- ID:
- ivo://CDS.VizieR/J/A+A/643/A177
- Title:
- Candidate Cluster Members with Deep learning
- Short Name:
- J/A+A/643/A177
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The next generation of extensive and data-intensive surveys are bound to produce a vast amount of data, which can be efficiently dealt with using machine-learning and deep-learning methods to explore possible correlations within the multi-dimensional parameter space. We explore the classification capabilities of convolution neural networks (CNNs) to identify galaxy cluster members (CLMs) by using Hubble Space Telescope (HST) images of fifteen galaxy clusters at redshift 0.19<~z<~0.60, observed as part of the CLASH and Hubble Frontier Field programmes. We used extensive spectroscopic information, based on the CLASH-VLT VIMOS programme combined with MUSE observations, to define the knowledge base. We performed various tests to quantify how well CNNs can identify cluster members on ht basis of imaging information only. Furthermore, we investigated the CNN capability to predict source memberships outside the training coverage, in particular, by identifying CLMs at the faint end of the magnitude distributions. We find that the CNNs achieve a purity-completeness rate >~90%, demonstrating stable behaviour across the luminosity and colour of cluster galaxies, along with a remarkable generalisation capability with respect to cluster redshifts. We concluded that if extensive spectroscopic information is available as a training base, the proposed approach is a valid alternative to catalogue-based methods because it has the advantage of avoiding photometric measurements, which are particularly challenging and time-consuming in crowded cluster cores. As a byproduct, we identified 372 photometric cluster members, with mag(F814)<25, to complete the sample of 812 spectroscopic members in four galaxy clusters RX J2248-4431, MACS J0416-2403, MACS J1206-0847 and MACS J1149+2223. When this technique is applied to the data that are expected to become available from forthcoming surveys, it will be an efficient tool for a variety of studies requiring CLM selection, such as galaxy number densities, luminosity functions, and lensing mass reconstruction.
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- ID:
- ivo://CDS.VizieR/J/ApJS/97/77
- Title:
- Catalog of Coma Cluster Galaxies
- Short Name:
- J/ApJS/97/77
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A homogeneous photometry catalog is presented for 450 galaxies with B25.5 <= 16 mag located in the 9.8 x 9.8 deg region centred on the Coma Cluster. The catalog is based on photographic photometry using an automated surface photometry software for data reduction applied to B-band Schmidt plates. The catalog provides accurate positions, isophotal and total magnitudes, major and minor axes, and a few other photometric parameters including rudimentary morphology (early or late type).
- ID:
- ivo://CDS.VizieR/J/ApJ/306/30
- Title:
- Catalog of distant galaxy clusters
- Short Name:
- J/ApJ/306/30
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A photographic survey for faint galaxies has been carried out with fine-grained photographic emulsions using the 1.2m Schmidt and 5m Hale telescopes, as well as the 4m Mayall telescope. A total of 418 clusters have been found with redshifts mostly in the range from 0.15 to 0.92. The survey was planned to minimize distance-dependent selection effects in the resulting catalog. In areas of sky where the deepest search was made, the sample is complete to about z=0.50; there are 11 clusters per square degree at this limit. At a redshift of 1.0 there should be 63 or 45 clusters per square degree depending on whether q_0_ is 0.0 or 0.5, provided there is no evolution.
- ID:
- ivo://CDS.VizieR/J/A+A/601/A145
- Title:
- Catalogue of cluster members
- Short Name:
- J/A+A/601/A145
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The hierarchical model of structure formation is a key prediction of the {LAMBDA} cold dark matter model, which can be tested by studying the large-scale environment and the substructure content of massive galaxy clusters. We present here a detailed analysis of the clusters RXC J0225.9-4154, RXC J0528.9-3927, and RXC J2308.3-0211, as part of a sample of massive X-ray luminous clusters located at intermediate redshifts. We used a multiwavelength analysis, combining WFI photometric observations, VIMOS spectroscopy, and the X-ray surface brightness maps. We investigated the optical morphology of the clusters, we looked for significant counterparts in the residual X-ray emission, and we ran several statistical tests to assess their dynamical state. We correlated the results to define various substructure features, to study their properties, and to quantify their influence on simple dynamical mass estimators. RXC J0225.9-4154 has a bi-modal core, and two massive galaxy groups are located in its immediate surroundings; they are aligned in an elongated structure that is also detected in X-rays at the 1{sigma} level. RXC J0528.9-3927 is located in a poor environment; an X-ray centroid shift and the presence of two central BCGs provide mild evidence for a recent and active dynamical history. RXC J2308.3-0211 has complex central dynamics, and it is found at the core of a superstes-cluster. The complexity of the cluster's central dynamics reflects the richness of its large-scale environment: RXC J0225 and RXC J2308 present a mass fraction in substructures larger than the typical 5-15%, whereas the isolated cluster RXC J0528 does not have any major substructures within its virial radius. The largest substructures are found in the cluster outskirts. The optical morphology of the clusters correlates with the orientation of their BCG, and with the position of the main axes of accretion.
