Outflows and the physical properties of quasars

TY - JOUR

T1 - Outflows and the physical properties of quasars

AU - Ganguly, Rajib

AU - Brotherton, Michael S.

AU - Cales, Sabrina

AU - Scoggins, Brian

AU - Shang, Zhaohui

AU - Vestergaard, Marianne

PY - 2007/8/10

Y1 - 2007/8/10

N2 - 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.

AB - 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.

KW - Quasars: Absorption lines

KW - Quasars: General

UR - http://www.scopus.com/inward/record.url?scp=40249113953&partnerID=8YFLogxK

U2 - 10.1086/519759

DO - 10.1086/519759

M3 - Journal article

AN - SCOPUS:40249113953

SN - 0004-637X

VL - 665

SP - 990

EP - 1003

JO - Astrophysical Journal

JF - Astrophysical Journal

IS - 2 I

ER -