- ID:
- ivo://CDS.VizieR/J/ApJS/240/39
- Title:
- Merging galaxy cluster deep observations
- Short Name:
- J/ApJS/240/39
- Date:
- 18 Jan 2022 14:59:05
- Publisher:
- CDS
- Description:
- Multi-band photometric and multi-object spectroscopic surveys of merging galaxy clusters allow for the characterization of the distributions of constituent DM and galaxy populations, constraints on the dynamics of the merging subclusters, and an understanding of galaxy evolution of member galaxies. We present deep photometric observations from Subaru/SuprimeCam and a catalog of 4431 spectroscopic galaxies from Keck/DEIMOS observations of 29 merging galaxy clusters ranging in redshift from z=0.07 to 0.55. The ensemble is compiled based on the presence of radio relics, which highlight cluster-scale collisionless shocks in the intracluster medium. Together with the spectroscopic and photometric information, the velocities, timescales, and geometries of the respective merging events may be tightly constrained. In this preliminary analysis, the velocity distributions of 28 of the 29 clusters are shown to be well fit by single Gaussians. This indicates that radio-relic mergers largely occur transverse to the line of sight and/or near-apocenter. In this paper, we present our optical and spectroscopic surveys, preliminary results, and a discussion of the value of radio-relic mergers for developing accurate dynamical models of each system.
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/602/A100
- Title:
- Merging groups and clusters from the SDSS data
- Short Name:
- J/A+A/602/A100
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Galaxy groups and clusters are the main tools to test cosmological models and to study the environmental effect of galaxy formation. This work aims to provide a catalogue of galaxy groups/clusters and potentially merging systems based on the SDSS main galaxy survey. We identify galaxy groups and clusters using the modified friends-of-friends (FoF) group finder that is designed specifically for flux-limited galaxy surveys. FoF group membership is refined by multimodality analysis to find subgroups and by using the group virial radius and escape velocity to expose unbound galaxies. We look for merging systems by comparing distances between group centres with group radii. The analysis results in a catalogue of 88 662 galaxy groups with at least two members. Among them are 6873 systems with at least 6 members which we consider as more reliable groups. We find 498 group mergers with up to six groups.
- ID:
- ivo://CDS.VizieR/J/MNRAS/458/226
- Title:
- MeSsI low-redshift merging cluster sample
- Short Name:
- J/MNRAS/458/226
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Merging galaxy systems provide observational evidence of the existence of dark matter and constraints on its properties. Therefore, statistically uniform samples of merging systems would be a powerful tool for several studies. In this paper, we present a new methodology for the identification of merging systems and the results of its application to galaxy redshift surveys. We use as a starting point a mock catalogue of galaxy systems, identified using friends-of-friends algorithms, that have experienced a major merger, as indicated by its merger tree. By applying machine learning techniques in this training sample, and using several features computed from the observable properties of galaxy members, it is possible to select galaxy groups that have a high probability of having experienced a major merger. Next, we apply a mixture of Gaussian techniques on galaxy members in order to reconstruct the properties of the haloes involved in such mergers. This methodology provides a highly reliable sample of merging systems with low contamination and precisely recovered properties. We apply our techniques to samples of galaxy systems obtained from the Sloan Digital Sky Survey Data Release 7, the Wide-Field Nearby Galaxy-Cluster Survey (WINGS) and the Hectospec Cluster Survey (HeCS). Our results recover previously known merging systems and provide several new candidates. We present their measured properties and discuss future analysis on current and forthcoming samples.
- ID:
- ivo://CDS.VizieR/J/A+A/546/A6
- Title:
- Metal abundances of galaxy clusters
- Short Name:
- J/A+A/546/A6
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This work measures the evolution of the iron content in galaxy clusters by a rigorous analysis of the data of 130 clusters at 0.1<z<1.3. This task is made difficult by a) the low signal-to-noise ratio of abundance measurements and the upper limits, b) possible selection effects, c) boundaries in the parameter space, d) non-Gaussian errors, e) the intrinsic variety of the objects studied, and f) abundance systematics. We introduce a Bayesian model to address all these issues at the same time, thus allowing cross-talk (covariance).
