Deep 1.4 GHz VLA Observations of the Radio Halo and Relic in Abell 2256

Abstract

We present deep VLA observations of the merging galaxy cluster Abell 2256. This cluster is known to possess diffuse steep spectrum radio relic emission in the peripheral regions. Our new observations provide the first detailed image of the central diffuse radio halo emission in this cluster. The radio halo extends over more than 800 kpc in the cluster core, while the relic emission covers a region of ~1125 x 520 kpc. A spectral index map of the radio relic shows a spectral steepening from the northwest toward the southeast edge of the emission, with an average spectral index between 1369 MHz and 1703 MHz of -1.2 across the relic. Polarization maps reveal high fractional polarization of up to 45% in the relic region with an average polarization of 20% across the relic region. The observed Faraday rotation measure is consistent with the Galactic estimate and the dispersion in the rotation measure is small, suggesting that there is very little contribution to the rotation measure of the relic from the intracluster medium. We use these Faraday properties of the relic to argue that it is located on the front side of the cluster.

21 pages, 14 figures (4 colour). Accepted to AJ

Cited by in corpus (17)

• Observations of extended radio emission in clusters
• A low-frequency radio halo associated with a cluster of galaxies
• Radio signature of cosmological structure formation shocks
• Simulating cosmic rays in clusters of galaxies - II. A unified scheme for radio halos and relics with predictions of the gamma-ray emission
• Cosmological Shocks in Adaptive Mesh Refinement Simulations and the Acceleration of Cosmic Rays
• A statistically-selected Chandra sample of 20 galaxy clusters -- I. Temperature and cooling time profiles
• Shock acceleration as origin of the radio relic in A521?
• Double relics in Abell 2345 and Abell 1240: spectral index and polarization analysis
• Simulating polarized Galactic synchrotron emission at all frequencies, the Hammurabi code
• New scaling relations in cluster radio halos and the re-acceleration model
• Low-Frequency study of two clusters of galaxies: A2744 and A2219
• Gamma rays from clusters of galaxies
• Simulating cosmic rays in clusters of galaxies - III. Non-thermal scaling relations and comparison to observations
• Deep Westerbork observations of Abell 2256 at 350 MHz
• Aperture Synthesis Observations of the Nearby Spiral NGC 6503: Modeling the Thin and Thick HI Disks
• The dynamical state of A548 from XMM-Newton data: X-ray and radio connection
• Diffuse Radio Emission in Abell 754