A multiwavelength view of the galaxy cluster Abell 523 and its peculiar diffuse radio source

Girardi, M.M.GirardiBoschin, W.W.BoschinGASTALDELLO, FABIOFABIOGASTALDELLOGiovannini, G.G.GiovanniniGOVONI, FEDERICAFEDERICAGOVONIMURGIA, MATTEOMATTEOMURGIABarrena, R.R.BarrenaETTORI, STEFANOSTEFANOETTORITrasatti, M.M.TrasattiVACCA, VALENTINAVALENTINAVACCA2020-05-132020-05-1320160035-8711http://hdl.handle.net/20.500.12386/24765We study the structure of the galaxy cluster Abell 523 (A523) at z = 0.104 using new spectroscopic data for 132 galaxies acquired at the Telescopio Nazionale Galileo, new photometric data from the Isaac Newton Telescope, and X-ray and radio data from the Chandra and Very Large Array archives. We estimate the velocity dispersion of the galaxy population, σ _V=949_{-60}^{+80} km s-1, and the X-ray temperature of the hot intracluster medium, kT = 5.3 ± 0.3 keV. We infer that A523 is a massive system: M200 ∼ 7-9 × 1014 M☉. The analysis of the optical data confirms the presence of two subclusters, 0.75 Mpc apart, tracing the SSW-NNE direction and dominated by the two brightest cluster galaxies (BCG1 and BCG2). The X-ray surface brightness is strongly elongated towards the NNE direction, and its peak is clearly offset from both the brightest cluster galaxies (BCGs). We confirm the presence of a 1.3 Mpc large radio halo, elongated in the ESE-WNW direction and perpendicular to the optical/X-ray elongation. We detect a significant radio/X-ray offset and radio polarization, two features which might be the result of a magnetic field energy spread on large spatial scales. A523 is found consistent with most scaling relations followed by clusters hosting radio haloes, but quite peculiar in the Pradio-LX relation: it is underluminous in the X-rays or overluminous in radio. A523 can be described as a binary head-on merger caught after a collision along the SSW-NNE direction. However, minor optical and radio features suggest a more complex cluster structure, with A523 forming at the crossing of two filaments along the SSW-NNE and ESE-WNW directions.STAMPAenA multiwavelength view of the galaxy cluster Abell 523 and its peculiar diffuse radio sourceArticle10.1093/mnras/stv28272-s2.0-84964499471000372265200041https://academic.oup.com/mnras/article/456/3/2829/10969852016MNRAS.456.2829GFIS/05 - ASTRONOMIA E ASTROFISICAScienze Fisiche Settori ERC (ERC) di riferimento::PE9 Universe sciences: astro-physics/chemistry/biology; solar systems; stellar, galactic and extragalactic astronomy, planetary systems, cosmology, space science, instrumentation