PKS 1004+13: A High-Inclination, Highly Absorbed Radio-loud QSO--the First Radio-loud Broad Absorption Line QSO at Low Redshift?

Abstract

The existence of broad absorption line (BAL) outflows in only radio-quiet QSOs was thought to be an important clue to mass ejection and the radio-loud-radio-quiet dichotomy. Recently, a few radio-loud BAL QSOs have been discovered at high redshift. We present evidence that PKS 1004+13 is a radio-loud BAL QSO. It would be the first known at low redshift (z_em=0.24) and one of the most radio-luminous. For PKS 1004+13, there appear to be broad absorption troughs of O VI, N V, Si IV, and C IV, indicating high-ionization outflows up to ~10,000 km s^-1. There are also two strong, broad (~550 km s^-1), high-ionization associated absorption systems that show partial covering of the continuum source. The strong UV absorption we have detected suggests that the extreme, soft X-ray weakness of PKS 1004+13 is primarily the result of absorption. The large radio-lobe dominance indicates BAL and associated gas at high inclinations to the central engine axis, perhaps in a line of sight that passes through an accretion disk wind.

Based on observations by the International Ultraviolet Explorer (IUE) satellite, collected at the Villafranca Satellite Tracking Station of the European Space Agency, and on data from IUE and the NASA/ESA Hubble Space Telescope (HST), retrieved from the Multimission Archive at the Space Telescope Science Institute (MAST). STScI is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555. Support for MAST for non-HST data is provided by the NASA Office of Space Science via grant NAG5-7584 and by other grants and contracts.