2011/04/04 by T. Venturi, G. Giacintucci, S. Giacintucci +5 · 18 citations
Physics and Astronomy · #Abell 2744 #Astronomy #Astrophysical Phenomena and Observations #Astrophysics #Cluster (spacecraft) #Galaxies: Formation, Evolution, Phenomena #Galaxy #Galaxy cluster #Giant Metrewave Radio Telescope #Halo #Physics #Radio Astronomy Observations and Technology #Radio galaxy #Radio halo #Radio spectrum #Radio telescope #Type-cD galaxy #X-shaped radio galaxy #astro-ph.CO
paper · pdf · doi:10.1111/j.1745-3933.2011.01057.x
published in Monthly Notices of the Royal Astronomical Society Letters 414(1), L65-L69 (Oxford University Press) · 5 pages, 4 figures, 1 table - Accepted for publication on Monthly Notices of the Royal Astronomical Society Letters
arxiv created 2011/04/04 · openalex publication_date 2011/04/20 · arxiv updated 2015/05/27 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Abstract Deep radio observations of the galaxy cluster Abell 781 have been carried out using the Giant Metrewave Radio Telescope at 325 MHz and have been compared to previous 610-MHz observations and to archival Very Large Array (VLA) 1.4-GHz data. The radio emission from the cluster is dominated by a diffuse source located at the outskirts of the X-ray emission, which we tentatively classify as a radio relic. We detected residual diffuse emission at the cluster centre at the level of S325 MHz∼ 15–20 mJy. Our analysis disagrees with Govoni et al., and on the basis of simple spectral considerations, we do not support their claim of a radio halo with the flux density of 20–30 mJy at 1.4 GHz. Abell 781, a massive and merging cluster, is an intriguing case. Assuming that the residual emission is indicative of the presence of a radio halo barely detectable at our sensitivity level, it could be a very steep spectrum source.