Impact of radio sources and cosmic infrared background on thermal Sunyaev-Zel'dovich - gravitational lensing cross correlation

TL;DR

This paper investigates how radio sources and cosmic infrared background influence the observed cross-correlation between the thermal Sunyaev-Zel'dovich effect and gravitational lensing, revealing significant impacts on measurements and interpretations.

Contribution

It quantifies the effects of radio sources and CIB on tSZ-lensing correlation, highlighting their roles in current observational tensions and the importance of minor radio source populations.

Findings

Residual CIB correlation is about 2% of the expected tSZ-lensing signal.

Radio sources can induce a negative correction of 10-30% in the observed correlation.

Radio-lensing correlation can resolve discrepancies between measurements and theoretical models.

Abstract

Cross correlation with thermal Sunyaev-Zel'dovich (tSZ) effect in cosmic microwave background observation and weak gravitational lensing effect in galaxy imaging survey opens a new window on constraining matter contents in the Universe at redshift less than 1. In this paper, we study the impact of radio sources and cosmic infrared background (CIB) on observed tSZ-lensing correlation. Assuming the best-fit model of CIB by the Planck satellite, we estimate that the residual correlation of CIB with large-scale structures will be of an order of $2\%$ of expected tSZ-lensing correlation from intracluster medium in current lensing surveys. On the other hand, despite large model uncertainties, we find that correlation of lensing and radio sources can induce a negative correction for the observed tSZ-lensing correlation with a $\sim10-30\%$ level. This is originated from positive cross correlation with radio sources and lensing at $\sim100\, {\rm GHz}$ frequency, whereas tSZ-lensing correlation should show a negative value in temperature fluctuations at that frequency. We also show that the negative correction by radio-lensing correlation can solve the tension between recent measurements of tSZ-lensing correlation and an expected signal from "universal" gas pressure profile of nearby galaxy clusters, when the radio sources with flat-spectral index are assumed to populate massive cluster-sized dark matte halos. Our results indicate that minor source population in radio bands can play an important role in determining observed tSZ-lensing correlation at $<10$ arcmin.