- ID:
- ivo://CDS.VizieR/J/ApJ/812/114
- Title:
- Grism Lens-Amplified Survey from Space (GLASS). I.
- Short Name:
- J/ApJ/812/114
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We give an overview of the Grism Lens Amplified Survey from Space (GLASS), a large Hubble Space Telescope program aimed at obtaining grism spectroscopy of the fields of 10 massive clusters of galaxies at redshift z=0.308-0.686, including the Hubble Frontier Fields (HFF). The Wide Field Camera 3 (WFC3) yields near-infrared spectra of the cluster cores covering the wavelength range 0.81-1.69{mu}m through grisms G102 and G141, while the Advanced Camera for Surveys in parallel mode provides G800L spectra of the infall regions of the clusters. The WFC3 spectra are taken at two almost orthogonal position angles in order to minimize the effects of confusion. After summarizing the scientific drivers of GLASS, we describe the sample selection as well as the observing strategy and data processing pipeline. We then utilize MACS J0717.5+3745, a HFF cluster and the first one observed by GLASS, to illustrate the data quality and the high-level data products. Each spectrum brighter than H_AB_=23 is visually inspected by at least two co-authors and a redshift is measured when sufficient information is present in the spectra. Furthermore, we conducted a thorough search for emission lines through all of the GLASS WFC3 spectra with the aim of measuring redshifts for sources with continuum fainter than H_AB_=23. We provide a catalog of 139 emission-line-based spectroscopic redshifts for extragalactic sources, including three new redshifts of multiple image systems (one probable, two tentative).
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- ID:
- ivo://CDS.VizieR/J/A+A/596/A14
- Title:
- Group catalogues of the local universe
- Short Name:
- J/A+A/596/A14
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Friends-of-friends algorithms are a common tool to detect galaxy groups and clusters in large survey data. In order to be as precise as possible, they have to be carefully calibrated using mock catalogues. We create an accurate and robust description of the matter distribution in the local Universe using the most up-to-date available data. This will provide the input for a specific cosmological test planned as follow-up to this work, and will be useful for general extragalactic and cosmological research. We create a set of galaxy group catalogues based on the 2MRS (Huchra et al., 2012, Cat. J/ApJS/199/26) and SDSS DR12 galaxy samples using a friends-of-friends based group finder algorithm. The algorithm is carefully calibrated and optimised on a new set of wide-angle mock catalogues from the Millennium simulation, in order to provide accurate total mass estimates of the galaxy groups taking into account the relevant observational biases in 2MRS and SDSS. We provide four different catalogues: (i) a 2MRS based group catalogue; (ii) a SDSS DR12 based group catalogue reaching out to a redshift z=0.11 with stellar mass estimates for 70% of the galaxies; (iii) a catalogue providing additional fundamental plane distances for all groups of the SDSS catalogue that host elliptical galaxies; (iv) a catalogue of the mass distribution in the local Universe based on a combination of our 2MRS and SDSS catalogues. While motivated by a specific cosmological test, three of the four catalogues that we produced are well suited to act as reference databases for a variety of extragalactic and cosmological science cases. Our catalogue of fundamental plane distances for SDSS groups provides further added value to this paper.
- ID:
- ivo://CDS.VizieR/J/MNRAS/494/2090
- Title:
- Group galaxies in ALFALFA survey
- Short Name:
- J/MNRAS/494/2090
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We estimate the HI mass function (HIMF) of galaxies in groups based on thousands of ALFALFA (Arecibo Legacy Fast ALFA survey) HI detections within the galaxy groups of four widely used SDSS (Sloan Digital Sky Survey) groups catalogues. Although differences between the catalogues mean that there is no one definitive group galaxy HIMF, in general we find that the low-mass slope is flat, in agreement with studies based on small samples of individual groups, and that the 'knee' mass is slightly higher than that of the global HIMF of the full ALFALFA sample. We find that the observed fraction of ALFALFA galaxies in groups is approximately 22 per cent. These group galaxies were removed from the full ALFALFA source catalogue to calculate the field HIMF using the remaining galaxies. Comparison between the field and group HIMFs reveals that group galaxies make only a small contribution to the global HIMF as most ALFALFA galaxies are in the field, but beyond the HIMF 'knee' group galaxies dominate. Finally we attempt to separate the group galaxy HIMF into bins of group halo mass, but find that too few low-mass galaxies are detected in the most massive groups to tightly constrain the slope, owing to the rarity of such groups in the nearby Universe where low-mass galaxies are detectable with existing HI surveys.
