Observations of the galaxy cluster CL 0217+70 and its surrounding region at 1.4 GHz with the Sardinia Radio Telescope

Abstract

We present the results of observations performed with the Sardinia Radio Telescope (SRT) at 1.3-1.8 GHz of the galaxy cluster CL 0217+70 and a $3^{\circ }\times 3^{\circ }$ region around it. We combine the SRT data with archival Very Large Array (VLA) data to obtain images having the VLA angular resolution, but sensitive up to largest scales. The SRT+VLA combination allows us to derive a cluster radio halo flux density higher by $\sim 14\%$ compared to the VLA-only data, although consistent within $1\sigma$. We derive a spectral index map between 140 MHz and 1.4 GHz, finding an extended region with spectral index $\alpha \sim 0.6$ on the external part of the south-eastern candidate relic, questioning the real nature of this relic. Moreover, we detect an extended emission outside the cluster in the south-eastern area, having an angular extension of $\sim 50$ arcmin on the longer side, which would correspond to $\sim 10$ Mpc at the cluster distance; the emissivity that this region would have if located at the cluster distance is in line with the one estimated in candidate filaments of the cosmic web; however, the peculiar orientation of this region, not pointed towards the cluster, and the low Galactic latitude of this cluster suggest that its origin can be due to a foreground emission originating in our Galaxy.

13 pages, 9 figures; accepted for publication in MNRAS

References in corpus (16)

• Diffuse Radio Emission from Galaxy Clusters
• A radio ridge connecting two galaxy clusters in a filament of the cosmic web
• Discovery of Magnetic Fields Along Stacked Cosmic Filaments as Revealed by Radio and X-Ray Emission
• Galaxy clusters enveloped by vast volumes of relativistic electrons
• A giant radio bridge connecting two clusters in Abell 1758
• Sardinia Radio Telescope wide-band spectral-polarimetric observations of the galaxy cluster 3C 129
• Observations of the galaxy cluster CIZA J2242.8+5301 with the Sardinia Radio Telescope
• Polarized accretion shocks from the cosmic web
• A 3.5 Mpc-long radio relic in the galaxy cluster ClG 0217+70
• Testing the cosmic ray content in galaxy clusters
• Using the polarization properties of double radio relics to probe the turbulent compression scenario
• Simulations of the polarized radio sky and predictions on the confusion limit in polarization for future radio surveys
• The role of Dark Matter sub-halos in the non-thermal emission of galaxy clusters
• ClG 0217+70: A massive merging galaxy cluster with a large radio halo and relics
• Sardinia Radio Telescope observations of the Coma Cluster
• Optical/X-ray/radio view of Abell 1213: A galaxy cluster with anomalous diffuse radio emission