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- ID:
- ivo://CDS.VizieR/J/A+A/297/61
- Title:
- E+A galaxies in Cl0939+472
- Short Name:
- J/A+A/297/61
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present results of a study of E+A galaxies in the cluster Cl0939+472 (z=0.41). We have used a series of narrow-band filters (FWHM~=90-200A) covering the range from 3800 to 9200A, and broad band B, R, I filters to obtain low resolution spectra for all galaxies brighter than R=22.5mag in a 5'x5' cluster field. Two of the narrow-band filters have been chosen to measure the 4000A-break index, and 3 filters were centered on the H_{beta}_, H_{gamma}_ and H_{delta}_ lines which are indicators of recent star formation.
- ID:
- ivo://CDS.VizieR/J/MNRAS/423/422
- Title:
- Early-type BCGs with star formation
- Short Name:
- J/MNRAS/423/422
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We identify a total of 120 early-type brightest cluster galaxies (BCGs) at 0.1<z<0.4 in two recent large cluster catalogues selected from the Sloan Digital Sky Survey (SDSS). They are selected with strong emission lines in their optical spectra, with both H{alpha} and [OII]{lambda}3727 line emission, which indicates significant ongoing star formation. They constitute about ~0.5 per cent of the largest, optically selected, low-redshift BCG sample, and the fraction is a strong function of cluster richness. Their star formation history can be well described by a recent minor and short starburst superimposed on an old stellar component, with the recent episode of star formation contributing on average only less than 1 per cent of the total stellar mass. We show that the more massive star-forming BCGs in richer clusters tend to have higher star formation rate (SFR) and specific SFR (SFR per unit galaxy stellar mass). We also compare their statistical properties with a control sample selected from X-ray luminous clusters, and show that the fraction of star-forming BCGs in X-ray luminous clusters is almost one order of magnitude larger than that in optically selected clusters. BCGs with star formation in cooling flow clusters usually have very flat optical spectra and show the most active star formation, which may be connected with cooling flows.
- ID:
- ivo://CDS.VizieR/J/AJ/127/2484
- Title:
- Early-type galaxies color evolution
- Short Name:
- J/AJ/127/2484
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a study of the color evolution of elliptical and S0 galaxies in six clusters of galaxies inside the redshift range 0.78<z<1.27. For each cluster, we used imaging from the Hubble Space Telescope (HST) to determine morphological types of the galaxies. These types were determined both by an automated technique and from visual inspection. We performed simulations to determine the accuracy of the automated classifications and found a success rate of ~75% at m(L*) or brighter magnitudes for most of our HST imaging data with the fraction of late-type galaxies identified as early-type galaxies to be ~10% at m(L*) to ~20% at m(L*+2). From ground-based optical and near-infrared imaging, we measured the zero point and scatter in the color-magnitude relation of the elliptical and S0 galaxy populations, which we combine with the sample of Stanford et al. (1998ApJ...492..461S), yielding a sample of cluster early-type galaxies that span a look-back time of almost 9Gyr from the present.
- ID:
- ivo://CDS.VizieR/J/A+A/496/683
- Title:
- Early-type galaxies in the Centaurus cluster
- Short Name:
- J/A+A/496/683
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We analyse the properties of the early-type dwarf galaxy population in the Centaurus cluster. We investigate the galaxy luminosity function, galaxy scaling relations down to M_V_=-10mag. On deep VLT/FORS1 V- and I-band images of the central part of the cluster, we identify cluster dwarf-galaxy candidates using both morphological and surface brightness selection criteria. The candidates' total magnitudes and central surface brightnesses are derived from the analysis of their surface brightness profiles.
