- ID:
- ivo://CDS.VizieR/J/ApJ/773/86
- Title:
- Star-forming galaxies in ACO 2029
- Short Name:
- J/ApJ/773/86
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Dense environments are known to quench star formation in galaxies, but it is still unknown what mechanism(s) are directly responsible. In this paper, we study the star formation of galaxies in A2029 and compare it to that of Coma, combining indicators at 24{mu}m, H{alpha}, and UV down to rates of 0.03M_{sun}_/yr. We show that A2029's star-forming galaxies follow the same mass-SFR relation as the field. The Coma cluster, on the other hand, has a population of galaxies with star formation rates (SFRs) significantly lower than the field mass-SFR relation, indicative of galaxies in the process of being quenched. Over half of these galaxies also host active galactic nuclei. Ram-pressure stripping and starvation/strangulation are the most likely mechanisms for suppressing the star formation in these galaxies, but we are unable to disentangle which is dominating. The differences we see between the two clusters' populations of star-forming galaxies may be related to their accretion histories, with A2029 having accreted its star-forming galaxies more recently than Coma. Additionally, many early-type galaxies in A2029 are detected at 24{mu}m and/or in the far-UV, but this emission is not directly related to star formation. Similar galaxies have probably been classified as star forming in previous studies of dense clusters, possibly obscuring some of the effects of the cluster environment on true star-forming galaxies.
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Search Results
- ID:
- ivo://CDS.VizieR/J/ApJ/786/L10
- Title:
- Stellar IMF mass normalization for z~1 galaxies
- Short Name:
- J/ApJ/786/L10
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The stellar initial mass function (IMF) is a key parameter for studying galaxy evolution. Here we measure the IMF mass normalization for a sample of 68 field galaxies in the redshift range 0.7-0.9 within the Extended Groth Strip. To do this we derive the total (stellar + dark matter) mass-to-light [(M/L)] ratio using axisymmetric dynamical models. Within the region where we have kinematics (about one half-light radius), the models assume (1) that mass follows light, implying negligible differences between the slope of the stellar and total density profiles, (2) constant velocity anisotropy ({beta}_z_=1-{sigma}_z_^2^/{sigma}_R_^2^=0.2), and (3) that galaxies are seen at the average inclination for random orientations (i.e., i=60{deg}, where i=90{deg} represents edge-on). The dynamical models are based on anisotropic Jeans equations, constrained by Hubble Space Telescope/Advanced Camera for Surveys imaging and the central velocity dispersion of the galaxies, extracted from good-quality spectra taken by the DEEP2 survey. The population (M/L) are derived from full-spectrum fitting of the same spectra with a grid of simple stellar population models. Recent dynamical modeling results from the ATLAS^3D^ project and numerical simulations of galaxy evolution indicate that the dark matter fraction within the central regions of our galaxies should be small. This suggests that our derived total (M/L) should closely approximate the stellar M/L. Our comparison of the dynamical (M/L) and the population (M/L) then implies that for galaxies with stellar mass M_*_>~10^11^ M_{sun}_, the average normalization of the IMF is consistent with a Salpeter slope, with a substantial scatter. This is similar to what is found within a similar mass range for nearby galaxies.
- ID:
- ivo://CDS.VizieR/J/A+A/597/A48
- Title:
- Stellar kinematics in CALIFA survey
- Short Name:
- J/A+A/597/A48
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the stellar kinematic maps of a large sample of galaxies from the integral-field spectroscopic survey CALIFA. The sample comprises 300 galaxies displaying a wide range of morphologies across the Hubble sequence, from ellipticals to late-type spirals. This dataset allows us to homogeneously extract stellar kinematics up to several effective radii. In this paper, we describe the level of completeness of this subset of galaxies with respect to the full CALIFA sample, as well as the virtues and limitations of the kinematic extraction compared to other well-known integral-field surveys. In addition, we provide averaged integrated velocity dispersion radial profiles for different galaxy types, which are particularly useful to apply aperture corrections for single aperture measurements or poorly resolved stellar kinematics of high-redshift sources. The work presented in this paper sets the basis for the study of more general properties of galaxies that will be explored in subsequent papers of the survey.
