- ID:
- ivo://CDS.VizieR/J/ApJ/875/60
- Title:
- SAMI Galaxy Survey: early-type gal. in A119 & A168
- Short Name:
- J/ApJ/875/60
- Date:
- 08 Mar 2022 13:03:14
- Publisher:
- CDS
- Description:
- We investigate the kinematic alignments of luminous early-type galaxies (M_r_<=-19.5mag) in A119 and A168 using the kinematic position angles (PA_kin_) from the Sydney-AAO Multi-object Integral-field spectrograph (SAMI) survey data, motivated by the implication of the galaxy spin alignment in a cosmological context. To increase the size of our sample for statistical significance, we also use the photometric position angles (PA_phot_) for galaxies that have not been observed by SAMI, if their ellipticities are higher than 0.15. Our luminous early-type galaxies tend to prefer the specific position angles in both clusters, confirming the results of Kim+ (2018ApJ...860L...3K), who recently found the kinematic alignment of early-type galaxies in the Virgo cluster based on the ATLAS3D integral-field spectroscopic data. This alignment signal is more prominent for galaxies in the projected phase-space regions dominated by infalling populations. Furthermore, the alignment angles are closely related to the directions of the filamentary structures around clusters. The results lead us to conclude that many cluster early-type galaxies are likely to be accreted along filaments while maintaining their spin axes, which are predetermined before cluster infall.
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Search Results
902. SAMI Pilot Survey
- ID:
- ivo://CDS.VizieR/J/MNRAS/454/2050
- Title:
- SAMI Pilot Survey
- Short Name:
- J/MNRAS/454/2050
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the SAMI Pilot Survey, consisting of integral field spectroscopy of 106 galaxies across three galaxy clusters, Abell 85, Abell 168 and Abell 2399. The galaxies were selected by absolute magnitude to have Mr<-20.25mag. The survey, using the Sydney-AAO Multi-object Integral field spectrograph (SAMI), comprises observations of galaxies of all morphological types with 75 per cent of the sample being early-type galaxies (ETGs) and 25 per cent being late-type galaxies (LTGs). Stellar velocity and velocity dispersion maps are derived for all 106 galaxies in the sample. The {lambda}_R_ parameter, a proxy for the specific stellar angular momentum, is calculated for each galaxy in the sample. We find a trend between {lambda}_R_ and galaxy concentration such that LTGs are less concentrated higher angular momentum systems, with the fast-rotating ETGs (FRs) more concentrated and lower in angular momentum. This suggests that some dynamical processes are involved in transforming LTGs to FRs, though a significant overlap between the {lambda}_R_ distributions of these classes of galaxies implies that this is just one piece of a more complicated picture. We measure the kinematic misalignment angle, {Psi}, for the ETGs in the sample, to probe the intrinsic shapes of the galaxies. We find the majority of FRs (83 per cent) to be aligned, consistent with them being oblate spheroids (i.e. discs). The slow rotating ETGs (SRs), on the other hand, are significantly more likely to show kinematic misalignment (only 38 per cent are aligned). This confirms previous results that SRs are likely to be mildly triaxial systems.
- ID:
- ivo://CDS.VizieR/J/MNRAS/423/2690
- Title:
- Sample of Compact Group (CG) galaxies
- Short Name:
- J/MNRAS/423/2690
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We construct a sample of 75863 star-forming galaxies with robust metallicity and star formation rate (SFR) measurements from the Sloan Digital Sky Survey Data Release 7, from which we select a clean sample of compact group (CG) galaxies. The CGs are defined to be close configurations of at least four galaxies that are otherwise apparently isolated. Our selection results in a sample of 112 spectroscopically identified CG galaxies, which can be further divided into groups that are either embedded within a larger structure, such as a cluster or large group, or truly isolated systems. The CGs then serve as a probe into the influence of large-scale environment on a galaxy's evolution, while keeping the local density fixed at high values. W
- ID:
- ivo://CDS.VizieR/J/AJ/129/1237
- Title:
- SARS galaxy luminosity profiles
- Short Name:
- J/AJ/129/1237
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have analyzed CCD images of 14 Abell clusters in the R filter of the Southern Abell Clusters Redshifts Survey (SARS) with cz<40,000km/s. We have obtained the luminosity profiles for 507 galaxies, of which 232 (46%) have known redshifts. In order to fit the luminosity profiles, we used the de Vaucouleurs law for bulge systems and an exponential profile for disk systems, and we also fitted the Sersic's law (r^n^) to all galaxy profiles.
