Outflows and the physical properties of quasars

Research output: Contribution to journalJournal articleResearchpeer-review

We have investigated a sample of 5088 quasars from the SDSS DR2 in order to determine how the frequency and properties of BALs depend on black hole mass, bolometric luminosity, Eddington fraction (L/LEdd), and spectral slope. We focus only on high-ionization BALs and find a number of significant results. While quasars accreting near the Eddington limit are more likely to show BALs than lower L/LEdd systems, BALs are present in quasars accreting at only a few percent Eddington. We find a stronger effect with bolometric luminosity, such that the most luminous quasars are more likely to show BALs. There is an additional effect, previously known, that BAL quasars are redder on average than unabsorbed quasars. The strongest effects involving the quasar physical properties and BAL properties are related to terminal outflow velocity. Maximum observed outflow velocities increase with both the bolometric luminosity and the blueness of the spectral slope, suggesting that the ultraviolet luminosity to a great extent determines the acceleration. These results support the idea of outflow acceleration via ultraviolet line scattering.

Original languageEnglish
JournalAstrophysical Journal
Volume665
Issue number2 I
Pages (from-to)990-1003
Number of pages14
ISSN0004-637X
DOIs
Publication statusPublished - 10 Aug 2007
Externally publishedYes

    Research areas

  • Quasars: Absorption lines, Quasars: General

ID: 229913097