- ID:
- ivo://CDS.VizieR/J/AJ/113/905
- Title:
- HI observations of galaxies
- Short Name:
- J/AJ/113/905
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present H I 21-cm line observations of 543 galaxies at low galactic latitude in the Galactic Anticenter region of the Zone of Avoidance (4h<={alpha}<=8h, 0{deg}=<{delta}=<37{deg}). The sample comprises 147 catalogued objects (from UGC, CGCG, MCG, and IRAS) still missing a redshift measurement and a list of 369 objects selected from an extensive optical compilation of galaxy candidates in this area. The spectra were acquired using the 305-m Arecibo telescope and cover a velocity range from -350 to +13800km/s at a resolution of about 16km/s. 196 galaxies were detected,59 of the catalogued ones and 137 from the optical compilation. The H I derived properties are presented, as is a discussion regarding the redshift distribution in this region. Our data seem to be consistent with a link across the Zone of Avoidance between the Pisces-Perseus supercluster and Abell 569.
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- ID:
- ivo://CDS.VizieR/J/A+A/442/137
- Title:
- HI observations of WHISP disk galaxies
- Short Name:
- J/A+A/442/137
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present HI observations of 68 early-type disk galaxies from the WHISP survey. They have morphological types between S0 and Sab and absolute B-band magnitudes between -14 and -22. These galaxies form the massive, high surface-brightness extreme of the disk galaxy population, few of which have been imaged in HI before. The HI properties of the galaxies in our sample span a large range; the average values of MHI/LB and DHI/D25 are comparable to the ones found in later-type spirals, but the dispersions around the mean are larger. No significant differences are found between the S0/S0a and the Sa/Sab galaxies.
- ID:
- ivo://CDS.VizieR/J/MNRAS/450/2025
- Title:
- HIPASS-ZoA HII regions
- Short Name:
- J/MNRAS/450/2025
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a Radio Recombination Line (RRL) survey of the Galactic plane from the Hi Parkes All-sky Survey and associated Zone of Avoidance survey, which mapped the region l=196{deg}-0{deg}-52{deg} and |b|<=5{deg} at 1.4GHz and 14.4-arcmin resolution. We combine three RRLs, H168{alpha}, H167{alpha}, and H166{alpha} to derive fully sampled maps of the diffuse ionized emission along the inner Galactic plane. The velocity information, at a resolution of 20km/s, allows us to study the spatial distribution of the ionized gas and compare it with that of the molecular gas, as traced by CO. The longitude-velocity diagram shows that the RRL emission is mostly associated with CO gas from the molecular ring and is concentrated within the inner 30{deg} of longitude. A map of the free-free emission in this region of the Galaxy is derived from the line-integrated RRL emission, assuming an electron temperature gradient with Galactocentric radius of 496+/-100K/kpc. Based on the thermal continuum map, we extracted a catalogue of 317 compact (<~15-arcmin) sources, with flux densities, sizes, and velocities. We report the first RRL observations of the southern ionized lobe in the Galactic Centre. The line profiles and velocities suggest that this degree-scale structure is in rotation. We also present new evidence of diffuse ionized gas in the 3-kpc arm. Helium and carbon RRLs are detected in this survey. The He line is mostly observed towards HII regions, whereas the C line is also detected further away from the source of ionization. These data represent the first observations of diffuse C RRLs in the Galactic plane at a frequency of 1.4GHz.
- ID:
- ivo://CDS.VizieR/J/A+A/324/877
- Title:
- HI properties of spiral and irregular galaxies
- Short Name:
- J/A+A/324/877
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the analysis of neutral hydrogen properties of 108 galaxies, based on short 21-cm observations with the Westerbork Synthesis Radio Telescope (WSRT). The results of two HI surveys are analysed to investigate the existence of relations between optical and HI properties, like diameters, hydrogen masses and average surface densities. For all galaxies in our sample we find that the HI diameter, defined at a surface density level of 1M_{sun}_/pc^2^, is larger than the optical diameter, defined at the 25^th^mag/arcsec^2^ isophotal level. The Hi-to-optical-diameter ratio does not depend on morphological type or luminosity. The strongest, physically meaningful, correlation for the sample of 108 galaxies is the one between logM_HI_ and logD_HI_, with a slope of 2. This implies that the HI surface density averaged over the whole HI disc is constant from galaxy to galaxy, independent of luminosity or type. The radial HI surface density profiles are studied using the technique of principal component analysis. We find that about 81% of the variation in the density profiles of galaxies can be explained by two dimensions. The most dominant component can be related to "scale" and the second principal component accounts for the variance in the behaviour of the radial profile in the central parts of galaxies (i.e. "peak or depression") . The third component accounts for 7% of the variation and is most likely responsible for bumps and wiggles in the observed density profiles.