- ID:
- ivo://CDS.VizieR/J/ApJ/749/150
- Title:
- Group galaxies in the RCS
- Short Name:
- J/ApJ/749/150
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We study the evolution of the red-galaxy fraction (f_red_) in 905 galaxy groups with 0.15<=z<0.52. The galaxy groups are identified by the "probability friends-of-friends" algorithm from the first Red-Sequence Cluster Survey (RCS1) photometric-redshift sample. There is a high degree of uniformity in the properties of the red sequence of the group galaxies, indicating that the luminous red-sequence galaxies in the groups are already in place by z~0.5 and that they have a formation epoch of z>~2. In general, groups at lower redshifts exhibit larger f_red_ than those at higher redshifts, showing a group Butcher-Oemler effect. We investigate the evolution of f_red_ by examining its dependence on four parameters, one of which can be classified as intrinsic and three of which can be classified as environmental: galaxy stellar mass (M_*_), total group stellar mass (M_*,grp_, a proxy for group halo mass), normalized group-centric radius (r_grp_), and local galaxy density ({Sigma}_5_).
- ID:
- ivo://CDS.VizieR/J/MNRAS/407/2207
- Title:
- Group of early-type galaxies
- Short Name:
- J/MNRAS/407/2207
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The fundamental plane of early-type galaxies is a rather tight three-parameter correlation discovered more than 20yr ago. It has resisted both a global and precise physical interpretation despite a consequent number of works, observational, theoretical or using numerical simulations. It appears that its precise properties depend on the population of galaxies in study. Instead of selecting a priori these populations, we propose to objectively construct homologous populations from multivariate analyses. We have undertaken multivariate cluster and cladistic analyses of a sample of 56 low-redshift galaxy clusters containing 699 early-type galaxies, using four parameters: effective radius, velocity dispersion, surface brightness averaged over effective radius and Mg_2_ index.
- ID:
- ivo://CDS.VizieR/J/ApJ/833/194
- Title:
- Group of galaxies in gravitational lens fields
- Short Name:
- J/ApJ/833/194
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- With a large, unique spectroscopic survey in the fields of 28 galaxy-scale strong gravitational lenses, we identify groups of galaxies in the 26 adequately sampled fields. Using a group-finding algorithm, we find 210 groups with at least 5 member galaxies; the median number of members is 8. Our sample spans redshifts of 0.04<=z_grp_<=0.76 with a median of 0.31, including 174 groups with 0.1<z_grp_<0.6. The groups have radial velocity dispersions of 60<={sigma}_grp_<=1200km/s with a median of 350km/s. We also discover a supergroup in field B0712+472 at z=0.29 that consists of three main groups. We recover groups similar to ~85% of those previously reported in these fields within our redshift range of sensitivity and find 187 new groups with at least five members. The properties of our group catalog, specifically, (1) the distribution of {sigma}_grp_, (2) the fraction of all sample galaxies that are group members, and (3) the fraction of groups with significant substructure, are consistent with those for other catalogs. The distribution of group virial masses agrees well with theoretical expectations. Of the lens galaxies, 12 of 26 (46%) (B1422+231, B1600+434, B2114+022, FBQS J0951+2635, HE0435-1223, HST J14113+5211, MG0751+2716, MGJ1654+1346, PG 1115+080, Q ER 0047-2808, RXJ1131-1231, and WFI J2033-4723) are members of groups with at least five galaxies, and one more (B0712+472) belongs to an additional, visually identified group candidate. There are groups not associated with the lens that still are likely to affect the lens model; in six of 25 (24%) fields (excluding the supergroup), there is at least one massive ({sigma}_grp_>=500km/s) group or group candidate projected within 2' of the lens.
