- ID:
- ivo://CDS.VizieR/J/A+AS/77/31
- Title:
- Survey at 408 MHz and 1420 MHz towards A 1314
- Short Name:
- J/A+AS/77/31
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The cluster of galaxies Abell 1314 has been observed with the Penticton synthesis telescope simultaneously at 408 MHz (73.5 cm wavelength) with a sensitivity (7 rms) near 70 mJy and at 1420 MHz (21.1 cm wavelength) with a sensitivity (5 rms) near 4.3 mJy. In addition to the 3 cluster sources detected, a further 64 background radio sources have been detected at 1420 MHz (the 20P radio survey), and 169 background sources at 408 MHz (the 21P radio survey). The surveys extend to a radius of 3.7 degrees at 408 MHz, and to 1.0 degree at 1420 MHz, from the map center at RA=11h31.5m, Dec=+49d20'. The differential source count for the background radio sources, derived at 408 MHz in the flux density range 90 mJy to 3.0 Jy, shows consistency with the Cambridge 5C5 survey at 408 MHz in a direction away from clusters of galaxies. Also, the differential count derived at 1420 MHz in the flux density range 10 mJy to 330 mJy is consistent with the Westerbork LBDS survey at a nearby frequency away from clusters of galaxies. We find no candidate for very steep spectrum "relic" sources in this cluster of galaxies, nor for very flat spectrum "blue" background radio galaxies behind the cluster.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/ApJS/218/8
- Title:
- Swift AGN and Cluster Survey (SACS). I.
- Short Name:
- J/ApJS/218/8
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Swift active galactic nucleus (AGN) and Cluster Survey (SACS) uses 125deg^2^ of Swift X-ray Telescope serendipitous fields with variable depths surrounding {gamma}-ray bursts to provide a medium depth (4x10^-15^erg/cm2/s) and area survey filling the gap between deep, narrow Chandra/XMM-Newton surveys and wide, shallow ROSAT surveys. Here, we present a catalog of 22563 point sources and 442 extended sources and examine the number counts of the AGN and galaxy cluster populations. SACS provides excellent constraints on the AGN number counts at the bright end with negligible uncertainties due to cosmic variance, and these constraints are consistent with previous measurements. We use Wide-field Infrared Survey Explorer (WISE) mid-infrared (MIR) colors to classify the sources. For AGNs we can roughly separate the point sources into MIR-red and MIR-blue AGNs, finding roughly equal numbers of each type in the soft X-ray band (0.5-2keV), but fewer MIR-blue sources in the hard X-ray band (2-8keV). The cluster number counts, with 5% uncertainties from cosmic variance, are also consistent with previous surveys but span a much larger continuous flux range. Deep optical or IR follow-up observations of this cluster sample will significantly increase the number of higher-redshift (z>0.5) X-ray-selected clusters.
- ID:
- ivo://CDS.VizieR/J/ApJS/222/13
- Title:
- Swift AGN and Cluster Survey (SWCL). II. SDSS
- Short Name:
- J/ApJS/222/13
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We study 203 (of 442) Swift AGN and Cluster Survey extended X-ray sources located in the SDSS DR8 footprint to search for galaxy over-densities in three-dimensional space using SDSS galaxy photometric redshifts and positions near the Swift cluster candidates. We find 104 Swift clusters with a >3{sigma} galaxy over-density. The remaining targets are potentially located at higher redshifts and require deeper optical follow-up observations for confirmation as galaxy clusters. We present a series of cluster properties including the redshift, brightest cluster galaxy (BCG) magnitude, BCG-to-X-ray center offset, optical richness, and X-ray luminosity. We also detect red sequences in ~85% of the 104 confirmed clusters. The X-ray luminosity and optical richness for the SDSS confirmed Swift clusters are correlated and follow previously established relations. The distribution of the separations between the X-ray centroids and the most likely BCG is also consistent with expectation. We compare the observed redshift distribution of the sample with a theoretical model, and find that our sample is complete for z<~0.3 and is still 80% complete up to z~0.4, consistent with the SDSS survey depth. These analysis results suggest that our Swift cluster selection algorithm has yielded a statistically well-defined cluster sample for further study of cluster evolution and cosmology. We also match our SDSS confirmed Swift clusters to existing cluster catalogs, and find 42, 23, and 1 matches in optical, X-ray, and Sunyaev-Zel'dovich catalogs, respectively, and so the majority of these clusters are new detections.