- 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/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.
- ID:
- ivo://CDS.VizieR/J/A+A/258/243
- Title:
- HRV of Abell 151 galaxies
- Short Name:
- J/A+A/258/243
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We use a sample of 65 redshifts to study the kinematics and dynamics of the cluster Abell 151. Data on individual galaxies are presented, and the accuracy of the determined velocities are discussed as well as some properties of the cluster. The velocity data reveal a foreground group and a background population at the same redshifts as the closely projected cluster A 166.
- ID:
- ivo://CDS.VizieR/J/ApJS/256/40
- Title:
- HST imaging survey of low-z Swift-BAT AGNs
- Short Name:
- J/ApJS/256/40
- Date:
- 03 Mar 2022 00:28:07
- Publisher:
- CDS
- Description:
- We present initial results from a Hubble Space Telescope snapshot imaging survey of the host galaxies of Swift-BAT active galactic nuclei (AGN) at z<0.1. The hard X-ray selection makes this sample relatively unbiased in terms of obscuration, compared to optical AGN selection methods. The high-resolution images of 154 target AGN enable us to investigate the detailed photometric structure of the host galaxies, such as the Hubble type and merging features. We find 48% and 44% of the sample to be hosted by early-type and late-type galaxies, respectively. The host galaxies of the remaining 8% of the sample are classified as peculiar galaxies because they are heavily disturbed. Only a minor fraction of host galaxies (18%-25%) exhibit merging features (e.g., tidal tails, shells, or major disturbance). The merging fraction increases strongly as a function of bolometric AGN luminosity, revealing that merging plays an important role in triggering luminous AGN in this sample. However, the merging fraction is weakly correlated with the Eddington ratio, suggesting that merging does not necessarily lead to an enhanced Eddington ratio. Type 1 and Type 2 AGN are almost indistinguishable in terms of their Hubble type distribution and merging fraction. However, the merging fraction of Type 2 AGN peaks at a lower bolometric luminosity compared with those of Type 1 AGN. This result may imply that the triggering mechanism and evolutionary stages of Type 1 and Type 2 AGN are not identical.
- ID:
- ivo://CDS.VizieR/J/ApJ/586/765
- Title:
- HST K-selected extremely red galaxies
- Short Name:
- J/ApJ/586/765
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We selected 115 extremely red objects (EROs) from deep Hubble Space Telescope (HST) WFPC2 archive data combined with ground-based K-band images, with (F814W-Ks)>=4, K-band signal-to-noise ratio >=5, and a median limiting Ks magnitude of ~18.7, over a corresponding area of 228 arcmin2, for a morphological study of the ERO galaxy population. The survey covered a total of ~409-arcmin^2^ over 77 separate WFPC2 fields. This is the first complete sample of bright EROs with high-resolution HST morphologies.
- ID:
- ivo://CDS.VizieR/J/ApJ/730/125
- Title:
- HST/NICMOS observations of bright IR galaxies
- Short Name:
- J/ApJ/730/125
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new results on the physical nature of infrared-luminous sources at 0.5<z<2.8 as revealed by HST/NICMOS imaging and Infrared Spectrograph mid-infrared spectroscopy. Our sample consists of 134 galaxies selected at 24um with a flux of S(24um)>0.9mJy. We find many (~60%) of our sources to possess an important bulge and/or central point source component, most of which reveal additional underlying structures after subtraction of a best-fit Sersic (or Sersic+PSF) profile. Based on visual inspection of the NIC2 images and their residuals, we estimate that ~80% of all our sources are mergers. We calculate lower and upper limits on the merger fraction to be 62% and 91%, respectively. At z<1.5, we observe objects in early (pre-coalescence) merging stages to be mostly disk and star formation dominated, while we find mergers to be mainly bulge dominated and active galactic nucleus (AGN)-starburst composites during coalescence and then AGN dominated in late stages. This is analogous to what is observed in local ULIRGs. Finally, we observe obscured ({tau}_9.7um_>3.36) quasars to live in faint and compact hosts and show that these are likely high-redshift analogs of local dense-core mergers. We find late-stage mergers to possess predominantly unobscured AGN spectra, but do not observe other morphological classes to carry any specific combination of {tau}_9.7um_ and polycyclic aromatic hydrocarbon (PAH) equivalent width.