- ID:
- ivo://CDS.VizieR/VII/251
- Title:
- SBS/Zwicky cluster relation
- Short Name:
- VII/251
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In the same area covered by Second Byurakan Survey and CGCG, there are 1677 SBS galaxies, of which 892 are positioned inside the contours of Zwicky clusters. Data on these galaxies and respective clusters are presented in different tables, according to whether they are galaxies which are members of clusters or their substructures, probable or possible members. Projection cases are considered separately.
- ID:
- ivo://CDS.VizieR/J/AJ/130/968
- Title:
- SDSS-C4 cluster catalog
- Short Name:
- J/AJ/130/968
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the C4 Cluster Catalog, a new sample of 748 clusters of galaxies identified in the spectroscopic sample of the Second Data Release (DR2, 2004AJ....128..502A) of the Sloan Digital Sky Survey (SDSS). The C4 cluster-finding algorithm identifies clusters as overdensities in a seven-dimensional position and color space, thus minimizing projection effects that have plagued previous optical cluster selection. The present C4 catalog covers ~2600deg^2^ of sky and ranges in redshift from z=0.02 to 0.17. The mean cluster membership is 36 galaxies (with measured redshifts) brighter than r=17.7, but the catalog includes a range of systems, from groups containing 10 members to massive clusters with over 200 cluster members with measured redshifts. The catalog provides a large number of measured cluster properties including sky location, mean redshift, galaxy membership, summed r-band optical luminosity (L_r_), and velocity dispersion, as well as quantitative measures of substructure and the surrounding large-scale environment. We use new, multicolor mock SDSS galaxy catalogs, empirically constructed from the {Lambda}CDM Hubble Volume (HV) Sky Survey output, to investigate the sensitivity of the C4 catalog to the various algorithm parameters (detection threshold, choice of passbands, and search aperture), as well as to quantify the purity and completeness of the C4 cluster catalog.
- ID:
- ivo://CDS.VizieR/J/other/NewA/58.61
- Title:
- SDSS DR9 galaxy clusters optical catalog
- Short Name:
- J/other/NewA/58.
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a new galaxy cluster catalog constructed from the Sloan Digital Sky Survey Data Release 9 (SDSS DR9) using an Adaptive Matched Filter (AMF) technique. Our catalog has 46479 galaxy clusters with richness {Lambda}_200_>20 in the redshift range 0.045<=z<0.641 in ~11500 deg^2^ of the sky. Angular position, richness, core and virial radii and redshift estimates for these clusters, as well as their error analysis, are provided as part of this catalog. In addition to the main version of the catalog, we also provide an extended version with a lower richness cut, containing 79368 clusters. This version, in addition to the clusters in the main catalog, also contains those clusters (with richness 10<{Lambda}_200_<20) which have a one-to-one match in the DR8 catalog developed by Wen et al (WHL). We obtain probabilities for cluster membership for each galaxy and implement several procedures for the identification and removal of false cluster detections. We cross-correlate the main AMF DR9 catalog with a number of cluster catalogs in different wavebands (Optical, X-ray). We compare our catalog with other SDSS-based ones such as the redMaPPer (Rykoff et al., 2014, Cat. J/ApJ/785/104, 26350 clusters) and the Wen et al. (WHL, 2012, Cat. J/ApJS/199/34) (132684 clusters) in the same area of the sky and in the overlapping redshift range. We match 97% of the richest Abell clusters (Richness group 3), the same as WHL, while redMaPPer matches ~90% of these clusters. Considering AMF DR9 richness bins, redMaPPer does not have one-to-one matches for 70% of our lowest richness clusters (20<{Lambda}_200_<40), while WHL matches 54% of these missed clusters (not present in redMaPPer). redMaPPer consistently does not possess one-to-one matches for ~20% AMF DR9 clusters with {Lambda}_200_>40, while WHL matches >=70% of these missed clusters on average. For comparisons with X-ray clusters, we match the AMF catalog with BAX, MCXC and a combined catalog from NORAS and REFLEX. We consistently obtain a greater number of one-to-one matches for X--ray clusters across higher luminosity bins (L_x_>6x10^44^erg/s) than redMaPPer while WHL matches the most clusters overall. For the most luminous clusters (L_x_>8), our catalog performs equivalently to WHL. This new catalog provides a wider sample than redMaPPer while retaining many fewer objects than WHL.
