Head-Tail Galaxies: Beacons of High-Density Regions in Clusters - AstrophysicsReport as inadecuate

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Abstract: Using radio data at 1.4 GHz from the ATCA we identify five head-tail HTgalaxies in the central region of the Horologium-Reticulum Supercluster HRS.Physical parameters of the HT galaxies were determined along with substructurein the HRS to probe the relationship between environment and radio properties.Using a density enhancement technique applied to 582 spectroscopic measurementsin the 2 degree x 2 degree region about A3125-A3128, we find all five HTgalaxies reside in regions of extremely high density >100 galaxies-Mpc^3. Infact, the environments surrounding HT galaxies are statistically denser thanthose environments surrounding non-HT galaxies and among the densestenvironments in a cluster. Additionally, the HT galaxies are found in regionsof enhanced X-ray emission and we show that the enhanced density continues outto substructure groups of 10 members. We propose that it is the high densitiesthat allow ram pressure to bend the HT galaxies as opposed to previouslyproposed mechanisms relying on exceptionally high peculiar velocities.

Author: Minnie Y. Mao 1, Melanie Johnston-Hollitt 1, Jamie B. Stevens 1, Simon J. Wotherspoon 1 1 School of Mathematics and Physics, Univ

Source: https://arxiv.org/

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