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V.T. Junkkarinen, R.D. Cohen (UCSD), F. Hamann (U. Florida), G.A. Shields (U. Texas)
We present HST/STIS UV and ground based optical spectra of eight broad absorption line (BAL) quasars with redshifts between 0.45 and 1.71. These quasars were selected to study chemical abundances in BAL regions by observing a large number of lines including: C III \lambda977, C IV \lambda1549, N III \lambda992, N V \lambda1240, O III \lambda833, O VI \lambda1034, Si IV \lambda1397, H I \lambda1216, S IV \lambda\lambda1073,1063, P V \lambda\lambda1118,1128, and Al III \lambda\lambda1855,1863. Of the seven BAL quasars in this sample with observable P V lines, two have definite detections and two more have weak features that could be broad P V absorption. Combined with previous detections of P V, these data show that P V absorption is often present in BAL quasars. The two BAL quasars with definite P V features are Q2111-4335 (P V at za = 1.629) and Q1435+5005 (P V at za = 1.529). Both of these quasars show weak, relatively narrow Al III absorption lines at the P V redshift. Previous observations of P V absorption in BAL quasars have been interpreted as BAL regions that partially cover the background source and have roughly solar metallicity and high column densities. Partial covering is required to reconcile the detection of less abundant elements like phosphorous to the non-black BALs due to abundant elements like hydrogen, silicon, oxygen, and carbon. The Q1435+5005 spectrum, with almost 100% deep Si IV and C IV lines and 85% deep P V lines, shows that the fractional covering by the high column density material can, in some cases, be close to 100%.
This research is based on work supported by the Space Telescope Science Institute under grant GO-07359.