- ID:
- ivo://CDS.VizieR/J/A+A/555/A110
- Title:
- Radio images of CIZA J2242.8+5301
- Short Name:
- J/A+A/555/A110
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Giant cluster radio relics are thought to form at shock fronts in the course of collisions between galaxy clusters. Via processes that are still poorly understood, these shocks accelerate or re-accelerate cosmic-ray electrons and might amplify magnetic fields. The best object to study this phenomenon is the galaxy cluster CIZA J2242.8+5301 as it shows the most undisturbed relic. By means of Giant Metrewave Radio Telescope (GMRT) and Westerbork Synthesis Radio Telescope (WSRT) data at seven frequencies spanning from 153MHz to 2272MHz, we study the synchrotron emission in this cluster. We aim at distinguishing between theoretical injection and acceleration models proposed for the formation of radio relics. We also study the head-tail radio sources to reveal the interplay between the merger and the cluster galaxies. We produced spectral index, curvature maps, and radio colour-colour plots and compared our data with predictions from models. We present one of the deepest 153MHz maps of a cluster ever produced, reaching a noise level of 1.5mJy/beam. We derive integrated spectra for four relics in the cluster, discovering extremely steep spectrum diffuse emission concentrated in multiple patches. We find a possible radio phoenix embedded in the relic to the south of the cluster. The spectral index of the northern relic retains signs of steepening from the front towards the back of the shock also at the radio frequencies below 600MHz. The spectral curvature in the same relic also increases in the downstream area. The data is consistent with the Komissarov-Gubanov injection models, meaning that the emission we observe is produced by a single burst of spectrally-aged accelerated radio electrons.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/MNRAS/390/289
- Title:
- Radio observations of A3158
- Short Name:
- J/MNRAS/390/289
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present 1.4- and 2.5-GHz Australia Telescope Compact Array (ATCA) observations of the galaxy cluster A3158 (z=0.0597) which is located within the central part of the Horologium-Reticulum supercluster (HRS). Spectroscopic data for the central part of the HRS suggest that A3158 is in a dynamically important position within the supercluster and that it is moving toward the double cluster system A3125/A3128 which marks the centre of the HRS. A total of 110 radio galaxies are detected in a 35-arcmin radius about the cluster at 1.4GHz, of which 30 are also detected at 2.5GHz.
- ID:
- ivo://CDS.VizieR/J/A+A/379/21
- Title:
- Radio-optically selected galaxy clusters I.
- Short Name:
- J/A+A/379/21
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The radiosource catalogs have been extracted from 31 NRAO VLA Sky Survey maps (NVSS, Condon et al., 1988AJ....115.1693C) over approximately 550 square degrees of sky in the region of the South Galactic Pole. File table1.dat contains the catalog of 13340 pointlike sources. For each source are given: Right Ascension and Declination, source name (if applicable), peak flux, flux rms from the fit, error on source position as estimated by the fitting algorithm, x and y pixel of the position where the peak has been detected on the map (starting position for the fit), control flags coming from the extraction algorithm, and name of the radio map where the source has been detected. The name is specified for (1) pointlike sources that are detected in a multiple system (name = DSnnnn or TSnnnn) (2) sources initially classified as components of a double system, which has been considered spurious on the basis of the distance between components (name = Cnnnn or DCnnnn). File table2.dat contains the catalog of 2662 double radiosources. For each source the following parameters are given both for the barycentre and the two components: Right Ascension and Declination, source name, peak flux, flux rms from the fit, error on source position as estimated by the fitting algorithm, distance between the components of the double system, x and y pixel of the position where the peak has been detected on the map (starting position for the fit), control flags coming from the extraction algorithm, and name of the radio map where the source has been detected.
- ID:
- ivo://CDS.VizieR/J/A+A/379/35
- Title:
- Radio-optically selected galaxy clusters. II.
- Short Name:
- J/A+A/379/35
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- File table1.dat contains data relative to spectroscopic and photometric observations of galaxies in 12 radio-optically selected candidate clusters. Observations have been acquired with the 3.6m ESO telescope, Chile. For each galaxy in the cluster, a sequential number, the magnitude in r-Gunn filter, the measured velocity, velocity rms, and notes to identify particular objects (emission galaxies, radiogalaxies and stars) are given.
