CHANDRA OBSERVATION OF ABELL 1142: A COOL-CORE CLUSTER LACKING A CENTRAL BRIGHTEST CLUSTER GALAXY?

Journal Article · Sun Apr 10 04:00:00 EDT 2016 · Astrophysical Journal

DOI:https://doi.org/10.3847/0004-637X/821/1/40· OSTI ID:22518501

Su, Yuanyuan; Weeren, Reinout van ^[1]; Buote, David A. ^[2]; Gastaldello, Fabio ^[3]

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1. Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)
2. Department of Physics and Astronomy, University of California, Irvine, 4129 Frederick Reines Hall, Irvine, CA 92697 (United States)
3. INAF-IASF-Milano, Via E. Bassini 15, I-20133 Milano (Italy)

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{sup −1}. This ongoing merger may have shock-heated the ICM from ≈2 keV to above 3 keV, which would explain the anomalous L{sub X}–T{sub X} 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.

• OSTI ID: 22518501
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 1 Vol. 821; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
BRIGHTNESS
COMPARATIVE EVALUATIONS
GALAXIES
GALAXY CLUSTERS
KEV RANGE
MASS
METALS
NONLUMINOUS MATTER
RED SHIFT
VELOCITY
X RADIATION