- ID:
- ivo://CDS.VizieR/J/A+A/635/A69
- Title:
- HIX galaxy survey. III.
- Short Name:
- J/A+A/635/A69
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This paper presents the analysis of optical integral field spectra for the HI eXtreme (HIX) galaxy sample. HIX galaxies host at least 2.5 times more atomic gas (HI) than expected from their optical R-band luminosity. Previous examination of their star formation activity and HI kinematics suggested that these galaxies stabilise their large HI discs (radii up to 94kpc) against star formation due to their higher than average baryonic specific angular momentum. A comparison to semi-analytic models further showed that the elevated baryonic specific angular momentum is inherited from the high spin of the dark matter host. In this paper we now turn to the gas-phase metallicity as well as stellar and ionised gas kinematics in HIX galaxies to gain insights on recent accretion of metal-poor gas or recent mergers. To do so we compare the stellar, ionised and atomic gas kinematics, and examine the variation of the gas-phase metallicity throughout the stellar disc of HIX galaxies. We find no indication for counter-rotation in any of the components, the central metallicities tend to be lower than average but as low as expected for galaxies of similar HI mass. Metallicity gradients are comparable to other less HI-rich, local star forming galaxies. We conclude that HIX galaxies show no conclusive evidence for recent major accretion or merger events. Their overall lower metallicities are likely due to them living in high spin halos, which slows down their evolution and thus enrichment of their interstellar medium.
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- ID:
- ivo://CDS.VizieR/J/ApJS/97/1
- Title:
- HST Quasar Absorption Line Key Project. X.
- Short Name:
- J/ApJS/97/1
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Sensitive H I 21cm emission line spectra have been measured for the directions to 143 quasars and AGNs chosen from the observing lists for the HST Quasar Absorption Line Key Project. Narrow-band and wide-band data were obtained with the NRAO 43m radio telescope for each object. The narrow-band data have a velocity resolution of 1km/s, extend from -220 to +170km/s, and are corrected for stray 21cm radiation. The wide-band data have a resolution of 4km/s and extend from -1000 to +1000km/s. The data are important for the interpretation of ultraviolet absorption lines near zero redshift in Key Project spectra. Twenty-two percent of the quasars lie behind Galactic high-velocity H I clouds with |VLSR|>100km/s whose presence can increase the equivalent width of interstellar absorption lines significantly. This paper contains the emission spectra and measures of the H I velocities and column densities along the sight line to each quasar. We discuss how the measurements can be used to estimate the visual and ultraviolet extinction toward each quasar and to predict the approximate strength of the strong ultraviolet resonance lines of neutral gas species in the HST Key Project spectra.
- ID:
- ivo://CDS.VizieR/VIII/68
- Title:
- Huchtmeier-Richter HI catalog
- Short Name:
- VIII/68
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The catalog contains all published HI observations (21cm) of external galaxies published until the middle of 1988. It contains almost 20,000 entries for over 10,000 galaxies based on more than 570 references. The HI data are basically just as they were originally published -- no numerical conversions were made and no error correction was attempted.
- ID:
- ivo://CDS.VizieR/J/A+A/600/A2
- Title:
- Hydrogen in diffuse molecular clouds
- Short Name:
- J/A+A/600/A2
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Recent sub-millimeter and far-infrared wavelength observations of absorption in the rotational ground state lines of various simple molecules against distant Galactic continuum sources have opened the possibility to study the chemistry of diffuse molecular clouds Milky Way-wide. In order to calculate abundances the column densities of molecular and atomic hydrogen, HI, must be known. We aim at determining the atomic hydrogen column densities for diffuse clouds located on the sight lines toward a sample of prominent high mass star forming regions that were intensely studied with the HIFI instrument onboard Herschel. Based on Jansky Very Large Array data, we employ the 21-cm HI absorption-line technique to construct profiles of the HI opacity versus radial velocity toward our target sources. These profiles are combined with lower resolution archival data of extended HI emission to calculate the HI column densities of the individual clouds along the sight lines. We employ Bayesian inference to estimate the uncertainties of the derived quantities. Our study delivers reliable estimates of the atomic hydrogen column density for a large number of diffuse molecular clouds at various Galactocentric distances. Together with column densities of molecular hydrogen derived from its surrogates observed with HIFI, the measurements can be used to characterize the clouds and, e.g., investigate the dependence of their chemistry on the molecular fraction.
- ID:
- ivo://CDS.VizieR/J/MNRAS/428/3355
- Title:
- Hydrogen volume densities in nearby galaxies
- Short Name:
- J/MNRAS/428/3355
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using a simple model of photodissociated atomic hydrogen on a galactic scale, it is possible to derive total hydrogen volume densities. These densities, obtained through a combination of atomic hydrogen, far-ultraviolet and metallicity data, provide an independent probe of the combined atomic and molecular hydrogen gas in galactic discs. We present a new, flexible and fully automated procedure using this simple model. This automated method will allow us to take full advantage of a host of available data on galaxies in order to calculate the total hydrogen volume densities of the giant molecular clouds surrounding sites of recent star formation. Until now this was only possible on a galaxy-by-galaxy basis using by-eye analysis of candidate photodissociation regions. We test the automated method by adopting various models for the dust-to-gas ratio and comparing the resulting densities for M74, including a new metallicity map of M74 produced by integral field spectroscopy. We test the procedure against previously published M83 volume densities based on the same method and find no significant differences. The range of total hydrogen volume densities obtained for M74 is approximately 5-700cm^-3^. Different dust-to-gas ratio models do not result in measurably different densities. The cloud densities presented here mean that M74 is added to the list of galaxies analysed using the assumption of photodissociated atomic hydrogen occurring near sites of recent star formation, and consolidate the method. For the first time, full metallicity maps are included in the analysis as opposed to metallicity gradients. The results will need to be compared with other tracers of the interstellar medium and photodissociation regions, such as CO and CII, in order to test our basic assumptions, specifically our assumption that the HI we detect originates in photodissociation regions.
