- ID:
- ivo://CDS.VizieR/J/ApJ/723/251
- Title:
- Keck/LRIS confirmation of Coma membership
- Short Name:
- J/ApJ/723/251
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Keck/LRIS multi-object spectroscopy has been carried out on 140 of some of the lowest and highest surface brightness faint (19<R<22) dwarf galaxy candidates in the core region of the Coma Cluster. These spectra are used to measure redshifts and establish membership for these faint dwarf populations. The primary goal of the low surface brightness sample is to test our ability to use morphological and surface brightness criteria to distinguish between Coma Cluster members and background galaxies using high resolution Hubble Space Telescope/Advanced Camera for Surveys images. Candidates were rated as expected members, uncertain, or expected background. From 93 spectra, 51 dwarf galaxy members and 20 background galaxies are identified. Our morphological membership estimation success rate is ~100% for objects expected to be members and better than ~90% for galaxies expected to be in the background. We confirm that low surface brightness is a very good indicator of cluster membership. High surface brightness galaxies are almost always background with confusion arising only from the cases of the rare compact elliptical (cE) galaxies. The more problematic cases occur at intermediate surface brightness. Many of these galaxies are given uncertain membership ratings, and these were found to be members about half of the time. In a sample of 47 high surface brightness, ultracompact dwarf candidates, 19 objects have redshifts which place them in the Coma Cluster, while another 6 have questionable redshift measurements but may also prove to be members.
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/526/A114
- Title:
- Kinematic profiles of Virgo early-type galaxies
- Short Name:
- J/A+A/526/A114
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new medium resolution kinematic data for a sample of 21 dwarf early-type galaxies (dEs) mainly in the Virgo cluster, obtained with the WHT and INT telescopes at the Roque de los Muchachos Observatory (La Palma, Spain). These data are used to study the origin of the dwarf elliptical galaxy population inhabiting clusters.
- ID:
- ivo://CDS.VizieR/J/AJ/106/1273
- Title:
- Kinematics of dense clusters of galaxies
- Short Name:
- J/AJ/106/1273
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have measured redshifts in the fields of the 31 R>=1 Abell clusters with 0.02<z<0.05 and |bII|>30{deg}, from medium resolution spectra (5 or 7{AA}). At least ten of the fields are severely contaminated by superimposed velocity peaks. We derive the mean velocities and velocity dispersions of the 25 dense peaks in the sample. The abundance of peaks, 6.6x10^-6^h^3^ Mpc^-3^, is consistent with the mean number density of R>1 Abell clusters (Bahcall & Soneira 1983ApJ...270...20B). The range of velocity dispersions is 304-1346 km/s. The median dispersion is 718 km/s. The subset of eight systems with cD galaxies has a median velocity dispersion of 792 km/s, close to that of non-cD systems (626 km/s). When these data are combined with 16 cD cluster velocity dispersions from our previous study (Zabludoff et al. 1990ApJS...74....1Z, and Dunn [Proceedings of NATO Conf. 1991]), eight of 25 cD galaxies have peculiar motions larger than half the cluster velocity dispersions. These findings further support the conclusions of Beers & Geller (1983ApJ...274..491B), and Dunn (1991), who argue that cD galaxies do not lie in the global kinematic center, but in local potential minima. If so, systems with speeding cD's are probably a guide to substructure in dynamically evolving systems.
- ID:
- ivo://CDS.VizieR/J/AJ/109/874
- Title:
- Kinematics of MKW and AWM Poor Clusters
- Short Name:
- J/AJ/109/874
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report 472 new redshifts for 416 galaxies in the regions of the 23 poor clusters of galaxies originally identified by Morgan, Kayser, and White, and Albert, White and Morgan. Eighteen of the poor clusters now have 10 or more available redshifts within 1.5h^-1 Mpc of the central galaxy; 11 clusters have at least 20 available redshifts. Based on the 21 clusters for which we have sufficient velocity information, the median velocity scale is 336 km/s, a factor of 2 smaller than found for rich clusters. Several of the poor clusters exhibit complex velocity distributions due to the presence of nearby clumps of galaxies. We check on the velocity of the dominant galaxy in each poor cluster relative to the remaining cluster members. Significantly high relative velocities of the dominant galaxy are found in only 4 of 21 poor clusters, 3 of which we suspect are due to contamination of the parent velocity distribution. Several statistical tests indicate that the D/cD galaxies are at the kinematic centers of the parent poor cluster velocity distributions. Mass-to-light ratios for 13 of the 15 poor clusters for which we have the required data are in the range 50 <= M/L_B(0) <= 200 Msun/Lsun. The complex nature of the regions surrounding many of the poor clusters suggests that these groupings may represent an early epoch of cluster formation. For example, the poor clusters MKW7 and MKW8 are shown to be gravitationally bound and likely to merge to form a richer cluster within the next several Gyrs. Eight of the nine other poor clusters for which simple two-body dynamical models can be carried out are consistent with being bound to other clumps in their vicinity. Additional complex systems with more than two gravitationally bound clumps are observed among the poor clusters.
