Dark Energy Survey Year 1 Results: The effect of intracluster light on photometric redshifts for weak gravitational lensing

TL;DR

This study assesses how intracluster light impacts photometric redshift estimates and weak lensing mass measurements, finding negligible bias for DES but potential issues for deeper surveys like LSST.

Contribution

It provides the first analysis of intracluster light effects on photometric redshifts and weak lensing mass estimates, offering guidance for future survey corrections.

Findings

Bias is negligible for DES with >=200 kpc scale cut.

Deeper surveys like LSST may require more conservative cuts or corrections.

Implications for achieving percent-level accuracy in cluster mass measurements.

Abstract

We study the effect of diffuse intracluster light on the critical surface mass density estimated from photometric redshifts of lensing source galaxies, and the resulting bias in a weak lensing measurement of galaxy cluster mass. Under conservative assumptions, we find the bias to be negligible for imaging surveys like the Dark Energy Survey (DES) with a recommended scale cut of >=200 kpc distance from cluster centers. For significantly deeper source catalogs from present and future surveys like the Large Synoptic Survey Telescope (LSST) program, more conservative scale and source magnitude cuts or a correction of the effect may be necessary to achieve per-cent level lensing measurement accuracy, especially at the massive end of the cluster population.