- ID:
- ivo://CDS.VizieR/J/MNRAS/458/3083
- Title:
- Abell 3888 galaxies redshifts
- Short Name:
- J/MNRAS/458/3083
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this paper we present new AAOmega spectroscopy of 254 galaxies within a 30 arcmin radius around Abell 3888. We combine these data with the existing redshifts measured in a one degree radius around the cluster and performed a substructure analysis. We confirm 71 member galaxies within the core of A3888 and determine a new average redshift and velocity dispersion for the cluster of 0.1535+/-0.0009 and 1181+/-197km/s, respectively. The cluster is elongated along an East-West axis and we find the core is bimodal along this axis with two subgroups of 26 and 41 members detected. Our results suggest that A3888 is a merging system putting to rest the previous conjecture about the morphological status of the cluster derived from X-ray observations. In addition to the results on A3888 we also present six newly detected galaxy overdensities in the field, three of which we classify as new galaxy clusters.
« Previous |
1 - 10 of 849
|
Next »
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/607/A131
- Title:
- Abell 520 galaxies redshifts
- Short Name:
- J/A+A/607/A131
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The mergers of galaxy clusters are the most energetic events in the universe after the Big Bang. An ever increasing fraction of local clusters exhibit signs of recent or past mergers. Our goal is to probe how these mergers affect the evolution and content of their member galaxies. We specifically aim to answer the following questions: Is the quenching of star formation in merging clusters enhanced when compared with relaxed clusters? Is the quenching accompanied by a (short lived) burst of star formation? We obtained optical spectroscopy of $>400$ galaxies in the field of the merging cluster Abell 520. We combine these observations with archival data to get a comprehensive picture of the state of star formation in the members of this merging cluster. Finally, we compare these observations with a control sample of 10 non-merging clusters at the same redshift from The Arizona Cluster Redshift Survey (ACReS). We split the member galaxies in passive, star forming or recently quenched depending on their spectra. The core of the merger shows a decreased fraction of star-forming galaxies compared to clusters in the non-merging sample. This region, dominated by passive galaxies, is extended along the axis of the merger. We find evidence of rapid quenching of the galaxies during the core passage with no signs of a star burst on the time scales of the merger. Additionally, we report the tentative discovery of an infalling group along the main filament feeding the merger, currently at ~2.5Mpc from the merger centre. This group contains a high fraction of star forming galaxies as well as ~2/3 of all the recently quenched galaxies in our survey.
- ID:
- ivo://CDS.VizieR/J/MNRAS/468/703
- Title:
- Abell 168 ultra-diffuse galaxies distribution
- Short Name:
- J/MNRAS/468/703
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Taking advantage of the Sloan Digital Sky Survey Stripe82 data, we have explored the spatial distribution of ultra-diffuse galaxies (UDGs) within an area of 8x8Mpc^2^ centred around the galaxy cluster Abell 168 (z=0.045). This intermediate massive cluster ({sigma}=550km/s) is surrounded by a complex large-scale structure. Our work confirms the presence of UDGs in the cluster and in the large-scale structure that surrounds it, and it is the first detection of UDGs outside clusters. Approximately 50 per cent of the UDGs analysed in the selected area inhabit the cluster region (~11+/-5 per cent in the core and ~39+/-9 per cent in the outskirts), whereas the remaining UDGs are found outside the main cluster structure (~50+/-11 per cent). The colours and the spatial distribution of the UDGs within this large-scale structure are more similar to dwarf galaxies than to L* galaxies, suggesting that most UDGs could be bona fide dwarf galaxies.
