Broad absorption line quasars in the Sloan Digital Sky Survey with VLA first radio detections

Citation
K. Menou et al., Broad absorption line quasars in the Sloan Digital Sky Survey with VLA first radio detections, ASTROPHYS J, 561(2), 2001, pp. 645-652
Citations number
32
Categorie Soggetti
Space Sciences
Journal title
ASTROPHYSICAL JOURNAL
ISSN journal
0004637X → ACNP
Volume
561
Issue
2
Year of publication
2001
Part
1
Pages
645 - 652
Database
ISI
SICI code
0004-637X(20011110)561:2<645:BALQIT>2.0.ZU;2-4
Abstract
We present 13 broad absorption line (BAL) quasars, including 12 new objects , identified in the Sloan Digital Sky Survey (SDSS) and matched within 2 " to sources in the FIRST radio survey catalog. The surface density of this s ample of radio-detected BAL quasars is 4.5 +/- 1.2 per 100 deg(2), i.e., ap proximately 4 times as high as previously found by the shallower FIRST Brig ht Quasar Survey (FBQS). A majority of these radio-detected BAL quasars are moderately radio-loud objects. The fraction of BAL quasars in the entire r adio quasar sample, 4.8% +/- 1.3%, is comparable to the fraction of BAL qua sars among the SDSS optical quasar sample (ignoring selection effects). We estimate that the true fraction of BAL quasars (mostly "HiBALs") in the rad io sample is 9.2% +/- 2.6%, once selection effects are accounted for. We ca ution that the absorption troughs of four of the 13 radio-detected quasars considered do not strictly satisfy the standard BALnicity criteria. One or possibly two of the new radio-detected BAL quasars are of the rare "FeLoBAL " type. BAL quasars are generally redder than the median SDSS quasar at the same redshift.