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- ID:
- ivo://CDS.VizieR/J/A+A/564/A85
- Title:
- Galaxy properties in clusters. II.
- Short Name:
- J/A+A/564/A85
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We explore the properties of galaxies on the outskirts of clusters and their dependence on recent dynamical history in order to understand the real impact that the cluster core has on the evolution of galaxies. We analyse the properties of more than 1000 galaxies brighter than M_r_^0.1^=-19.6 on the outskirts of 90 clusters (1<r/r_vir_<2) in the redshift range 0.05<z<0.10. Using the line of sight velocity of galaxies relative to the cluster's mean, we selected low and high velocity subsamples. Theoretical predictions indicate that a significant fraction of the first subsample should be backsplash galaxies, that is, objects that have already orbited near the cluster centre. A significant proportion of the sample of high relative velocity (HV) galaxies seems to be composed of infalling objects. Our results suggest that, at fixed stellar mass, late-type galaxies in the low-velocity (LV) sample are systematically older, redder, and have formed fewer stars during the last 3Gyrs than galaxies in the HV sample. This result is consistent with models that assume that the central regions of clusters are effective in quenching the star formation by means of processes such as ram pressure stripping or strangulation. At fixed stellar mass, LV galaxies show some evidence of having higher surface brightness and smaller size than HV galaxies. These results are consistent with the scenario where galaxies that have orbited the central regions of clusters are more likely to suffer tidal effects, producing loss of mass as well as a re-distribution of matter towards more compact configurations. Finally, we found a higher fraction of ET galaxies in the LV sample, supporting the idea that the central region of clusters of galaxies may contribute to the transformation of morphological types towards earlier types.
- ID:
- ivo://CDS.VizieR/J/MNRAS/236/207
- Title:
- Galaxy redshift catalogue
- Short Name:
- J/MNRAS/236/207
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present redshifts and blue magnitudes for a sample of 264 'field' galaxies virtually complete to a limiting magnitude of bj~=16.80mag. The galaxies were selected by sampling one galaxy in every three in order of apparent magnitude on each of nine high-latitude UK Schmidt (UKST) fields. Photometric data were provided by COSMOS machine measures of UKST plates, zero-pointed with CCD photometry. The spectral data came from observations with the 1.9-m telescope at the South African Astronomical Observatory (SAAO), and the resulting radial velocities have a precision of ~+/-130km/s. This survey augments substantially the Durham/AAT redshift survey. In this paper we discuss the observational techniques and reduction procedures.
6944. Galaxy Redshifts
- ID:
- ivo://CDS.VizieR/VII/36
- Title:
- Galaxy Redshifts
- Short Name:
- VII/36
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Catalog of Galaxy Redshifts was compiled by Dr. Rood to enter the most accurate redshift for each entry in the Uppsala General Catalog of Galaxies below 15000 km/s, plus some fainter galaxies in the fields of rich clusters, plus some southern galaxies. The catalog is 99 percent complete for declinations north of -2.5deg and blue magnitude (Pmag) brighter than 13. The present documentation is mostly adapted from the "Documentation of the Machine-Readable Version of the Catalog of Galaxy Redshifts" by Theresa A. Nagy and Robert S. Hill, May 1981, prepared for NASA GSFC, Greenbelt, No SSD-T-5069-0013-81.
- ID:
- ivo://CDS.VizieR/J/MNRAS/243/390
- Title:
- Galaxy redshift survey in a Coma strip
- Short Name:
- J/MNRAS/243/390
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- (no description available)
6946. Galaxy rotation curves
- ID:
- ivo://CDS.VizieR/J/ApJ/636/721
- Title:
- Galaxy rotation curves
- Short Name:
- J/ApJ/636/721
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We apply the modified acceleration law obtained from Einstein gravity coupled to a massive skew-symmetric field F_{mu}{nu}{lambda}_ to the problem of explaining galaxy rotation curves without exotic dark matter. Our sample of galaxies includes low surface brightness (LSB) and high surface brightness (HSB) galaxies and an elliptical galaxy. In those cases for which photometric data are available, a best fit via the single parameter (M/L)_stars_ to the luminosity of the gaseous (HI plus He) and luminous stellar disks is obtained. In addition, a best fit to the rotation curves of galaxies is obtained in terms of a parametric mass distribution (independent of luminosity observations) - a two-parameter fit to the total galactic mass (or mass-to-light ratio M/L) and a core radius associated with a model of the galaxy cores - using a nonlinear least-squares fitting routine including estimated errors. The fits are compared to those obtained using Milgrom's phenomenological MOND model and to the predictions of the Newtonian/Kepler acceleration law.