- ID:
- ivo://CDS.VizieR/VII/238
- Title:
- HYPERLEDA. II. Homogenized HI data
- Short Name:
- VII/238
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- After a compilation of HI data from 611 references and new observations made in Nancay, we produce a catalog of homogenized HI data for 16781 galaxies. The homogenization is made using the EPIDEMIC method from which all data are progressively converted into the adopted standard. The result is a catalog giving: 1) the logarithm of twice the maximum rotation velocity, log2V_M_^sini^, converted to the system of Mathewson et al. (1996ApJS..107...97M). This quantity is given without correction for inclination; 2) the HI magnitude, m_21_, (area of the 21-cm line width expressed in magnitude) converted to the flux system of Theureau et al. (1998A&AS..130..333T); 3) the HI velocity, V_HI_, expressed with the optical definition (i.e., using wavelengths instead frequencies). The typical uncertainties are: 0.04 for log2V_M_^sini^, 0.25mag for m_21_ and 9km/s for V_HI_.
- ID:
- ivo://CDS.VizieR/J/ApJS/93/211
- Title:
- IUE survey of H I Ly{alpha} absorption. I.
- Short Name:
- J/ApJS/93/211
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We measure Galactic interstellar neutral hydrogen column densities by analyzing archival interstellar Ly{alpha} absorption line data toward 554 B2 and hotter stars observed at high resolution with the IUE satellite. This study more than doubles the number of lines of sight with measures of N(H I) based on Ly{alpha}. We have included the scattered light background correction algorithm of Bianchi and Bohlin (1984A&A...134...31B) in our data reduction. We use the correlation between the Balmer discontinuity [c_1_] index and the stellar Ly{alpha} absorption in order to assess the effects of stellar Ly alpha contamination. Approximately 40% of the B stars with measured [c_1_] index, exhibit serious stellar Ly{alpha} contamination. Table 1 contains the derived values of the interstellar N(H I) for 393 stars with at most small amounts of stellar contamination. Table 2 lists the observed values of total N(H I) for 161 stars with suspected stellar Ly alpha contamination and/or uncertain stellar parameters.
- ID:
- ivo://CDS.VizieR/J/AJ/129/1311
- Title:
- J-band photometry of ADBS Galaxies
- Short Name:
- J/AJ/129/1311
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of a J-band study of the H I-selected Arecibo Dual-Beam Survey (ADBS, Cat. J/ApJS/130/177) and Arecibo Slice Survey (AS, Cat. J/ApJS/119/159) galaxy samples using Two Micron All Sky Survey data.
- ID:
- ivo://CDS.VizieR/J/ApJ/777/42
- Title:
- Kinematic and HI data for the NFGS
- Short Name:
- J/ApJ/777/42
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We relate transitions in galaxy structure and gas content to refueling, here defined to include both the external gas accretion and the internal gas processing needed to renew reservoirs for star formation. We analyze two z=0 data sets: a high-quality ~200 galaxy sample (the Nearby Field Galaxy Survey, data release herein) and a volume-limited ~3000 galaxy sample with reprocessed archival data. Both reach down to baryonic masses ~10^9^M_{sun}_ and span void-to-cluster environments. Two mass-dependent transitions are evident: (1) below the "gas-richness threshold" scale (V~125km/s), gas-dominated quasi-bulgeless Sd-Im galaxies become numerically dominant; while (2) above the "bimodality" scale (V~200km/s), gas-starved E/S0s become the norm. Notwithstanding these transitions, galaxy mass (or V as its proxy) is a poor predictor of gas-to-stellar mass ratio M_gas_/M_*_. Instead, M_gas_/M_*_ correlates well with the ratio of a galaxy's stellar mass formed in the last Gyr to its preexisting stellar mass, such that the two ratios have numerically similar values. This striking correspondence between past-averaged star formation and current gas richness implies routine refueling of star-forming galaxies on Gyr timescales. We argue that this refueling underlies the tight M_gas_/M_*_ versus color correlations often used to measure "photometric gas fractions." Furthermore, the threshold and bimodality scale transitions reflect mass-dependent demographic shifts between three refueling regimes--accretion-dominated, processing-dominated, and quenched. In this picture, gas-dominated dwarfs are explained not by inefficient star formation but by overwhelming gas accretion, which fuels stellar mass doubling in <~1Gyr. Moreover, moderately gas-rich bulged disks such as the Milky Way are transitional, becoming abundant only in the narrow range between the threshold and bimodality scales.
- ID:
- ivo://CDS.VizieR/J/MNRAS/366/1096
- Title:
- Kinematic distance ambiguity
- Short Name:
- J/MNRAS/366/1096
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We investigate the use of HI data to resolve the near/far ambiguity in kinematic distances of massive young stellar object (MYSO) candidates. Kinematic distances were obtained from ^13^CO 1-0 (and N_2_H^+^) spectral-line observations with the Mopra Telescope towards 94 candidates selected from the Red MSX Source (RMS) survey in the fourth Galactic quadrant (282{deg}<l<350{deg}). HI data from the Southern Galactic Plane Survey (SGPS) were used in conjunction with the HI self-absorption (SA) technique to determine the near or far distance. We resolved the kinematic distance ambiguity to 70 per cent of the sources. We can also simultaneously solve for any multiple line-of-sight component sources. We discuss the advantages and disadvantages of this technique in comparison with other methods, and also perform confidence checks on the reliability of using the HI SA technique.
