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- ID:
- ivo://CDS.VizieR/J/A+A/319/67
- Title:
- HI observations of dwarf galaxies in voids
- Short Name:
- J/A+A/319/67
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report HI-observations of a sample of 43 optically selected galaxies from the Heidelberg-void project. Only emission-line galaxies have been selected. The HI-detection rate was 67%. The observed sample is a mix in late-type morphology objects with a spread in luminosity. They were compared to other samples with similar selection effects and mixtures. The detected galaxies have a high HI content and their M_HI_/L_B_ values are systematically higher than expected from a local field comparison sample. Especially, for the 10 dwarfs in our sample (8.2<=logL_B_<=9.2) which appear to be highly isolated, a mean M_HI_/L_B_=1.8 was derived which is higher than for all comparison samples, including those with the same restricted luminosity range. We discuss a trend in our data between the relative HI-content and the surrounding galaxy density holding from very high densities (Virgo-cluster) to the very isolated objects at the rims of the voids. We also present HI observations of 7 HII-galaxies of the University of Michigan (UM) sample.
- ID:
- ivo://CDS.VizieR/J/AJ/127/3235
- Title:
- HIRES atlas of all RBGS galaxies
- Short Name:
- J/AJ/127/3235
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present high-resolution 12, 25, 60, and 100{mu}m images of 106 interacting galaxy systems contained in the IRAS Revised Bright Galaxy Sample (RBGS, Sanders et al., Cat. <J/AJ/126/1607>), a complete sample of all galaxies having a 60{mu}m flux density greater than 5.24Jy. These systems were selected to have at least two distinguishable galaxies separated by less than three average galactic diameters, and thus we have excluded very widely separated systems and very advanced mergers. Additionally, some systems have been included that are more than three galactic diameters apart, yet have separations less than 4 and are thus likely to suffer from confusion in the RBGS. The new complete survey has the same properties as the prototype survey of Surace et al., 1993AJ....105..864S.
- ID:
- ivo://CDS.VizieR/J/ApJ/833/270
- Title:
- HI-selected-Lyman limit system metallicities
- Short Name:
- J/ApJ/833/270
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We measured metallicities for 33 z=3.4-4.2 absorption line systems drawn from a sample of HI-selected-Lyman limit systems (LLSs) identified in Sloan Digital Sky Survey (SDSS) quasar spectra and stratified based on metal line features. We obtained higher-resolution spectra with the Keck Echellette Spectrograph and Imager, selecting targets according to our stratification scheme in an effort to fully sample the LLS population metallicity distribution. We established a plausible range of HI column densities and measured column densities (or limits) for ions of carbon, silicon, and aluminum, finding ionization-corrected metallicities or upper limits. Interestingly, our ionization models were better constrained with enhanced {alpha}-to-aluminum abundances, with a median abundance ratio of [{alpha}/Al]=0.3. Measured metallicities were generally low, ranging from [M/H]=-3 to -1.68, with even lower metallicities likely for some systems with upper limits. Using survival statistics to incorporate limits, we constructed the cumulative distribution function (CDF) for LLS metallicities. Recent models of galaxy evolution propose that galaxies replenish their gas from the low-metallicity intergalactic medium (IGM) via high-density HI "flows" and eject enriched interstellar gas via outflows. Thus, there has been some expectation that LLSs at the peak of cosmic star formation (z~3) might have a bimodal metallicity distribution. We modeled our CDF as a mix of two Gaussian distributions, one reflecting the metallicity of the IGM and the other representative of the interstellar medium of star-forming galaxies. This bimodal distribution yielded a poor fit. A single Gaussian distribution better represented the sample with a low mean metallicity of [M/H]~-2.5.
