- ID:
- ivo://CDS.VizieR/J/MNRAS/450/2261
- Title:
- Galaxy cluster outskirts probed by Chandra
- Short Name:
- J/MNRAS/450/2261
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We studied the physical properties of the intracluster medium (ICM) in the virialization region of a sample of 320 clusters (0.056<z<1.24, kT>~3keV) in the Chandra archive. With the emission measure profiles from this large sample, the typical gas density, gas slope and gas fraction can be constrained out to and beyond R200. We observe a steepening of the density profiles beyond R500 with {beta}~0.68 at R500 and {beta}~1 at R200 and beyond. By tracking the direction of the cosmic filaments approximately with the ICM eccentricity, we report that galaxy clusters deviate from spherical symmetry, with only small differences between relaxed and disturbed systems. We also did not find evolution of the gas density with redshift, confirming its self-similar evolution. The value of the baryon fraction reaches the cosmic value at R200; however, systematics due to non-thermal pressure support and clumpiness might enhance the measured gas fraction, leading to an actual deficit of the baryon budget with respect to the primordial value. This study has important implications for understanding the ICM physics in the outskirts.
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Search Results
- ID:
- ivo://CDS.VizieR/J/ApJ/774/40
- Title:
- Galaxy clusters aligned with quasars. III.
- Short Name:
- J/ApJ/774/40
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present Gemini/GMOS-S multi-object spectroscopy of 31 galaxy cluster candidates at redshifts between 0.2 and 1.0 and centered on QSO sight lines taken from Lopez et al. (Paper I, J/ApJ/679/1144). The targets were selected based on the presence of an intervening MgII absorption system at a similar redshift to that of a galaxy cluster candidate lying at a projected distance <2h_71_^-1^Mpc from the QSO sight line (a "photometric hit"). The absorption systems span rest-frame equivalent widths between 0.015 and 2.028{AA}. The general population of our confirmed absorbing galaxies have luminosities L_B_~L_B_^*^ and mean rest-frame colors (R_c_-z') typical of S_cd_ galaxies.
- ID:
- ivo://CDS.VizieR/J/A+A/611/A94
- Title:
- 6 galaxy clusters ATCA 2.1GHz images
- Short Name:
- J/A+A/611/A94
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A fraction of galaxy clusters host diffuse radio sources whose origins are investigated through multi-wavelength studies of cluster samples. We investigate the presence of diffuse radio emission in a sample of seven galaxy clusters in the largely unexplored intermediate redshift range (0.3<z<0.44). In search of diffuse emission, deep radio imaging of the clusters are presented from wide band (1.1-3.1GHz), full resolution (~5-arcsec) observations with the Australia Telescope Compact Array (ATCA). The visibilities were also imaged at lower resolution after point source modelling and subtraction and after a taper was applied to achieve better sensitivity to low surface brightness diffuse radio emission. In case of non-detection of diffuse sources, we set upper limits for the radio power of injected diffuse radio sources in the field of our observations. Furthermore, we discuss the dynamical state of the observed clusters based on an X-ray morphological analysis with XMM-Newton. We detect a giant radio halo in PSZ2 G284.97-23.69 (z=0.39) and a possible diffuse source in the nearly relaxed cluster PSZ2 G262.73-40.92 (z=0.421). Our sample contains three highly disturbed massive clusters without clear traces of diffuse emission at the observed frequencies. We were able to inject modelled radio halos with low values of total flux density to set upper detection limits; however, with our high-frequency observations we cannot exclude the presence of RH in these systems because of the sensitivity of our observations in combination with the high z of the observed clusters.
