- 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.
Number of results to display per page
Search Results
- 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.
3966. 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.
- ID:
- ivo://CDS.VizieR/J/AJ/105/1251
- Title:
- Velocities in Pisces-Perseus supercluster.
- Short Name:
- J/AJ/105/1251
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Measurements of 544 radial velocities, 229 optical and 315 in the 21cm HI line, are presented for galaxies, mostly in the declination strip +33.5 deg<Dec<+39.5deg in the region of the Pisces-Perseus supercluster. These are combined with other available data to investigate the linear structure identified as the main supercluster ridge. The main ridge of the supercluster extends at least 50h^-1Mpc before it disappears into the zone of avoidance east of Perseus. Confinement both on the plane of the sky and in the velocity dimension imply an axial ratio of greater than ten to one and an inclination with respect to the plane of the sky of less than about 12 degrees. The smoothed volume density contrast over the whole ridge averages more than a factor of 6 relative to the average density derived for the whole sample. The relative proximity, low inclination to the plane of the sky, and high contrast relative to the foreground and background, help to make the Pisces-Perseus filament one of the most prominent features in the extragalactic sky on large scales.
- ID:
- ivo://CDS.VizieR/J/A+A/521/A78
- Title:
- Velocities in the A2345 cluster
- Short Name:
- J/A+A/521/A78
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The connection of cluster mergers with the presence of extended, diffuse radio sources in galaxy clusters is still debated. We aim to obtain new insights into the internal dynamics of the cluster Abell 2345. This cluster exhibits two non-symmetric radio relics well studied through recent, deep radio data. Our analysis is based on redshift data for 125 galaxies acquired at the Telescopio Nazionale Galileo and on new photometric data acquired at the Isaac Newton Telescope. We also use ROSAT/HRI archival X-ray data. We combine galaxy velocities and positions to select 98 cluster galaxies and analyze the internal dynamics of the cluster.
- ID:
- ivo://CDS.VizieR/J/MNRAS/369/1351
- Title:
- Velocities in the possible Eridanus group
- Short Name:
- J/MNRAS/369/1351
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We examine a possible supergroup in the direction of the Eridanus constellation using 6dF Galaxy Survey second data release (6dFGS DR2) positions and velocities together with Two-Micron All-Sky Survey and Hyper-Lyon-Meudon Extragalactic DAtabase photometry. We perform a friends-of-friends analysis to determine which galaxies are associated with each substructure before examining the properties of the constituent galaxies.
- ID:
- ivo://CDS.VizieR/J/MNRAS/434/772
- Title:
- Velocities in ZwCl2341.1+0000 field
- Short Name:
- J/MNRAS/434/772
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We study the dynamical status of the galaxy system ZwCl 2341.1+0000, a filamentary multi-Mpc galaxy structure associated with a complex diffuse radio emission. Our analysis is mainly based on new spectroscopic data for 128 galaxies acquired at the Italian Telescopio Nazionale Galileo. We also use optical data available in the Sloan Digital Sky Survey and X-ray data from the Chandra archive. We select 101 cluster member galaxies and compute the cluster redshift <z>~0.2693 and the global line-of-sight velocity dispersion {sigma}_V_~1000km/s. Our optical analysis agrees with the presence of at least three, likely four or more, optical subclusters causing the south-south-east-north-north-west (SSE-NNW) elongation of the galaxy distribution and a significant velocity gradient in the south-north direction. In particular, we detect an important low-velocity subclump in the southern region, roughly coincident with the brightest peak of the diffuse radio emission but with a clear offset between the optical and radio peaks. We also detect one (or two) optical subcluster(s) at north, in correspondence with the second brightest radio emission, and another one in the central cluster region, where a third diffuse radio source has been recently detected. A more refined analysis involving the study of the 2D galaxy distribution suggests an even more complex structure. Depending on the adopted model, we obtain a mass estimate M_sys_~1-3x10^15^h_70_^-1^M_{sun} for the whole system. As for the X-ray analysis, we confirm the SSE-NNW elongation of the intracluster medium and detect four significant peaks. The X-ray emission is strongly asymmetric and offsetted with respect to the galaxy distribution, thus suggesting a merger caught in the phase of post-core-core passage. Our findings support two possible hypotheses for the nature of the diffuse radio emission of ZwCl 2341.1+0000: a two relics + halo scenario or diffuse emission associated with the infall and merging of several galaxy groups during the first phase of the cluster formation.
