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

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 clust...

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Bibliographic Details
Published in:The Astrophysical journal 2016-04, Vol.821 (1), p.40-40
Main Authors: Su, Yuanyuan, Buote, David A., Gastaldello, Fabio, Weeren, Reinout van
Format: Article
Language:English
Subjects:
ASTROPHYSICS, COSMOLOGY AND ASTRONOMY
BRIGHTNESS
Clusters
COMPARATIVE EVALUATIONS
Coolers
dark matter
Dynamical systems
Galactic clusters
Galactic halos
GALAXIES
galaxies: clusters: individual (Abell 1142)
galaxies: clusters: intracluster medium
galaxies: individual (NGC 3492, IC 664)
galaxies: ISM
GALAXY CLUSTERS
KEV RANGE
MASS
METALS
NONLUMINOUS MATTER
RED SHIFT
Scaling
VELOCITY
X RADIATION
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Summary: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.
ISSN:0004-637X
1538-4357
DOI:10.3847/0004-637X/821/1/40