- ID:
- ivo://CDS.VizieR/J/A+A/606/A122
- Title:
- Catalogue of X-ray luminous clusters members
- Short Name:
- J/A+A/606/A122
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A robust determination of galaxy cluster mass is crucial to use them as cosmological probes, or to study the physics governing their formation and evolution. Applying various estimators on well-defined cluster samples is a mandatory step in characterising their respective systematics. Our main goal is to compare the results of three dynamical mass estimators to the X-ray hydrostatic values. Here we focus on massive galaxy clusters at intermediate redshifts z~0.3. We estimated dynamical masses with the virial theorem, the Jeans equation, and the caustic method using wide-field VIMOS spectroscopy; the hydrostatic masses were obtained previously from XMM-Newton observations.We investigated the role of colour selection and the impact of substructures on the dynamical estimators.
- ID:
- ivo://CDS.VizieR/J/MNRAS/259/233
- Title:
- Cluster SC2008-57(A3667)
- Short Name:
- J/MNRAS/259/233
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- (Abstract of the paper) We present the results of photometric and spectroscopic observations of the cluster of galaxies SC2008-57 (A3667). The observations have resulted in a catalogue with positions and magnitudes for 203 galaxies, complete at b_25 = 18.0, and radial velocities for 128 galaxies, 91 per cent complete at b_25 = 17.5. The cluster can be classified as type L because its galaxy distribution is highly flattened. It shows two strong concentrations: a main concentration, centred on the cluster brightest galaxy (a D galaxy) and coincident with the peak of X-ray emission, and a substructure around the second brightest galaxy (also a D galaxy). Most of the galaxies in this substructure seem to be bound to the second-brightest galaxy, forming a dynamical subunit inside the cluster. The extreme flattening of the cluster may at least partially be due to the presence of the substructure. The cluster also shows evidence for luminosity segregation, with the brightest galaxies being preferentially found in high galaxy density regions. Most of the luminosity segregation, however, is produced by galaxies associated with the two clumps around the D galaxies, suggesting that dynamical friction is effective in subclusters with low velocity dispersions and may be associated with the formation of D galaxies. The velocity dispersion of SC2008-57 is high, about 1200 km/s, but consistent with the observed X-ray luminosity. The cluster mass, derived using several estimators, is about 2.6 x 10^15 M_solar. Both the cluster mass and velocity dispersion may be overestimates due to the presence of the substructure.
- 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/A+A/534/A109
- Title:
- MCXC Meta-Catalogue X-ray galaxy Clusters
- Short Name:
- J/A+A/534/A109
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the compilation and properties of a meta-catalogue of X-ray detected clusters of galaxies, the MCXC. This very large catalogue is based on publicly available ROSAT All Sky Survey-based (NORAS, REFLEX, BCS, SGP, NEP, MACS, and CIZA) and serendipitous (160SD, 400SD, SHARC, WARPS, and EMSS) cluster catalogues. Data have been systematically homogenised to an overdensity of 500, and duplicate entries from overlaps between the survey areas of the individual input catalogues are carefully handled. The MCXC comprises 1743 clusters with virtually no duplicate entries. For each cluster the MCXC provides three identifiers, a redshift, coordinates, membership in the original catalogue, and standardised 0.1-2.4keV band luminosity L_500_, total mass M_500_, and radius R_500_. The meta-catalogue additionally furnishes information on overlaps between the input catalogues and the luminosity ratios when measurements from different surveys are available, and gives notes on individual objects.
- ID:
- ivo://CDS.VizieR/J/ApJ/723/985
- Title:
- Orientation of galaxies in galaxy clusters
- Short Name:
- J/ApJ/723/985
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an analysis of the spatial orientations of galaxies in 247 optically selected rich Abell clusters which have at least 100 members in the considered area. We investigated the relation between angles that give information about galaxy angular momenta and the number of members in each structure. The position angles of the galaxies' major axes, as well as two angles describing the spatial orientation of the galaxy plane, were tested for isotropy by applying three different statistical tests. It is found that the values of the statistics increase with the amount of the galaxies' members, which is equivalent to the existence of a relation between anisotropy and the number of galaxies in a cluster. The search for connection between the galaxies' alignments and Bautz-Morgan (BM) morphological types of examined clusters showed a weak dependence. A statistically marginal relation between velocity dispersion and cluster richness was observed. In addition, it was found that the velocity dispersion decreases with BM type at almost 3{sigma} level. These results show the dependence of alignments with respect to clusters' richness, which can be regarded as an environmental effect.
- ID:
- ivo://CDS.VizieR/VII/110A
- Title:
- Rich Clusters of Galaxies
- Short Name:
- VII/110A
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This is an all-sky catalog of 4073 rich clusters of galaxies, each having at least 30 members within the magnitude range m_3_ to m_3_ + 2 (m_3_ is the magnitude of the third brightest cluster member) and each with a nominal redshift less than 0.2. The southern data have been collected from a survey of UK 1.2 m Schmidt telescope IIIa-J plates and films and have been reduced to the systems defined by the northern data previously published by G.O. Abell. A revised northern catalog, including Bautz-Morgan types and redshifts where known, is also included.
