- ID:
- ivo://CDS.VizieR/J/AJ/131/716
- Title:
- H{alpha} scale length in Virgo and field spirals
- Short Name:
- J/AJ/131/716
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The scale lengths of the old stars and ionized gas distributions are compared for similar samples of Virgo Cluster members and field spiral galaxies via H{alpha} and broad R-band surface photometry. While the R-band and H{alpha} scale lengths are, on average, comparable for the combined sample, we find significant differences between the field and cluster samples. While the H{alpha} scale lengths of the field galaxies are a factor of 1.14+/-0.07 longer, on average, than their R-band scale lengths, the H{alpha} scale lengths of Virgo Cluster members are, on average, 20% smaller than their R-band scale lengths.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/553/A91
- Title:
- Halpha3 survey of Virgo and Coma galaxies
- Short Name:
- J/A+A/553/A91
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the analysis of the galaxy structural parameters from H{alpha}3, an H{alpha} narrow-band imaging follow-up survey of ~800 galaxies selected from the HI Arecibo Legacy Fast ALFA Survey (ALFALFA) in the Local Supercluster, including the Virgo cluster, and in the Coma Supercluster. Taking advantage of H{alpha}3 which provides the complete census of the recent star-forming, HI-rich galaxies in the local universe, we aim to investigate the structural parameters of both the young (<10Myr) and the old (>1Gyr) stellar populations. By comparing the sizes of these stellar components we investigated the spatial scale on which galaxies are growing at the present cosmological epoch and the role of the environment in quenching the star-formation activity. We computed the concentration, asymmetry, and clumpiness (CAS) structural parameters both for recently born and old stars. To quantify the sizes we computed half-light radii and a new parameter dubbed EW/r based on the half-light radius of the H{alpha} Equivalent Width map. To highlight the environmental perturbation, we adopt an updated calibration of the HI-deficiency parameter that we use to divide the sample in unperturbed and perturbed galaxies. The concentration index computed in the r band depends on the stellar mass and on the Hubble type, these variables being related since most massive galaxies are bulge dominated thus most concentrated. Going toward later spirals and irregulars both the concentration index and the mass decrease along with the bulge-to-disk ratio. Blue Compact dwarfs represent an exception since they have similar mass but they are more concentrated than dwarf irregulars. The asymmetry and the clumpiness increase along the spiral sequence up to Sc-Sd but they decrease going toward dwarfs whose light distribution is smooth and more symmetric. When measured on H{alpha} images, the CAS parameters do not exhibit obvious correlations with Hubble type. Irrespective of whether we used the ratio between effective radii or the EW/r parameter, we found that the concentration index is the main parameter that describes the current growth of isolated galaxies but, for a fixed concentration, the stellar mass plays a second order role. At the present epoch, massive galaxies are growing inside-out, conversely the dwarfs are growing on the scale of their already assembled mass.
- ID:
- ivo://CDS.VizieR/J/MNRAS/462/1910
- Title:
- H-ATLAS NGP LOFAR radio catalogue
- Short Name:
- J/MNRAS/462/1910
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present Low-Frequency Array (LOFAR) High-Band Array observations of the Herschel-ATLAS North Galactic Pole survey area. The survey we have carried out, consisting of four pointings covering around 142deg^2^ of sky in the frequency range 126-173MHz, does not provide uniform noise coverage but otherwise is representative of the quality of data to be expected in the planned LOFAR wide-area surveys, and has been reduced using recently developed 'facet calibration' methods at a resolution approaching the full resolution of the data sets (~10x6 arcsec) and an rms off-source noise that ranges from 100{mu}Jy beam^-1^ in the centre of the best fields to around 2mJy/beam at the furthest extent of our imaging. We describe the imaging, cataloguing and source identification processes, and present some initial science results based on a 5{sigma} source catalogue. These include (i) an initial look at the radio/far-infrared correlation at 150 MHz, showing that many Herschel sources are not yet detected by LOFAR; (ii) number counts at 150MHz, including, for the first time, observational constraints on the numbers of star-forming galaxies; (iii) the 150-MHz luminosity functions for active and star-forming galaxies, which agree well with determinations at higher frequencies at low redshift, and show strong redshift evolution of the star-forming population; and (iv) some discussion of the implications of our observations for studies of radio galaxy life cycles.
- ID:
- ivo://CDS.VizieR/J/A+A/414/905
- Title:
- H-band photometry in Pisces-Perseus disk galaxies
- Short Name:
- J/A+A/414/905
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We investigate the scaling relations of bulge and disk structural parameters for a sample of 108 disk galaxies. Structural parameters of individual galaxies are obtained from two-dimensional bulge/disk decomposition of their H-band surface brightness distributions. Bulges are modelled with a generalized exponential (Sersic) with variable integer shape index n.
- ID:
- ivo://CDS.VizieR/J/A+AS/137/101
- Title:
- H-band photometry in Pisces-Perseus spirals
- Short Name:
- J/A+AS/137/101
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The paper presents results of an H-band imaging survey of spiral galaxies in the Perseus-Pisces supercluster area. The derived global photometric parameters of the sample galaxies (magnitudes, diameters, etc.) are collected in Table 3.
