Low Redshift BAL QSOs in the Eigenvector 1 Context

TL;DR

This study characterizes the geometry of low redshift BAL QSOs, revealing their association with Population A quasars, and suggests that luminosity and black hole mass ratio influence outflow properties, supporting a disk wind model.

Contribution

It provides new insights into the geometry and physical mechanisms of BAL QSOs at low redshift, including correlations with luminosity and a proposed outflow model involving the BLR.

Findings

Most low redshift BAL QSOs are Population A quasars.

A correlation between terminal velocity and absolute V magnitude suggests luminosity-to-mass ratio influences outflows.

CIV emission profiles support a disk wind/outflow scenario with a half opening angle < 50 degrees.

Abstract

We attempt to characterize the geometry of Broad Absorption Line (BAL) QSOs by studying a low redshift sample of 12 sources. We find that the majority of these sources are Population A quasars as defined in (broad H-beta FWHM > 4000 kms/s; Sulenticet al 2000). A possible correlation between terminal velocity and absolute V magnitude suggests that the bolometric luminosity to black hole mass ratio \lm is a governing factor with classical BAL sources showing the highest values. CIV 1549 emission in classical BAL sources shows a profile blueshift that supports a disk wind/outflow scenario with a half opening angle of < 50 deg. Observation of ``secondary'' mini-BAL features in the CIV 1549 emission profile motivates us to model BALs with an additional component that may be involved with the BLR outflow and co-axial with the accretion disk.