- ID:
- ivo://CDS.VizieR/VIII/29A
- Title:
- 1400-MHz Survey of 1478 Abell Clusters of Galaxies
- Short Name:
- VIII/29A
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This catalog contains observations of Abell clusters of galaxies which were obtained with the Green Bank 91-m telescope at 1400 MHz with an angular resolution of 10'x11' (RAxDEC). This catalog extends the sample of clusters originally published in Owen (1974AJ.....79..427O). The primary goals of this survey were to observe all Abell (1958ApJS....3..211A, Cat. VII/4) clusters with m10 (magnitude of the tenth brightest galaxy in the cluster) less than or equal to 17.0 and declinations north of -19 degrees, to observe all clusters with richness>=3 regardless of m10, and to obtain observations of a representative sample of the rest of the catalog (m10>=17.0; richness<=2). The abelclus.dat file contains ALL 957 detected sources (also beyond 0.5 corrected Abell radii). It contains 525 sources within 0.5 corrected Abell radii, while the published table1.dat file contains 487 entries corresponding to 485 distinct sources (in 442 clusters). The catalog entries contains the flux density at 1400 MHz, the Abell cluster number, richness class, distance class, m10, redshift estimate (z), corrected Abell cluster radius, right ascension (B1950), declination (B1950), deconvolved major and minor source axis lengths, position angle, and distance of the source from the cluster center.
- ID:
- ivo://CDS.VizieR/J/A+AS/74/315
- Title:
- 327 MHz Survey of the A262 cluster region
- Short Name:
- J/A+AS/74/315
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This catalog contains a survey at 327 MHz of the A262 cluster region. The survey was performed with the WSRT Telescope in the redundancy mode, and covers a circular region of 21 square degrees towards A262 (RA = 01h49m50s, decl = 35d54'20" -- B1950). The synthesized beam width is 56" x 93" (RA x DEC). 309 sources were detected, with a detection limit of 7 mJy (~5 sigma) at the field center. Nine of these galaxies have been identified with galaxies of the A262 cluster.
- ID:
- ivo://CDS.VizieR/J/A+A/406/867
- Title:
- Mid-IR galaxies in Virgo cluster. III.
- Short Name:
- J/A+A/406/867
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present ISOCAM imaging data at 6.75 and 15{mu}m for 145 galaxies in the Virgo cluster and in the Coma/A1367 supercluster. Of these, 99 form a complete, optically-selected, volume-limited sample including galaxies in the core and in the periphery of the Virgo cluster, suitable for statistical analysis. 34 of the Virgo galaxies were resolved by ISOCAM: for these objects we present mid-IR images, radial light and colour profiles, as well as effective and isophotal radii, surface brightness and light concentration indices.
- ID:
- ivo://CDS.VizieR/J/ApJ/800/80
- Title:
- MIR properties of galaxies in A2199 at z~0.03
- Short Name:
- J/ApJ/800/80
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We study the mid-infrared (MIR) properties of the galaxies in the A2199 supercluster at z=0.03 to understand the star formation activity of galaxy groups and clusters in the supercluster environment. Using the Wide-field Infrared Survey Explorer (WISE) data, we find no dependence of mass-normalized integrated star formation rates of galaxy groups/clusters on their virial masses. We classify the supercluster galaxies into three classes in the MIR color-luminosity diagram: MIR blue cloud (massive, quiescent, and mostly early-type), MIR star-forming sequence (mostly late-type), and MIR green valley galaxies. These MIR green valley galaxies are distinguishable from the optical green valley galaxies in the sense that they belong to the optical red sequence. We find that the fraction of each MIR class does not depend on the virial mass of each group/cluster. We compare the cumulative distributions of surface galaxy number density and cluster/group-centric distance for the three MIR classes. MIR green valley galaxies show the distribution between MIR blue cloud and MIR star-forming (SF) sequence galaxies. However, if we fix galaxy morphology, early- and late-type MIR green valley galaxies show different distributions. Our results suggest a possible evolutionary scenario of these galaxies: (1) late-type MIR SF sequence galaxies --> (2) late-type MIR green valley galaxies --> (3) early-type MIR green valley galaxies --> (4) early-type MIR blue cloud galaxies. In this sequence, the star formation of galaxies is quenched before the galaxies enter the MIR green valley, and then morphological transformation occurs in the MIR green valley.
