IDCS J1426.5+3508: Sunyaev-Zel'dovich Measurement of a Massive IR-selected Cluster at z=1.75

TL;DR

This paper reports the detection of the most distant and massive galaxy cluster at z=1.75 via Sunyaev-Zel'dovich effect, confirming its mass and rarity, and discusses future prospects for high-redshift cluster studies.

Contribution

First Sunyaev-Zel'dovich detection of a z=1.75 galaxy cluster, demonstrating the method's effectiveness at high redshift and mass, and highlighting its role alongside infrared surveys.

Findings

Detected Sunyaev-Zel'dovich decrement at 31 GHz.

Estimated cluster mass of approximately 4.3 x 10^{14} Msun.

Most distant and massive cluster detected via SZ effect to date.

Abstract

We report 31 GHz CARMA observations of IDCS J1426.5+3508, an infrared-selected galaxy cluster at z = 1.75. A Sunyaev-Zel'dovich decrement is detected towards this cluster, indicating a total mass of M200 = (4.3 +/- 1.1) x 10^{14} Msun in agreement with the approximate X-ray mass of ~5 x 10^{14} Msun. IDCS J1426.5+3508 is by far the most distant cluster yet detected via the Sunyaev-Zel'dovich effect, and the most massive z >= 1.4 galaxy cluster found to date. Despite the mere ~1% probability of finding it in the 8.82 deg^2 IRAC Distant Cluster Survey, IDCS J1426.5+3508 is not completely unexpected in LCDM once the area of large, existing surveys is considered. IDCS J1426.5+3508 is, however, among the rarest, most extreme clusters ever discovered, and indeed is an evolutionary precursor to the most massive known clusters at all redshifts. We discuss how imminent, highly sensitive Sunyaev-Zel'dovich experiments will complement infrared techniques for statistical studies of the formation of the most massive galaxy clusters in the z > 1.5 Universe, including potential precursors to IDCS J1426.5+3508.