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

Yuanyuan Su, David A. Buote, Fabio Gastaldello, Reinout Van Weeren

Research output: Contribution to journalArticlepeer-review

8 Scopus citations

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 languageEnglish
Article number40
JournalAstrophysical Journal
Volume821
Issue number1
DOIs
StatePublished - Apr 10 2016

Bibliographical note

Publisher Copyright:
© 2016. The American Astronomical Society. All rights reserved.

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

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