- ID:
- ivo://CDS.VizieR/J/MNRAS/446/2144
- Title:
- Galaxy And Mass Assembly: red & blue galaxies
- Short Name:
- J/MNRAS/446/2144
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We measure the mass functions for generically red and blue galaxies, using a z<0.12 sample of logM_*_>8.7 field galaxies from the Galaxy And Mass Assembly (GAMA) survey. Our motivation is that, as we show, the dominant uncertainty in existing measurements stems from how "red" and "blue" galaxies have been selected/defined. Accordingly, we model our data as two naturally overlapping populations, each with their own mass function and colour-mass relation, which enables us characterize the two populations without having to specify a priori which galaxies are "red" and "blue". Our results then provide the means to derive objective operational definitions for the terms "red" and "blue", which are based on the phenomenology of the colour-mass diagrams. Informed by this descriptive modelling, we show that (1) after accounting for dust, the stellar colours of "blue" galaxies do not depend strongly on mass; (2) the tight, flat "dead sequence" does not extend much below logM_*_~10.5; instead, (3) the stellar colours of "red" galaxies vary rather strongly with mass, such that lower mass "red" galaxies have bluer stellar populations; (4) below logM_*_~9.3, the "red" population dissolves into obscurity, and it becomes problematic to talk about two distinct populations; as a consequence, (5) it is hard to meaningfully constrain the shape, including the existence of an upturn, of the "red" galaxy mass function below logM_*_~9.3. Points 1-4 provide meaningful targets for models of galaxy formation and evolution to aim for.
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Search Results
- ID:
- ivo://CDS.VizieR/J/ApJ/763/127
- Title:
- Galaxy clusters discovered in the SPT survey
- Short Name:
- J/ApJ/763/127
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a catalog of galaxy cluster candidates, selected through their Sunyaev-Zel'dovich (SZ) effect signature in the first 720deg^2^ of the South Pole Telescope (SPT) survey. This area was mapped with the SPT in the 2008 and 2009 austral winters to a depth of ~18{mu}K_CMB_-arcmin at 150GHz; 550deg^2^ of it was also mapped to ~44{mu}K_CMB_-arcmin at 95GHz. Based on optical imaging of all 224 candidates and near-infrared imaging of the majority of candidates, we have found optical and/or infrared counterparts for 158, which we then classify as confirmed galaxy clusters. Of these 158 clusters, 135 were first identified as clusters in SPT data, including 117 new discoveries reported in this work. This catalog triples the number of confirmed galaxy clusters discovered through the SZ effect. We report photometrically derived (and in some cases spectroscopic) redshifts for confirmed clusters and redshift lower limits for the remaining candidates. The catalog extends to high redshift with a median redshift of z=0.55 and maximum confirmed redshift of z=1.37. Forty-five of the clusters have counterparts in the ROSAT bright or faint source catalogs from which we estimate X-ray fluxes. Based on simulations, we expect the catalog to be nearly 100% complete above M_500_{approx}5x10^14^M_{sun}_h^-1^_70_ at z>~0.6. There are 121 candidates detected at signal-to-noise ratio greater than five, at which the catalog purity is measured to be 95%.
- ID:
- ivo://CDS.VizieR/J/ApJS/216/27
- Title:
- Galaxy clusters discovered in the SPT-SZ survey
- Short Name:
- J/ApJS/216/27
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a catalog of galaxy clusters selected via their Sunyaev-Zel'dovich (SZ) effect signature from 2500deg^2^ of South Pole Telescope (SPT) data. This work represents the complete sample of clusters detected at high significance in the 2500deg^2^ SPT-SZ survey, which was completed in 2011. A total of 677 (409) cluster candidates are identified above a signal-to-noise threshold of {xi}=4.5 (5.0). Ground- and space-based optical and near-infrared (NIR) imaging confirms overdensities of similarly colored galaxies in the direction of 516 (or 76%) of the {xi}>4.5 candidates and 387 (or 95%) of the {xi}>5 candidates; the measured purity is consistent with expectations from simulations. Of these confirmed clusters, 415 were first identified in SPT data, including 251 new discoveries reported in this work. We estimate photometric redshifts for all candidates with identified optical and/or NIR counterparts; we additionally report redshifts derived from spectroscopic observations for 141 of these systems. The mass threshold of the catalog is roughly independent of redshift above z~0.25 leading to a sample of massive clusters that extends to high redshift. The median mass of the sample is M_500c_({rho}_crit_)~3.5x10^14^M_{sun}_h_70_^-1^, the median redshift is z_med_=0.55, and the highest-redshift systems are at z>1.4. The combination of large redshift extent, clean selection, and high typical mass makes this cluster sample of particular interest for cosmological analyses and studies of cluster formation and evolution.