- ID:
- ivo://CDS.VizieR/J/MNRAS/453/1201
- Title:
- Radio properties of brightest cluster galaxies
- Short Name:
- J/MNRAS/453/1201
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We examine the radio properties of the brightest cluster galaxies (BCGs) in a large sample of X-ray selected galaxy clusters comprising the Brightest Cluster Sample (BCS), the extended BCS and ROSAT-ESO Flux Limited X-ray cluster catalogues. We have multifrequency radio observations of the BCG using a variety of data from the Australia Telescope Compact Array, Jansky Very Large Array and Very Long Baseline Array telescopes. The radio spectral energy distributions of these objects are decomposed into a component attributed to on-going accretion by the active galactic nuclei (AGN) that we refer to as 'the core', and a more diffuse, ageing component we refer to as the 'non-core'. These BCGs are matched to previous studies to determine whether they exhibit emission lines (principally H{alpha}), indicative of the presence of a strong cooling cluster core. We consider how the radio properties of the BCGs vary with cluster environmental factors. Line emitting BCGs are shown to generally host more powerful radio sources, exhibiting the presence of a strong, distinguishable core component in about 60 per cent of cases. This core component more strongly correlates with the BCG's [OIII] 5007{AA} line emission. For BCGs in line emitting clusters, the X-ray cavity power correlates with both the extended and core radio emission, suggestive of steady fuelling of the AGN over bubble-rise time-scales in these clusters.
- ID:
- ivo://CDS.VizieR/J/ApJ/882/69
- Title:
- Radio relic merging galaxy cluster substructures
- Short Name:
- J/ApJ/882/69
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Golovich et al. (2019, J/ApJS/240/39) present an optical imaging and spectroscopic survey of 29 radio relic merging galaxy clusters. In this paper, we study this survey to identify substructure and quantify the dynamics of the mergers. Using a combined photometric and spectroscopic approach, we identify the minimum number of substructures in each system to describe the galaxy populations and estimate the line-of-sight velocity difference between likely merging subclusters. We find that the line-of-sight velocity components of the mergers are typically small compared with the maximum 3D relative velocity (usually <1000km/s and often consistent with zero). We also compare our systems to n-body simulation analogs and estimate the viewing angle of the clean mergers in our ensemble. We find that the median system's separation vector lies within 40{deg} (17{deg}) at a 90% (50%) confidence level. This suggests that the merger axes of these systems are generally in or near the plane of the sky, matching findings in magnetohydrodynamical simulations. In 28 of the 29 systems we identify substructures in the galaxy population aligned with the radio relic(s) and presumed associated merger-induced shock. From this ensemble, we identify eight systems to include in a "gold" sample that is prime for further observation, modeling, and simulation study. Additional papers will present weak-lensing mass maps and dynamical modeling for each merging system, ultimately leading to new insight into a wide range of astrophysical phenomena at some of the largest scales in the universe.
- ID:
- ivo://CDS.VizieR/J/ApJ/686/859
- Title:
- Radio sources at 0.327, 1.4, 4.5, 8.5GHz
- Short Name:
- J/ApJ/686/859
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an analysis of the energetics and particle content of the lobes of 24 radio galaxies at the cores of cooling clusters. The radio lobes in these systems have created visible cavities in the surrounding hot, X-ray-emitting gas, which allow direct measurement of the mechanical jet power of radio sources over six decades of radio luminosity, independently of the radio properties themselves. We find that jet (cavity) power increases with radio synchrotron power approximately as P_jet_~L^{beta}^_radio_, where 0.35<={beta}<=0.70 depending on the bandpass of measurement and state of the source. Furthermore, we place limits on the magnetic field strengths and particle content of the radio lobes using a variety of X-ray constraints. We find that the lobe magnetic field strengths vary between a few to several tens of microgauss depending on the age and dynamical state of the lobes.
- ID:
- ivo://CDS.VizieR/J/AJ/118/625
- Title:
- Radio sources in Abell 2125 and 2645
- Short Name:
- J/AJ/118/625
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Abell clusters 2125 and 2645 have different radio source populations, despite being very similar in richness (Abell class 4) and redshift (0.25). The number density of radio sources in Abell 2125 is almost an order of magnitude more than that in Abell 2645, based on observations to the same optical and radio luminosities of the two clusters. About 30% of the radio sources in Abell 2125 shows signs of star formation, with the largest concentration of them in the southwest clump 2Mpc from the cluster center.
- ID:
- ivo://CDS.VizieR/J/ApJS/120/147
- Title:
- Radio sources in 14 Abell clusters
- Short Name:
- J/ApJS/120/147
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a VLA C-configuration imaging survey of 14 rich Abell clusters. The observations were undertaken with the intent of characterizing the galaxy orbits within the cluster by combining galaxy redshifts with indicators of orbital shape. We present maps of the observed clusters, detailed maps of resolved sources detected in the survey, comparisons with optical images of the clusters, and tables of source parameters for all detected sources with measured flux values.
- ID:
- ivo://CDS.VizieR/J/AJ/134/897
- Title:
- Radio sources toward galaxy clusters at 30GHz
- Short Name:
- J/AJ/134/897
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Extragalactic radio sources are a significant contaminant in cosmic microwave background and Sunyaev-Zel'dovich effect experiments. Deep interferometric observations with the BIMA and OVRO arrays are used to characterize the spatial, spectral, and flux distributions of radio sources toward massive galaxy clusters at 28.5GHz. We compute counts of millijansky source fluxes from 89 fields centered on known massive galaxy clusters and 8 noncluster fields.
