- ID:
- ivo://CDS.VizieR/J/ApJS/199/36
- Title:
- H{alpha} survey of nearby clusters of galaxies
- Short Name:
- J/ApJS/199/36
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of a wide-field H{alpha} imaging survey of eight nearby (z=0.02-0.03) Abell clusters. We have measured H{alpha} fluxes and equivalent widths for 465 galaxies, of which 360 are new detections. The survey was designed to obtain complete emission-line-selected inventories of star-forming galaxies in the inner regions of these clusters, extending to star formation rates below 0.1M_{sun}_/yr. This paper describes the observations, data processing, and source identification procedures, and presents an H{alpha} and R-band catalog of detected cluster members and other candidates. Future papers in the series will use these data to study the completeness of spectroscopically based star formation surveys, and to quantify the effects of cluster environment on the present-day populations of star-forming galaxies. The data will also provide a valuable foundation for imaging surveys of redshifted H{alpha} emission in more distant clusters.
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/553/A91
- Title:
- Halpha3 survey of Virgo and Coma galaxies
- Short Name:
- J/A+A/553/A91
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the analysis of the galaxy structural parameters from H{alpha}3, an H{alpha} narrow-band imaging follow-up survey of ~800 galaxies selected from the HI Arecibo Legacy Fast ALFA Survey (ALFALFA) in the Local Supercluster, including the Virgo cluster, and in the Coma Supercluster. Taking advantage of H{alpha}3 which provides the complete census of the recent star-forming, HI-rich galaxies in the local universe, we aim to investigate the structural parameters of both the young (<10Myr) and the old (>1Gyr) stellar populations. By comparing the sizes of these stellar components we investigated the spatial scale on which galaxies are growing at the present cosmological epoch and the role of the environment in quenching the star-formation activity. We computed the concentration, asymmetry, and clumpiness (CAS) structural parameters both for recently born and old stars. To quantify the sizes we computed half-light radii and a new parameter dubbed EW/r based on the half-light radius of the H{alpha} Equivalent Width map. To highlight the environmental perturbation, we adopt an updated calibration of the HI-deficiency parameter that we use to divide the sample in unperturbed and perturbed galaxies. The concentration index computed in the r band depends on the stellar mass and on the Hubble type, these variables being related since most massive galaxies are bulge dominated thus most concentrated. Going toward later spirals and irregulars both the concentration index and the mass decrease along with the bulge-to-disk ratio. Blue Compact dwarfs represent an exception since they have similar mass but they are more concentrated than dwarf irregulars. The asymmetry and the clumpiness increase along the spiral sequence up to Sc-Sd but they decrease going toward dwarfs whose light distribution is smooth and more symmetric. When measured on H{alpha} images, the CAS parameters do not exhibit obvious correlations with Hubble type. Irrespective of whether we used the ratio between effective radii or the EW/r parameter, we found that the concentration index is the main parameter that describes the current growth of isolated galaxies but, for a fixed concentration, the stellar mass plays a second order role. At the present epoch, massive galaxies are growing inside-out, conversely the dwarfs are growing on the scale of their already assembled mass.
- ID:
- ivo://CDS.VizieR/J/A+A/576/A16
- Title:
- H{alpha}3 V. Coma cluster
- Short Name:
- J/A+A/576/A16
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Neutral hydrogen represents the major observable baryonic constituent of galaxies that fuels the formation of stars through transformation of molecular hydrogen. The emission of the hydrogen recombination line H{alpha} is the most direct tracer of the process that transforms gas (fuel) into stars. We continue to present H{alpha}3 (acronym for H{alpha}-{alpha}{alpha}), an extensive H{alpha}+[NII] narrow-band imaging campaign of galaxies selected from the HI Arecibo Legacy Fast ALFA Survey (ALFALFA), using the instrumentation available at the San Pedro Martir (SPM) observatory (Mexico). In 48 nights since 2011 we were able to carry out the H{alpha} imaging observations of 724 galaxies in the region of the Coma supercluster 10h<RA<16h ; 24{deg}<Dec<28{deg} and 3900<cz<9000km/s. Of these, 603 are selected from the ALFALFA and constitute a 97% complete sample. They provide for the first time a complete census of the massive star formation properties of local gas-rich galaxies belonging to different environments (cluster vs. filaments), morphological types (spirals vs. dwarf Irr), over a wide range of stellar mass (~10^8^-10^11.5^M_{sun}_) in the Coma supercluster. The present Paper V provides H{alpha} data and derived star formation rates for the observed galaxies.
