2016/03/04 by G. A. Ogrean, R. J. van Weeren, C. Jones +24 · 1 citation
Physics and Astronomy · #Astronomy and Astrophysical Research #Astrophysical Phenomena and Observations #Cluster (spacecraft) #Cold dark matter #Dark matter #Galaxies: Formation, Evolution, Phenomena #Galaxy cluster #Halo #Radio halo #Sky #Substructure #Surface brightness #astro-ph.CO #astro-ph.GA #astro-ph.HE
paper · pdf · doi:10.3847/0004-637x/819/2/113
Accepted to ApJ
openalex publication_date 2016/03/04 · arxiv created 2016/03/18 · arxiv updated 2016/03/30 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
ABSTRACT The Hubble Space Telescope Frontier Fields cluster MACS J1149.6+2223 is one of the most complex merging clusters, believed to consist of four dark matter halos. We present results from deep (365 ks) Chandra observations of the cluster, which reveal the most distant cold front ( z = 0.544) discovered to date. In the cluster outskirts, we also detect hints of a surface brightness edge that could be the bow shock preceding the cold front. The substructure analysis of the cluster identified several components with large relative radial velocities, thus indicating that at least some collisions occur almost along the line of sight. The inclination of the mergers with respect to the plane of the sky poses significant observational challenges at X-ray wavelengths. MACS J1149.6+2223 possibly hosts a steep-spectrum radio halo. If the steepness of the radio halo is confirmed, then the radio spectrum, combined with the relatively regular ICM morphology, could indicate that MACS J1149.6+2223 is an old merging cluster.