Abstract
Abell 1142 is a low-mass galaxy cluster at low redshift containing two comparable brightest cluster galaxies (BCGs) resembling a scaled-down version of the Coma Cluster. Our Chandra analysis reveals an X-ray emission peak, roughly 100 kpc away from either BCG, which we identify as the cluster center. The emission center manifests itself as a second beta-model surface brightness component distinct from that of the cluster on larger scales. The center is also substantially cooler and more metal-rich than the surrounding intracluster medium (ICM), which makes Abell 1142 appear to be a cool-core cluster. The redshift distribution of its member galaxies indicates that Abell 1142 may contain two subclusters, each of which contain one BCG. The BCGs are merging at a relative velocity of ≈1200 km s-1. This ongoing merger may have shock-heated the ICM from ≈2 keV to above 3 keV, which would explain the anomalous LX-TX scaling relation for this system. This merger may have displaced the metal-enriched "cool core" of either of the subclusters from the BCG. The southern BCG consists of three individual galaxies residing within a radius of 5 kpc in projection. These galaxies should rapidly sink into the subcluster center due to the dynamical friction of a cuspy cold dark matter halo.
| Original language | English |
|---|---|
| Article number | 40 |
| Journal | Astrophysical Journal |
| Volume | 821 |
| Issue number | 1 |
| DOIs | |
| State | Published - Apr 10 2016 |
Bibliographical note
Publisher Copyright:© 2016. The American Astronomical Society. All rights reserved.
Funding
We are thankful for helpful discussions with William Forman, Manoj Kaplinghat, Tiziana Venturi, and Ralph Kraft. D.A.B. and Y.S. gratefully acknowledge partial support from the National Aeronautics and Space Administration under grant No. NNX13AF14G issued through the Astrophysics Data Analysis Program. Partial support for this work was also provided by NASA through Chandra Award No. GO2-13159X issued by the Chandra X-ray Observatory Center, which is operated by the Smithsonian Astrophysical Observatory for and on behalf of NASA under contract NAS8-03060. This publication makes use of data products from the Two Micron All-Sky Survey, which is a joint project of the University of Massachusetts and the Infrared Processing and Analysis Center/California Institute of Technology, funded by the National Aeronautics and Space Administration and the National Science Foundation. Funding for the SDSS and SDSS-II has been provided by the Alfred P. Sloan Foundation, the Participating Institutions, the National Science F Foundation, the U.S. Department of Energy, the National Aeronautics and Space Administration, the Japanese Monbukagakusho, the Max Planck Society, and the Higher Education Funding Council for England. The SDSS Web Site is?http://www.sdss.org/. The SDSS is managed by the Astrophysical Research Consortium for the Participating Institutions. This paper is dedicated to the loving memory of Y. S.'s late grandfather Hua Li.
| Funders | Funder number |
|---|---|
| Ralph Kraft | |
| National Science Foundation Arctic Social Science Program | |
| U.S. Department of Energy EPSCoR | |
| National Aeronautics and Space Administration | NAS8-03060, NNX13AF14G |
| National Aeronautics and Space Administration | |
| Alfred P Sloan Foundation | |
| Higher Education Funding Council for England | |
| Fritz-Haber-Institut der Max-Planck-Gesellschaft |
Keywords
- dark matter
- galaxies: ISM
- galaxies: clusters: individual (Abell 1142)
- galaxies: clusters: intracluster medium
- galaxies: individual (NGC 3492, IC 664)
ASJC Scopus subject areas
- Astronomy and Astrophysics
- Space and Planetary Science