- ID:
- ivo://CDS.VizieR/J/MNRAS/439/1796
- Title:
- Galaxy clusters at z=0.23 and 0.45 X-ray emission
- Short Name:
- J/MNRAS/439/1796
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The thermal, chemical, and kinematic properties of the potentially multiphase circum/intergalactic medium at the virial radii of galaxy clusters remain largely uncertain. We present an X-ray study of Abell 2246 and GMBCG J255.34805+64.23661 (z=0.23 and 0.45), two foreground clusters of the UV-bright QSO HS 1700+6416, based on 240ks Chandra/Advanced CCD Imaging Spectrometer observations. We detect enhanced diffuse X-ray emission to the projected distances beyond r_200_ radii of these two clusters. The large-scale X-ray emission is consistent with being azimuthally symmetric at the projected radii of the QSO (0.36 and 0.8 times the radii of the two clusters). Assuming a spherical symmetry, we obtain the de-projected temperature and density profiles of the X-ray-emitting gas. Excluding the cool cores that are detected, we find that the mean temperature of the hot gas is ~4.0keV for Abell 2246 and 5.5keV for GMBCG J255.34805+64.23661, although there are indications for temperature drop at large radii. From these results, we can estimate the density and pressure distributions of the hot gas along the QSO sightline. We further infer the radial entropy profile of Abell 2246 and compare it with the one expected from purely gravitational hierarchical structure formation. This comparison shows that the intracluster medium in the outer region of the clusters is likely in a clumpy and multiphased state. These results, together with the upcoming Hubble Space Telescope/Cosmic Origins Spectrograph observations of the QSO sightline, will enable a comprehensive investigation of the multiphase medium associated with the clusters.
- ID:
- ivo://CDS.VizieR/J/ApJ/763/127
- Title:
- Galaxy clusters discovered in the SPT survey
- Short Name:
- J/ApJ/763/127
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a catalog of galaxy cluster candidates, selected through their Sunyaev-Zel'dovich (SZ) effect signature in the first 720deg^2^ of the South Pole Telescope (SPT) survey. This area was mapped with the SPT in the 2008 and 2009 austral winters to a depth of ~18{mu}K_CMB_-arcmin at 150GHz; 550deg^2^ of it was also mapped to ~44{mu}K_CMB_-arcmin at 95GHz. Based on optical imaging of all 224 candidates and near-infrared imaging of the majority of candidates, we have found optical and/or infrared counterparts for 158, which we then classify as confirmed galaxy clusters. Of these 158 clusters, 135 were first identified as clusters in SPT data, including 117 new discoveries reported in this work. This catalog triples the number of confirmed galaxy clusters discovered through the SZ effect. We report photometrically derived (and in some cases spectroscopic) redshifts for confirmed clusters and redshift lower limits for the remaining candidates. The catalog extends to high redshift with a median redshift of z=0.55 and maximum confirmed redshift of z=1.37. Forty-five of the clusters have counterparts in the ROSAT bright or faint source catalogs from which we estimate X-ray fluxes. Based on simulations, we expect the catalog to be nearly 100% complete above M_500_{approx}5x10^14^M_{sun}_h^-1^_70_ at z>~0.6. There are 121 candidates detected at signal-to-noise ratio greater than five, at which the catalog purity is measured to be 95%.
- ID:
- ivo://CDS.VizieR/J/ApJS/216/27
- Title:
- Galaxy clusters discovered in the SPT-SZ survey
- Short Name:
- J/ApJS/216/27
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a catalog of galaxy clusters selected via their Sunyaev-Zel'dovich (SZ) effect signature from 2500deg^2^ of South Pole Telescope (SPT) data. This work represents the complete sample of clusters detected at high significance in the 2500deg^2^ SPT-SZ survey, which was completed in 2011. A total of 677 (409) cluster candidates are identified above a signal-to-noise threshold of {xi}=4.5 (5.0). Ground- and space-based optical and near-infrared (NIR) imaging confirms overdensities of similarly colored galaxies in the direction of 516 (or 76%) of the {xi}>4.5 candidates and 387 (or 95%) of the {xi}>5 candidates; the measured purity is consistent with expectations from simulations. Of these confirmed clusters, 415 were first identified in SPT data, including 251 new discoveries reported in this work. We estimate photometric redshifts for all candidates with identified optical and/or NIR counterparts; we additionally report redshifts derived from spectroscopic observations for 141 of these systems. The mass threshold of the catalog is roughly independent of redshift above z~0.25 leading to a sample of massive clusters that extends to high redshift. The median mass of the sample is M_500c_({rho}_crit_)~3.5x10^14^M_{sun}_h_70_^-1^, the median redshift is z_med_=0.55, and the highest-redshift systems are at z>1.4. The combination of large redshift extent, clean selection, and high typical mass makes this cluster sample of particular interest for cosmological analyses and studies of cluster formation and evolution.