- ID:
- ivo://CDS.VizieR/J/AJ/110/463
- Title:
- Kinematics of the Shapley supercluster
- Short Name:
- J/AJ/110/463
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a new analysis of the kinematics of the Shapley supercluster based on radial velocities for 1087 galaxies in the clusters A3558 (Shapley 8), A3528 (Klemola 21), A3532 (Klemola 22), A3530, A3556 (SC 1321-314), A3559 (CE 1327-292), A3560, A3562, SC 1329-314 and in the intercluster region of the core of the supercluster, of which 367 are new measurements. We also present accurate positions from APM and MAMA scans of the ESO/SERC Southern Sky Survey photographic plates. We obtain new velocity dispersions and estimate the masses of the member clusters, evaluating dynamical models of the supercluster. The supercluster is found to be significantly flattened. We find that for Omega_0=0.3, H_0=75km/s/Mpc, the gravitational pull of the supercluster may account for up to 25% of the peculiar velocity of the Local Group required to explain the dipole anisotropy of the Cosmic Microwave Background radiation, in which case the mass of the supercluster would be dominated by intercluster dark matter. This fractional contribution would be considerably higher for combinations of significantly lower values of Omega_0 and higher values of H_0.
- ID:
- ivo://CDS.VizieR/J/ApJ/579/93
- Title:
- KPNO/Deeprange distant cluster survey
- Short Name:
- J/ApJ/579/93
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have conducted an automated search for galaxy clusters within a contiguous 16deg^2^ I-band survey in the north Galactic hemisphere. A matched filter detection algorithm identifies 444 cluster candidates in the range 0.2<~z<~1.2. The full catalog is presented along with the results from a follow-up spectroscopic survey.
- ID:
- ivo://CDS.VizieR/J/ApJ/528/123
- Title:
- KRI photometry of galaxies near B2 1335+28
- Short Name:
- J/ApJ/528/123
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We previously reported a significant clustering of red galaxies (R-K=3.56) around the radio-loud quasar B2 1335+28 at z=1.086. In this paper, we establish the existence of a rich cluster at the quasar redshift and study the properties of the cluster galaxies through further detailed analysis of the photometric data. We also list the positions, K-band magnitudes, and colors of all K<19 objects. The near-infrared (NIR) K-band imaging data presented in earlier paper, together with some additional K-band data, is newly analyzed to study the extent of the clustering of the red galaxies. We also constrain the cluster redshift by applying a robust photometric redshift estimator and find a strong peak around z=1.1. The color distribution of the galaxies in the cluster is quite broad, and the fraction of blue galaxies (70%) is much larger than in intermediate-redshift clusters.
- ID:
- ivo://CDS.VizieR/J/A+A/628/A3
- Title:
- LAE z~3-7 luminosity functions
- Short Name:
- J/A+A/628/A3
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Lyman-alpha luminosity function (LF) based on deep observations of four lensing clusters. The precise aim of the present study is to further constrain the abundance of Lyman-alpha emitters (LAEs) by taking advantage of the magnification provided by lensing clusters. We blindly selected a sample of 156 LAEs, with redshifts between 2.9<z<6.7 and magnification-corrected Lyman alpha luminosities in the range 39<LogL_Ly{alpha}_[erg/s]<43. The price to pay to benefit from magnification is a reduction of the effective volume of the survey, together with a more complex analysis procedure. To properly take into account the individual differences in detection conditions (including lensing configurations, spatial and spectral morphologies) when computing the LF, a new method based on the 1/Vmax approach was implemented. The LAE LF has been obtained in four different redshift bins with constraints down to logL_Ly{alpha}_=40.5. From our data only, no significant evolution of LF mean slope can be found. When performing a Schechter analysis including data from the literature to complete the present sample a steep faint-end slope was measured varying from {alpha}=-1.69^+0.08^_-0.08_ to {alpha}=-1.87^+0.12^_-0.12_ between the lowest and the highest redshift bins. The contribution of the LAE population to the star formation rate density at z~6 is ~<50% depending on the luminosity limit considered, which is of the same order as the Lyman-break galaxy (LBG) contribution. The evolution of the LAE contribution with redshift depends on the assumed escape fraction of Lyman-alpha photons, and appears to slightly increase with increasing redshift when this fraction is conservatively set to one.
- ID:
- ivo://CDS.VizieR/J/MNRAS/366/645
- Title:
- LARCS. 11 X-ray luminous clusters
- Short Name:
- J/MNRAS/366/645
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the analysis of the spectroscopic and photometric catalogues of 11 X-ray luminous clusters at 0.07<z<0.16 from the Las Campanas/Anglo-Australian Telescope Rich Cluster Survey. Our spectroscopic data set consists of over 1600 galaxy cluster members, of which two-thirds are outside r_200_. These spectra allow us to assign cluster membership using a detailed mass model and expand on our previous work on the cluster colourmagnitude relation (CMR) where membership was inferred statistically.
- ID:
- ivo://CDS.VizieR/J/MNRAS/357/1357
- Title:
- Large-scale clumpy structure in Lynx region
- Short Name:
- J/MNRAS/357/1357
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the discovery of a probable large-scale structure composed of many galaxy clumps around the known twin clusters at z=1.26 and 1.27 in the Lynx region. Our analysis is based on deep, panoramic, and multicolour imaging, 26.4x24.1arcmin^2^ in VRi'z' bands with the Suprime-Cam on the 8.2-m Subaru telescope. This unique, deep and wide-field imaging data set allows us for the first time to map out the galaxy distribution in the highest-redshift supercluster known.