- ID:
- ivo://CDS.VizieR/J/MNRAS/445/630
- Title:
- Early-type galaxies in Ursa Major cluster
- Short Name:
- J/MNRAS/445/630
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using SDSS-DR7 and NASA/IPAC Extragalactic Database spectroscopic data, we identify 166 galaxies as members of the Ursa Major cluster with M_r_<-13.5mag. We morphological classify all galaxies by means of carefully inspecting g-, r-, i-band colour and monochromatic images. We show that the Ursa Major cluster is dominated by late-type galaxies, but also contains a significant number of early-type galaxies, particularly in the dwarf regime. We present further evidence for the existence of several subgroups in the cluster, consistent with previous findings. The early-type fraction is found to correlate with the mass of the subgroup. We also investigate environmental effects by comparing the properties of the Ursa Major early-type dwarf galaxies to those of the Virgo cluster. In contrast to the Virgo, the red sequence of the Ursa Major cluster is only sparsely populated in the optical and ultraviolet colour-magnitude relations. It also shows a statistically significant gap between -18<M_r_<-17mag, i.e. the Ursa Major cluster lacks early-type dwarf galaxies at the bright end of their luminosity function. We discover that the majority of early-type dwarf galaxies in the Ursa Major cluster have blue cores with hints of recent or ongoing star formation. We suggest that gravitational tidal interactions can trigger central blue star-forming regions in early-type dwarfs. After that, star formation would only fade completely when the galaxies experience ram-pressure stripping or harassment, both of which are nearly absent in the Ursa Major cluster.
- ID:
- ivo://CDS.VizieR/J/A+AS/139/483
- Title:
- Early-type gal. kinematics in compact groups
- Short Name:
- J/A+AS/139/483
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present measurements of stellar kinematics for seven early-type galaxies in HCG 67, HCG 74, and HCG 79. These data are aimed at studying the relation between the environment and the dynamics, structure and stellar content of early-type galaxies. In the present three groups, the kinematic features we observed cannot be associated unambiguously to physical interactions. Visible morphological peculiarities do not appear correlated with kinematical perturbations.
- ID:
- ivo://CDS.VizieR/VII/175
- Title:
- Edinburgh-Durham Southern Galaxy Cat. - Cluster Cat.
- Short Name:
- VII/175
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the Edinburgh-Durham Cluster Catalogue (EDCC). This is the first machine-based, objectively selected sample of clusters of galaxies. It consists of 737 clusters or groups of all richnesses, over 0.5 sr of sky, centred on the South Galactic Pole (SGP). The primary galaAy data set for the cluster survey is the Edinburgh-Durham Southern Galaxy Catalogue (EDSGC). The EDCC was constructed using an automatic peak-finding algorithm and is complete to m_10_(b_j_) = 18.75. In a comparison with the Abell clusters in the same region, we detect 80 per cent of their rich clusters nominally brighter than our completion limit in addition to many new systems. This suggests that the EDCC is 90 per cent complete for Abell-type clusters. We also conclude that the Abell magnitude system is biased towards bright magnitudes for most of their clusters, and that their richness estimates are prone to a larger uncertainty than they suggest. The EDCC therefore supersedes the Abell catalogue as a data base for statistical studies of cluster properties.
- ID:
- ivo://CDS.VizieR/J/MNRAS/274/1071
- Title:
- Edinburgh-Milano cluster redshift survey
- Short Name:
- J/MNRAS/274/1071
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this paper, we present the redshifts of the galaxies and galaxy clusters which form the Edinburgh-Milano (EM) cluster redshift survey. A total of 777 galaxy redshifts have been measured in 94 clusters extracted from the digitized Edinburgh-Durham Cluster Catalogue. We also present the radial velocity dispersions for 37 clusters. Observational and data reduction techniques are discussed in detail, together with the strategy adopted to determine the mean redshift of a cluster and to identify and discard plausible phantom clusters. Some 10 per cent of our clusters show heavy contamination, indicating that projection is a serious problem for optically selected, rich clusters. The median velocity dispersion estimated for a subsample of richness R>=1 clusters is 742+/-63km/s. From a simple comparison with {OMEGA}=1 cold dark matter models of structure formation, these results favour a biasing parameter b=1.6-2.0 and are inconsistent with a bias outside of the range b=1.3-2.5.
- ID:
- ivo://CDS.VizieR/J/ApJ/566/744
- Title:
- EEMSS new X-ray clusters
- Short Name:
- J/ApJ/566/744
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The complete ensemble of Einstein Imaging Proportional Counter (IPC) X-ray images has been reprocessed and reanalyzed using a multiaperture source detection algorithm. A catalog of 772 new source candidates detected within the 38' diameter central regions of the 1435 IPC fields comprising the Extended Medium-Sensitivity Survey (EMSS) has been compiled. By comparison, 478 EMSS sources fall within the same area of sky. A randomly selected subsample of 133 fields was examined; 73 sources were detected and compared with 49 original EMSS sources in the same region of sky.