- ID:
- ivo://CDS.VizieR/J/AJ/110/2131
- Title:
- M/L for Draco and UMi. I.
- Short Name:
- J/AJ/110/2131
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have measured 206 radial velocities for 94 probable members in the Ursa Minor dwarf spheroidal galaxy and 167 velocities for 91 probable members in the Draco dwarf spheroidal galaxy. These velocities were obtained using the KPNO 4m telescope with the Hydra multifiber positioner and bench spectrograph in 1992, 1993, and 1994. Both simulations and repeated measurements show that the median uncertainty in these velocities is 4.0km/s. Our velocities are compared with the other major datasets for Draco and Ursa Minor. Aside from a small zero-point difference, there is excellent agreement between the Hydra velocities and the Olszewski et al. MMT echelle velocities. Comparison with the Hargreaves et al. Ursa Minor velocities reveals inconsistencies which we ascribe to underestimated errors in the Hargreaves et al. data. After correcting for zero-point differences, we combine the three major sets of velocities. Our spectra recovered all of the known Carbon (C) stars in Draco and Ursa Minor and revealed one new C star in Draco and two in Ursa Minor. In addition, one star whose velocity is consistent with membership in Ursa Minor has a deep and wide HBeta absorption line in its spectrum. An initial discussion of the kinematics of the two galaxies is presented. The systemic velocities of Draco and Ursa Minor are -293.3+/-1.0 and -274+/-1.0km/s, respectively. Ursa Minor shows apparent rotation about a position angle of 75deg with an amplitude of about 3km/s; the morphological major axis is 53+/-5deg. No such rotation is found in Draco. We find a velocity dispersion of 10.4+/-0.9km/s for Ursa Minor including all stars and 8.8+/-0.8km/s excluding the star with the most extreme velocity. In Draco we find 10.7+/-0.9km/s including all stars and 8.5+/-0.7km/s excluding the three stars with the most extreme velocities. These dispersions are consistent with the dispersions measured in the other two studies and confirm that Draco and Ursa Minor have the largest mass-to-light ratios of any of the dwarf spheroidals.
- ID:
- ivo://CDS.VizieR/J/ApJS/229/20
- Title:
- MMT/Hectospec redshift survey for Abell 2029
- Short Name:
- J/ApJS/229/20
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Based on an extensive redshift survey for galaxy clusters Abell 2029 and Coma, we measure the luminosity functions (LFs) and stellar mass functions (SMFs) for the entire cluster member galaxies. Most importantly, we measure the velocity dispersion functions (VDFs) for quiescent members. The MMT/Hectospec redshift survey for galaxies in A2029 identifies 982 spectroscopic members; for 838 members, we derive the central velocity dispersion from the spectroscopy. Coma is the only other cluster surveyed as densely. The LFs, SMFs, and VDFs for A2029 and Coma are essentially identical. The SMFs of the clusters are consistent with simulations. The A2029 and Coma VDFs for quiescent galaxies have a significantly steeper slope than those of field galaxies for velocity dispersion 100km/s. The cluster VDFs also exceed the field at velocity dispersion 250km/s. The differences between cluster and field VDFs are potentially important tests of simulations and of the formation of structure in the universe.
