Signature of outflows in strong MgII absorbers in quasar sightlines

TL;DR

This study finds a correlation between quasar luminosity and MgII absorber velocities, suggesting that many absorbers are driven by quasar radiation outflows originating near the dust sublimation radius.

Contribution

It demonstrates a power-law relationship between MgII absorber velocity offsets and quasar luminosity, supporting a radiation-driven outflow model.

Findings

Velocity offset beta increases with bolometric luminosity as a power law.

A significant fraction of MgII absorbers are associated with quasar outflows.

Outflows are likely launched from the dust sublimation radius.

Abstract

We report a correlation between velocity offset (beta = v/c) of strong Mg II absorption systems and the bolometric luminosity (L_bol) of quasars in SDSS-DR7. We find that, beta shows a power law increase with L_bol, with a slope (~ 1/4). We find that such a relation of beta with L_bol is expected for outflows driven by scattering of black hole radiation by dust grains, and which are launched from the innermost dust survival radius. Our results indicate that a significant fraction of the strong MgII absorbers, in the range of beta = (0--0.4) may be associated with the quasars themselves.