The Frequency and Radio Properties of Broad Absorption Line Quasars

A sample of 67 Broad Absorption Line quasars (BALQSOs) from the Large Bright Quasar Survey (LBQS) is used to estimate the observed and intrinsic fraction of BAL quasars in optically--selected samples at intermediate (B_J \simeq 18.5) magnitudes. The observed BALQSO fraction in the redshift range 1.5 < z < 3.0 is 15\pm3%. A well--determined, empirical, k--correction, to allow for the differences in the spectral energy distributions of non--BALQSOs and BALQSOs shortward of \simeq 2100A in the restframe, is applied to the sample. The result is an estimate of the intrinsic fraction of BALQSOs, in the redshift range 1.5 < z < 3.0, of 22+/-4%. This value is twice that commonly cited for the occurrence of BALQSOs in optically--selected samples and the figure is in reasonable agreement with that from a preliminary analysis of the SDSS Early Data Release. The fraction of BALQSOs predicted to be present in an optical survey with flux limits equivalent to that of the FIRST Bright Quasar Survey (FBQS) is shown to be \simeq 20%. The BALQSO fractions derived from the FBQS and the LBQS suggest that optically--bright BALQSOs are half as likely as non-BALQSOs to be detectable as S_1.4GHz > 1mJy radio sources.Comment: Accepted for publication in AJ, April 2003 Issu

An Extraordinary Scattered Broad Emission Line in a Type 2 QSO

An infrared-selected, narrow-line QSO has been found to exhibit an extraordinarily broad Halpha emission line in polarized light. Both the extreme width (35,000 km/sec full-width at zero intensity) and 3,000 km/sec redshift of the line centroid with respect to the systemic velocity suggest emission in a deep gravitational potential. An extremely red polarized continuum and partial scattering of the narrow lines at a position angle common to the broad-line emission imply extensive obscuration, with few unimpeded lines of sight to the nucleus.Comment: 4 pages, 1 figure, to appear in the Astrophysical Journal Letter

Broad P V Absorption in the BALQSO, PG 1254+047: Column Densities, Ionizations and Metal Abundances in BAL Winds

This paper discusses the detection of P V 1118,1128 and other broad absorption lines (BALs) in archival HST spectra of the low-redshift BALQSO, PG 1254+047. The P V identification is secured by excellent redshift and profile coincidences with the other BALs, such as C IV 1548,1550 and Si IV 1393,1403, and by photoionization calculations showing that other lines near this wavelength, e.g. Fe III 1123, should be much weaker than P V. The observed BAL strengths imply that either 1) there are extreme abundance ratios such as [C/H] >~ +1.0, [Si/H] >~ +1.8 and [P/C] >~ +2.2, or 2) at least some of the lines are much more optically thick than they appear. I argue that the significant presence of P V absorption indicates severe line saturation, which is disguised in the observed (moderate-strength) BALs because the absorber does not fully cover the continuum source(s) along our line(s) of sight. Computed optical depths for all UV resonance lines show that the observed BALs are consistent with solar abundances if 1) the ionization parameter is at least moderately high, log U >~ -0.6, 2) the total hydrogen column density is log N_H(cm-2) >~ 22.0, and 3) the optical depths in strong lines like C IV and O VI 1032,1038 are >~25 and >~80, respectively. These optical depths and column densities are at least an order of magnitude larger than expected from the residual intensities in the BAL troughs, but they are consistent with the large absorbing columns derived from X-ray observations of BALQSOs. The outflowing BALR, at velocities from -15,000 to -27,000 km/s in PG 1254+047, is therefore a strong candidate for the X-ray absorber in BALQSOs.Comment: 16 pages (LaTeX) plus 8 pages of figures in one file (pg1254_figs.ps.gz), in press with Ap