- ID:
- ivo://CDS.VizieR/J/A+A/550/A23
- Title:
- HI shells in Leiden/Argentina/Bonn HI survey
- Short Name:
- J/A+A/550/A23
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We analyse the all-sky Leiden/Argentina/Bonn HI survey, where we identify shells belonging to the Milky Way. We used an identification method based on the search of continuous regions of a low brightness temperature that are compatible with given properties of HI shells. We found 333 shells in the whole Galaxy. The size distribution of shells in the outer Galaxy is fitted by a power law with the coefficient of 2.6 corresponding to the index 1.8 in the distribution of energy sources. Their surface density decreases exponentially with a scale length of 2.8kpc. The surface density of shells with radii >100pc in the solar neighbourhood is around 4 per kpc^2^ and the 2D porosity is around 0.7.
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/437/101
- Title:
- HI shells in the outer Milky Way
- Short Name:
- J/A+A/437/101
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present results of a method for an automatic search for HI shells in 3D data cubes and apply it to the Leiden-Dwingeloo HI survey of the northern Milky Way. In the 2nd Galactic quadrant, where identifications of structures are not substantially influenced by overlapping, we find nearly 300 structures.
- 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.
6408. HI supershells catalogue
- ID:
- ivo://CDS.VizieR/J/A+A/564/A116
- Title:
- HI supershells catalogue
- Short Name:
- J/A+A/564/A116
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The HI supershells catalogue was carried out making use of the Leiden-Argentine-Bonn (LAB) HI survey in the outer part of the Galaxy. The identification of the supershell candidates was made using a combination of two techniques: a visual inspection one plus an automatic searching algorithm. A total of 566 supershell candidates were identified. Most of them (347) are located in the second galactic quadrant, while 219 were found in the third one.
6409. HI survey of AGNs
- ID:
- ivo://CDS.VizieR/J/ApJS/177/103
- Title:
- HI survey of AGNs
- Short Name:
- J/ApJS/177/103
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have conducted a new Arecibo survey for HI emission for 113 galaxies with broad-line (type 1) active galactic nuclei (AGNs) out to recession velocities as high as ~35000km/s. The primary aim of the study is to obtain sensitive HI spectra for a well-defined, uniformly selected sample of active galaxies that have estimates of their black hole masses in order to investigate correlations between HI properties and the characteristics of the AGNs. HI emission was detected in 66 out of the 101 (65%) objects with spectra uncorrupted by radio frequency interference, among which 45 (68%) have line profiles with adequate signal-to-noise ratio and sufficiently reliable inclination corrections to yield robust deprojected rotational velocities. This paper presents the basic survey products, including an atlas of HI spectra, measurements of HI flux, line width, profile asymmetry, optical images, optical spectroscopic parameters, as well as a summary of a number of derived properties pertaining to the host galaxies. To enlarge our primary sample, we also assemble all previously published HI measurements of type 1 AGNs for which we can estimate black hole masses, which total an additional 53 objects. The final comprehensive compilation of 154 broad-line active galaxies, by far the largest sample ever studied, forms the basis of our companion paper, which uses the HI database to explore a number of properties of the AGN host galaxies.
- 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.