- ID:
- ivo://CDS.VizieR/J/A+A/590/A92
- Title:
- VCC 2062 CO(1-0) data cubes
- Short Name:
- J/A+A/590/A92
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The physical mechanisms driving star formation (SF) in galaxies are still not fully understood. Tidal dwarf galaxies (TDGs), made of gas ejected during galaxy interactions, seem to be devoid of dark matter and have a near-solar metallicity. The latter makes it possible to study molecular gas and its link to SF using standard tracers (CO, dust) in a peculiar environment. We present a detailed study of a nearby TDG in the Virgo Cluster, VCC 2062, using new high-resolution CO(1-0) data from the Plateau de Bure, deep optical imaging from the Next Generation Virgo Cluster Survey (NGVS), and complementary multiwavelength data. Until now, there was some doubt whether VCC 2062 was a true TDG, but the new deep optical images from the NGVS reveal a stellar bridge between VCC 2062 and its parent galaxy, NGC 4694, which is clear proof of its tidal origin. Several high-resolution tracers (H{alpha}, UV, 8um, and 24um) of the star formation rate (SFR) are compared to the molecular gas distribution as traced by the CO(1-0). Coupled with the SFR tracers, the NGVS data are used with the CIGALE code to model the stellar populations throughout VCC 2062, yielding a declining SFR in the recent past, consistent with the low H{alpha}/UV ratio, and a high burst strength. HI emission covers VCC 2062, whereas the CO is concentrated near the HI maxima. The CO peaks correspond to two very distinct regions: one with moderate SF to the NE and one with only slightly weaker CO emission but with nearly no SF. Even where SF is clearly present, the SFR is below the value expected from the surface density of the molecular and the total gas as compared to spiral galaxies and other TDGs. After discussing different possible explanations, we conclude that the low surface brightness is a crucial parameter to understand the low SFR.
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Search Results
- ID:
- ivo://CDS.VizieR/J/ApJ/660/1186
- Title:
- VCC galaxies classification with SDSS
- Short Name:
- J/ApJ/660/1186
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- From a quantitative analysis of 413 Virgo Cluster early-type dwarf galaxies (dEs) with SDSS imaging data, we find that the dE class can be divided into multiple subpopulations that differ significantly in their morphology and clustering properties. Three dE subclasses are shaped like thick disks and show no central clustering: (1) dEs with disk features like spiral arms or bars, (2) dEs with central star formation, and (3) ordinary, bright dEs that have no or only a weak nucleus.
- ID:
- ivo://CDS.VizieR/J/A+A/552/A8
- Title:
- 454 VCC galaxies revised coordinates
- Short Name:
- J/A+A/552/A8
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We study the dust content of a large optical input sample of 910 early-type galaxies (ETG) in the Virgo cluster, also extending to the dwarf ETG, and examine the results in relation to those on the other cold ISM components. We have searched for far-infrared emission in all galaxies in the input sample using the 250um image of the Herschel Virgo Cluster Survey (HeViCS). This image covers a large fraction of the cluster with an area of ~55 square degrees. For the detected ETG we measured fluxes in five bands from 100 to 500um, and estimated the dust mass and temperature with modified black-body fits. Dust is detected above the completeness limit of 25.4mJy at 250um in 46 ETG, 43 of which are in the optically complete part of the input sample. In addition, dust is present at fainter levels in another six ETG. We detect dust in the four ETG with synchrotron emission, including M 87.
