The VST ATLAS Quasar Survey II: Halo mass profiles of galaxies, LRGs and galaxy clusters via quasar and CMB lensing

TL;DR

This study uses quasar and CMB lensing to measure the halo mass profiles of galaxies, LRGs, and clusters, revealing insights into galaxy-halo connections and testing cosmological models.

Contribution

It provides new measurements of halo mass profiles via lensing, compares HOD models with observations, and highlights discrepancies in lensing amplitudes.

Findings

Galaxy clusters fit NFW profiles with expected masses.

Galaxy-quasar cross-correlation aligns with previous SDSS results.

Observed lensing amplitudes suggest potential model tensions.

Abstract

We cross-correlate a low-contamination subset of the VST ATLAS g < 22.5 quasar catalogue with g < 21.5 galaxy clusters, r < 21 galaxies and r < 19.5 Luminous Red Galaxies (LRGs) to probe their halo mass profiles via quasar magnification bias caused by weak lensing. In the case of galaxy clusters we find that at small scales their mass profiles are well fitted by Navarro, Frenk and White (NFW) models with masses within the expected range. For the galaxies, we find consistency with previous SDSS-based results for the galaxy-quasar cross-correlation and the galaxy auto-correlation functions. Disagreement as to whether the cross-correlation results are in tension with $\Lambda$CDM appears due to different assumptions as to whether galaxies trace mass. We conclude that halo occupation distribution (HOD) models fit the galaxy - quasar lensing results better than models where galaxies trace the mass. We further test the cluster and galaxy HOD models in the 2-halo range using the Planck Cosmic Microwave Background (CMB) lensing map, finding that the cross-correlation with both the poorest clusters and the galaxies may be marginally over-predicted by the above HOD models. Finally, we measure the magnification bias of LRGs using both quasar and CMB lensing and find that the observed quasar lensing amplitude may be $\approx 2\times$ too high and, on larger scales, the CMB lensing amplitude may be too low to be explained by a standard LRG HOD model.