- ID:
- ivo://CDS.VizieR/J/ApJ/819/L27
- Title:
- Stellar masses of optical & IR QSO hosts
- Short Name:
- J/ApJ/819/L27
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The relation between star formation rates (SFRs) and stellar masses, i.e., the galaxy main sequence, is a useful diagnostic of galaxy evolution. We present the distributions relative to the main sequence of 55 optically selected PG and 12 near-IR-selected Two Micron All Sky Survey (2MASS) quasars at z<=0.5. We estimate the quasar host stellar masses from Hubble Space Telescope or ground-based AO photometry, and the SFRs through the mid-infrared aromatic features and far-IR photometry. We find that PG quasar hosts more or less follow the main sequence defined by normal star-forming galaxies while 2MASS quasar hosts lie systematically above the main sequence. PG and 2MASS quasars with higher nuclear luminosities seem to have higher specific SFRs (sSFRs), although there is a large scatter. No trends are seen between sSFRs and SMBH masses, Eddington ratios, or even morphology types (ellipticals, spirals, and mergers). Our results could be placed in an evolutionary scenario with quasars emerging during the transition from ULIRGs/mergers to ellipticals. However, combined with results at higher redshift, they suggest that quasars can be widely triggered in normal galaxies as long as they contain abundant gas and have ongoing star formation.
- ID:
- ivo://CDS.VizieR/J/ApJ/777/18
- Title:
- Stellar mass functions of galaxies to z=4
- Short Name:
- J/ApJ/777/18
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present measurements of the stellar mass functions (SMFs) of star-forming and quiescent galaxies to z=4 using a sample of 95675 K_s_-selected galaxies in the COSMOS/UltraVISTA field (Muzzin et al. 2013ApJS..206....8M). The SMFs of the combined population are in good agreement with previous measurements and show that the stellar mass density of the universe was only 50%, 10%, and 1% of its current value at z~0.75, 2.0, and 3.5, respectively. The quiescent population drives most of the overall growth, with the stellar mass density of these galaxies increasing as {rho}_star_{prop.to}(1+z)^-4.7+/-0.4^ since z=3.5, whereas the mass density of star-forming galaxies increases as {rho}_star_{prop.to}(1+z)^-2.3 +/-0.2^. At z>2.5, star-forming galaxies dominate the total SMF at all stellar masses, although a non-zero population of quiescent galaxies persists to z=4. Comparisons of the K_s_-selected star-forming galaxy SMFs with UV-selected SMFs at 2.5<z<4 show reasonable agreement and suggest that UV-selected samples are representative of the majority of the stellar mass density at z>3.5. We estimate the average mass growth of individual galaxies by selecting galaxies at fixed cumulative number density. The average galaxy with log(M_star_/M_{sun}_)=11.5 at z=0.3 has grown in mass by only 0.2dex (0.3dex) since z=2.0 (3.5), whereas those with log(M_star_/M_{sun}_)=10.5 have grown by >1.0dex since z=2. At z<2, the time derivatives of the mass growth are always larger for lower-mass galaxies, which demonstrates that the mass growth in galaxies since that redshift is mass-dependent and primarily bottom-up. Lastly, we examine potential sources of systematic uncertainties in the SMFs and find that those from photo-z templates, stellar population synthesis modeling, and the definition of quiescent galaxies dominate the total error budget in the SMFs.
- ID:
- ivo://CDS.VizieR/J/ApJ/821/101
- Title:
- Stellar MFP for massive quiescent z<0.7 galaxies
- Short Name:
- J/ApJ/821/101
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We examine the evolution of the relation between stellar mass surface density, velocity dispersion, and half-light radius --the stellar mass fundamental plane (MFP)-- for quiescent galaxies at z<0.6. We measure the local relation from galaxies in the Sloan Digital Sky Survey and the intermediate redshift relation from ~500 quiescent galaxies with stellar masses 10<~log(M*/M_{sun}_)<~11.5. Nearly half of the quiescent galaxies in our intermediate redshift sample are compact. After accounting for important selection and systematic effects, the velocity dispersion distribution of galaxies at intermediate redshifts is similar to that of galaxies in the local universe. Galaxies at z<0.6 appear to be smaller (<~0.1dex) than galaxies in the local sample. The orientation of the stellar MFP is independent of redshift for massive quiescent galaxies at z<0.6 and the zero-point evolves by ~0.04dex. Compact quiescent galaxies fall on the same relation as the extended objects. We confirm that compact quiescent galaxies are the tail of the size and mass distribution of the normal quiescent galaxy population.
- ID:
- ivo://CDS.VizieR/J/A+A/429/101
- Title:
- Stellar populations of CL 0048-2942
- Short Name:
- J/A+A/429/101
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a detailed study of the cluster CL 0048-2942, located at z~0.64, based on a photometric and spectroscopic catalogue of 54 galaxies in a 5x5arcmin^2^ region centred in that cluster. Of these, 23 galaxies were found to belong to the cluster. Based on this sample, the line-of-sight velocity dispersion of the cluster is approximately 680+/-140km/s.
