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The dynamical distinction between elliptical and lenticular galaxies in distant clusters: further evidence for the recent origin of S0 galaxies

Moran, Sean M. and Loh, Boon Liang and Ellis, Richard S. and Treu, Tommaso and Bundy, Kevin and MacArthur, Lauren A. (2007) The dynamical distinction between elliptical and lenticular galaxies in distant clusters: further evidence for the recent origin of S0 galaxies. Astrophysical Journal, 665 (2). pp. 1067-1073. ISSN 0004-637X.

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We examine resolved spectroscopic data obtained with the Keck II telescope for 44 spheroidal galaxies in the fields of two rich clusters, Cl 0024+16 (z = 0.40) and MS 0451-03 (z = 0.54) and contrast this with similar data for 23 galaxies within the redshift interval 0.3 < z < 0.65 in the GOODS northern field. For each galaxy we examine the case for systemic rotation, derive central stellar velocity dispersions σ and photometric ellipticities ε. Using morphological classifications obtained via Hubble Space Telescope imaging as the basis, we explore the utility of our kinematic quantities in distinguishing between pressure-supported ellipticals and rotationally supported lenticulars (S0s). We demonstrate the reliability of using the v/(1 - e ) versus σ and v/σ versus distributions as discriminators, finding that the two criteria correctly identify 63% ± 3% and 80% ± 2% of S0s at z ~ 0.5, respectively, along with 76^[+8][-3]% and 79% ± 2% of ellipticals. We test these diagnostics using equivalent local data in the Coma Cluster, and find that the diagnostics are similarly accurate at z = 0. Our measured accuracies are comparable to the accuracy of visual classification of morphologies, but avoid the band-shifting and surface brightness effects that hinder visual classification at high redshifts. As an example application of our kinematic discriminators, we then examine the morphology-density relation for elliptical and S0 galaxies separately at z ~ 0.5. We confirm, from kinematic data alone, the recent growth of rotationally supported spheroidals. We discuss the feasibility of extending the method to a more comprehensive study of cluster and field galaxies to z ≃ 1, in order to verify in detail the recent density-dependent growth of S0 galaxies.

Item Type:Article
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URLURL TypeDescription
Moran, Sean M.0000-0002-9194-5071
Ellis, Richard S.0000-0001-7782-7071
Treu, Tommaso0000-0002-8460-0390
Bundy, Kevin0000-0001-9742-3138
Additional Information:© 2007 American Astronomical Society. Print publication: Issue 2 (2007 August 20); received 2007 January 4; accepted for publication 2007 April 30. Faint object spectroscopy at with DEIMOS at Keck Observatory is made possible with the efforts of P. Amico, S. Faber, and G. Wirth. The analysis pipeline for reducing DEIMOS data was developed at UC Berkeley with support from NSF grant AST-0071048. R. S. E. acknowledges financial support from NSF grant AST-0307859 and STScI grants HST-GO-08559.01-A and HST-GO-09836.01-A.
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Subject Keywords:galaxies: clusters: general; galaxies: elliptical and lenticular, cD; galaxies: evolution; galaxies: spiral; galaxies: stellar content
Issue or Number:2
Record Number:CaltechAUTHORS:20090415-113206678
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:13984
Deposited By: Jason Perez
Deposited On:20 Apr 2009 19:30
Last Modified:05 Nov 2019 23:29

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