相关论文: Revised statistics of radio halos and the re-accel…
Giant radio halos are mega-parsec scale synchrotron sources detected in a fraction of massive and merging galaxy clusters. Radio halos provide one of the most important pieces of evidence for non-thermal components in large scale structure.…
In this paper we show expectations on the radio--X-ray luminosity correlation of radio halos at 120 MHz. According to the "turbulent re-acceleration scenario", low frequency observations are expected to detect a new population of radio…
A significant fraction of galaxy clusters exhibits cluster wide radio halos. We give a simple prediction of the local and higher redshift radio halo luminosity function (RHLF) on the basis of (i) an observed and a theoretical X-ray cluster…
Context. Radio halos are megaparsec-scale diffuse radio sources{ mostly} located at the centres of merging galaxy clusters. The common mechanism invoked to explain their origin is the re-acceleration of relativistic particles caused by…
The GMRT Radio Halo Survey, carried out at 610 MHz to investigate the statistical properties of cluster radio halos in a complete cluster sample selected in the redshift interval z=0.2-0.4, has significantly improved our understanding of…
Aims. We present the first results of an ongoing project devoted to the search of giant radio halos in galaxy clusters located in the redshift range z=0.2--0.4. One of the main goals of our study is to measure the fraction of massive galaxy…
In this Letter, we report the discovery of a radio halo in the high-redshift galaxy cluster PSZ2 G099.86+58.45 ($z=0.616$) with the LOw Frequency ARray (LOFAR) at 120-168 MHz. This is one of the most distant radio halos discovered so far.…
A fraction of galaxy clusters harbor diffuse radio sources known as radio halos. The currently adopted scenario for their formation is based on second-order Fermi re-acceleration of seed electrons that is driven by merger-driven turbulence…
Radio observations discovered large scale non thermal sources in the central Mpc regions of dynamically disturbed galaxy clusters (radio halos). The morphological and spectral properties of these sources suggest that the emitting electrons…
Giant radio halos (RH) are Mpc-scale synchrotron sources detected in a significant fraction of massive and merging galaxy clusters.Their statistical properties can be used to discriminate among various models for their origin. Theoretical…
A fraction of galaxy clusters host diffuse radio sources called radio halos, radio relics and mini-halos. We present the sample and first results from the Extended GMRT Radio Halo Survey (EGRHS)- an extension of the GMRT Radio Halo Survey…
We present a first estimate based on a cosmological gasdynamics simulation of galaxy cluster radio halo counts to be expected in forthcoming low-frequency radio surveys. Our estimate is based on a FLASH simulation of the LCDM model for…
Diffuse cluster-scale synchrotron radio emission is discovered in an increasing number of galaxy clusters in the form of radio halos (RHs), probing the presence of relativistic electrons and magnetic fields in the intra-cluster medium. The…
Radio halos are diffuse synchrotron sources observed in dynamically unrelaxed galaxy clusters. Current observations and models suggest that halos trace turbulent regions in the intra-cluster medium where mildly relativistic particles are…
Many galaxy clusters host Mpc scale diffuse radio sources called radio halos. Their origin is connected to the processes that lead to the formation of clusters themselves. In order to unveil this connection, statistical studies of radio…
We present the results of the GMRT cluster radio halo survey. The main purposes of our observational project are to measure which fraction of massive galaxy clusters in the redshift range z=0.2--0.4 hosts a radio halo, and to constrain the…
Radio halos are synchrotron diffuse sources at the centre of a fraction of galaxy clusters. The study of large samples of clusters with adequate radio and X-ray data is necessary to investigate the origin of radio halos and their connection…
The most important evidence of non-thermal phenomena in galaxy clusters comes from Giant Radio Halos (GRHs), synchrotron radio sources extended over Mpc scales, detected in a growing number of massive galaxy clusters. A promising…
Radio halos are synchrotron radio sources detected in some massive galaxy clusters. Their Mpc-size indicates that (re)acceleration processes are taking place in the host cluster. X-ray catalogues of galaxy clusters have been used in the…
Non-thermal properties of galaxy clusters have been studied with detailed and deep radio images in comparison with X-ray data. While much progress has been made, most of the studied clusters are at a relatively low redshift (z < 0.3). We…