- 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.
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Search Results
- ID:
- ivo://CDS.VizieR/J/MNRAS/460/2143
- Title:
- HI size-mass relation of galaxies
- Short Name:
- J/MNRAS/460/2143
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We revisit the HI size-mass (D_HII_-M_HI_) relation of galaxies with a sample of more than 500 nearby galaxies covering over five orders of magnitude in HI mass and more than 10 B-band magnitudes. The relation is remarkably tight with a scatter {sigma}~0.06dex, or 14 per cent. The scatter does not change as a function of galaxy luminosity, HI richness or morphological type. The relation is linked to the fact that dwarf and spiral galaxies have a homogeneous radial profile of HI surface density in the outer regions when the radius is normalized by D_HI_. The early-type disc galaxies typically have shallower HI radial profiles, indicating a different gas accretion history. We argue that the process of atomic-to-molecular gas conversion or star formation cannot explain the tightness of the D_HI_-M_HI_ relation. This simple relation puts strong constraints on simulation models for galaxy formation.
- ID:
- ivo://CDS.VizieR/VIII/77
- Title:
- HI spectral properties of galaxies
- Short Name:
- VIII/77
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a homogeneous compilation of HI spectral parameters extracted from global 21cm line spectra for some 9000 galaxies in the local universe (heliocentric velocity -200<V_{sun}_<28,000km/s) obtained with a variety of large single-dish radio telescopes but reanalyzed using a single set of parameter extraction algorithms. Corrections to the observed HI line flux for source extent and pointing offsets and to the HI line widths for instrumental broadening and smoothing are applied according to model estimates to produce a homogenous catalog of derived properties with quantitative error estimates. Where the redshift is available from optical studies, we also provide flux measurements for an additional 156 galaxies classified as marginal HI detections and rms noise limits for 494 galaxies classified as nondetections.
- ID:
- ivo://CDS.VizieR/J/A+A/558/A18
- Title:
- HI spectra of extremely metal-poor (XMP) galaxies
- Short Name:
- J/A+A/558/A18
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Extremely metal-poor (XMP) galaxies are chemically, and possibly dynamically, primordial objects in the local Universe. Our objective is to characterize the HI content of the XMP galaxies as a class, using as a reference the list of 140 known local XMPs compiled by Morales-Luis et al. (2011, Cat. J/ApJ/743/77). We have observed 29 XMPs, which had not been observed before at 21 cm, using the Effelsberg radio telescope. This information was complemented with Hi data published in literature for a further 53 XMPs. In addition, optical data from the literature provided morphologies, stellar masses, star-formation rates and metallicities.
- ID:
- ivo://CDS.VizieR/VII/239A
- Title:
- History and Accurate Positions for the NGC/IC Objects
- Short Name:
- VII/239A
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The files icpos.dat and ngcpos.dat are intended to provide a handy source for fairly accurate positions for the NGC/IC objects. They have only one entry per object, giving an unweighted mean position followed by the number of positions used in calculating that mean, the calculated standard deviations in RA and Dec, and the sources used. The precision to which the position is given reflects the precision of the most precise position in the full list. Note that precision does not necessarily reflect accuracy, especially with unweighted means. However, obvious blunders have been rejected, and many objects have enough accurately-measured positions now that overall accuracy will not suffer much from poor positions out on the wings of the "bell curve". Note also that the standard deviations reflect more accurately the uncertainties in the unweighted mean positions rather than the mean errors. Errors in published positions (see the "refs.dat" file) are almost always underestimated, so quoting the standard deviation increases the qualitative perception of the errors to about what they should be in an ideal world. Mean errors can be easily calculated by dividing the standard deviations by the square root of the number of positions used. Finally, these positions are on the FK5 system, and are not reduced to the International Celestial Reference Frame (ICRF). However, the FK5 optical system is consistent with ICRF to within the known errors of the older system (see Ma et al, 1998AJ....116..516M and references therein for more information about ICRF). The individual positions are reported in the files icdata.dat and ngcdata.dat. The files icnotes.txt and ngcnotes.txt contain discussions about ambiguous, non-existent or other mysterious NGC/IC objects. A detailed introduction to the contents of these discussion files can be found in the "ninotes.txt" file.