- ID:
- ivo://CDS.VizieR/J/A+A/540/A106
- Title:
- SDSS-DR8 groups and clusters of galaxies
- Short Name:
- J/A+A/540/A106
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We create a new catalogue of groups and clusters for the SDSS Data Release 8 sample. We add environmental parameters to our catalogue, together with other galaxy parameters (e.g., morphology), missing from our previous catalogues. We use a modified friends-of-friends (FoF) method with a variable linking length in the transverse and radial directions to eliminate selection effects and to find reliably as many groups as possible to track the supercluster network. We use the groups of galaxies as a basis to determine the luminosity density field. We take into account various selection effects caused by a magnitude limited sample. Our final sample contains 576493 galaxies and 77858 groups. The group catalogue is available at http://www.aai.ee/~elmo/dr8groups/ and from the Strasbourg Astronomical Data Center (CDS).
- ID:
- ivo://CDS.VizieR/J/MNRAS/422/25
- Title:
- SDSS DR7 groups, clusters and filaments
- Short Name:
- J/MNRAS/422/25
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have developed a multiscale structure identification algorithm for the detection of overdensities in galaxy data that identifies structures having radii within a user-defined range. Our "multiscale probability mapping" technique combines density estimation with a shape statistic to identify local peaks in the density field. This technique takes advantage of a user-defined range of scale sizes, which are used in constructing a coarse-grained map of the underlying fine-grained galaxy distribution, from which overdense structures are then identified. In this study we have compiled a catalogue of groups and clusters at 0.025<z<0.24 based on the Sloan Digital Sky Survey (SDSS), Data Release 7, quantifying their significance and comparing with other catalogues. Most measured velocity dispersions for these structures lie between 50 and 400km/s. A clear trend of increasing velocity dispersion with radius from 0.2 to 1Mpc/h is detected, confirming the lack of a sharp division between groups and clusters. A method for quantifying elongation is also developed to measure the elongation of group and cluster environments. By using our group and cluster catalogue as a coarse-grained representation of the galaxy distribution for structure sizes of <~1Mpc/h, we identify 53 filaments (from an algorithmically derived set of 100 candidates) as elongated unions of groups and clusters at 0.025<z<0.13. These filaments have morphologies that are consistent with previous samples studied.
- ID:
- ivo://CDS.VizieR/J/A+A/514/A102
- Title:
- SDSS DR7 groups of galaxies
- Short Name:
- J/A+A/514/A102
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We extract groups of galaxies as flux-limited and volume-limited samples from the SDSS Data Release 7 to study the supercluster-void network and environmental properties of groups therein. Volume-limited catalogues are particularly useful for comparison of numerical simulations of dark matter halos and the large-scale structure with observations. Extraction of a volume-limited sample of galaxies and groups requires special care to avoid excluding too much observational data. We use a modified friends-of-friends (FoF) method with a slightly variable linking length to obtain a preliminary flux-limited sample. We use the flux-limited groups as the basic sample to include as many galaxies as possible in the volume-limited samples. To determine the scaling of the linking length we calibrated group sizes and mean galaxy number densities within groups by magnitude dilution of a nearby group sub-sample to follow the properties of groups with higher luminosity limits. Our final flux-limited sample contains 78800 groups, and volume-limited subsamples with absolute magnitude limits M_r_=-18, -19, -20, and -21 contain 5463, 12590, 18973, and 9139 groups, respectively, in the DR7 main galaxy main area survey. The spatial number densities of our groups within the subsamples, as well as the mean sizes and rms velocities of our groups practically do not change from sub-sample to sub-sample. This means that the catalogues are homogeneous and well suited for comparison with simulations.