494. HCG HI-deficiency
- ID:
- ivo://CDS.VizieR/J/A+A/325/473
- Title:
- HCG HI-deficiency
- Short Name:
- J/A+A/325/473
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present HI observations of 54 Hickson Compact Groups (HCG) of which 41 have been detected in the 21-cm line of neutral hydrogen. For 13 objects upper limits have been obtained. The integrated M_HI_/L_B_ values of the observed HCGs scatter over a large range of values showing strong HI-deficiencies for a great number of objects.
- ID:
- ivo://CDS.VizieR/J/ApJ/862/172
- Title:
- HeCS-red: Hectospec surveys of redMaPPer clusters
- Short Name:
- J/ApJ/862/172
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We use dense redshift surveys to explore the properties of galaxy clusters selected from the redMaPPer catalog. Our new survey, Hectospec Cluster Survey of red-sequence-selected clusters (HeCS-red), includes 10589 new or remeasured redshifts from MMT/Hectospec observations of 27 redMaPPer clusters at redshifts z=0.08-0.25 with large estimated richnesses (richness estimate {lambda}>64). Our spectra confirm that each candidate cluster corresponds to a large overdensity in redshift space. The redMaPPer photometric redshifts have a slight bias toward higher redshifts. We measure the relation between velocity dispersion {sigma}p and {lambda}. The relation shows intrinsic scatter of 24% (and a range of 2x) in velocity dispersion at fixed richness. We extend our analysis to HeCS-red-ext, a sample that includes several clusters selected by X-ray flux or Sunyaev-Zeldovich signal. The heterogeneous sample of 121 clusters in HeCS-red-ext shows similar intrinsic scatter in the {sigma}p-{lambda} relation as the HeCS-red sample, but the range of {sigma}p at fixed richness increases to 3x. We evaluate the membership probability estimates Pmem for individual galaxies provided by redMaPPer. The spectroscopic membership fraction is larger than Pmem for 0.05<=P_mem_<=0.7; conversely, the spectroscopic membership fraction is smaller than P_mem_ at P_mem_>=0.8. We compare spectroscopic richness estimates with redMaPPer richness estimates and find good agreement on average, but a range of a factor of two in spectroscopic richness at fixed redMaPPer richness. Overall, within the high-richness and low-redshift cut of our sample, spectroscopically estimated parameters such as velocity dispersion correlate well with photometric richness estimates, although the relations contain substantial scatter.
- ID:
- ivo://CDS.VizieR/J/ApJ/767/15
- Title:
- Hectospec Cluster Survey (HeCS)
- Short Name:
- J/ApJ/767/15
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The infall regions of galaxy clusters represent the largest gravitationally bound structures in a {Lambda}CDM universe. Measuring cluster mass profiles into the infall regions provides an estimate of the ultimate mass of these halos. We use the caustic technique to measure cluster mass profiles from galaxy redshifts obtained with the Hectospec Cluster Survey (HeCS), an extensive spectroscopic survey of galaxy clusters with MMT/Hectospec. We survey 58 clusters selected by X-ray flux at 0.1<z<0.3. The survey includes 22680 unique MMT/Hectospec redshifts for individual galaxies; 10145 of these galaxies are cluster members. For each cluster, we acquired high signal-to-noise spectra for ~200 cluster members and a comparable number of foreground/background galaxies. The cluster members trace out infall patterns around the clusters. The members define a very narrow red sequence. We demonstrate that the determination of velocity dispersion is insensitive to the inclusion of bluer members (a small fraction of the cluster population). We apply the caustic technique to define membership and estimate the mass profiles to large radii. The ultimate halo mass of clusters (the mass that remains bound in the far future of a {Lambda}CDM universe) is on average (1.99+/-0.11)M_200_, a new observational cosmological test in essential agreement with simulations. Summed profiles binned in M_200_ and in L_X_demonstrate that the predicted Navarro-Frenk-White form of the density profile is a remarkably good representation of the data in agreement with weak lensing results extending to large radius. The concentration of these summed profiles is also consistent with theoretical predictions.