- ID:
- ivo://CDS.VizieR/J/A+A/566/A71
- Title:
- HI study of 18 nearby dwarf galaxies
- Short Name:
- J/A+A/566/A71
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We investigate the dynamics of starbursting dwarf galaxies, using both new and archival HI observations. We consider 18 nearby galaxies that have been resolved into single stars by HST observations, providing their star-formation history and total stellar mass. We find that 9 objects have a regularly rotating HI disk, 7 have a kinematically disturbed HI disk, and 2 show unsettled HI distributions. Two galaxies (NGC 5253 and UGC 6456) show a velocity gradient along the minor axis of the HI disk, which we interpret as strong radial motions. For galaxies with a regularly rotating disk we derive rotation curves, while for galaxies with a kinematically disturbed disk we estimate the rotation velocities in their outer parts. We derive baryonic fractions within about 3 optical scale lengths and find that, on average, baryons constitute at least 30% of the total mass. Despite the star formation having injected 10^56^ergs in the ISM in the past 500 Myr, these starbursting dwarfs have both baryonic and gas fractions similar to those of typical dwarf irregulars, suggesting that they did not eject a large amount of gas out of their potential wells.
- ID:
- ivo://CDS.VizieR/J/A+A/319/401
- Title:
- HI survey of polar ring galaxies. II.
- Short Name:
- J/A+A/319/401
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of a neutral hydrogen survey conducted with the 100-m radiotelescope at Effelsberg of 44 northern objects in the polar-ring galaxy atlas of Whitmore et al. (1990AJ....100.1489W). These observations were performed to complement the Green Bank observations of polar-ring galaxies (Paper I, 1994AJ....107...99R). We detected 29 of these above our detection limit of a few mJy. The relative content of neutral hydrogen (M_HI_/L_B_) of the early-type galaxies (E, S0) in this sample is significantly higher than for galaxies of the same morphological types from comparison samples, i.e. for elliptical galaxies M_HI_/L_B_=0.17+/-0.09 and for S0 galaxies M_HI_/L_B_=0.75+/-0.13 which is about 6 times the mean value from the comparison samples for the same morphological types.
- ID:
- ivo://CDS.VizieR/J/A+A/386/140
- Title:
- HI survey of polar ring galaxies. IV.
- Short Name:
- J/A+A/386/140
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A total of 33 polar ring galaxies and polar ring galaxy candidates were observed in the 21-cm HI line with the 64-m Parkes radio telescope. The objects, selected by their optical morphology, are all south of declination -39{deg} and in only 5 of them had been reported previously. HI line emission was detected towards 18 objects, though in 3 cases the detection may be confused by another galaxy in the telescope beam, and one is a marginal detection. Eight objects were detected for the first time in HI, of which 5 did not have previously known redshifts.
- ID:
- ivo://CDS.VizieR/J/A+A/370/765
- Title:
- HI synthesis observations in UMa cluster
- Short Name:
- J/A+A/370/765
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this data paper we present the results of an extensive 21 cm-line synthesis imaging survey of 43 spiral galaxies in the nearby Ursa Major cluster using the Westerbork Synthesis Radio Telescope. Detailed kinematic information in the form of position-velocity diagrams and rotation curves is presented in an atlas together with HI channel maps, 21 cm continuum maps, global HI profiles, radial HI surface density profiles, integrated HI column density maps, and HI velocity fields. The relation between the corrected global HI linewidth and the rotational velocities Vmax and Vflat as derived from the rotation curves is investigated. Inclination angles obtained from the optical axis ratios are compared to those derived from the inclined HI disks and the HI velocity fields. The galaxies were not selected on the basis of their HI content but solely on the basis of their cluster membership and inclination which should be suitable for a kinematic analysis. The observed galaxies provide a well-defined, volume limited and equidistant sample, useful to investigate in detail the statistical properties of the Tully-Fisher relation and the dark matter halos around them.
1570. HIX galaxy survey. I.
- ID:
- ivo://CDS.VizieR/J/MNRAS/467/1083
- Title:
- HIX galaxy survey. I.
- Short Name:
- J/MNRAS/467/1083
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the HI eXtreme (HIX) galaxy survey targeting some of the most HI rich galaxies in the Southern hemisphere. The 13 HIX galaxies have been selected to host the most massive HI discs at a given stellar luminosity. We compare these galaxies to a control sample of average galaxies detected in the HI Parkes All Sky Survey (HIPASS). As the control sample is matched in stellar luminosity, we find that the stellar properties of HIX galaxies are similar to the control sample. Furthermore, the specific star formation rate and optical morphology do not differ between HIX and control galaxies. We find, however, the HIX galaxies to be less efficient in forming stars. For the most HI massive galaxy in our sample (ESO075-G006, logM_HI_[M_{sun}_]=(10.8+/-0.1)), the kinematic properties are the reason for inefficient star formation and HI excess. Examining the Australian Telescope Compact Array (ATCA) HI imaging and Wide Field Spectrograph (WiFeS) optical spectra of ESO075-G006 reveals an undisturbed galaxy without evidence for recent major, violent accretion events. A tilted ring fitted to the HI disc together with the gas-phase oxygen abundance distribution supports the scenario that gas has been constantly accreted on to ESO075-G006 but the high specific angular momentum makes ESO075-G006 very inefficient in forming stars. Thus, a massive HI disc has been built up.