- ID:
- ivo://CDS.VizieR/J/ApJS/146/209
- Title:
- STIS emission-line galaxies observations
- Short Name:
- J/ApJS/146/209
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In the first 3 years of operation the Space Telescope Imaging Spectrograph (STIS) obtained slitless spectra of ~2500 fields in parallel to prime Hubble Space Telescope (HST) observations as part of the STIS parallel survey (SPS). The archive contains ~300 fields at high Galactic latitude (|b|>30{deg}) with spectroscopic exposure times greater than 3000s. This sample contains 219 fields (excluding special regions and requiring a consistent grating angle) observed between 1997 June 6 and 2000 September 21, with a total survey area of ~160-arcmin^2^. At this depth, the SPS detects an average of one emission-line galaxy per three fields. We present the analysis of these data and the identification of 131 low- to intermediate-redshift galaxies detected by optical emission lines. The sample contains 78 objects with emission lines that we infer to be redshifted [O II] {lambda}3727 emission at 0.43<z<1.7. The comoving number density of these objects is comparable to that of H{alpha}-emitting galaxies in the NICMOS parallel observations. One quasar and three probable Seyfert galaxies are detected. Many of the emission-line objects show morphologies suggestive of mergers or interactions. The reduced data are available upon request from the authors.
- ID:
- ivo://CDS.VizieR/J/ApJ/850/66
- Title:
- Stripe 82X survey multiwavelength catalog
- Short Name:
- J/ApJ/850/66
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Multiwavelength surveys covering large sky volumes are necessary to obtain an accurate census of rare objects such as high-luminosity and/or high-redshift active galactic nuclei (AGNs). Stripe 82X is a 31.3 X-ray survey with Chandra and XMM-Newton observations overlapping the legacy Sloan Digital Sky Survey Stripe 82 field, which has a rich investment of multiwavelength coverage from the ultraviolet to the radio. The wide-area nature of this survey presents new challenges for photometric redshifts for AGNs compared to previous work on narrow-deep fields because it probes different populations of objects that need to be identified and represented in the library of templates. Here we present an updated X-ray plus multiwavelength matched catalog, including Spitzer counterparts, and estimated photometric redshifts for 5961 (96% of a total of 6181) X-ray sources that have a normalized median absolute deviation, {sigma}_nmad_=0.06, and an outlier fraction, {eta}=13.7%. The populations found in this survey and the template libraries used for photometric redshifts provide important guiding principles for upcoming large-area surveys such as eROSITA and 3XMM (in X-ray) and the Large Synoptic Survey Telescope (optical).
- ID:
- ivo://CDS.VizieR/J/ApJ/757/22
- Title:
- Strong and weak lensing analysis of A2261
- Short Name:
- J/ApJ/757/22
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We precisely constrain the inner mass profile of A2261 (z=0.225) for the first time and determine that this cluster is not "overconcentrated" as found previously, implying a formation time in agreement with {Lambda}CDM expectations. These results are based on multiple strong-lensing analyses of new 16-band Hubble Space Telescope imaging obtained as part of the Cluster Lensing and Supernova survey with Hubble (CLASH; Postman et al. 2012, Cat. J/ApJS/199/25). Combining this with revised weak-lensing analyses of Subaru wide-field imaging with five-band Subaru + KPNO photometry, we place tight new constraints on the halo virial mass M_vir_=(2.2+/-0.2)x10^15^M_{sun}_h^-1^_70_ (within r_vir_{approx}3Mpc.h^-1^_70_) and concentration c_vir_=6.2+/-0.3 when assuming a spherical halo. This agrees broadly with average c(M, z) predictions from recent {Lambda}CDM simulations, which span 5<~<c><~8. Our most significant systematic uncertainty is halo elongation along the line of sight (LOS). To estimate this, we also derive a mass profile based on archival Chandra X-ray observations and find it to be ~35% lower than our lensing-derived profile at r_2500_~600kpc. Agreement can be achieved by a halo elongated with a ~2:1 axis ratio along our LOS. For this elongated halo model, we find M_vir_=(1.7+/-0.2)x10^15^M_{sun}_h^-1^_70_ and c_vir_=4.6+/-0.2, placing rough lower limits on these values. The need for halo elongation can be partially obviated by non-thermal pressure support and, perhaps entirely, by systematic errors in the X-ray mass measurements. We estimate the effect of background structures based on MMT/Hectospec spectroscopic redshifts and find that these tend to lower M_vir_ further by ~7% and increase c_vir_by ~5%.
