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- ID:
- ivo://CDS.VizieR/J/ApJ/569/689
- Title:
- Distant cluster hunting. II.
- Short Name:
- J/ApJ/569/689
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present and analyze the optical and X-ray catalogs of moderate-redshift cluster candidates from the ROSAT Optical X-Ray Survey, or ROXS. The survey covers the sky area contained in the fields of view of 23 deep archival ROSAT PSPC pointings, 4.8 square degrees. The cross-correlated cluster catalogs were constructed by comparing two independent catalogs extracted from the optical and X-ray bandpasses, using a matched-filter technique for the optical data and a wavelet technique for the X-ray data. We cross-identified cluster candidates in each catalog.
- ID:
- ivo://CDS.VizieR/J/A+A/607/A56
- Title:
- Distant clusters of galaxies in the 2XMM/SDSS
- Short Name:
- J/A+A/607/A56
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Galaxy clusters at high redshift are important to test cosmological models and models for the growth of structure. They are difficult to find in wide-angle optical surveys, however, leaving dedicated follow-up of X-ray selected candidates as one promising identification route. We aim to increase the number of galaxy clusters beyond the SDSS-limit, z~0.75. We compiled a list of extended X-ray sources from the 2XMMp catalogue within the footprint of the Sloan Digital Sky Survey. Fields without optical counterpart were selected for further investigation. Deep optical imaging and follow-up spectroscopy were obtained with the Large Binocular Telescope, Arizona (LBT), of those candidates not known to the literature. From initially 19 candidates, selected by visually screening X-ray images of 478 XMM-Newton observations and the corresponding SDSS images, 6 clusters were found in the literature. Imaging data through r,z filters were obtained for the remaining candidates, and 7 were chosen for multi-object (MOS) spectroscopy. Spectroscopic redshifts, optical magnitudes, and X-ray parameters (flux, temperature, and luminosity) are presented for the clusters with spectroscopic redshifts. The distant clusters studied here constitute one additional redshift bin for studies of the L-T relation, which does not seem to evolve from high to low redshifts. The selection method of distant galaxy clusters presented here was highly successful. It is based solely on archival optical (SDSS) and X-ray (XMM-Newton) data. Out of 19 selected candidates, 6 of the 7 candidates selected for spectroscopic follow-up were verified as distant clusters, a further candidate is most likely a group of galaxies at z~1.21. Out of the remaining 12 candidates, 6 were known previously as galaxy clusters, one object is a likely X-ray emission from an AGN radio jet, and for 5 we see no clear evidence for them to be high-redshift galaxy clusters.
- ID:
- ivo://CDS.VizieR/J/AJ/125/1660
- Title:
- Distant compact groups from DPOSS
- Short Name:
- J/AJ/125/1660
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have identified 84 small, high-density groups of galaxies out to z~0.2 in a region of 2000deg^2^ around the north Galactic pole using the digitized Second Palomar Observatory Sky Survey. The groups have at least four galaxies satisfying more stringent criteria than those used by Hickson in his pioneering work in 1982: the adopted limiting surface brightness for each group is brighter (24mag/arcsec^2^ instead of 26mag/arcsec^2^), and the spread in magnitude among the member galaxies is narrower (2mag instead of 3). We also adopt a slightly modified version of the isolation criterion used by Hickson, in order to avoid rejecting groups with projected nearby faint background galaxies. A 10% contamination rate due to projection effects is expected for this sample based on extensive simulations.
- ID:
- ivo://CDS.VizieR/J/ApJS/142/153
- Title:
- Distant galaxy clusters photometry
- Short Name:
- J/ApJS/142/153
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present optical and near-infrared photometry of 45 clusters of galaxies at 0.1<z<1.3. Galaxy catalogs in each cluster were defined at the longest wavelength available, generally the K band, down to approximately 2mag below M*. We include finding chart images of the band used for catalog definition. The photometry has been used in previously published papers to examine the origin and evolution of galaxies in distant clusters. Beginning in 1991, we sought to make use of the advent of relatively large format near-IR detectors to study the galaxy populations of distant clusters. We collected imaging data in both the near-IR and the optical on a large sample of clusters drawn from several samples. These data were analyzed and detailed results were presented on the evolution of early-type galaxies at moderate redshifts in Stanford, Eisenhardt, & Dickinson (1995ApJ...450..512S, 1998ApJ...492..461S), on the evolution of the K-band luminosity function in De Propris et al. (1999AJ....118..719D), on the Butcher-Oemler effect in K-selected galaxy samples in De Propris et al. (2003, ApJ, submitted), and on the evolution of early-type galaxies in high-redshift clusters in Holden et al. (2003, ApJ, in press). So far the photometry for these various studies has been published for only two clusters, Abell 370 and Abell 851 in Stanford et al. (1995ApJ...450..512S). In this paper, we present the photometry on the other 43 clusters used in our published work on distant clusters.