- ID:
- ivo://CDS.VizieR/J/MNRAS/392/135
- Title:
- Galaxy clusters from SDSS
- Short Name:
- J/MNRAS/392/135
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We use Sloan Digital Sky Survey (SDSS) data to investigate galaxy cluster properties of the systems first detected within Digitized Second Palomar Observatory Sky Survey. With the high-quality photometry of SDSS, we derived new photometric redshifts and estimated richness and optical luminosity. For a subset of low-redshift (z<=0.1) clusters, we have used SDSS spectroscopic data to identify groups in redshift space in the region of each cluster, complemented with massive systems from the literature to assure the continuous mass sampling. A method to remove interlopers is applied, and a virial analysis is performed resulting in the estimates of velocity dispersion, mass and a physical radius for each low-z system.
- ID:
- ivo://CDS.VizieR/J/A+A/540/A123
- Title:
- Galaxy clusters from SDSS DR8
- Short Name:
- J/A+A/540/A123
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The study of the signatures of multimodality in groups and clusters of galaxies, an environment for most of the galaxies in the Universe, gives us information about the dynamical state of clusters and about merging processes, which affect the formation and evolution of galaxies, groups and clusters, and larger structures - superclusters of galaxies and the whole cosmic web. We search for the presence of substructure, a non-Gaussian, asymmetrical velocity distribution of galaxies, and large peculiar velocities of the main galaxies in clusters with at least 50 member galaxies, drawn from the SDSS DR8.
- ID:
- ivo://CDS.VizieR/J/ApJS/253/56
- Title:
- Galaxy clusters from the DESI surveys. I.
- Short Name:
- J/ApJS/253/56
- Date:
- 11 Mar 2022
- Publisher:
- CDS
- Description:
- Based on the photometric redshift catalog of Zou+ (2019ApJS..242....8Z), we apply a fast clustering algorithm to identify 540432 galaxy clusters at z<=1 in the DESI legacy imaging surveys, which cover a sky area of about 20000deg^2^. Monte Carlo simulations indicate that the false-detection rate of our detecting method is about 3.1%. The total masses of galaxy clusters are derived using a calibrated richness-mass relation that is based on the observations of X-ray emission and the Sunyaev and Zel'dovich effect. The median redshift and mass of our detected clusters are about 0.53 and 1.23x10^14^M_{sun}_, respectively. Comparing with previous clusters identified using the data of the Sloan Digital Sky Survey; we can recognize most of them, especially those with high richness. Our catalog will be used for further statistical studies on galaxy clusters and environmental effects on galaxy evolution, etc.
- ID:
- ivo://CDS.VizieR/J/A+A/494/845
- Title:
- Galaxy clusters in the CFHTLS
- Short Name:
- J/A+A/494/845
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We investigate the gain of added leverage and completeness of the constructed cluster catalogue, of applying the matched-filter detection algorithm to multiple passbands. In particular, we investigate the gain from having both i'- and z'-band data available when searching for galaxy clusters at z>~1. We applied a matched filter detection method to the CFHTLS r'- and z'-band data of the four Deep fields and compared the cluster catalogues with the one extracted from the i'-band data presented in a previous paper. We also applied the matched filter to the Deep fields but with the limiting magnitudes appropriate for the much larger Wide survey in order to understand the best combination of i'- and z'-band depth for the most efficient cluster searches based on this algorithm.
