- ID:
- ivo://CDS.VizieR/J/ApJ/594/154
- Title:
- 160 square degree ROSAT survey
- Short Name:
- J/ApJ/594/154
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the revised catalog of galaxy clusters detected as extended X-ray sources in the 160 Square Degree ROSAT Survey, including spectroscopic redshifts and X-ray luminosities for 200 of the 201 members. The median redshift is z_median_=0.25, and the median X-ray luminosity is L_X,median_=4.2x10^43^h_50_^2^erg/s (0.5-2.0keV). This is the largest high-redshift sample of X-ray-selected clusters published to date. There are 73 objects at z>0.3 and 22 objects at z>0.5 drawn from a statistically complete flux-limited survey with a median object flux of 1.4x10^-13^erg/cm^2^/s. We describe the optical follow-up of these clusters with an emphasis on our spectroscopy, which has yielded 155 cluster redshifts, 110 of which are presented here for the first time. These measurements, combined with 45 from the literature and other sources, provide near-complete spectroscopic coverage for our survey. We discuss the final optical identifications for the extended X-ray sources in the survey region and compare our results to similar X-ray cluster searches.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/312/745
- Title:
- SSRS groups of galaxies redshift neighbourhood
- Short Name:
- J/A+A/312/745
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Southern Sky Redshift Survey (SSRS) includes 13 groups of 5 or more members with velocities >=2000km/s. By measuring redshifts and accumulating data from the literature, we increase the total number of known group members from 89 to 218. We also measured new redshifts for 59 foreground/background galaxies superimposed on the group neighborhoods. The velocity dispersions of the groups are remarkably stable.
- ID:
- ivo://CDS.VizieR/J/A+A/647/A135
- Title:
- 35 star clusters and fields in the SMC
- Short Name:
- J/A+A/647/A135
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this work we study 35 stellar clusters in the Small Magellanic Cloud (SMC) in order to provide their mean metallicities and ages. We also provide mean metallicities of the fields surrounding the clusters. We used Stroemgren photometry obtained with the 4.1 m SOAR telescope and take advantage of (b-y) and m1 colors for which there is a metallicity calibration presented in the literature. The spatial metallicity and age distributions of clusters across the SMC are investigated using the results obtained by Stroemgren photometry. We confirm earlier observations that younger, more metal-rich star clusters are concentrated in the central regions of the galaxy, while older, more metal-poor clusters are located farther from the SMC center. We construct the age-metallicity relation for the studied clusters and find good agreement with theoretical models of chemical enrichment, and with other literature age and metallicity values for those clusters. We also provide the mean metallicities for old and young populations of the field stars surrounding the clusters, and find the latter to be in good agreement with recent studies of the SMC Cepheid population. Finally, the Stroemgren photometry obtained for this study is made publicly available.
- ID:
- ivo://CDS.VizieR/J/MNRAS/453/1965
- Title:
- Star-forming compact groups
- Short Name:
- J/MNRAS/453/1965
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a local sample (z<0.15) of 280 star-forming compact groups (SFCGs) of galaxies identified in the ultraviolet Galaxy Evolution EXplorer (GALEX) All-sky Imaging Survey (AIS). So far, just one prototypical example of SFCG, the Blue Infalling Group, has been studied in detail in the Local Universe. The sample of SFCGs is mainly the result of applying a Friends-of-Friends group finder in the space of celestial coordinates with a maximum linking-length of 1.5 arcmin and choosing groups with a minimum number of four members of bright UV-emitting 17<FUV<20.5 sources (mostly galaxies) from the GALEX/AIS catalogue. The result from the search are 280 galaxy groups composed by 226, 39, 11 and 4 groups of four, five, six and seven bright ultraviolet (UV) members, respectively. Only 59 of these 280 newly identified SFCGs have a previous catalogued group counterpart. Group redshifts are available for at least one member in 75 per cent of the SFCGs, and over 40 per cent of the SFCGs have redshifts measured for two or more galaxies. 26 of the SFCGs appear to be located in the infalling regions of clusters with known redshift. The SFCG sample presents a combination of properties different from the group samples studied up to now, such as low-velocity dispersions (sigma_l-o-s_~120km/s), small crossing-times (H_0_t_c_~0.05) and high star formation content (95 per cent of star-forming galaxies). This points to the SFCGs being in an evolutionary stage distinct from those groups selected in the optical and near-infrared ranges. Once redshifts are obtained to discard interlopers, SFCGs will constitute a unique sample of SFCGs.
- ID:
- ivo://CDS.VizieR/J/ApJ/773/86
- Title:
- Star-forming galaxies in ACO 2029
- Short Name:
- J/ApJ/773/86
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Dense environments are known to quench star formation in galaxies, but it is still unknown what mechanism(s) are directly responsible. In this paper, we study the star formation of galaxies in A2029 and compare it to that of Coma, combining indicators at 24{mu}m, H{alpha}, and UV down to rates of 0.03M_{sun}_/yr. We show that A2029's star-forming galaxies follow the same mass-SFR relation as the field. The Coma cluster, on the other hand, has a population of galaxies with star formation rates (SFRs) significantly lower than the field mass-SFR relation, indicative of galaxies in the process of being quenched. Over half of these galaxies also host active galactic nuclei. Ram-pressure stripping and starvation/strangulation are the most likely mechanisms for suppressing the star formation in these galaxies, but we are unable to disentangle which is dominating. The differences we see between the two clusters' populations of star-forming galaxies may be related to their accretion histories, with A2029 having accreted its star-forming galaxies more recently than Coma. Additionally, many early-type galaxies in A2029 are detected at 24{mu}m and/or in the far-UV, but this emission is not directly related to star formation. Similar galaxies have probably been classified as star forming in previous studies of dense clusters, possibly obscuring some of the effects of the cluster environment on true star-forming galaxies.
