A Probable Overabundance of Phosphorus in the Broad Absorption Line Region of the QSO PG 0946+301
Session 42 -- Metallicity in AGN and the Near-AGN Environment
Oral presentation, 8:30am - 12:30pm, June 14, 1995, 9:20am - 6:30pm

## [42.08] A Probable Overabundance of Phosphorus in the Broad Absorption Line Region of the QSO PG 0946+301

V. T. Junkkarinen, E. A. Beaver, E. M. Burbidge, R. D. Cohen, F. Hamann, R. W. Lyons (CASS/UCSD), T. A. Barlow (Caltech)

HST/FOS UV spectra (G190H and G270H) of the BALQSO PG 0946+301 (V = 16, $\rm z_e$ = 1.223) show absorption features that correspond to P V $\lambda$$\lambda1118,1128 and P IV \lambda951 at the redshift (\rm z_a = 1.149) of the strongest absorption component in the Si IV \lambda$$\lambda$1394,1403 and C IV $\lambda$$\lambda1548,1551 absorption troughs. All of the features mentioned above have a FWHM of roughly 550 \rm km~s^{-1}. The resolution of the G270H and G190H spectra is about half this value, and random unblended Ly \alpha forest lines have widths near the instrumental resolution. The large widths of the apparent P V and P IV features increase the probability that these features are at least somehow associated with the BAL region. Modeling the absorption near \lambda1120\AA \ (rest) with only seven Fe III lines (rest wavelengths from 1122.5\AA \ to 1131.4 \AA ), using a template created from the Si IV BAL, produces a significantly worse fit than modeling that spectral region with broad P V \lambda$$\lambda$1118,1128 absorption. We conclude that the most likely identification is P V. The inferred column densities for C IV and P V are: N(C IV) $\approx$ $9 \times 10^{15}$ $\rm cm^{-2}$ and N (P V) $\approx$ $7 \times 10^{14}$ $\rm cm^{-2}$. If the above column density estimates are accurate and the BAL region is photoionized, then the estimated elemental abundance ratio is C/P $\approx$ 13. Since the cosmic abundance ratio C/P = 1000 (Gravese and Anders, 1989 Cosmic Abundances of Matter, AIP, Conf. Proc. ed. C. J. Waddington (New York: AIP), 183), phosphorus is probably overabundant relative to carbon by a factor of 80 in the PG 0946+301 BALR. We compare our results with other evidence for enchanced element abundances in BALQSOs (Turnshek, 1988, in QSO Absorption Lines: Probing the Universe, 8 and Korista et al. 1992, ApJ, 401, 529).

This research has been supported in part by NASA NAS5--29293 and NAG5--1630.