Identifying dynamically young galaxy groups via wide-angle tail galaxies: a case study in the cosmos field at z= 0.53*

Oklopčić, Antonija and Smolčić, Vernesa and Giodini, S. and Zamorani, G. and Bîrzan, L. and Schinnerer, E. and Carilli, C. L. and Finoguenov, A. and Lilly, S. and Koekemoer, A. and Scoville, N. Z. (2010) Identifying dynamically young galaxy groups via wide-angle tail galaxies: a case study in the cosmos field at z= 0.53*. Astrophysical Journal, 713 (1). pp. 484-490. ISSN 0004-637X

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We present an analysis of a wide-angle tail (WAT) radio galaxy located in a galaxy group in the COSMOS field at a redshift of z = 0.53 (hereafter CWAT-02). We find that the host galaxy of CWAT-02 is the brightest galaxy in the group although it does not coincide with the center of mass of the system. Estimating (1) the velocity of CWAT-02, relative to the intra-cluster medium, and (2) the line-of-sight peculiar velocity of CWAT-02’s host galaxy, relative to the average velocity of the group, we find that both values are higher than those expected for a dominant galaxy in a relaxed system. This suggests that CWAT-02’s host group is dynamically young and likely in the process of an ongoing group merger. Our results are consistent with previous findings showing that the presence of a WAT galaxy in a galaxy group or cluster can be used as an indicator of dynamically young non-relaxed systems. Taking the unrelaxed state of CWAT-02’s host group into account, we discuss the impact of radio-active galactic nucleus (AGN) heating from CWAT-02 onto its environment, in the context of the missing baryon problem in galaxy groups. Our analysis strengthens recent results suggesting that radio-AGN heating may be powerful enough to expel baryons from galaxy groups.

Item Type: Article
Keywords: cosmology: observations, galaxies: active, galaxies: evolution, galaxies: fundamental parameters, radio continuum: galaxies
Date: 2010
Subjects: NATURAL SCIENCES > Physics > Astronomy and Astrophysics
Additional Information: © 2010 American Astronomical Society. Received 2009 November 6; accepted for publication 2010 February 23; published 2010 March 23. Based on observations with the National Radio Astronomy Observatory, which is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc.
Divisions: Faculty of Science > Department of Physics
Publisher: IOP Publishing
Depositing User: Vernesa Smolčić
Date Deposited: 22 Apr 2015 13:55
Last Modified: 24 Feb 2016 15:41

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