- ID:
- ivo://CDS.VizieR/J/ApJ/791/18
- Title:
- Galaxy samples rest-frame ultraviolet structure
- Short Name:
- J/ApJ/791/18
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the rest-frame UV wavelength dependence of the Petrosian-like half-light radius (r_50_), and the concentration parameter for a sample of 198 star-forming galaxies at 0.5 < z < 1.5. We find a ~5% decrease in r_50_ from 1500 {AA} to 3000 {AA}, with half-light radii at 3000 {AA} ranging from 0.6 kpc to 6 kpc. We also find a decrease in concentration of ~0.07 (1.9 < C_3000_< 3.9). The lack of a strong relationship between r_50_and wavelength is consistent with a model in which clumpy star formation is distributed over length scales comparable to the galaxy's rest-frame optical light. While the wavelength dependence of r_50_is independent of size at all redshifts, concentration decreases more sharply in the far-UV (~1500 {AA}) for large galaxies at z ~ 1. This decrease in concentration is caused by a flattening of the inner ~20% of the light profile in disk-like galaxies, indicating that the central regions have different UV colors than the rest of the galaxy. We interpret this as a bulge component with older stellar populations and/or more dust. The size-dependent decrease in concentration is less dramatic at z ~ 2, suggesting that bulges are less dusty, younger, and/or less massive than the rest of the galaxy at higher redshifts.
- ID:
- ivo://CDS.VizieR/J/ApJ/824/124
- Title:
- Galaxy stellar and baryonic mass functions
- Short Name:
- J/ApJ/824/124
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this work, we present galaxy stellar and baryonic (stars plus cold gas) mass functions (SMF and BMF) and their halo mass dependence for two volume-limited data sets. The first, RESOLVE-B, coincides with the Stripe 82 footprint and is extremely complete down to baryonic mass M_bary_~10^9.1^M_{sun}_, probing the gas-rich dwarf regime below M_bary_~10^10^M_{sun}_. The second, ECO, covers a ~40x larger volume (containing RESOLVE-A) and is complete to M_bary_~10^9.4^M_{sun}_. To construct the SMF and BMF we implement a new "cross-bin sampling" technique with Monte Carlo sampling from the full likelihood distributions of stellar or baryonic mass. Our SMFs exhibit the "plateau" feature starting below M_star_~10^10^M_{sun}_ that has been described in prior work. However, the BMF fills in this feature and rises as a straight power law below ~10^10^M_{sun}_, as gas-dominated galaxies become the majority of the population. Nonetheless, the low-mass slope of the BMF is not as steep as that of the theoretical dark matter halo MF. Moreover, we assign group halo masses by abundance matching, finding that the SMF and BMF, separated into four physically motivated halo mass regimes, reveal complex structure underlying the simple shape of the overall MFs. In particular, the satellite MFs are depressed below the central galaxy MF "humps" in groups with mass<10^13.5^M_{sun}_ yet rise steeply in clusters. Our results suggest that satellite destruction and stripping are active from the point of nascent group formation. We show that the key role of groups in shaping MFs enables reconstruction of a given survey's SMF or BMF based on its group halo mass distribution.
- ID:
- ivo://CDS.VizieR/VI/143
- Title:
- Galaxy stellar mass assembly
- Short Name:
- VI/143
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Semi-analytical models (SAMs) are currently the best way to understand the formation of galaxies within the cosmic dark-matter structures. They are able to give a statistical view of the variety of the evolutionary histories of galaxies in terms of star formation and stellar mass assembly. While they reproduce the local stellar mass functions, correlation functions and luminosity functions fairly well, they fail to match observations at high redshift (z>=3) in most cases, particularly in the low-mass range. The inconsistency between models and observations indicates that the history of gas accretion in galaxies, within their host dark-matter halo, and the transformation of gas into stars, are not followed well. We briefly present a new version of the GalICS semi-analytical model. With this new model, we explore the impact of classical mechanisms, such as supernova feedback or photoionization, on the evolution of the stellar mass assembly and the star formation rate. Even with strong efficiency, these two processes cannot explain the observed stellar mass function and star formation rate distribution or the stellar mass versus dark matter halo mass relation. We thus introduce an ad hoc modification of the standard paradigm, based on the presence of a no-star-forming gas component, and a concentration of the star-forming gas in galaxy discs. The main idea behind the existence of the no-star-forming gas reservoir is that only a fraction of the total gas mass in a galaxy is available to form stars. The reservoir generates a delay between the accretion of the gas and the star formation process. This new model is in much better agreement with the observations of the stellar mass function in the low-mass range than the previous models and agrees quite well with a large set of observations, including the redshift evolution of the specific star formation rate. However, it predicts a large amount of no-star-forming baryonic gas, potentially larger than observed, even if its nature has still to be examined in the context of the missing baryon problem.
- ID:
- ivo://CDS.VizieR/J/ApJS/122/109
- Title:
- Galaxy structural parameters
- Short Name:
- J/ApJS/122/109
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The evolution of the structure of galaxies as a function of redshift is investigated using two parameters: the metric radius of the galaxy (R_eta_) and the power at high spatial frequencies in the disk of the galaxy (chi). A direct comparison is made between nearby (z~0) and distant (0.2<~z<~1) galaxies by following a fixed range in rest frame wavelengths. The data of the nearby galaxies comprise 136 broadband images at ~4500 E observed with the 0.9 m telescope at Kitt Peak National Observatory (23 galaxies) and selected from the catalog of digital images of Frei et al. (113 galaxies, 1996AJ....111..174F). The high-redshift sample comprises 94 galaxies selected from the Hubble Deep Field (HDF) observations with the Hubble Space Telescope using the Wide Field Planetary Camera 2 in four broad bands that range between ~3000 and ~9000 E (Williams et al., 1997, Cat. <J/AJ/112/1335>).