Revealing environmental dependence of molecular gas content in a distant X-ray cluster at z=2.51

Wang, Tao, Elbaz, David, Daddi, Emanuele, Liu, Daizhong, Kodama, Tadayuki, Tanaka, Ichi, Schreiber, Corentin, Zanella, Anita, Valentino, Francesco, Sargent, Mark, Kohno, Kotaro, Xiao, Mengyuan, Pannella, Maurilio, Cisela, Laure, Gobat, Raphael and Koyama, Yusei (2018) Revealing environmental dependence of molecular gas content in a distant X-ray cluster at z=2.51. Astrophysical Journal, 867 (2). pp. 1-7. ISSN 0004-637X

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We present a census of the molecular gas properties of galaxies in the most distant known X-ray cluster, CLJ1001, at z=2.51, using deep observations of CO(1-0) with JVLA. In total 14 cluster members with M∗>1010.5M⊙ are detected, including all the massive star-forming members within the virial radius, providing the largest galaxy sample in a single cluster at z>2 with CO(1-0) measurements. We find a large variety in the gas content of these cluster galaxies, which is correlated with their relative positions (or accretion states), with those closer to the cluster core being increasingly gas-poor. Moreover, despite their low gas content, the galaxies in the cluster center exhibit an elevated star formation efficiency (SFE=SFR/Mgas) compared to field galaxies, suggesting that the suppression on the SFR is likely delayed compared to that on the gas content. Their gas depletion time is around tdep∼400 Myrs, comparable to the cluster dynamical time. This implies that they will likely consume all their gas within a single orbit around the cluster center, and form a passive cluster core by z∼2. This result is one of the first direct pieces of evidence for the influence of environment on the gas reservoirs and SFE of z>2 cluster galaxies, thereby providing new insights into the rapid formation and quenching of the most massive galaxies in the early universe.

Item Type: Article
Schools and Departments: School of Mathematical and Physical Sciences > Physics and Astronomy
Research Centres and Groups: Astronomy Centre
Subjects: Q Science > QB Astronomy
Depositing User: Mark Sargent
Date Deposited: 28 Nov 2018 11:29
Last Modified: 28 Nov 2018 11:30

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