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Chandra centres for COSMOS X-ray galaxy groups: differences in stellar properties between central dominant and offset brightest group galaxies

Gozaliasl, Ghassem and Capak, Peter and Scoville, Nick Z. (2019) Chandra centres for COSMOS X-ray galaxy groups: differences in stellar properties between central dominant and offset brightest group galaxies. Monthly Notices of the Royal Astronomical Society, 483 (3). pp. 3545-3565. ISSN 0035-8711. doi:10.1093/mnras/sty3203.

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We present the results of a search for galaxy clusters and groups in the ∼2 deg^2 of the COSMOS field using all available X-ray observations from the XMM–Newton and Chandra observatories. We reach an X-ray flux limit of 3×10^(−16) erg cm^(−2)s^(−1) in the 0.5–2 keV range, and identify 247 X-ray groups with M_(200c) = 8×10^(12) -3×10^(14)M⊙ at a redshift range of 0.08 ≤ z < 1.53, using the multiband photometric redshift and the master spectroscopic redshift catalogues of the COSMOS. The X-ray centres of groups are determined using high-resolution Chandra imaging. We investigate the relations between the offset of the brightest group galaxies (BGGs) from halo X-ray centre and group properties and compare with predictions from semi-analytic models and hydrodynamical simulations. We find that BGG offset decreases with both increasing halo mass and decreasing redshift with no strong dependence on the X-ray flux and SNR. We show that the BGG offset decreases as a function of increasing magnitude gap with no considerable redshift-dependent trend. The stellar mass of BGGs in observations extends over a wider dynamic range compared to model predictions. At z < 0.5, the central dominant BGGs become more massive than those with large offsets by up to 0.3 dex, in agreement with model prediction. The observed and predicted log-normal scatter in the stellar mass of both low- and large-offset BGGs at fixed halo mass is ∼0.3 dex.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Gozaliasl, Ghassem0000-0002-0236-919X
Capak, Peter0000-0003-3578-6843
Scoville, Nick Z.0000-0002-0438-3323
Additional Information:© 2018 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society. This article is published and distributed under the terms of the Oxford University Press, Standard Journals Publication Model ( Accepted 2018 November 16. Received 2018 November 15; in original form 2018 April 4. Published: 27 November 2018. This work has been supported by grants from the Finnish Academy of Science to the University of Helsinki and the Euclid project, decision numbers 266918 and 1295113. GG wishes to thank Mr. Donald Smart for very useful comments. ST acknowledges support from the ERC Consolidator Grant funding scheme (project Context, grant no. 648179). The Cosmic Dawn Center is funded by the Danish National Research Foundation. We used data of the Millennium simulation from the web application providing online access, constructed as activities of the German Astrophysics Virtual Observatory.
Group:COSMOS, Infrared Processing and Analysis Center (IPAC), Astronomy Department
Funding AgencyGrant Number
Academy of Finland266918
Academy of Finland1295113
European Research Council (ERC)648179
Danish National Research FoundationUNSPECIFIED
Issue or Number:3
Record Number:CaltechAUTHORS:20190329-084716225
Persistent URL:
Official Citation:Ghassem Gozaliasl, Alexis Finoguenov, Masayuki Tanaka, Klaus Dolag, Francesco Montanari, Charles C Kirkpatrick, Eleni Vardoulaki, Habib G Khosroshahi, Mara Salvato, Clotilde Laigle, Henry J McCracken, Olivier Ilbert, Nico Cappelluti, Emanuele Daddi, Guenther Hasinger, Peter Capak, Nick Z Scoville, Sune Toft, Francesca Civano, Richard E Griffiths, Michael Balogh, Yanxia Li, Jussi Ahoranta, Simona Mei, Angela Iovino, Bruno M B Henriques, Ghazaleh Erfanianfar, Chandra centres for COSMOS X-ray galaxy groups: differences in stellar properties between central dominant and offset brightest group galaxies, Monthly Notices of the Royal Astronomical Society, Volume 483, Issue 3, March 2019, Pages 3545–3565,
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:94289
Deposited By: Tony Diaz
Deposited On:29 Mar 2019 16:02
Last Modified:16 Nov 2021 17:04

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