2020/09/16 by X. Zhang, A. Simionescu, J. S. Kaastra +7
Physics and Astronomy · #Astronomy and Astrophysical Research #Astrophysical Phenomena and Observations #Cluster (spacecraft) #Galaxies: Formation, Evolution, Phenomena #Galaxy #Galaxy cluster #Halo #Intracluster medium #Radio galaxy #Radio halo #Redshift #Surface brightness #astro-ph.CO #astro-ph.HE
paper · pdf · doi:10.1051/0004-6361/202039028
published as A&A 642, L3 (2020) · 5 pages, 4 figures, 1 table. Accepted for publication in A&A Letters
arxiv created 2020/09/16 · openalex publication_date 2020/09/16 · openalex created_date 2020/09/21 · arxiv updated 2020/10/07 · openalex updated_date 2026/08/06
We present an analysis of archival Chandra data of the merging galaxy cluster ClG 0217+70. The Fe XXV He α X-ray emission line is clearly visible in the 25 ks observation, allowing a precise determination of the redshift of the cluster as z = 0.180 ± 0.006. We measure k T 500 = 8.3 ± 0.4 keV and estimate M 500 = (1.06 ± 0.11) × 10 15 M ⊙ based on existing scaling relations. Correcting both the radio and X-ray luminosities with the revised redshift reported here, which is much larger than previously inferred based on sparse optical data, this object is no longer an X-ray underluminous outlier in the L X − P radio scaling relation. The new redshift also means that, in terms of physical scale, ClG 0217+70 hosts one of the largest radio halos and one of the largest radio relics known to date. Most of the relic candidates lie in projection beyond r 200 . The X-ray morphological parameters suggest that the intracluster medium is still dynamically disturbed. Two X-ray surface brightness discontinuities are confirmed in the northern and southern parts of the cluster, with density jumps of 1.40 ± 0.16 and 3.0 ± 0.6, respectively. We also find a 700 × 200 kpc X-ray faint channel in the western part of the cluster, which may correspond to compressed heated gas or increased non-thermal pressure due to turbulence or magnetic fields.