- ID:
- ivo://CDS.VizieR/J/A+A/633/A139
- Title:
- Abundances of RXC J2248.7-4431 galaxies
- Short Name:
- J/A+A/633/A139
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Aims. Gas-phase metallicities offer insight into the chemical evolution of galaxies as they reflect the recycling of gas through star formation and galactic inflows and outflows. Environmental effects such as star-formation quenching mechanisms play an important role in shaping the evolution of galaxies. Clusters of galaxies at z<0.5 are expected to be the sites where environmental effects can be clearly observed with present-day telescopes. Methods. We explored the Frontier Fields cluster RX J2248-443 at z=0.348 with VIMOS/VLT spectroscopy from CLASH-VLT, which covers a central region corresponding to almost 2 virial radii. The fluxes of [OII]{lambda}3727, H{beta}, [OIII]{lambda}5007, H{alpha} and [NII]{lambda}6584 emission lines were measured allowing the derivation of (O/H) gas metallicities, star formation rates based on extinction-corrected H{alpha} fluxes, and contamination from active galactic nuclei. We compared our sample of cluster galaxies to a population of field galaxies at similar redshifts. Results. We use the location of galaxies in projected phase-space to distinguish between cluster and field galaxies. Both populations follow the star-forming sequence in the diagnostic diagrams, which allow the ionising sources in a galaxy to be disentangled, with only a low number of galaxies classified as Seyfert II. Both field and cluster galaxies follow the "main sequence" of star-forming galaxies, with no substantial difference observed between the two populations. In the mass-metallicity (MZ) plane, both high-mass field and cluster galaxies show comparable (O/H)s to the local SDSS MZ relation, with an offset of low-mass galaxies (log(M/M_{sun}_)<9.2) towards higher metallicities. While both the metallicities of "accreted" (R<R_500_) and "infalling" (R>R_500_) cluster members are comparable at all masses, the cluster galaxies from the "mass complete" bin (which is the intermediate mass bin in this study: 9.2<log(M/M_{sun}_)<10.2), show more enhanced metallicities than their field counterparts by a factor of 0.065 dex with a ~1.8{sigma} significance. The intermediate-mass field galaxies are in accordance with the expected (O/H)s from the fundamental metallicity relation, while the cluster members deviate strongly from the model predictions, namely by a factor of ~0.12dex. The results of this work are in accordance with studies of other clusters at z<0.5 and favour the scenario in which the hot halo gas of low- and intermediate-mass cluster galaxies is removed due to ram pressure stripping, leading to an increase in their gas-phase metallicity.
- ID:
- ivo://CDS.VizieR/J/A+A/445/765
- Title:
- A Catalog of Edge-on Disk Galaxies
- Short Name:
- J/A+A/445/765
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Spiral galaxies range from bulge-dominated early-type galaxies to late types with little or no bulge. Cosmological models do not predict the formation of disk-dominated, essentially bulgeless galaxies, yet these objects exist. A particularly striking and poorly understood example of bulgeless galaxies are flat or superthin galaxies with large axis ratios. We therefore embarked on a study aimed at a better understanding of these enigmatic objects, starting by compiling a statistically meaningful sample with well-defined properties. The disk axis ratios can be most easily measured when galaxies are seen edge-on. We used data from the Sloan Digital Sky Survey (SDSS) in order to identify edge-on galaxies with disks in a uniform, reproducible, automated fashion. In the five-color photometric database of the SDSS Data Release 1 (DR1, http://www.sdss.org/dr1) (2099 deg^2) we identified 3169 edge-on disk galaxies, which we subdivided into disk galaxies with bulge, intermediate types, and simple disk galaxies without any obvious bulge component. We subdivided these types further into subclasses: Sa(f), Sb(f), Sc(f), Scd(f), Sd(f), Irr(f), where the (f) indicates that these galaxies are seen edge-on. Here we present our selection algorithm and the resulting catalogs of the 3169 edge-on disk galaxies including the photometric, morphological, and structural parameters of our targets. A number of incompleteness effects affect our catalog, but it contains almost a factor of four more bulgeless galaxies with prominent simple disks (flat galaxies) within the area covered here than optical previous catalogs, which were based on the visual selection from photographic plates (Karachentsev et al. 1999, see Cat. VII/219). We find that approximately 15% of the edge-on disk galaxies in our catalog are flat galaxies, demonstrating that these galaxies are fairly common, especially among intermediate- mass star-forming galaxies. Bulgeless disks account for roughly one third of our galaxies when also puffy disks and edge-on irregulars are included. Our catalog provides a uniform database for a multitude of follow-up studies of bulgeless galaxies in order to constrain their intrinsic and environmental properties and their evolutionary status.