- ID:
- ivo://CDS.VizieR/J/A+A/547/A57
- Title:
- Swift X-ray Telescope Cluster Survey
- Short Name:
- J/A+A/547/A57
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a new sample of X-ray selected galaxy groups and clusters serendipitously observed with Swift and the X-ray Telescope (XRT). We searched the XRT archive for extended sources among 336 GRB fields with galactic latitude |b|>20{deg}. Our selection algorithm yields a flux-limited sample of 72 X-ray groups and clusters with a well defined selection function and negligible contamination. The sky coverage of the survey goes from the total 40deg^2^ to 1deg^2^ at a flux limit of 10^-14^erg/s/cm^-2 (0.5-2keV). All the X-ray sources are detected in the Swift-XRT soft (0.5-2keV) band.
- ID:
- ivo://CDS.VizieR/J/A+A/567/A89
- Title:
- Swift X-ray Telescope Cluster Survey. II.
- Short Name:
- J/A+A/567/A89
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a spectral analysis of a new, flux-limited sample of 72 X-ray selected clusters of galaxies identified with the X-ray Telescope (XRT) on board the Swift satellite down to a flux limit of ~10^-14^erg/s/cm2 (SWXCS). We carry out a detailed X-ray spectral analysis with the twofold aim of measuring redshifts and characterizing the properties of the intracluster medium (ICM) for the majority of the SWXCS sources. Optical counterparts and spectroscopic or photometric redshifts for some of the sources are obtained with a cross-correlation with the NASA/IPAC Extragalactic Database. Additional photometric redshifts are computed with a dedicated follow-up program with the Telescopio Nazionale Galileo and a cross-correlation with the SDSS. In addition, we also blindly search for the Hydrogen-like and He-like iron K_{alpha}_ emission line complex in the X-ray spectrum. We detect the iron emission lines in 35% of the sample, and hence obtain a robust measure of the X-ray redshift z_X_ with typical rms error 1-5%. We use z_X_ whenever the optical redshift is not available. Finally, for all the sources with measured redshift, background-subtracted spectra are fitted with a single-temperature mekal model to measure global temperature, X-ray luminosity and iron abundance of the ICM. We perform extensive spectral simulations to accounts for fitting bias, and to assess the robustness of our results. We derive a criterion to select reliable best-fit models and an empirical formula to account for fitting bias. The bias-corrected values are then used to investigate the scaling properties of the X-ray observables.
- ID:
- ivo://CDS.VizieR/J/ApJS/216/28
- Title:
- SWXCS III. Cluster catalog from 2005-2012 Swift data
- Short Name:
- J/ApJS/216/28
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the Swift X-ray Cluster Survey (SWXCS) catalog obtained using archival data from the X-ray telescope (XRT) on board the Swift satellite acquired from 2005 February to 2012 November, extending the first release of the SWXCS. The catalog provides positions, soft fluxes, and, when possible, optical counterparts for a flux-limited sample of X-ray group and cluster candidates. We consider the fields with Galactic latitude |b|>20{deg} to avoid high H I column densities. We discard all of the observations targeted at groups or clusters of galaxies, as well as particular extragalactic fields not suitable to search for faint extended sources. We finally select ~3000 useful fields covering a total solid angle of ~400deg^2^. We identify extended source candidates in the soft-band (0.5-2keV) images of these fields using the software EXSdetect, which is specifically calibrated for the XRT data. Extensive simulations are used to evaluate contamination and completeness as a function of the source signal, allowing us to minimize the number of spurious detections and to robustly assess the selection function. Our catalog includes 263 candidate galaxy clusters and groups down to a flux limit of 7x10^-15^erg/cm2/s in the soft band, and the logN-logS is in very good agreement with previous deep X-ray surveys. The final list of sources is cross-correlated with published optical, X-ray, and Sunyaev-Zeldovich catalogs of clusters. We find that 137 sources have been previously identified as clusters in the literature in independent surveys, while 126 are new detections. Currently, we have collected redshift information for 158 sources (60% of the entire sample).