- ID:
- ivo://CDS.VizieR/J/ApJ/833/283
- Title:
- HI-selected Lyman limit systems metallicities
- Short Name:
- J/ApJ/833/283
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the first results from our KODIAQ Z survey aimed at determining the metallicity distribution and physical properties of the z>~2 partial and full Lyman limit systems (pLLSs and LLSs; 16.2<=logN_HI_<19), which are probed of the interface regions between the intergalactic medium (IGM) and galaxies. We study 31 HI-selected pLLSs and LLSs at 2.3<z<3.3 observed with Keck/HIRES in absorption against background QSOs. We compare the column densities of metal ions to HI and use photoionization models to assess the metallicity. The metallicity distribution of the pLLSs/LLSs at 2.3<z<3.3 is consistent with a unimodal distribution peaking at [X/H]~-2. The metallicity distribution of these absorbers therefore evolves markedly with z since at z<~1 it is bimodal with peaks at [X/H]~-1.8 and -0.3. There is a substantial fraction (25%-41%) of pLLSs/LLSs with metallicities well below those of damped Ly{alpha} absorbers (DLAs) at any studied z from z<~1 to z~2-4, implying reservoirs of metal-poor, cool, dense gas in the IGM/galaxy interface at all z. However, the gas probed by pLLSs and LLSs is rarely pristine, with a fraction of 3%-18% for pLLSs/LLSs with [X/H]<=-3. We find C/{alpha} enhancement in several pLLSs and LLSs in the metallicity range -2<~[X/H]<~-0.5, where C/{alpha} is 2-5 times larger than observed in Galactic metal-poor stars or high-redshift DLAs at similar metallicities. This is likely caused by preferential ejection of carbon from metal-poor galaxies into their surroundings.
- ID:
- ivo://CDS.VizieR/J/ApJS/244/16
- Title:
- HLF photometric catalog in GOODS-S v2.0
- Short Name:
- J/ApJS/244/16
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This manuscript describes the public release of the Hubble Legacy Fields (HLF) project photometric catalog for the extended GOODS-South region from the Hubble Space Telescope (HST) archival program AR-13252. The analysis is based on the version 2.0 HLF data release that now includes all ultraviolet (UV) imaging, combining three major UV surveys. The HLF data combines over a decade worth of 7475 exposures taken in 2635 orbits totaling 6.3Ms with the HST Advanced Camera for Surveys Wide Field Channel (ACS/WFC) and the Wide Field Camera 3 (WFC3) UVIS/IR Channels in the greater GOODS-S extragalactic field, covering all major observational efforts (e.g., GOODS, GEMS, CANDELS, ERS, UVUDF, and many other programs; see Illingworth+ arXiv:1606.00841). The HLF GOODS-S catalogs include photometry in 13 bandpasses from the UV (WFC3/UVIS F225W, F275W, and F336W filters), optical (ACS/WFC F435W, F606W, F775W, F814W and F850LP filters), to near-infrared (WFC3/IR F098M, F105W, F125W, F140W and F160W filters). Such a data set makes it possible to construct the spectral energy distributions (SEDs) of objects over a wide wavelength range from high-resolution mosaics that are largely contiguous. Here, we describe a photometric analysis of 186474 objects in the HST imaging at wavelengths 0.2-1.6{mu}m. We detect objects from an ultra-deep image combining the PSF-homogenized and noise-equalized F850LP, F125W, F140W, and F160W images, including Gaia astrometric corrections. SEDs were determined by carefully taking the effects of the point-spread function in each observation into account.
- ID:
- ivo://CDS.VizieR/J/AJ/122/1289
- Title:
- H magnitude and radial velocities of A1644
- Short Name:
- J/AJ/122/1289
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We discuss H-band (1.65{mu}m) near-infrared photometry of the central 9h^-2^Mpc^2^ of Abell 1644 (A1644) to a limiting M_H_~M*_H_+3 (throughout this paper H_0_=100h*km/s/Mpc). here are 861 galaxies in the photometric survey region. We also measured radial velocities of 155 galaxies; 141 of these are cluster members within 2.44h^-1^Mpc of the cluster center.
