Sardinia Radio Telescope observations of the Coma Cluster

Abstract

We present deep total intensity and polarization observations of the Coma cluster at 1.4 and 6.6 GHz performed with the Sardinia Radio Telescope. By combining the single-dish 1.4 GHz data with archival Very Large Array observations we obtain new images of the central radio halo and of the peripheral radio relic where we properly recover the brightness from the large scale structures. At 6.6 GHz we detect both the relic and the central part of the halo in total intensity and polarization. These are the highest frequency images available to date for these radio sources in this galaxy cluster. In the halo, we find a localized spot of polarized signal, with fractional polarization of about 45%. The polarized emission possibly extends along the north-east side of the diffuse emission. The relic is highly polarized, up to 55%, as usually found for these sources. We confirm the halo spectrum is curved, in agreement with previous single-dish results. The spectral index is alpha=1.48 +/- 0.07 at a reference frequency of 1 GHz and varies from alpha ~1.1, at 0.1 GHz, up to alpha ~ 1.8, at 10 GHz. We compare the Coma radio halo surface brightness profile at 1.4 GHz (central brightness and e-folding radius) with the same properties of the other halos, and we find that it has one of the lowest emissivities observed so far. Reanalyzing the relic's spectrum in the light of the new data, we obtain a refined radio Mach number of M=2.9 +/- 0.1.

arXiv comment27 pages, 18 figures, this article has been accepted for publication in MNRAS Published by Oxford University Press on behalf of the Royal Astronomical Society

References in corpus (56)

• The Temperature of the Cosmic Microwave Background
• The GMRT 150 MHz All-sky Radio Survey: First Alternative Data Release TGSS ADR1
• Clusters of galaxies : observational properties of the diffuse radio emission
• Cosmic rays in galaxy clusters and their non-thermal emission
• GaLactic and Extragalactic All-sky Murchison Widefield Array (GLEAM) survey I: A low-frequency extragalactic catalogue
• Particle reacceleration in Coma cluster: radio properties and hard X-ray emission
• The LOFAR Two-metre Sky Survey -- V. Second data release
• Particle Acceleration on Megaparsec Scales in a Merging Galaxy Cluster
• Compressible Turbulence in Galaxy Clusters: Physics and Stochastic Particle Re-acceleration
• The Coma cluster magnetic field from Faraday rotation measures
• An Accurate Flux Density Scale from 50 MHz to 50 GHz
• Bow shock and radio halo in the merging cluster A520
• GLEAM: The GaLactic and Extragalactic All-sky MWA survey
• Radio signature of cosmological structure formation shocks
• Diffusive Shock Acceleration Simulations of Radio Relics
• The diffuse radio emission from the Coma cluster at 2.675 GHz and 4.85 GHz
• Diffuse Radio Emission in/around the Coma Cluster: Beyond Simple Accretion
• XMM-Newton Observation of the Northwest Radio Relic Region in Abell 3667
• The intracluster magnetic field power spectrum in Abell 2255
• A2255: the First Detection of Filamentary Polarized Emission in a Radio Halo
• Deep 1.4 GHz VLA Observations of the Radio Halo and Relic in Abell 2256
• The On The Fly Imaging Technique
• Integrated Polarization Properties of 3C48, 3C138, 3C147, and 3C286
• Double relics in Abell 2345 and Abell 1240: spectral index and polarization analysis
• Comparative analysis of the diffuse radio emission in the galaxy clusters A1835, A2029, and Ophiuchus
• Shock acceleration efficiency in radio relics
• Revealing the magnetic field in a distant galaxy cluster: discovery of the complex radio emission from MACS J0717.5 +3745
• Measurements and simulation of Faraday rotation across the Coma radio relic
• Sardinia Radio Telescope observations of Abell 194 - the intra-cluster magnetic field power spectrum
• Diffusive Shock Acceleration at Cosmological Shock Waves
• The Sardinia Radio Telescope: From a Technological Project to a Radio Observatory
• A double radio halo in the close pair of galaxy clusters Abell 399 and Abell 401
• Deep multi-frequency rotation measure tomography of the galaxy cluster A2255
• First X-ray evidence for a shock at the Coma relic
• Radio Halos From Simulations And Hadronic Models I: The Coma cluster
• The Coma cluster at LOFAR frequencies I: insights into particle acceleration mechanisms in the radio bridge
• Discovery of new faint radio emission on 8$\arcdeg$ to 3$\arcmin$ scales in the Coma field, and some Galactic and extragalactic implications
• Tempestuous life beyond R_500: X-ray view on the Coma cluster with SRG/eROSITA. I. X-ray morphology, recent merger, and radio halo connection
• Observations of a nearby filament of galaxy clusters with the Sardinia Radio Telescope
• Duty cycle of the radio galaxy B2 0258+35
• A multiwavelength view of the galaxy cluster Abell 523 and its peculiar diffuse radio source
• Discovery of diffuse emission in the galaxy cluster A1689
• Understanding the radio relic emission in the galaxy cluster MACS J0717.5+3745: spectral analysis
• Modification of cluster radio halo appearance by the thermal Sunyaev-Zeldovich effect
• Very Small Array observations of the Sunyaev-Zel'dovich effect in nearby galaxy clusters
• The impact of the SZ effect on cm-wavelength (1-30 GHz) observation of galaxy cluster radio relics
• Polarization of cluster radio halos with upcoming radio interferometers
• Sardinia Radio Telescope wide-band spectral-polarimetric observations of the galaxy cluster 3C 129
• A perfect power-law spectrum even at highest frequencies: The Toothbrush relic
• Observations of the galaxy cluster CIZA J2242.8+5301 with the Sardinia Radio Telescope
• Probing magnetic helicity with synchrotron radiation and Faraday rotation
• Tempestuous life beyond R500: X-ray view on the Coma cluster with SRG/eROSITA. II. Shock & Relic
• Is the Sunyaev-Zeldovich effect responsible for the observed steepening in the spectrum of the Coma radio halo ?
• Evidence for a pressure discontinuity at the position of the Coma relic from Planck Sunyaev-Zel'dovich effect data
• Spectro-polarimetric observations of the CIZA J2242.8+5301 northern radio relic: no evidence of high-frequency steepening
• Effect of turbulent reacceleration on electrons produced by dark matter annihilation in the Coma cluster

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• Observations of the galaxy cluster CL 0217+70 and its surrounding region at 1.4 GHz with the Sardinia Radio Telescope
• Constraints on dark matter annihilation and turbulent reacceleration set by high-frequency observations of the radio halo in the Coma cluster