- ID:
- ivo://CDS.VizieR/J/MNRAS/403/2063
- Title:
- SXDF X-ray groups and galaxy clusters
- Short Name:
- J/MNRAS/403/2063
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of a search for galaxy clusters in the Subaru-XMM Deep Field (SXDF). We reach a depth for a total cluster flux in the 0.5-2keV band of 2x10^-15^erg/cm^2^/s over one of the widest XMM-Newton contiguous raster surveys, covering an area of 1.3deg^2^. Cluster candidates are identified through a wavelet detection of extended X-ray emission. The red-sequence technique allows us to identify 57 cluster candidates. We report on the progress with the cluster spectroscopic follow-up and derive their properties based on the X-ray luminosity and cluster scaling relations.
- ID:
- ivo://CDS.VizieR/J/A+A/445/819
- Title:
- Systems of galaxies in Shapley supercluster
- Short Name:
- J/A+A/445/819
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Based on the largest compilation of galaxies with redshift in the region of the Shapley Supercluster (Proust et al., 2004 in prep., 2006A&A...447..133P), we identified 122 galaxy systems, 60 of which are new systems. Using the SuperCOSMOS catalogue, we have assigned b_j_ magnitudes to each galaxy in our compilation. The sample of galaxy systems was used to estimate the mass function of systems in the range 10^13^ to 10^15^M_{sun}/h^-1^. We computed a lower value to the total mass in the region of the Shapley Supercluster with this mass function. Using 15 mock catalogues we derived the mean mass that these kinds of systems have before comparing it with that obtained from the real data.
- ID:
- ivo://CDS.VizieR/J/MNRAS/461/248
- Title:
- 44 SZ-selected galaxy clusters ACT observations
- Short Name:
- J/MNRAS/461/248
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present galaxy velocity dispersions and dynamical mass estimates for 44 galaxy clusters selected via the Sunyaev-Zel'dovich (SZ) effect by the Atacama Cosmology Telescope. Dynamical masses for 18 clusters are reported here for the first time. Using N-body simulations, we model the different observing strategies used to measure the velocity dispersions and account for systematic effects resulting from these strategies. We find that the galaxy velocity distributions may be treated as isotropic, and that an aperture correction of up to 7 per cent in the velocity dispersion is required if the spectroscopic galaxy sample is sufficiently concentrated towards the cluster centre. Accounting for the radial profile of the velocity dispersion in simulations enables consistent dynamical mass estimates regardless of the observing strategy. Cluster masses M_200_ are in the range (1-15)x10^14^M_{sun}_. Comparing with masses estimated from the SZ distortion assuming a gas pressure profile derived from X-ray observations gives a mean SZ-to-dynamical mass ratio of 1.10+/-0.13, but there is an additional 0.14 systematic uncertainty due to the unknown velocity bias; the statistical uncertainty is dominated by the scatter in the mass-velocity dispersion scaling relation. This ratio is consistent with previous determinations at these mass scales.
1040. The A3528 complex
- ID:
- ivo://CDS.VizieR/J/MNRAS/320/387
- Title:
- The A3528 complex
- Short Name:
- J/MNRAS/320/387
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of a redshift survey of galaxies in the A3528 complex, a chain of interacting clusters in the core of the Shapley Concentration. The spectroscopic observations were performed at the 3.6-m ESO telescope at La Silla, equipped with the OPTOPUS multifibre spectrograph, on the nights of 1991 March 8-9 (for the Field 10) and from 1993 February 23-27.
