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Galaxy Evolution in Overdense Environments at High Redshift: Passive Early-type Galaxies in a Cluster at z ~ 2

Strazzullo, V. and Gobat, R. and Daddi, E. and Onodera, M. and Carollo, M. and Dickinson, M. and Renzini, A. and Arimoto, N. and Cimatti, A. and Finoguenov, A. and Chary, R.-R. (2013) Galaxy Evolution in Overdense Environments at High Redshift: Passive Early-type Galaxies in a Cluster at z ~ 2. Astrophysical Journal, 772 (2). Art. No. 118. ISSN 0004-637X. doi:10.1088/0004-637X/772/2/118.

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We present a study of galaxy populations in the central region of the IRAC-selected, X-ray-detected galaxy cluster Cl J1449+0856 at z = 2. Based on a sample of spectroscopic and photometric cluster members, we investigate stellar populations and the morphological structure of cluster galaxies over an area of ~0.7 Mpc^2 around the cluster core. The cluster stands out as a clear overdensity both in redshift space and in the spatial distribution of galaxies close to the center of the extended X-ray emission. The cluster core region (r < 200 kpc) shows a clearly enhanced passive fraction with respect to field levels. However, together with a population of massive, passive galaxies mostly with early-type morphologies, the cluster core also hosts massive, actively star-forming, often highly dust reddened sources. Close to the cluster center, a multi-component system of passive and star-forming galaxies could represent the future brightest cluster galaxy still forming. We observe a clear correlation between passive stellar populations and an early-type morphology, in agreement with field studies at similar redshift. Passive early-type galaxies in this cluster are typically a factor of 2-3 smaller than similarly massive early types at z ~ 0. On the other hand, these same objects are on average larger by a factor of ~2 than field early-types at similar redshift, lending support to recent claims of an accelerated structural evolution in high-redshift dense environments. These results point toward the early formation of a population of massive galaxies, already evolved both in their structure and stellar populations, coexisting with still actively forming massive galaxies in the central regions of young clusters 10 billion years ago.

Item Type:Article
Related URLs:
URLURL TypeDescription DOIArticle Paper
Daddi, E.0000-0002-3331-9590
Carollo, M.0000-0003-1624-7609
Dickinson, M.0000-0001-5414-5131
Renzini, A.0000-0002-7093-7355
Finoguenov, A.0000-0002-4606-5403
Chary, R.-R.0000-0001-7583-0621
Alternate Title:Galaxy evolution in overdense environments at high redshift: passive early-type galaxies in a cluster at redshift 2
Additional Information:© 2013 The American Astronomical Society. Received 2012 December 20; accepted 2013 May 13; published 2013 July 15. We thank Maurilio Pannella, Anna Cibinel, Mark Sargent, Matthieu Béthermin, Gabriella De Lucia, and Stefano Andreon for their useful inputs, suggestions or comments at various stages of this work. V.S., R.G., and E.D. were supported by grants ERC-StG UPGAL 240039 and ANR-08-JCJC-0008. A.C. acknowledges the grants ASI n.I/023/12/0 “Attività relative alla fase B2/C per la missione Euclid” and MIUR PRIN 2010-2011 “The Dark Universe and the Cosmic Evolution of Baryons: from Current Surveys to Euclid.” Partly based on data collected at the Subaru Telescope, operated by the National Astronomical Observatory of Japan, and at the Very Large Telescope, operated by the European Southern Observatory. Partly based on observations made under program GO-11648 with the NASA/ESA Hubble Space Telescope, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. Partly based on observations made under programs GTO-64 and GO-80103 with the Spitzer Space Telescope, which is operated by the Jet Propulsion Laboratory, California Institute of Technology under a contract with NASA.
Group:Infrared Processing and Analysis Center (IPAC)
Funding AgencyGrant Number
European Research Council (ERC)240039
Agence Nationale pour la Recherche (ANR)ANR-08-JCJC-0008
Agenzia Spaziale Italiana (ASI)I/023/12/0
Ministero dell'Istruzione, dell'Università e della Ricerca (MIUR)UNSPECIFIED
NASANAS 5-26555
Subject Keywords:galaxies: clusters: individual (Cl J1449+0856) – galaxies: evolution – galaxies: high-redshift – galaxies: stellar content – galaxies: structure
Issue or Number:2
Record Number:CaltechAUTHORS:20130827-141148771
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Official Citation:Galaxy Evolution in Overdense Environments at High Redshift: Passive Early-type Galaxies in a Cluster at z ~ 2 V. Strazzullo et al. 2013 ApJ 772 118
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:40962
Deposited By: Tony Diaz
Deposited On:27 Aug 2013 23:53
Last Modified:10 Nov 2021 04:24

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