Detailed Cluster Mass and Light profiles of A1703, A370 and RXJ1347-11 from Deep Subaru Imaging

TL;DR

This study uses multi-colour Subaru imaging to accurately separate cluster members from foreground and background galaxies in three massive clusters, enabling detailed analysis of their mass and light profiles, and revealing consistent luminosity functions and M/L ratio behaviors.

Contribution

It introduces a method leveraging multi-colour space to effectively distinguish cluster members, improving the accuracy of cluster mass and light profile measurements.

Findings

Luminosity functions show similar faint-end slopes (~ -1.0) with no faint-end upturn.

M/L ratio peaks at ~0.2r_{vir} and declines towards the virial radius.

Radial M/L decline is linked to the distribution of galaxy types within clusters.

Abstract

Weak lensing work can be badly compromised by unlensed foreground and cluster members which dilute the true lensing signal. We show how the lensing amplitude in multi-colour space can be harnessed to securely separate cluster members from the foreground and background populations for three massive clusters, A1703 (z=0.258), A370 (z=0.375) and RXJ1347-11 (z=0.451) imaged with Subaru. The luminosity functions of these clusters when corrected for dilution, show similar faint-end slopes, \alpha ~= -1.0, with no marked faint-end upturn to our limit of M_R ~= -15.0, and only a mild radial gradient. In each case, the radial profile of the M/L ratio peaks at intermediate radius, ~=0.2r_{vir}, at a level of 300-500(M/L_R)_\odot, and then falls steadily towards ~100(M/L_R)_{\odot} at the virial radius, similar to the mean field level. This behaviour is likely due to the relative paucity of central late-type galaxies, whereas for the E/S0-sequence only a mild radial decline in M/L is found for each cluster. We discuss this behaviour in the context of detailed simulations where predictions for tidal stripping may now be tested accurately with observations.