A weak lensing comparability study of galaxy mergers that host AGNs

TL;DR

This study uses weak gravitational lensing to compare the mass density profiles of different galaxy types, finding no significant link between merger activity, quasar hosting, and dark matter halo profiles.

Contribution

It provides the first comparative analysis of halo profiles across galaxy types hosting quasars and post-starburst galaxies, revealing no strong connection between black hole activity and dark matter halos.

Findings

No difference in halo profiles among galaxy types.

Quasar-hosting galaxies have similar mass profiles to non-quasar galaxies.

Mass profiles are consistent with isothermality.

Abstract

We compared the total mass density profiles of three different types of galaxies using weak gravitational lensing: (i) 29 galaxies that host quasars at z~0.32 that are in a post-starburst (PSQ) phase with high star formation indicating recent merger activity, (ii) 22 large elliptical galaxies from the SLACS sample that do not host a quasar at z~0.23, and (iii) 17 galaxies that host moderately luminous quasars at z~0.36 powered by disk instabilities, but with no intense star formation. On an initial test we found no evidence for a connection between the merger state of a galaxy and the profile of the halo, with the PSQ profile comparable to that of the other two samples and consistent with the Leauthaud et al. (2014) study of moderately luminous quasars in COSMOS. Given the compatibility of the two quasar samples, we combined these and found no evidence for any connection between black hole activity and the dark matter halo. All three mass profiles remained compatible with isothermality given the present data.