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Head-tail Galaxies: beacons of high-density regions in clusters


Mao, MY and Johnston-Hollitt, M and Stevens, JB and Wotherspoon, SJ, Head-tail Galaxies: beacons of high-density regions in clusters, Royal Astronomical Society. Monthly Notices, 392, (2) pp. 1070-1079. ISSN 0035-8711 (2009) [Refereed Article]

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DOI: doi:10.1111/j.1365-2966.2008.14141.x


Using radio data at 1.4 GHz from the Australia Telescope Compact Array (ATCA), we identify five head–tail (HT) galaxies in the central region of the Horologium–Reticulum Supercluster (HRS). Physical parameters of the HT galaxies were determined along with substructure in the HRS to probe the relationship between environment and radio properties. Using a density enhancement technique applied to 582 spectroscopic measurements in the 2°× 2° region about A3125/A3128, we find all five HT galaxies reside in regions of extremely high density (>100 galaxies Mpc−3). In fact, the environments surrounding HT galaxies are statistically denser than those environments surrounding non-HT galaxies and among the densest environments in a cluster. Additionally, the HT galaxies are found in regions of enhanced X-ray emission and we show that the enhanced density continues out to substructure groups of 10 members. We propose that it is the high densities that allow ram pressure to bend the HT galaxies as opposed to previously proposed mechanisms relying on exceptionally high peculiar velocities.

Item Details

Item Type:Refereed Article
Keywords:galaxies: clusters: general • radio continuum: galaxies • galaxies: clusters: individual: A3125 • galaxies: clusters: individual: A3128
Research Division:Physical Sciences
Research Group:Astronomical sciences
Research Field:Cosmology and extragalactic astronomy
Objective Division:Expanding Knowledge
Objective Group:Expanding knowledge
Objective Field:Expanding knowledge in the physical sciences
UTAS Author:Mao, MY (Miss Minnie Mao)
UTAS Author:Johnston-Hollitt, M (Dr Melanie Johnston-Hollitt)
UTAS Author:Stevens, JB (Dr Jamie Stevens)
UTAS Author:Wotherspoon, SJ (Dr Simon Wotherspoon)
ID Code:58782
Year Published:2009
Web of Science® Times Cited:25
Deposited By:Physics
Deposited On:2009-10-27
Last Modified:2010-03-25
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