- ID:
- ivo://CDS.VizieR/J/ApJ/821/113
- Title:
- HCG and RSCG compact group galaxies with WISE
- Short Name:
- J/ApJ/821/113
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Compact groups provide an environment to study the growth of galaxies amid multiple prolonged interactions. With their dense galaxy concentrations and relatively low velocity dispersions, compact groups mimic the conditions of hierarchical galaxy assembly. Compact group galaxies are known to show a bimodality in Spitzer IRAC infrared color space: galaxies are preferentially either quiescent with low specific star formation rates (SSFRs) or prolifically forming stars-galaxies with moderate levels of specific star formation are rare. Previous Spitzer IRAC studies identifying this "canyon" have been limited by small number statistics. We utilize whole-sky Wide-field Infrared Survey Explorer (WISE) data to study 163 compact groups, thereby tripling our previous sample and including more galaxies with intermediate mid-IR colors indicative of moderate SSFRs. We define a distinct WISE mid-IR color space (log[f_12_/f_4.6_]) versus (log[f_22_/f_3.4_]) that we use to identify canyon galaxies from the larger sample. We confirm that compact group galaxies show a bimodal distribution in the mid-infrared and identify 37 canyon galaxies with reliable photometry and intermediate mid-IR colors. Morphologically, we find that the canyon harbors a large population of both Sa-Sbc and E/S0 type galaxies, and that they fall on the optical red sequence rather than the green valley. Finally, we provide a catalog of WISE photometry for 567 of 652 galaxies selected from the sample of 163 compact groups.
- ID:
- ivo://CDS.VizieR/J/A+A/591/A108
- Title:
- HD61005 SPHERE H and Ks images
- Short Name:
- J/A+A/591/A108
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Debris disks offer valuable insights into the latest stages of circumstellar disk evolution, and can possibly help us to trace the outcomes of planetary formation processes. In the age range 10 to 100Myr, most of the gas is expected to have been removed from the system, giant planets (if any) must have already been formed, and the formation of terrestrial planets may be on-going. Pluto-sized planetesimals, and their debris released in a collisional cascade, are under their mutual gravitational influence, which may result into non-axisymmetric structures in the debris disk. Here we present new VLT/SPHERE and ALMA observations of the debris disk around the 40Myr-old solar-type star HD61005. We resolve the disk at unprecedented resolution both in the near-infrared (in scattered and polarized light) and at millimeter wavelengths. We perform a detailed modeling of these observations, including the spectral energy distribution. Thanks to the new observations, we propose a solution for both the radial and azimuthal distribution of the dust grains in the debris disk. We find that the disk has a moderate eccentricity and that the dust density is two times larger at the pericenter compared to the apocenter. With no giant planets detected in our observations, we investigate alternative explanations besides planet-disk interactions to interpret the inferred disk morphology. We postulate that the morphology of the disk could be the consequence of a massive collision between 1000km-sized bodies at 61 au. If this interpretation holds, it would put stringent constraints on the formation of massive planetesimals at large distances from the star.
- ID:
- ivo://CDS.VizieR/J/ApJ/745/95
- Title:
- Herschel FIR & submm photometry of KINGFISH sample
- Short Name:
- J/ApJ/745/95
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- New far-infrared and submillimeter photometry from the Herschel Space Observatory is presented for 61 nearby galaxies from the Key Insights on Nearby Galaxies: A Far-Infrared Survey with Herschel (KINGFISH) sample. The spatially integrated fluxes are largely consistent with expectations based on Spitzer far-infrared photometry and extrapolations to longer wavelengths using popular dust emission models. Dwarf irregular galaxies are notable exceptions, as already noted by other authors, as their 500{mu}m emission shows evidence for a submillimeter excess. In addition, the fraction of dust heating attributed to intense radiation fields associated with photodissociation regions is found to be (21+/-4)% larger when Herschel data are included in the analysis. Dust masses obtained from the dust emission models of Draine & Li (2007ApJ...657..810D) are found to be on average nearly a factor of two higher than those based on single-temperature modified blackbodies, as single blackbody curves do not capture the full range of dust temperatures inherent to any galaxy. The discrepancy is largest for galaxies exhibiting the coolest far-infrared colors.
- ID:
- ivo://CDS.VizieR/J/ApJ/842/133
- Title:
- HI-bearing ultra-diffuse ALFALFA galaxies
- Short Name:
- J/ApJ/842/133
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a sample of 115 very low optical surface brightness, highly extended, HI-rich galaxies carefully selected from the ALFALFA survey that have similar optical absolute magnitudes, surface brightnesses, and radii to recently discovered "ultra-diffuse" galaxies (UDGs). However, these systems are bluer and have more irregular morphologies than other UDGs, are isolated, and contain significant reservoirs of HI. We find that while these sources have normal star formation rates for HI-selected galaxies of similar stellar mass, they have very low star formation efficiencies. We further present deep optical and HI-synthesis follow-up imaging of three of these HI-bearing ultra-diffuse sources. We measure HI diameters extending to ~40kpc, but note that while all three sources have large HI diameters for their stellar mass, they are consistent with the HI mass-HI radius relation. We further analyze the HI velocity widths and rotation velocities for the unresolved and resolved sources, respectively, and find that the sources appear to inhabit halos of dwarf galaxies. We estimate spin parameters, and suggest that these sources may exist in high spin parameter halos, and as such may be potential HI-rich progenitors to the ultra-diffuse galaxies observed in cluster environments.
- ID:
- ivo://CDS.VizieR/J/AJ/133/1104
- Title:
- HI 21cm observations of Pegasus galaxies
- Short Name:
- J/AJ/133/1104
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present neutral hydrogen observations of 54 galaxies in the Pegasus Cluster. The observations include single-dish HI measurements, obtained with the Arecibo telescope for all 54 galaxies in the sample, as well as HI images obtained with the Very Large Array (VLA) for 10 of these.