- ID:
- ivo://CDS.VizieR/J/A+A/479/927
- Title:
- Group of galaxies in SDSS 5
- Short Name:
- J/A+A/479/927
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We extract groups of galaxies from the SDSS Data Release 5 to study the supercluster-void network and environmental properties of groups therein. Groups of galaxies as density enhancements can be used to determine the luminosity density field of the supercluster-void network. We use a modified friends-of-friends (FoF) method with slightly variable linking lengths in transverse and radial directions to eliminate selection effects and to reliably find as many groups as possible. To determine the scaling of the linking length we calibrated group sizes and mean galaxy number densities within groups by shifting nearby groups to larger distances. Our final sample contains 17143 groups in the equatorial (E), and 33219 groups in the northern (N) part of the DR5 survey. The mean sizes and velocity dispersions of our groups practically do not change with their distance. This means that the selection effects have been properly taken into account when generating the group catalogue.
- ID:
- ivo://CDS.VizieR/VII/256
- Title:
- Groups of Galaxies from CfA2 Redshift Survey
- Short Name:
- VII/256
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The catalog contains statistically homogeneous and physically well graunded groups of galaxies based on the CfA2 redshift survey (Cat. J/ApJS/121/287) in the area of space 1000km/s<=cz<=15000km/s, |bII|>=20{deg}. For identification of groups we used a modification of a friends of friends (FoF) method. Principles of friendship and definition of values of presented there free parameters described in Mahtessian (1988Afz....28..255M, 1997Ap.....40..285M). There are 1971 groups with 2 or more members, for a total of 6787 members (46.3%); 765 of the groups have 3 or more members with 4375 galaxies (28.1%). The others 8790 (56.4%) galaxies make a sample of "single" galaxies. The catalog includes group numbers, numbers of members, equatorial coordinates, Virgo-centric radial velocities, line-of-sight-velocity dispersions, integrated group luminosities, and relative quantity of false members.
- ID:
- ivo://CDS.VizieR/J/AJ/154/96
- Title:
- Groups of galaxies from from SDSS-DR7
- Short Name:
- J/AJ/154/96
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We investigate the dependence of stellar population properties of galaxies on group dynamical stage for a subsample of the Yang catalog. We classify groups according to their galaxy velocity distribution into Gaussian (G) and Non-Gaussian (NG). Using two totally independent approaches, we have shown that our measurement of Gaussianity is robust and reliable. Our sample covers Yang's groups in the redshift range 0.03{<=}z{<=}0.1, with mass {>=}10^14^M_{Sun}_. The new method, called Hellinger Distance, to determine whether a group has a velocity distribution Gaussian or NG is very effective in distinguishing between the two families. NG groups present halo masses higher than the G ones, confirming previous findings. Examining the skewness and kurtosis of the velocity distribution of G and NG groups, we find that faint galaxies in NG groups are mainly infalling, for the first time, into the groups. We show that considering only faint galaxies in the outskirts; those in NG groups are older and more metal-rich than those in G groups. Also, examining the Projected Phase Space of cluster galaxies, we see that bright and faint galactic systems in G groups are in dynamical equilibrium-which does not seem to be the case in NG groups. These findings suggest that NG systems have a higher infall rate, assembling more galaxies that have experienced preprocessing before entering the group.
- ID:
- ivo://CDS.VizieR/VII/84A
- Title:
- Groups of Galaxies. III. The CfA Survey
- Short Name:
- VII/84A
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The catalog contains statistically homogeneous groups of galaxies based on the Harvard-Smithsonian Center for Astrophysics (CfA) redshift survey. Groups in the catalog are all density enhancements in redshift space of a factor greater than 20. All groups contain at least three members. There are 176 groups in the catalog and 102 groups have been identified in one or more previous studies. The catalog includes group numbers, numbers of members, equatorial coordinates, mean flow-corrected galactocentric velocities, line-of-sight-velocity dispersion, integrated group magnitudes, crossing times for the groups, and mean harmonic radii of the groups.