- ID:
- ivo://CDS.VizieR/J/ApJ/819/63
- Title:
- Hectospec survey of SZ clusters (HeCS-SZ)
- Short Name:
- J/ApJ/819/63
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We estimate cluster masses and velocity dispersions for 123 clusters from optical spectroscopy to compare the Sunyaev-Zeldovich (SZ) mass proxy and dynamical masses. Our new survey, HeCS-SZ (Hectospec Cluster Survey of SZ-selected clusters), includes 7721 new or remeasured redshifts from MMT/Hectospec observations of 21 SZ-selected clusters at redshifts z=0.05-0.20. We supplement the Hectospec data with spectra from the Sloan Digital Sky Survey (SDSS) and cluster data from the Cluster Infall Regions in SDSS project and the Hectospec Cluster Survey, our Hectospec survey of clusters selected by X-ray flux. We measure the scaling relation between velocity dispersion and SZ mass estimates from the integrated Compton parameter for an SZ-complete sample of 83 clusters. The observed relation agrees very well with a simple virial scaling from mass (based on SZ) to velocity dispersion. The SZ mass estimates (calibrated with hydrostatic X-ray mass estimates) are not significantly biased compared to dynamical mass estimates under the assumption of small velocity bias of galaxies compared to dark matter particles. Significant mass bias in SZ mass estimates could relieve tension between cosmological results from Planck SZ cluster counts and Planck CMB data. In principle, SZ mass bias and velocity bias of galaxies could conspire to yield good agreement, but the required velocity bias is {sigma}_galaxy_~0.77{sigma}_DM_, outside the range of recent models of velocity bias in the literature. More likely, SZ mass bias and velocity bias are both small, and the tension between SZ cluster counts and CMB data requires another explanation.
- ID:
- ivo://CDS.VizieR/J/A+A/513/A15
- Title:
- Heidelberg InfraRed Optical Cluster Survey, HIROCS
- Short Name:
- J/A+A/513/A15
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We describe a survey for distant clusters of galaxies that identified clusters as local overdensities in the 3D galaxy distribution. Optical and near-IR imaging in B, R, i, z, and H are used to derive photometric redshifts for objects as faint as m*+1 at a redshift of 1.5. We outline the astrometric and photometric data reduction. The 3D cluster search, based on the photometric redshifts, is described.
- ID:
- ivo://CDS.VizieR/J/A+A/407/31
- Title:
- Heliocentric radial velocities in Abell 376
- Short Name:
- J/A+A/407/31
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a dynamical analysis of the galaxy cluster Abell 376 based on a set of 73 velocities, most of them measured at Pic du Midi and Haute-Provence observatories and completed with data from the literature. Data on individual galaxies are presented and the accuracy of the determined velocities is discussed as well as some properties of the cluster. We obtained an improved mean redshift value z=0.0478^+0.005_-0.006_ and velocity dispersion {sigma}=852^+120^_-76_km/s. Our analysis indicates that inside a radius of ~900h_70_^-1^kpc (~15-arcmin) the cluster is well relaxed without any remarkable feature and the X-ray emission traces fairly well the galaxy distribution. A possible substructure is seen at 20-arcmin from the centre towards the Southwest direction, but is not confirmed by the velocity field. This SW clump is, however, kinematically bound to the main structure of Abell 376. A dense condensation of galaxies is detected at 46 arcmin (projected distance 2.6h_70_^-1^Mpc) from the centre towards the Northwest and analysis of the apparent luminosity distribution of its galaxies suggests that this clump is part of the large scale structure of Abell 376. X-ray spectroscopic analysis of ASCA data resulted in a temperature kT=4.3+/-0.4keV and metal abundance Z=0.32+/-0.08Z_{sun}. The velocity dispersion corresponding to this temperature using the T_X_-{sigma} scaling relation is in agreement with the measured galaxies velocities.
- ID:
- ivo://CDS.VizieR/J/AJ/115/6
- Title:
- Hercules supercluster kinematics
- Short Name:
- J/AJ/115/6
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Hercules supercluster consists of the Abell clusters A2147, A2151, and A2152. Previous studies of the kinematics have been confounded by the difficulty of correctly assigning galaxies to the individual clusters, which are not well separated. Our study has a total of 468 available velocities for galaxies in the region, 175 of them new. There are 414 galaxies in the supercluster, about 3 times the number used in the previous supercluster study. We verify the existence of the three individual clusters and compute their individual dynamical parameters. We investigate several techniques for assigning galaxy membership to clusters in this crowded field. We use the Kaye's mixture model (Ashman, Bird, & Zepf, 1994AJ....108.2348A) algorithm to separate the galaxies into clusters; we find that A2152 has a higher mean velocity than previous studies have reported. A2147 and A2152 also have lower velocity dispersions: 821^+68^_-55_ and 715^+81^_-61_km/s, respectively. The assignment of galaxies to either A2152 or A2147 requires velocity and position information. We study the kinematics of the supercluster using the two-body formalism of Beers, Geller, & Huchra (1982ApJ...257...23B) and conclude that A2147 and A2151 are probably bound to each other and that the supercluster as a whole may also be bound. The mass of the supercluster, if bound, is (7.6+/-2.0)x10^15^h^-1^M_{sun}_; with the supercluster luminosity, (1.4+/-0.2)x10^13^h^-2^L_{sun}_, this yields {OMEGA}=0.34+/-0.1.
