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

Understand

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.