A SPITZER-SELECTED GALAXY CLUSTER AT z = 1.62

Journal Article · Sun Jun 20 00:00:00 EDT 2010 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/716/2/1503· OSTI ID:21452900

Papovich, C; Finkelstein, K D; Finkelstein, S L; Tran, K -V ^[1]; Momcheva, I; McCarthy, P ^[2]; Willmer, C N. A.; Rieke, M; Sivanandam, S ^[3]; Brodwin, M ^[4]; Dunlop, J S; McLure, R J ^[5]; Farrah, D ^[6]; Khan, S A ^[7]; Lotz, J ^[8]; Rudnick, G ^[9]; Pacaud, F ^[10]; Pierre, M ^[11]

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1. George P. and Cynthia Woods Mitchell Institute for Fundamental Physics and Astronomy, and Department of Physics and Astronomy, Texas A and M University, College Station, TX 77843-4242 (United States)
2. Observatories, Carnegie Institution of Washington, 813 Santa Barbara Street, Pasadena, CA 91101 (United States)
3. Steward Observatory, University of Arizona, 933 N. Cherry Avenue, Tucson, AZ 85721 (United States)
4. Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)
5. Institute for Astronomy, Royal Observatory, University of Edinburgh, Edinburgh (United Kingdom)
6. Astronomy Centre, University of Sussex, Falmer, Brighton (United Kingdom)
7. Pontificia Universidad Catolica, Departamento de Astronomia y Astrofisica, 4860 Av. Vicuna Mackenna, Casilla 306, Santiago 22 (Chile)
8. National Optical Astronomy Observatories, 950 N. Cherry Avenue, Tucson, AZ 85719 (United States)
9. Department of Physics and Astronomy, University of Kansas, 1251 Wescoe Hall Drive, Lawrence, KS 66045-7582 (United States)
10. Argelander Institute for Astronomy, Bonn University, Auf dem Huegel 71, 53121 Bonn (Germany)
11. Service d'Astrophysique, CEA Saclay, 91191 Gif sur Yvette (France)

We report the discovery of a galaxy cluster at z = 1.62 located in the Spitzer Wide-Area Infrared Extragalactic survey XMM-LSS field. This structure was selected solely as an overdensity of galaxies with red Spitzer/Infrared Array Camera colors, satisfying ([3.6] - [4.5]){sub AB}> - 0.1 mag. Photometric redshifts derived from the Subaru XMM Deep Survey (BViz bands), the UKIRT Infrared Deep Survey-Ultra-Deep Survey (UKIDSS-UDS, JK bands), and from the Spitzer Public UDS survey (3.6-8.0 {mu}m) show that this cluster corresponds to a surface density of galaxies at z {approx} 1.6 that is >20{sigma} above the mean at this redshift. We obtained optical spectroscopic observations of galaxies in the cluster region using IMACS on the Magellan telescope. We measured redshifts for seven galaxies in the range z = 1.62-1.63 within 2.8 arcmin (<1.4 Mpc) of the astrometric center of the cluster. A posteriori analysis of the XMM data in this field reveal a weak (4{sigma}) detection in the [0.5-2 keV] band compatible with the expected thermal emission from such a cluster. The color-magnitude diagram of the galaxies in this cluster shows a prominent red sequence, dominated by a population of red galaxies with (z - J)>1.7 mag. The photometric-redshift probability distributions for the red galaxies are strongly peaked at z = 1.62, coincident with the spectroscopically confirmed galaxies. The rest-frame (U - B) color and scatter of galaxies on the red sequence are consistent with a mean luminosity-weighted age of 1.2 {+-} 0.1 Gyr, yielding a formation redshift z-bar{sub f}=2.35{+-}0.10, and corresponding to the last significant star formation period in these galaxies.

• OSTI ID: 21452900
• Journal Information: Astrophysical Journal, Vol. 716, Issue 2; Other Information: DOI: 10.1088/0004-637X/716/2/1503; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
COLOR
EMISSION
GALACTIC EVOLUTION
GALAXIES
GALAXY CLUSTERS
LUMINOSITY
PROBABILITY
RED SHIFT
STARS
TELESCOPES
UNIVERSE
EVOLUTION
OPTICAL PROPERTIES
ORGANOLEPTIC PROPERTIES
PHYSICAL PROPERTIES