PKS 2351-154 comma A HIGH REDSHIFT QUASAR: WARM ABSORBER AND METALLICITY

PKS 2351154 is the only known high redshifted quasar (z2.665) which showsdramatic changes in Xray flux as well as in its absorbing column density in theUV and Xray regime. The most likely explanation is provided by a warm absorberlocated in the local environment of the active nucleus. As warm absorbersstrongly reflect the metallicity, the observations proposed here open a uniquechance to determine the metallicity of the material accreting into the centralmassive black hole of a quasar from the quasar age. Comparing the proposedobservation with different measurements of other (warm absorbed) quasars of themetal enrichment as function of the redshift can be studied and the physicalconditions of the local environment of the black hole can be compared. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]