2002/09/04 by Alin Tolea, Julian H. Krolik, Z. Tsvetanov +1 · 5 citations
Computer Science · Physics and Astronomy · #Advanced Image Processing Techniques #Astrophysical Phenomena and Observations #Galaxies: Formation, Evolution, Phenomena #astro-ph
paper · pdf · doi:10.1086/344563
published as Astrophys.J. 578 (2002) L31-L36 · accepted by Ap J Letters
arxiv created 2002/09/04 · openalex publication_date 2002/09/24 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/01
A new broad absorption line (BAL) quasar sample is derived from the first data released by the Sloan Digital Sky Survey. With 116 objects, it is the largest BAL quasar sample yet assembled. Over the redshift range 1.8 ≤ z ≤ 3.8, the crude fraction with broad absorption in the C IV line is ≃15%. This fraction may be subject to small selection-efficiency adjustments. There are also hints of redshift dependence in the BAL quasar fraction. The sample is large enough to permit the first estimate of the distribution of the "balnicity index": subject to certain arbitrary parameters in the definition of this quantity, it is very broad, with (roughly) equal numbers of objects per logarithmic interval of balnicity. BAL quasars are also found to be redder on average than non-BAL quasars. The fraction of radio-loud BAL quasars is (weakly) consistent with the fraction of radio-loud ordinary quasars.