- ID:
- ivo://CDS.VizieR/J/A+A/581/A10
- Title:
- VEGAS: A VST Early-type GAlaxy Survey
- Short Name:
- J/A+A/581/A10
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the VST Early-type GAlaxy Survey (VEGAS), which is designed to obtain deep multiband photometry in g, r, i, of about one hundred nearby galaxies down to 27.3, 26.8, and 26mag/arcsec^2^ respectively, using the ESO facility VST/OmegaCAM. The goals of the survey are 1) to map the light distribution up to ten effective radii, r_e_; 2) to trace color gradients and surface brightness fluctuation gradients out to a few r_e_ for stellar population characterization; and 3) to obtain a full census of the satellite systems (globular clusters and dwarf galaxies) out to 20% of the galaxy virial radius. The external regions of galaxies retain signatures of the formation and evolution mechanisms that shaped them, and the study of nearby objects enables a detailed analysis of their morphology and interaction features. To clarify the complex variety of formation mechanisms of early-type galaxies (ETGs), wide and deep photometry is the primary observational step, which at the moment has been pursued with only a few dedicated programs. The VEGAS survey has been designated to provide these data for a volume-limited sample with exceptional image quality. In this commissioning photometric paper we illustrate the capabilities of the survey using g- and i-band VST/OmegaCAM images of the nearby galaxy NGC 4472 and of smaller ETGs in the surrounding field. Our surface brightness profiles reach rather faint levels and agree excellently well with previous literature. Genuine new results concern the detection of an intracluster light tail in NGC 4472 and of various substructures at increasing scales. We have also produced extended (g-i) color profiles. The VST/OmegaCAM data that we acquire in the context of the VEGAS survey provide a detailed view of substructures in the optical emission from extended galaxies, which can be as faint as a hundred times below the sky level.
- ID:
- ivo://CDS.VizieR/J/A+A/576/A14
- Title:
- VEGAS-SSS photometry of NGC3115
- Short Name:
- J/A+A/576/A14
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a study of globular clusters (GCs) and other small stellar systems (SSSs) in the field of NGC 3115, observed as part of the ongoing wide-field imaging survey VEGAS, carried out with the 2.6m VST telescope. We used deep g and i observations of NGC 3115, a well-studied lenticular galaxy that is covered excellently well in the scientific literature. This is fundamental to test the methodologies, verify the results, and probe the capabilities of the VEGAS-SSS. Leveraging the large field of view of the VST allowed us to accurately study the distribution and properties of SSSs as a function of galactocentric distance, well beyond ~20 galaxy effective radii, in a way that is rarely possible. Our analysis of colors, magnitudes, and sizes of SSS candidates confirms the results from existing studies, some of which were carried out with 8-10m class telescopes, and further extends them to previously unreached galactocentric distances with similar accuracy. In particular, we find a color bimodality for the GC population and a de Vaucouleurs profile for the surface density of GCs similar to the galaxy light profile. The radial color gradient of blue and red GCs previously found, for instance, by the SLUGGS survey with Subaru and Keck data, is further extended out to the largest galactocentric radii inspected, ~65kpc. In addition, the surface density profiles of blue and red GCs taken separately are well approximated by a r1/4 density profile, with the fraction of blue GCs being slightly larger at larger radii. We do not find hints of a trend for the red GC subpopulation and for the GC turnover magnitude to vary with radius, but we observe a ~0.2mag difference in the turnover magnitude of the blue and red GC subpopulations. Finally, from inspecting SSS sizes and colors, we obtain a list of ultracompact dwarf galaxies and GC candidates suitable for future spectroscopic follow-up. In conclusion, our study shows i) the reliability of the methodologies developed to study SSSs in the field of bright early-type galaxies, and ii) the great potential of the VEGAS survey to produce original results on SSSs science, mainly thanks to the wide-field imaging adopted.
- ID:
- ivo://CDS.VizieR/J/MNRAS/326/473
- Title:
- Vel. Distribution of low-luminosity E galaxies
- Short Name:
- J/MNRAS/326/473
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The shape of the line-of-sight velocity distribution (LOSVD) is measured for a sample of 14 elliptical galaxies, predominantly low-luminosity ellipticals. The sample is dominated by galaxies in the Virgo cluster but also contains ellipticals in nearby groups and low density environments. The parameterization of the LOSVD due to Gerhard and van der Marel & Franx is adopted, which measures the asymmetrical and symmetrical deviations of the LOSVD from a Gaussian by the amplitudes h3 and h4 of the Gauss-Hermite series. Rotation, velocity dispersion, h3 and h4 are determined as a function of radius for both major and minor axes using the Fourier Correlation Quotient method of Bender (1990). Galaxy spectra are rebinned in the direction of the spectroscopic slit to a minimum signal-to-noise ratio (S/N) of 60 per angstrom. Rotation and velocity dispersion are determined separately for S/N = 30 per angstrom.
