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

Journal
Date Issued
2016
Author(s)
Girardi, M.
•
Boschin, W.
•
•
•
•
•
Barrena, R.
•
•
Trasatti, M.
•
DOI
Abstract
We 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.
Volume
456
Issue
3
Start page
2829
Uri
Url
Issn Identifier
0035-8711
Ads BibCode
2016MNRAS.456.2829G
Rights
open.access
File(s)
Loading...
Thumbnail Image
Name

Monthly Notices of the Royal Astronomical Society 2016 Girardi.pdf

Description
PDF editoriale
Size

5.45 MB

Format

Adobe PDF

Checksum (MD5)

e5e2251cd532c37a2786d748bf1c94a9

Loading...
Thumbnail Image
Name

1510.05951.pdf

Description
postprint
Size

1.26 MB

Format

Adobe PDF

Checksum (MD5)

db62ad16bc5d5773b63cef93c65728ac