Observing broad-absorption line quasars with Spectrum-Rontgen-Gamma

Broad-absorption line quasars are found to have extremely weak soft X-ray e mission when compared with other optically selected quasars. In the only ex ample of PHL 5200 for which a detailed X-ray spectrum has been obtained wit h ASCA, strong absorption in the source appears to be responsible for the l ack of soft Xray emission. Broad-band X-ray observations of a sample of BAL QSOs are proposed with a high throughput mission SPECTRUM-RONTGEN-GAMMA (S RG), to find out whether these sources are intrinsically weak over the enti re bandwidth of X-rays or only in the soft X-rays due to absorption resulti ng from the line of sight passing through large column density clouds. Simu ltaneous UV observations will help to constrain the ionization state of the absorbers, and also improve the overall UV to X-ray continuum measurements in them.