- ID:
- ivo://CDS.VizieR/J/ApJS/245/10
- Title:
- A catalog of galaxies in direction of Perseus
- Short Name:
- J/ApJS/245/10
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a catalog of 5437 morphologically classified sources in the direction of the Perseus galaxy cluster core, among them 496 early-type low-mass galaxy candidates. The catalog is primarily based on V-band imaging data acquired with the William Herschel Telescope, which we used to conduct automated source detection and derive photometry. We additionally reduced archival Subaru multiband imaging data in order to measure aperture colors and perform a morphological classification, benefiting from 0.5" seeing conditions in the r-band data. Based on morphological and color properties, we extracted a sample of early-type low-mass galaxy candidates with absolute V-band magnitudes in the range of -10 to -20mag. In the color-magnitude diagram, the galaxies are located where the red sequence for early-type cluster galaxies is expected, and they lie on the literature relation between absolute magnitude and Sersic index. We classified the early-type dwarf candidates into nucleated and nonnucleated galaxies. For the faint candidates, we found a trend of increasing nucleation fraction toward brighter luminosity or higher surface brightness, similar to what is observed in other nearby galaxy clusters. We morphologically classified the remaining sources as likely background elliptical galaxies, late-type galaxies, edge-on disk galaxies, and likely merging systems and discussed the expected contamination fraction through non-early-type cluster galaxies in the magnitude-size surface brightness parameter space. Our catalog reaches its 50% completeness limit at an absolute V-band luminosity of -12mag and a V-band surface brightness of 26mag/arcsec^2^. This makes it the largest and deepest catalog with coherent coverage compared to previous imaging studies of the Perseus cluster.
- ID:
- ivo://CDS.VizieR/J/ApJS/185/1
- Title:
- A catalog of star formation and metallicity
- Short Name:
- J/ApJS/185/1
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We applied the VESPA algorithm to the Sloan Digital Sky Survey (DR7) of the Main Galaxies and Luminous Red Galaxies samples. The result is a catalog of stellar masses, detailed star formation and metallicity histories and dust content of nearly 800000 galaxies. We make the catalog public via a T-SQL database. We present the results using a range of stellar population and dust models, and will continue to update the catalog as new and improved models are made public. We also present a brief exploration of the catalog, and show that the quantities derived are robust: luminous red galaxies can be described by one to three populations, whereas a main galaxy sample galaxy needs on average two to five; red galaxies are older and less dusty; the dust values we recover are well correlated with measured Balmer decrements and star formation rates are also in agreement with previous measurements. We find that whereas some derived quantities are robust to the choice of modelling, many are still not.
- ID:
- ivo://CDS.VizieR/J/A+AS/132/255
- Title:
- A catalogue of Mg_2_ indices
- Short Name:
- J/A+AS/132/255
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a catalogue of published absorption-line Mg_2_ index measurements of galaxies and globular clusters. The catalogue consists in four tables and is maintained up-to-date in the database HYPERCAT (http://www-obs.univ-lyon1.fr/~prugniel/cgi-bin/hypercat/). The measurements are listed together with the references to the original articles where the data were published. A coded description of the observations is provided. Compiled raw data are aperture- corrected and, when it is possible, transformed to the homogeneous system. The zeropoints and re-scaling of errors are provided. The catalogue gather in total 3706 measurements for 1409 objects from 70 datasets. Total of 46 different publications were used to compile the catalogue. This catalogue will be updated. Check at the above given URL for recent version.
- ID:
- ivo://CDS.VizieR/J/A+AS/144/475
- Title:
- Accurate positions for 17124 galaxies
- Short Name:
- J/A+AS/144/475
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This paper gives accurate coordinates and diameters for 3301 galaxies, companions of UGC galaxies. (about 2764 companions were not yet available in electronic form). In addition previously poor equatorial coordinates are re-measured for 13823 galaxies. These coordinates which have an accuracy of 5'' or better will be used for facilitating the cross-identification with forthcoming catalogues of millions of galaxies.
- ID:
- ivo://CDS.VizieR/J/PASP/110/779
- Title:
- Accurate Positions for MCG Galaxies
- Short Name:
- J/PASP/110/779
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have measured accurate celestial coordinates for over 4000 extragalactic objects primarily drawn from a list of MCG galaxies with no recently published accurate positions. We used IPAC's Skyview program to display FITS images clipped from the Digitized Sky Survey, and to measure the coordinates. The standard deviations in the new positions depend slightly on the measurement command used, but are on the order of 1.0 arcsec to 1.2 arcsec (internal errors). The table of data includes all the duplicate measurements we made, as well as corrections and additions made after the PASP paper was submitted, so has 5120 entries.