- ID:
- ivo://CDS.VizieR/J/ApJ/769/82
- Title:
- H_2_ masses in a broad sample of galaxies
- Short Name:
- J/ApJ/769/82
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- To assess how external factors such as local interactions and fresh gas accretion influence the global interstellar medium of galaxies, we analyze the relationship between recent enhancements of central star formation and total molecular-to-atomic (H_2_/HI) gas ratios, using a broad sample of field galaxies spanning early-to-late type morphologies, stellar masses of 10^7.2^-10^11.2^M_{sun}_, and diverse stages of evolution. We find that galaxies occupy several loci in a "fueling diagram" that plots H_2_/HI ratio versus mass-corrected blue-centeredness, a metric tracing the degree to which galaxies have bluer centers than the average galaxy at their stellar mass. Spiral galaxies of all stellar masses show a positive correlation between H_2_/HI ratio and mass-corrected blue-centeredness. When combined with previous results linking mass-corrected blue-centeredness to external perturbations, this correlation suggests a systematic link between local galaxy interactions and molecular gas inflow/replenishment. Intriguingly, E/S0 galaxies show a more complex picture: some follow the same correlation, some are quenched, and a distinct population of blue-sequence E/S0 galaxies (with masses below key scales associated with transitions in gas richness) defines a separate loop in the fueling diagram. This population appears to be composed of low-mass merger remnants currently in late- or post-starburst states, in which the burst first consumes the H_2_ while the galaxy center keeps getting bluer, then exhausts the H_2_, at which point the burst population reddens as it ages. Multiple lines of evidence suggest connected evolutionary sequences in the fueling diagram. In particular, tracking total gas-to-stellar mass ratios within the fueling diagram provides evidence of fresh gas accretion onto low-mass E/S0s emerging from their central starburst episodes. Drawing on a comprehensive literature search, we suggest that virtually all galaxies follow the same evolutionary patterns found in our broad sample.
- ID:
- ivo://CDS.VizieR/J/ApJ/685/235
- Title:
- Host and companion galaxies in the SDSS
- Short Name:
- J/ApJ/685/235
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We measure the number of companions per galaxy (N_c_) as a function of r-band absolute magnitude for both the Sloan Digital Sky Survey (DR5) and the Croton and coworkers semianalytic catalog, 2006MNRAS.365...11C, applied to the Millennium Run simulation (Springel et al., 2005Natur.435..629S). For close pairs with projected separations of 5-20kpc/h, velocity differences less than 500km/s, and luminosity ratios between 1:2 and 2:1, we find good agreement between the observations and simulations, with N_c_ consistently close to 0.02 over the range -22<M_r_<-18. For larger pair separations, N_c_(M_r_) instead becomes increasingly steep toward the faint end, implying that luminosity-dependent clustering plays an important role on small scales. Using the simulations to assess and correct for projection effects, we infer that the real-space N_c_(M_r_) for close pairs peaks at about M^*^ and declines by at least a factor of 2 as M_r_ becomes fainter. Conversely, by measuring the number density of close companions, we estimate that at least 90% of all major mergers occur between galaxies which are fainter than L^*^. Finally, measurements of the luminosity density of close companions indicate that L^*^ galaxies likely dominate in terms of the overall importance of major mergers in the evolution of galaxy populations at low redshift.
- ID:
- ivo://CDS.VizieR/J/AJ/126/63
- Title:
- Host galaxies of 2MASS-QSOs with z<=3
- Short Name:
- J/AJ/126/63
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present and discuss optical imaging of 76 active galactic nuclei (AGNs) that represent the selected Two Micron All Sky Survey (2MASS) sample for z<0.3, from a full list of 243. They are found to have dust-obscured nuclei, residing in host galaxies that show a high fraction (greater than 70%) of tidal interactions. The derived luminosities of the AGNs and host galaxies are similar to traditionally selected AGNs, and they may comprise some 40% of the total AGN population at low redshift. We have measured a number of host galaxy properties and discuss their distributions and interrelations. We compare the 2MASS AGNs with optically selected samples and the IRAS-selected galaxy samples and discuss the differences in terms of merger processes and initial conditions.