- ID:
- ivo://CDS.VizieR/J/A+A/303/661
- Title:
- Star-forming galaxies in the Coma Cluster
- Short Name:
- J/A+A/303/661
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In a field of 1deg radius centered in the Coma cluster of galaxies, UV ({lambda}=2000 A) observations with a 40-cm balloon-borne imaging telescope (FOCA) have provided a list of 442 UV sources brighter than m_UV_=18, which are identified in the Godwin (1983) catalogue. 254 are identified as galaxies, 178 as star-like objects and 10 as galaxy-star pairs, unresolved in the UV image.
- ID:
- ivo://CDS.VizieR/J/ApJ/856/15
- Title:
- Stellar mass-metallicity relation. I.
- Short Name:
- J/ApJ/856/15
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the stellar mass-stellar metallicity relationship (MZR) in the galaxy cluster Cl0024+1654 at z~0.4 using full-spectrum stellar population synthesis modeling of individual quiescent galaxies. The lower limit of our stellar mass range is M*=10^9.7^M_{sun}_, the lowest galaxy mass at which individual stellar metallicity has been measured beyond the local universe. We report a detection of an evolution of the stellar MZR with observed redshift at 0.037+/-0.007dex per Gyr, consistent with the predictions from hydrodynamical simulations. Additionally, we find that the evolution of the stellar MZR with observed redshift can be explained by an evolution of the stellar MZR with the formation time of galaxies, i.e., when the single stellar population (SSP)-equivalent ages of galaxies are taken into account. This behavior is consistent with stars forming out of gas that also has an MZR with a normalization that decreases with redshift. Lastly, we find that over the observed mass range, the MZR can be described by a linear function with a shallow slope ([Fe/H]{propto}(0.16+/-0.03)logM*). The slope suggests that galaxy feedback, in terms of mass-loading factor, might be mass-independent over the observed mass and redshift range.
- ID:
- ivo://CDS.VizieR/J/MNRAS/460/2862
- Title:
- Stellar mass of brightest cluster galaxies
- Short Name:
- J/MNRAS/460/2862
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using a sample of 98 galaxy clusters recently imaged in the near-infrared with the European Southern Observatory (ESO) New Technology Telescope, WIYN telescope and William Herschel Telescope, supplemented with 33 clusters from the ESO archive, we measure how the stellar mass of the most massive galaxies in the universe, namely brightest cluster galaxies (BCGs), increases with time. Most of the BCGs in this new sample lie in the redshift range 0.2<z<0.6, which has been noted in recent works to mark an epoch over which the growth in the stellar mass of BCGs stalls. From this sample of 132 clusters, we create a subsample of 102 systems that includes only those clusters that have estimates of the cluster mass. We combine the BCGs in this subsample with BCGs from the literature, and find that the growth in stellar mass of BCGs from 10 billion years ago to the present epoch is broadly consistent with recent semi-analytic and semi-empirical models. As in other recent studies, tentative evidence indicates that the stellar mass growth rate of BCGs may be slowing in the past 3.5 billion years. Further work in collecting larger samples, and in better comparing observations with theory using mock images, is required if a more detailed comparison between the models and the data is to be made.
- ID:
- ivo://CDS.VizieR/J/A+A/429/101
- Title:
- Stellar populations of CL 0048-2942
- Short Name:
- J/A+A/429/101
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a detailed study of the cluster CL 0048-2942, located at z~0.64, based on a photometric and spectroscopic catalogue of 54 galaxies in a 5x5arcmin^2^ region centred in that cluster. Of these, 23 galaxies were found to belong to the cluster. Based on this sample, the line-of-sight velocity dispersion of the cluster is approximately 680+/-140km/s.
- ID:
- ivo://CDS.VizieR/J/MNRAS/409/1455
- Title:
- Stellar populations of early-type galaxies
- Short Name:
- J/MNRAS/409/1455
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The influence of environment on the formation and evolution of early-type galaxies is, as yet, an unresolved issue. Constraints can be placed on models of early-type galaxy formation and evolution by examining their stellar populations as a function of environment. We present a catalogue of galaxies well suited to such an investigation. The magnitude-limited (b_J_<=19.45) sample was drawn from four clusters (Coma, A1139, A3558 and A930 at <z>=0.04) and their surrounds. The catalogue contains luminosities, redshifts, velocity dispersions and Lick line strengths for 416 galaxies, of which 245 are classified as early types. Luminosity-weighted ages, metallicities and {alpha}-element abundance ratios have been estimated for 219 of these early types. We also outline the steps necessary for measuring fully calibrated Lick indices and estimating the associated stellar population parameters using up-to-date methods and stellar population models. In a subsequent paper we perform a detailed study of the stellar populations of early-type galaxies in clusters and investigate the effects of environment.