- ID:
- ivo://CDS.VizieR/J/MNRAS/392/135
- Title:
- Galaxy clusters from SDSS
- Short Name:
- J/MNRAS/392/135
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We use Sloan Digital Sky Survey (SDSS) data to investigate galaxy cluster properties of the systems first detected within Digitized Second Palomar Observatory Sky Survey. With the high-quality photometry of SDSS, we derived new photometric redshifts and estimated richness and optical luminosity. For a subset of low-redshift (z<=0.1) clusters, we have used SDSS spectroscopic data to identify groups in redshift space in the region of each cluster, complemented with massive systems from the literature to assure the continuous mass sampling. A method to remove interlopers is applied, and a virial analysis is performed resulting in the estimates of velocity dispersion, mass and a physical radius for each low-z system.
- ID:
- ivo://CDS.VizieR/J/A+A/540/A123
- Title:
- Galaxy clusters from SDSS DR8
- Short Name:
- J/A+A/540/A123
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The study of the signatures of multimodality in groups and clusters of galaxies, an environment for most of the galaxies in the Universe, gives us information about the dynamical state of clusters and about merging processes, which affect the formation and evolution of galaxies, groups and clusters, and larger structures - superclusters of galaxies and the whole cosmic web. We search for the presence of substructure, a non-Gaussian, asymmetrical velocity distribution of galaxies, and large peculiar velocities of the main galaxies in clusters with at least 50 member galaxies, drawn from the SDSS DR8.
- ID:
- ivo://CDS.VizieR/J/MNRAS/289/263
- Title:
- Galaxy clusters from the APM galaxy survey
- Short Name:
- J/MNRAS/289/263
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We describe the construction of catalogues of galaxy clusters from the APM Galaxy survey using an automated algorithm based on Abell-like selection criteria. We investigate the effects of varying several parameters in our selection algorithm, including the magnitude range and radius from the cluster centre used to estimate the cluster richnesses. We quantify the accuracy of the photometric distance estimates by comparing them with measured redshifts, and we investigate the stability and completeness of the resulting catalogues. We find that the angular correlation functions for different cluster catalogues are in good agreement with one another, and are also consistent with the observed amplitude of the spatial correlation function of rich clusters.
- ID:
- ivo://CDS.VizieR/J/ApJS/253/56
- Title:
- Galaxy clusters from the DESI surveys. I.
- Short Name:
- J/ApJS/253/56
- Date:
- 11 Mar 2022
- Publisher:
- CDS
- Description:
- Based on the photometric redshift catalog of Zou+ (2019ApJS..242....8Z), we apply a fast clustering algorithm to identify 540432 galaxy clusters at z<=1 in the DESI legacy imaging surveys, which cover a sky area of about 20000deg^2^. Monte Carlo simulations indicate that the false-detection rate of our detecting method is about 3.1%. The total masses of galaxy clusters are derived using a calibrated richness-mass relation that is based on the observations of X-ray emission and the Sunyaev and Zel'dovich effect. The median redshift and mass of our detected clusters are about 0.53 and 1.23x10^14^M_{sun}_, respectively. Comparing with previous clusters identified using the data of the Sloan Digital Sky Survey; we can recognize most of them, especially those with high richness. Our catalog will be used for further statistical studies on galaxy clusters and environmental effects on galaxy evolution, etc.
