An X-Ray[endash]Selected Galaxy Cluster at [bold [ital z]] = 1. 26

Journal Article · Thu Jul 01 00:00:00 EDT 1999 · Astronomical Journal

DOI:https://doi.org/10.1086/300934· OSTI ID:6083897

Rosati, P ^[1]; Stanford, S A ^[2]; Eisenhardt, P R ^[3]; Elston, R ^[4]; Spinrad, H; Stern, D ^[5]; Dey, A ^[6]

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1. Physics Department, University of California at Davis, Davis, CA 95616 (United States) European Southern Observatory, Karl-Schwarzschild-Strasse 2, D-85748 Garching bei Muenchen (Germany)
2. Institute of Geophysics and Planetary Physics, Lawrence Livermore National Laboratory, P.O. Box 808, L-413, Livermore, CA 94550 (United States)
3. Physics Department, University of California at Davis, Davis, CA 95616 (United States) Jet Propulsion Laboratory, California Institute of Technology, Mail Stop 100-22, Pasadena, CA 91109 (United States)
4. Physics Department, University of California at Davis, Davis, CA 95616 (United States) Department of Astronomy, University of Florida, P.O. Box 112055, Gainesville, FL 32611 (United States)
5. Department of Astronomy, 601 Campbell Hall No. 3411, University of California, Berkeley, CA 94720 (United States)
6. National Optical Astronomy Observatories, 950 North Che

We report the discovery of an X-ray[endash]luminous galaxy cluster at z=1.26. RX J0848.9+4452 was selected as an X-ray cluster candidate in the [ital ROSAT] Deep Cluster Survey on the basis of its spatial extent. Deep optical and near-IR imaging have revealed a galaxy overdensity around the peak of the X-ray emission, with a significant excess of red objects with [ital J][minus][ital K] colors typical of elliptical galaxies at z[gt]1. Spectroscopic observations at the Keck II Telescope have secured six galaxy redshifts in the range 1.257[lt]z[lt]1.267 ([l angle]z[r angle]=1.261) within a 35[double prime] radius around the peak X[endash]ray emission. This system lies only 4 arcmin;2 away (5.0thinsph[sup [minus]1] [sub 50] comoving Mpc, q[sub 0] =0.5) from the galaxy cluster ClG J0848+4453, which was identified at z=1.273 in a near-IR field galaxy survey and is also known to be X-ray luminous. Assuming that the X-ray emission is entirely due to hot intracluster gas, both these systems have similar rest-frame luminosities L[sub X] [approx]1[times]10[sup 44] ergs s[sup [minus]1] (0.5[endash]2.0 keV band). In combination with our spectrophotometric data for the entire 30 arcmin[sup 2] field, this suggests the presence of a superstructure consisting of two collapsed, possibly virialized, clusters, the first detected to date at z[gt]1. [copyright] [ital [copyright] 1999.] [ital The American Astronomical Society]

• OSTI ID: 6083897
• Journal Information: Astronomical Journal, Journal Name: Astronomical Journal Vol. 118:1; ISSN ANJOAA; ISSN 0004-6256
• Country of Publication: United States
• Language: English

Related Subjects

661300* -- Other Aspects of Physical Science-- (1992-)
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
BRIGHTNESS
ELECTROMAGNETIC RADIATION
GALACTIC EVOLUTION
GALAXY CLUSTERS
INTERGALACTIC SPACE
IONIZING RADIATIONS
LUMINOSITY
OPTICAL PROPERTIES
PHYSICAL PROPERTIES
RADIATIONS
RED SHIFT
SPACE
SPECTRA
X RADIATION
X-RAY SPECTRA