ATCA observations of the MACS-Planck Radio Halo Cluster Project. I. New detection of a radio halo in PLCK G285.0-23.7
Aims: We investigate the possible presence of diffuse radio emission in the intermediate redshift, massive cluster PLCK G285.0-23.7 (z = 0.39, M500 = 8.39 × 1014M☉).
Methods: Our 16 cm-band ATCA observations of PLCK G285.0-23.7 allow us to reach a rms noise level of 11 μJy/beam on the wide-band (1.1-3.1 GHz), full-resolution ( 5 arcsec) image of the cluster, making it one of the deepest ATCA images yet published. We also re-image visibilities at lower resolution in order to achieve a better sensitivity to low-surface-brightness extended radio sources.
Results: We detect one of the lowest luminosity radio halos known at z > 0.35, characterised by a slight offset from the well-studied 1.4 GHz radio power vs. cluster mass correlation. Similarly to most known radio-loud clusters (I.e. those hosting diffuse non-thermal sources), PLCK G285.0-23.7 has a disturbed dynamical state. Our analysis reveals a similarly elongated X-ray and radio morphology. While the size of the radio halo in PLCK G285.0-23.7 is smaller than lower redshift radio-loud clusters in the same mass range, it shows a similar correlation with the cluster virial radius, as expected in the framework of hierarchical structure formation.
Astronomy and Astrophysics
- Pub Date:
- November 2016
- galaxies: clusters: general;
- galaxies: clusters: individual: PLCK G285.0-23.7;
- radio continuum: galaxies;
- galaxies: clusters: intracluster medium;
- radiation mechanisms: non-thermal;
- Astrophysics - Cosmology and Nongalactic Astrophysics;
- Astrophysics - Astrophysics of Galaxies
- 11 pages, 8 figures, accepted for publication on A&