Black Hole - Bulge Relationship of Post-Starburst Quasars at z \sim 0.3

TL;DR

This study measures stellar velocity dispersions in six post-starburst quasars at z ~ 0.3, revealing their placement on the MBH - sigma* relation and providing new insights into black hole-host galaxy co-evolution beyond the local universe.

Contribution

First direct measurements of sigma* in post-starburst quasars at z ~ 0.3, expanding the understanding of black hole and galaxy relations at intermediate redshifts.

Findings

Post-starburst quasars lie on or above the local MBH - sigma* relation.

They are generally consistent with the MBH - Lbulge relation.

Some bulges may be dynamically peculiar based on Faber-Jackson relation analysis.

Abstract

The MBH - {\sigma}\ast relation has been studied extensively for local galaxies, but to date there have been scarce few direct measurements of stellar velocity dispersions for systems beyond the local universe. We investigate black hole and host galaxy properties of six "post-starburst quasars" at z \sim 0.3. Spectra of these objects simultaneously display features from the active nucleus including broad emission lines and a host galaxy Balmer absorption series indicative of the post-starburst stellar population. These are the first measurements of {\sigma}\ast in such objects, and we significantly increase the number of directly-measured non-local objects on the MBH - {\sigma}\ast diagram. The "post-starburst quasars" of our sample fall on or above the locally defined MBH - {\sigma}\ast relation, a result that is consistent with previous MBH - {\sigma}\ast studies of samples at z > 0.1. However, they are generally consistent with the MBH-Lbulge relation. Futhermore, their location on the Faber-Jackson relation suggests that some of the bulges may be dynamically peculiar.