Desai, V. and Dalcanton, J. J. and Aragón-Salamanca, A. and Jablonka, P. and Poggianti, B. and Gogarten, S. M. and Simard, L. and Milvang-Jensen, B. and Rudnick, G. and Zaritsky, D. and Clowe, D. and Halliday, C. and Pelló, R. and Saglia, R. and White, S. (2007) The Morphological Content of 10 EDisCS Clusters at 0.5 < z < 0.8. Astrophysical Journal, 660 (2). pp. 1151-1164. ISSN 0004-637X http://resolver.caltech.edu/CaltechAUTHORS:20100218-113519002
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We describe Hubble Space Telescope (HST) imaging of 10 of the 20 ESO Distant Cluster Survey (EDisCS) fields. Each ~40 arcmin^2 field was imaged in the F814W filter with the Advanced Camera for Surveys Wide Field Camera. Based on these data, we present visual morphological classifications for the ~920 sources per field that are brighter than I_(auto) = 23 mag. We use these classifications to quantify the morphological content of 10 intermediate-redshift (0.5 < z < 0.8) galaxy clusters within the HST survey region. The EDisCS results, combined with previously published data from seven higher redshift clusters, show no statistically significant evidence for evolution in the mean fractions of elliptical, S0, and late-type (Sp+Irr) galaxies in clusters over the redshift range 0.5 < z < 1.2. In contrast, existing studies of lower redshift clusters have revealed a factor of ~2 increase in the typical S0 fraction between z = 0.4 and 0, accompanied by a commensurate decrease in the Sp+Irr fraction and no evolution in the elliptical fraction. The EDisCS clusters demonstrate that cluster morphological fractions plateau beyond z ≈ 0.4. They also exhibit a mild correlation between morphological content and cluster velocity dispersion, highlighting the importance of careful sample selection in evaluating evolution. We discuss these findings in the context of a recently proposed scenario in which the fractions of passive (E, S0) and star-forming (Sp, Irr) galaxies are determined primarily by the growth history of clusters.
|Additional Information:||© 2007 The American Astronomical Society. Received 2006 November 13; accepted 2007 January 25. We greatly appreciate the timely and cheerful assistance of Galina Soutchkova in planning the HST observations. We also thank the referee, Manolis Plionis, for feedback which improved the paper. V. D. acknowledges funding from the Graduate Student Researchers Program. This work was supported by NASA grant HST-GO-09476.01. J. J. D. was partially supported by the Alfred P. Sloan Foundation. The Medium Deep Survey catalog is based on observations with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute (STScI), which is operated by the Association of Universities for Research in Astronomy, Inc., underNASA contractNAS5-26555. The Medium-Deep Survey analysis was funded by the HST WFPC2 Teamand STScI grants GO2684, GO6951, GO7536, and GO8384 to Richard Griffiths and Kavan Ratnatunga at Carnegie Mellon University.|
|Subject Keywords:||galaxies : clusters : general; galaxies : evolution; galaxies : formation|
|Official Citation:||The Morphological Content of 10 EDisCS Clusters at 0.5 < z < 0.8 V. Desai, J. J. Dalcanton, A. Aragón-Salamanca, P. Jablonka, B. Poggianti, S. M. Gogarten, L. Simard, B. Milvang-Jensen, G. Rudnick, D. Zaritsky, D. Clowe, C. Halliday, R. Pelló, R. Saglia, and S. White 2007 ApJ 660 1151-1164 doi: 10.1086/513310|
|Usage Policy:||No commercial reproduction, distribution, display or performance rights in this work are provided.|
|Deposited By:||Tony Diaz|
|Deposited On:||19 Feb 2010 17:41|
|Last Modified:||26 Dec 2012 11:47|
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