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JKCS 041: a Coma cluster progenitor at z = 1.803

Andreon, S. and Newman, A. B. and Trinchieri, G. and Raichoor, A. and Ellis, R. S. and Treu, T. (2014) JKCS 041: a Coma cluster progenitor at z = 1.803. Astronomy and Astrophysics, 565 . Art. No. A120. ISSN 0004-6361.

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Using deep two-color near-infrared HST imaging and unbiased grism spectroscopy, we present a detailed study of the z = 1.803 JKCS 041 cluster. We confirm, for the first time for a high-redshift cluster, a mass of log M ≳ 14.2 in solar units using four different techniques based on the X-ray temperature, the X-ray luminosity, the gas mass, and the cluster richness. JKCS 041 is thus a progenitor of a local system like the Coma cluster. Our rich dataset and the abundant population of 14 spectroscopically confirmed red-sequence galaxies allows us to explore the past star formation history of this system in unprecedented detail. Our most interesting result is a prominent red sequence down to stellar masses as low as log M/M_⊙ = 9.8, corresponding to a mass range of 2 dex. These quiescent galaxies are concentrated around the cluster center with a core radius of 330 kpc. There are only few blue members and avoid the cluster center. In JKCS 041 quenching was therefore largely completed by a look-back time of 10 Gyr, and we can constrain the epoch at which this occurred via spectroscopic age-dating of the individual galaxies. Most galaxies were quenched about 1.1 Gyr prior to the epoch of observation. The less-massive quiescent galaxies are somewhat younger, corresponding to a decrease in age of 650 Myr per mass dex, but the scatter in age at fixed mass is only 380 Myr (at log M/M⊙ = 11). There is no evidence for multiple epochs of star formation across galaxies. The size–mass relation of quiescent galaxies in JKCS 041 is consistent with that observed for local clusters within our uncertainties, and we place an upper limit of 0.4 dex on size growth at fixed stellar mass (95% confidence). Comparing our data on JKCS 041 with 41 clusters at lower redshift, we find that the form of the mass function of red sequence galaxies has hardly evolved in the past 10 Gyr, both in terms of its faint-end slope and characteristic mass. Despite observing JKCS 041 soon after its quenching and the three-fold expected increase in mass in the next 10 Gyr, it is already remarkably similar to present-day clusters.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Newman, A. B.0000-0001-7769-8660
Ellis, R. S.0000-0001-7782-7071
Treu, T.0000-0002-8460-0390
Additional Information:© 2014 ESO. Article published by EDP Sciences. Received 18 November 2013; Accepted 3 May 2014. S.A. acknowledges Veronica Strazzullo for comments on an early version of this draft and Stefano Ettori and Fabio Gastaldello for the JKCS 041 gas mass computation. We acknowledge HST, program 12927, and CFHT, see full-text acknowledgements at and html. A.R. acknowledges financial contribution from the agreement ASI-INAF I/009/10/0 and from Osservatorio Astronomico di Brera.
Funding AgencyGrant Number
Osservatorio Astronomico di BreraUNSPECIFIED
Subject Keywords:galaxies: clusters: individual: JKCS041; galaxies: clusters: general; galaxies: elliptical and lenticular, cD; galaxies: evolution; methods: statistical
Record Number:CaltechAUTHORS:20140707-093704943
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Official Citation:Andreon, S., Newman, A. B., Trinchieri, G., Raichoor, A., Ellis, R. S., & Treu, T. (2014). JKCS 041: a Coma cluster progenitor at z = 1.803. A&A, 565, A120.
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:46869
Deposited By: Jason Perez
Deposited On:07 Jul 2014 19:40
Last Modified:03 Oct 2019 06:47

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