Spectro-polarimetric observations of the CIZA J2242.8+5301 northern radio relic: no evidence of high-frequency steepening

Abstract

Observations of radio relics at very high frequency (>10 GHz) can help to understand how particles age and are (re-)accelerated in galaxy cluster outskirts and how magnetic fields are amplified in these environments. In this work, we present new single-dish 18.6 GHz Sardinia Radio Telescope and 14.25 GHz Effelsberg observations of the well known northern radio relic of CIZA J2242.8+5301. We detected the relic which shows a length of $\sim$1.8 Mpc and a flux density equal to ${\mathrm{S}}_{14.25\mathrm{GHz}}=(9.5\pm 3.9)\mathrm{mJy}$ and ${\mathrm{S}}_{18.6\mathrm{GHz}}=(7.67\pm 0.90)\mathrm{mJy}$ at 14.25 GHz and 18.6 GHz respectively. The resulting best-fit model of the relic spectrum from 145 MHz to 18.6 GHz is a power-law spectrum with spectral index $\alpha =1.12\pm 0.03$: no evidence of steepening has been found in the new data presented in this work. For the first time, polarisation properties have been derived at 18.6 GHz, revealing an averaged polarisation fraction of $\sim 40\%$ and a magnetic field aligned with the 'filaments' or 'sheets' of the relic.

10 pages, 8 figures

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Cited by in corpus (14)

• Exploring the spectral properties of radio relics I: Integrated spectral index and Mach number
• Radio fossils, relics, and haloes in Abell 3266: cluster archaeology with ASKAP-EMU and the ATCA
• A perfect power-law spectrum even at highest frequencies: The Toothbrush relic
• Polarized accretion shocks from the cosmic web
• Deep low-frequency radio observations of Abell 2256 II: The ultra-steep spectrum radio halo
• Turbulent magnetic fields in the merging galaxy cluster MACS J0717.5+3745: polarization analysis
• Morphology of radio relics II: Properties of polarised emission
• Using the polarization properties of double radio relics to probe the turbulent compression scenario
• Radio halos and relics from extended cosmic-ray ion distributions with strong diffusion in galaxy clusters
• Probing particle acceleration in Abell 2256: from to 16 MHz to gamma rays
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• Sardinia Radio Telescope observations of the Coma Cluster
• Filaments in and between galaxy clusters at low and mid-frequency with the SKA telescope
• Modelling the Energy Spectra of Radio Relics