Mean Occupation Function of High Redshift Quasars from the Planck Cluster Catalog

TL;DR

This study measures how quasars are distributed within dark matter halos at high redshift, revealing a power-law relationship indicating increasing quasar fraction with halo mass up to redshift 1.

Contribution

First direct measurement of quasar occupation in dark matter halos at redshift ~1 using Planck SZ and SDSS data, establishing a power-law model for quasar distribution.

Findings

Quasar occupation follows a power-law with halo mass.

Quasar fraction increases with halo mass at high redshift.

Distribution consistent with monotonic increase up to z~1.

Abstract

We characterise the distribution of quasars within dark matter halos using a direct measurement technique for the first time at redshifts as high as $z \sim 1$. Using the Planck Sunyaev-Zeldovich (SZ) catalogue for galaxy groups and the Sloan Digital Sky Survey (SDSS) DR12 quasar dataset, we assign host clusters/groups to the quasars and make a measurement of the mean number of quasars within dark matter halos as a function of halo mass. We find that a simple power-law fit of $\log\left <N\right> = (2.11 \pm 0.01) \log (M) -(32.77 \pm 0.11)$ can be used to model the quasar fraction in dark matter halos. This suggests that the quasar fraction increases monotonically as a function of halo mass even to redshifts as high as $z\sim 1$.