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 M _ { \mbox { \scriptsize 200 ,m } } = ( 4.3 \pm 1.1 ) \times 10 ^ { 14 } M _ { \odot } in agreement with the approximate X-ray mass of \sim 5 \times 10 ^ { 14 } M _ { \odot } .
IDCS J1426.5+3508 is by far the most distant cluster yet detected via the Sunyaev–Zel ’ dovich effect , and the most massive z \geq 1.4 galaxy cluster found to date .
Despite the mere \sim 1 \% probability of finding it in the 8.82 deg ^ { 2 } IRAC Distant Cluster Survey , IDCS J1426.5+3508 is not completely unexpected in \Lambda CDM 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 .