WITNESSING THE FORMATION OF A BRIGHTEST CLUSTER GALAXY IN A NEARBY X-RAY CLUSTER

Journal Article · Sat Jul 10 04:00:00 EDT 2010 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/717/2/958· OSTI ID:21455208

Rasmussen, Jesper; Mulchaey, John S; Bai, Lei ^[1]; Ponman, Trevor J; Raychaudhury, Somak ^[2]; Dariush, Ali ^[3]

---

1. Carnegie Observatories, 813 Santa Barbara Street, Pasadena, CA 91101 (United States)
2. School of Physics and Astronomy, University of Birmingham, Edgbaston, Birmingham B15 2TT (United Kingdom)
3. School of Physics and Astronomy, Cardiff University, Queens Buildings, The Parade, Cardiff, CF24 3AA (United Kingdom)

The central dominant galaxies in galaxy clusters constitute the most massive and luminous galaxies in the universe. Despite this, the formation of these brightest cluster galaxies (BCGs) and the impact of this on the surrounding cluster environment remain poorly understood. Here we present multiwavelength observations of the nearby poor X-ray cluster MZ 10451, in which both processes can be studied in unprecedented detail. Chandra observations of the intracluster medium (ICM) in the cluster core, which harbors two optically bright early-type galaxies in the process of merging, show that the system has retained a cool core and a central metal excess. This suggests that any merger-induced ICM heating and mixing remain modest at this stage. Tidally stripped stars seen around either galaxy likely represent an emerging intracluster light component, and the central ICM abundance enhancement may have a prominent contribution from in situ enrichment provided by these stars. The smaller of the merging galaxies shows evidence for having retained a hot gas halo, along with tentative evidence for some obscured star formation, suggesting that not all BCG major mergers at low redshift are completely dissipationless. Both galaxies are slightly offset from the peak of the ICM emission, with all three lying on an axis that roughly coincides with the large-scale elongation of the ICM. Our data are consistent with a picture in which central BCGs are built up by mergers close to the cluster core, by galaxies infalling on radial orbits aligned with the cosmological filaments feeding the cluster.

• OSTI ID: 21455208
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 2 Vol. 717; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ABUNDANCE
COSMIC RAY SOURCES
COSMIC X-RAY SOURCES
ELEMENTS
EMISSION
EVOLUTION
GALACTIC EVOLUTION
GALAXIES
GALAXY CLUSTERS
METALS
ORBITS
RED SHIFT
STARS
UNIVERSE
X-RAY GALAXIES