Optical followup of galaxy clusters detected by the South Pole Telescope

TL;DR

This paper discusses the optical followup observations of galaxy clusters detected by the South Pole Telescope, aiming to characterize their properties and support cosmological research.

Contribution

It presents a comprehensive optical and near-infrared followup program for SPT-detected clusters, including imaging, redshift measurement, and contamination estimation.

Findings

Identification of high-significance SPT clusters

Photometric redshift measurements for clusters

Assessment of candidate list contamination

Abstract

The South Pole Telescope (SPT) is a 10 meter telescope operating at mm wavelengths. It has recently completed a three-band survey covering 2500 sq. degrees. One of the survey's main goals is to detect galaxy clusters using Sunyaev-Zeldovich effect and use these clusters for a variety of cosmological and astrophysical studies such as the dark energy equation of state, the primordial non-gaussianity and the evolution of galaxy populations. Since 2005, we have been engaged in a comprehensive optical and near-infrared followup program (at wavelengths between 0.4 and 5 {\mu}m) to image high-significance SPT clusters, to measure their photometric redshifts, and to estimate the contamination rate of the candidate lists. These clusters are then used for various cosmological and astrophysical studies.