- ID:
- ivo://CDS.VizieR/J/AJ/123/51
- Title:
- Distribution of Abell and APM clusters
- Short Name:
- J/AJ/123/51
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a comparison of how well the large-scale structure of the universe is traced by clusters from the Abell catalog and from the Automated Plate Measuring Facility (APM). We investigate selection functions for both cluster catalogs, using samples of all clusters (including clusters with estimated redshifts) and samples of clusters with measured redshifts. We present a catalog of superclusters of galaxies, based on APM clusters up to a redshift z_lim_=0.13.
- ID:
- ivo://CDS.VizieR/J/MNRAS/392/1509
- Title:
- Distribution of AGNs in galaxy clusters
- Short Name:
- J/MNRAS/392/1509
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an analysis of the X-ray point source populations in 182 Chandra images of galaxy clusters at z>0.1 with exposure time >10ks, as well as 44 non-cluster fields. The analysis of the number and flux of these sources, using a detailed pipeline to predict the distribution of non-cluster sources in each field, reveals an excess of X-ray point sources associated with the galaxy clusters. A sample of 148 galaxy clusters at 0.1<z<0.9 , with no other nearby clusters, shows an excess of 230 cluster sources in total, an average of ~1.5 sources per cluster. The lack of optical data for these clusters limits the physical interpretation of this result, as we cannot calculate the fraction of cluster galaxies hosting X-ray sources. However, the fluxes of the excess sources indicate that over half of them are very likely to be active galactic nuclei (AGN), and the radial distribution shows that they are quite evenly distributed over the central 1Mpc of the cluster, with almost no sources found beyond this radius. We also use this pipeline to successfully reproduce the results of previous studies, particularly the higher density of sources in the central 0.5Mpc of a few cluster fields, but show that these conclusions are not generally valid for this larger sample of clusters. We conclude that some of these differences may be due to the sample properties, such as the size and redshift of the clusters studied, or a lack of publications for cluster fields with no excess sources. This paper also presents the basic X-ray properties of the galaxy clusters, and in subsequent papers in this series the dependence of the AGN population on these cluster properties will be evaluated.
- ID:
- ivo://CDS.VizieR/J/A+A/539/A106
- Title:
- DPOSS II compact group survey. EMMI-NTT sample
- Short Name:
- J/A+A/539/A106
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of a redshift survey of 138 candidate compact groups from the DPOSS II catalogue, which extends the available redshift range of spectroscopically confirmed compact groups of galaxies to redshift z~0.2. In this survey, we aim to confirm group membership via spectroscopic redshift information, to measure the characteristic properties of the confirmed groups, namely their mass, radius, luminosity, velocity dispersion, and crossing time, and to compare them with those of nearby compact groups. Using information available from the literature, we also studied the surrounding group environment and searched for additional, previously unknown, group members, or larger scale structures to whom the group might be associated.
- ID:
- ivo://CDS.VizieR/J/A+AS/95/1
- Title:
- Dumb-bell galaxies in Southern Rich Clusters
- Short Name:
- J/A+AS/95/1
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- (no description available)
- ID:
- ivo://CDS.VizieR/J/MNRAS/404/1745
- Title:
- Dwarf galaxies in Coma supercluster
- Short Name:
- J/MNRAS/404/1745
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We analyse Spitzer Multiband Imaging Photometer (MIPS) 24um observations, and Sloan Digital Sky Survey Data Release 7 optical broad-band photometry and spectra, to investigate the star formation (SF) properties of galaxies residing in the Coma supercluster region. We find that SF in dwarf galaxies is quenched only in the high-density environment at the centre of clusters and groups, but that passively evolving massive galaxies are found in all environments, indicating that massive galaxies can become passive via internal processes. The SF-density relation observed for the massive galaxies is weaker relative to the dwarfs, but both show a trend for the fraction of star-forming galaxies (f_SF_) declining to ~0 in the cluster cores. We find that active galactic nucleus activity is also suppressed among massive galaxies residing in the cluster cores.
