Testing Models of Quasar Hosts With Strong Gravitational Lensing by Quasar Hosts

TL;DR

This study compares two models of quasar host halos using strong gravitational lensing data, showing that lensing probabilities differ significantly between models and can be used to distinguish them observationally.

Contribution

It demonstrates that strong gravitational lensing can effectively test and differentiate between HOD and CS models of quasar host halos using simulation and observational data.

Findings

Lensing probability differs by over two orders of magnitude between models.

At CANDELS survey depth, models can be distinguished at 3-4 sigma confidence.

Lensing provides a powerful test for quasar host halo models.

Abstract

We perform a statistical analysis of strong gravitational lensing by quasar hosts of background galaxies, in the two competing models of dark matter halos of quasars, HOD and CS models. Utilizing the BolshoiP Simulation we demonstrate that strong gravitational lensing provides a potentially very powerful test of models of quasar hosting halos. For quasars at $z=0.5$, the lensing probability by quasars of background galaxies in the HOD model is higher than that of the CS model by two orders of magnitude or more for lensing image separations in the range of $\theta\sim 1.2-12~$arcsec. To observationally test this, we show that, as an example, at the depth of the CANDELS wide field survey and with a quasar sample of $1000$ at $z=0.5$, the two models can be differentiated at $3-4\sigma$ confidence level.