than is needed to explain the EXOSAT observations. A very high minimum column density (>10²² cm^-2) is needed if the absorption is intrinsic to the quasar. The 4 keV monochromatic luminosity emitted by the quasar is 9.1 × 10²⁸ ergs s^-l Hz^-I.