- ID:
- ivo://CDS.VizieR/J/ApJ/835/153
- Title:
- Galaxy environment in the 3D-HST fields (z=0.5-3)
- Short Name:
- J/ApJ/835/153
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We make publicly available a catalog of calibrated environmental measures for galaxies in the five 3D-Hubble Space Telescope (HST)/CANDELS deep fields. Leveraging the spectroscopic and grism redshifts from the 3D-HST survey, multiwavelength photometry from CANDELS, and wider field public data for edge corrections, we derive densities in fixed apertures to characterize the environment of galaxies brighter than JH_140_<24mag in the redshift range 0.5<z<3.0. By linking observed galaxies to a mock sample, selected to reproduce the 3D-HST sample selection and redshift accuracy, each 3D-HST galaxy is assigned a probability density function of the host halo mass, and a probability that it is a central or a satellite galaxy. The same procedure is applied to a z=0 sample selected from Sloan Digital Sky Survey. We compute the fraction of passive central and satellite galaxies as a function of stellar and halo mass, and redshift, and then derive the fraction of galaxies that were quenched by environment specific processes. Using the mock sample, we estimate that the timescale for satellite quenching is t_quench_~2-5Gyr; it is longer at lower stellar mass or lower redshift, but remarkably independent of halo mass. This indicates that, in the range of environments commonly found within the 3D-HST sample (M_h_<~10^14^M_{sun}_), satellites are quenched by exhaustion of their gas reservoir in the absence of cosmological accretion. We find that the quenching times can be separated into a delay phase, during which satellite galaxies behave similarly to centrals at fixed stellar mass, and a phase where the star formation rate drops rapidly ({tau}_f_~0.4-0.6Gyr), as shown previously at z=0. We conclude that this scenario requires satellite galaxies to retain a large reservoir of multi-phase gas upon accretion, even at high redshift, and that this gas sustains star formation for the long quenching times observed.
- ID:
- ivo://CDS.VizieR/J/ApJ/552/427
- Title:
- Galaxy groups a intermediate redshifts
- Short Name:
- J/ApJ/552/427
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Galaxy groups likely to be virialized are identified within the CNOC2, (Yee et al., 2000, Cat. <J/ApJS/129/475>) intermediate-redshift galaxy survey. The resulting groups have a median velocity dispersion, {sigma}1=~200km/s. The virial mass-to-light ratios, using k-corrected and evolution-compensated luminosities, have medians in the range of 150-250h M_{suns}_/L_{sun}_, depending on group definition details. The number-velocity dispersion relation at {sigma}1>~200km/s is in agreement with the low-mass extrapolation of the cluster-normalized Press-Schechter model. Lower velocity dispersion groups are deficient relative to the Press-Schechter model. The two-point group-group autocorrelation function has r0=6.8+/-0.3h^-1^Mpc, which is much larger than the correlations of individual galaxies, but about as expected from biased clustering. The mean number density of galaxies around group centers falls nearly as a power law with r^-2.5^ and has no well-defined core. The projected velocity dispersion of galaxies around group centers is either flat or slowly rising outward. The combination of a steeper than isothermal density profile and the outward rising velocity dispersion implies that the mass-to-light ratio of groups rises with radius if the velocity ellipsoid is isotropic but could be nearly constant if the galaxy orbits are nearly circular. Such strong tangential anisotropy is not supported by other evidence. Although the implication of a rising M/L must be viewed with caution, it could naturally arise through dynamical friction acting on the galaxies in a background of "classical" collisionless dark matter.
- ID:
- ivo://CDS.VizieR/J/A+A/578/A61
- Title:
- Galaxy groups in the 2M++
- Short Name:
- J/A+A/578/A61
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We provide the galaxy group sample used as tracers of the large scale structure in the work to study the compact group environment.
