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Galaxy infall by interacting with its environment: a comprehensive study of 340 galaxy clusters

Galaxy infall by interacting with its environment: a comprehensive study of 340 galaxy clusters
Galaxy infall by interacting with its environment: a comprehensive study of 340 galaxy clusters
To study systematically the evolution of the angular extents of the galaxy, intracluster medium (ICM), and dark matter components in galaxy clusters, we compiled the optical and X-ray properties of a sample of 340 clusters with redshifts <0.5, based on all the available data from the Sloan Digital Sky Survey and Chandra/XMM-Newton. For each cluster, the member galaxies were determined primarily with photometric redshift measurements. The radial ICM mass distribution, as well as the total gravitational mass distribution, was derived from a spatially resolved spectral analysis of the X-ray data. When normalizing the radial profile of galaxy number to that of the ICM mass, the relative curve was found to depend significantly on the cluster redshift; it drops more steeply toward the outside in lower-redshift subsamples. The same evolution is found in the galaxy-to-total mass profile, while the ICM-to-total mass profile varies in an opposite way. The behavior of the galaxy-to-ICM distribution does not depend on the cluster mass, suggesting that the detected redshift dependence is not due to mass-related effects, such as sample selection bias. Also, it cannot be ascribed to various redshift-dependent systematic errors. We interpret that the galaxies, the ICM, and the dark matter components had similar angular distributions when a cluster was formed, while the galaxies traveling in the interior of the cluster have continuously fallen toward the center relative to the other components, and the ICM has slightly expanded relative to the dark matter although it suffers strong radiative loss. This cosmological galaxy infall, accompanied by an ICM expansion, can be explained by considering that the galaxies interact strongly with the ICM while they are moving through it. The interaction is considered to create a large energy flow of 1044?45 erg s?1 per cluster from the member galaxies to their environment, which is expected to continue over cosmological timescales.
1538-4357
1-21
Gu, Liyi
85f0b244-910c-4038-92f7-70af30496e91
Wen, Zhonglue
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Gandhi, Poshak
5bc3b5af-42b0-4dd8-8f1f-f74048d4d4a9
Inada, Naohisa
1ae97f9d-42f9-4166-8f28-79ac505333dd
Kawaharada, Madoka
8a90e97a-80e0-4fb5-b73c-daf76ce1c262
Kodama, Tadayuki
5a7c44de-9969-4ce7-bfd8-24d0c8716168
Konami, Saori
a3ad8cea-95b0-48af-b3dc-4e2d9e74a9ed
Nakazawa, Kazuhiro
b098c49c-a310-4ac1-8099-26113c89924c
Xu, Haiguang
6b4f8168-73de-4428-9d5c-f0e1237be11c
Makishima, Kazuo
73a9b59c-87d2-4705-bdcd-e7c2d88ef9df
Gu, Liyi
85f0b244-910c-4038-92f7-70af30496e91
Wen, Zhonglue
f69ba1e0-496f-44f9-897d-a3c2d232b398
Gandhi, Poshak
5bc3b5af-42b0-4dd8-8f1f-f74048d4d4a9
Inada, Naohisa
1ae97f9d-42f9-4166-8f28-79ac505333dd
Kawaharada, Madoka
8a90e97a-80e0-4fb5-b73c-daf76ce1c262
Kodama, Tadayuki
5a7c44de-9969-4ce7-bfd8-24d0c8716168
Konami, Saori
a3ad8cea-95b0-48af-b3dc-4e2d9e74a9ed
Nakazawa, Kazuhiro
b098c49c-a310-4ac1-8099-26113c89924c
Xu, Haiguang
6b4f8168-73de-4428-9d5c-f0e1237be11c
Makishima, Kazuo
73a9b59c-87d2-4705-bdcd-e7c2d88ef9df

Gu, Liyi, Wen, Zhonglue, Gandhi, Poshak, Inada, Naohisa, Kawaharada, Madoka, Kodama, Tadayuki, Konami, Saori, Nakazawa, Kazuhiro, Xu, Haiguang and Makishima, Kazuo (2016) Galaxy infall by interacting with its environment: a comprehensive study of 340 galaxy clusters. The Astrophysical Journal, 826 (1), 1-21. (doi:10.3847/0004-637X/826/1/72).

Record type: Article

Abstract

To study systematically the evolution of the angular extents of the galaxy, intracluster medium (ICM), and dark matter components in galaxy clusters, we compiled the optical and X-ray properties of a sample of 340 clusters with redshifts <0.5, based on all the available data from the Sloan Digital Sky Survey and Chandra/XMM-Newton. For each cluster, the member galaxies were determined primarily with photometric redshift measurements. The radial ICM mass distribution, as well as the total gravitational mass distribution, was derived from a spatially resolved spectral analysis of the X-ray data. When normalizing the radial profile of galaxy number to that of the ICM mass, the relative curve was found to depend significantly on the cluster redshift; it drops more steeply toward the outside in lower-redshift subsamples. The same evolution is found in the galaxy-to-total mass profile, while the ICM-to-total mass profile varies in an opposite way. The behavior of the galaxy-to-ICM distribution does not depend on the cluster mass, suggesting that the detected redshift dependence is not due to mass-related effects, such as sample selection bias. Also, it cannot be ascribed to various redshift-dependent systematic errors. We interpret that the galaxies, the ICM, and the dark matter components had similar angular distributions when a cluster was formed, while the galaxies traveling in the interior of the cluster have continuously fallen toward the center relative to the other components, and the ICM has slightly expanded relative to the dark matter although it suffers strong radiative loss. This cosmological galaxy infall, accompanied by an ICM expansion, can be explained by considering that the galaxies interact strongly with the ICM while they are moving through it. The interaction is considered to create a large energy flow of 1044?45 erg s?1 per cluster from the member galaxies to their environment, which is expected to continue over cosmological timescales.

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1602.01524v1.pdf - Accepted Manuscript
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Accepted/In Press date: 3 February 2016
e-pub ahead of print date: 22 July 2016
Published date: 22 July 2016
Organisations: Astronomy Group

Identifiers

Local EPrints ID: 399901
URI: http://eprints.soton.ac.uk/id/eprint/399901
ISSN: 1538-4357
PURE UUID: 93e9d711-3821-4551-b9dd-6962e3c5f540
ORCID for Poshak Gandhi: ORCID iD orcid.org/0000-0003-3105-2615

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Date deposited: 02 Sep 2016 10:51
Last modified: 10 Dec 2019 01:33

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