- ID:
- ivo://CDS.VizieR/J/A+A/547/A44
- Title:
- Velocities and BR photometry of Abell 1995
- Short Name:
- J/A+A/547/A44
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Abell 1995 is a puzzling galaxy cluster hosting a powerful radio halo, but it has not yet been recognized as a obvious cluster merger, as usually expected for clusters with diffuse radio emission. We aim at an exhaustive analysis of the internal structure of Abell 1995 to verify that this cluster is really dynamically relaxed, as reported in previous studies. We base our analysis on new and archival spectroscopic and photometric data for 126 galaxies in the field of Abell 1995. The study of the hot intracluster medium was performed on X-ray archival data.
- ID:
- ivo://CDS.VizieR/J/ApJ/368/54
- Title:
- Velocities and Photometry for E and S0 galaxies
- Short Name:
- J/ApJ/368/54
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- (Abstract from the paper) New spectroscopy and photometry have been obtained for 136 elliptical and S0 galaxies in the direction of the large-scale streaming flow attributed to the great attractor. Measurements of central velocity dispersion (sigma), total B magnitudes (B_T), the photometric parameter D_n, and the absorption-line index Mgi_2 are presented. Both internal and external comparisons indicate that measurements of log{sigma} are accurate to 0.05 dex, B_T to 0.15 mag, D_n to 0.015 dex, and Mg_2 to 0.017 mag. These data have been used in a previous paper by Dressler and Faber to estimate distances for these galaxies via the D_n - {sigma} relation. It is shown in this paper that the D_n - Mg_2 relation also predicts the same trends of peculiar velocity with distance, but with less accuracy. The relative accuracy of other distance indicators for elliptical galaxies is also discussed.
- ID:
- ivo://CDS.VizieR/J/ApJ/649/201
- Title:
- Velocities and Washington photometry in Carina dSph
- Short Name:
- J/ApJ/649/201
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A new large-area Washington M, T2+DDO51 filter survey of more than 10deg^2^ around the Carina dSph galaxy reveals a spectroscopically confirmed power-law radial density break population of Carina giant stars extending several degrees beyond the central King profile. Magellan telescope MIKE spectroscopy establishes the existence of Carina stars to at least 4.5 times its central King limiting radius, rlim, and primarily along Carina's major axis. To keep these stars bound to the dSph would require a global Carina mass-to-light ratio of M/L>=6300(M/L)_{sun}}. The MIKE velocities, supplemented with ~950 additional Carina field velocities from archived VLT+GIRAFFE spectra with r<~rlim, demonstrate a nearly constant Carina velocity dispersion (sigma_v_) to just beyond r=rlim and both a rising and a velocity shear at still larger radii. Together, the observational evidence suggests that the discovered extended Carina population represents tidal debris from the dSph.
3970. Velocities in NGC 4449
- ID:
- ivo://CDS.VizieR/J/AJ/124/3157
- Title:
- Velocities in NGC 4449
- Short Name:
- J/AJ/124/3157
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A detailed kinematic analysis of ionized gas in the nearby irregular galaxy NGC 4449 is presented. Observations were conducted in the spectral lines of H{alpha} and [S II]. Our scanning Fabry-Perot interferometric observations are presented from both a global and a local perspective. We have analyzed the global velocity field, the spatially extended diffuse gaseous component, and the H II region populations and, furthermore, have determined the rotation curve based on the heliocentric radial velocities of the global H{alpha} spatial distribution.
