- ID:
- ivo://CDS.VizieR/J/MNRAS/360/185
- Title:
- VI photometry of the Leo II galaxy
- Short Name:
- J/MNRAS/360/185
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present V and I photometry of a 9.4'x9.4' field centered on the dwarf spheroidal galaxy Leo II. The Tip of the Red Giant Branch is identified at I^TRGB^=17.83+/-0.03 and adopting <[M/H]>=-1.53+/-0.2 from the comparison of RGB stars with Galactic templates, we obtain a distance modulus (m-M)_0=21.84+/-0.13, corresponding to a distance D=233+/-15kpc. Two significant bumps have been detected in the Luminosity Function of the Red Giant Branch. The fainter bump (B1, at V=21.79+/-0.05) is the RGB bump of the dominant stellar population while the brightest one (B2, at V=21.36+/-0.05) may be identified as the Asymptotic Giant Branch Clump of the same population. The luminosity of the main RGB bump (B1) suggest that the majority of RGB stars in Leo II belongs to a population that is >~4Gyr younger than the classical Galactic globular clusters. The stars belonging to the He-burning Red Clump are shown to be significantly more centrally concentrated than RR Lyrae and Blue Horizontal Branch stars, probing the existence of an age/metallicity radial gradient in this remote dwarf spheroidal.
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+AS/120/153
- Title:
- VI photometry of Ton 2 cluster
- Short Name:
- J/A+AS/120/153
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Ton 2 is among the less-known Galactic globular clusters. We present for the first time colour magnitude diagrams in the V, I bands. We used the ESO NTT telescope under an excellent seeing of 0.6". The horizontal branch is red and close to the red giant branch, tilted by some differential reddening. The horizontal branch morphology and the red giant branch curvature suggest a metallicity similar to that of 47 Tucanae. We derive a reddening of E(B-V)=1.26 and a distance d_{sun}_=6.4kpc. Therefore, Ton 2 is =~2.0kpc from the Galactic center, and it appears to belong to the bulge population, being however only moderately metal rich.
- ID:
- ivo://CDS.VizieR/J/A+AS/118/303
- Title:
- VI Photometry of variables in NGC 2243
- Short Name:
- J/A+AS/118/303
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Tables 3-13 contain V and I band light curves for 6 variables reported in the paper. Tables 14 and 15 contain VI photometry presented in Figs. 5 and 9, respectively.
- ID:
- ivo://CDS.VizieR/J/AJ/123/840
- Title:
- VI photometry of variable stars in Fornax
- Short Name:
- J/AJ/123/840
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a search for variable stars in the Fornax dwarf galaxy covering an area of half a square degree. We have ~30 epochs of VI data. We found and determined periods for more than 500 RR Lyrae, 17 anomalous Cepheids, and six Population II Cepheids. In addition we have 85 candidate long-period variables, the majority of which were previously unknown. We estimate that the average metal abundance of RR Lyrae stars is [Fe/H]~=-1.6dex.
- ID:
- ivo://CDS.VizieR/J/A+AS/127/423
- Title:
- VI photometry of Westerlund 1 and 2
- Short Name:
- J/A+AS/127/423
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have carried out CCD observations of stars in the region of the open cluster Westerlund 1 through the V and I passbands. The direct images were obtained with the 24-inch telescope of the University of Toronto Southern Observatory situated at Las Campanas Observatory, Chile. After cross-correlating all independent V, (V-I) tables we have obtained a improved set of colour and magnitude values as compared to those based on a single measure.
- ID:
- ivo://CDS.VizieR/II/364
- Title:
- VIRAC. The VVV Infrared Astrometric Catalogue
- Short Name:
- II/364
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present VIRAC version 1, a near-infrared proper motion and parallax catalogue of the VISTA Variables in the Via Lactea (VVV) survey for 312587642 unique sources averaged across all overlapping pawprint and tile images covering 560deg^2^ of the bulge of the Milky Way and southern disc. The catalogue includes 119 million high-quality proper motion measurements, of which 47 million have statistical uncertainties below 1mas/yr. In the 11<K_s_<14 magnitude range, the high-quality motions have a median uncertainty of 0.67mas/yr. The catalogue also includes 6935 sources with quality-controlled 5{sigma} parallaxes with a median uncertainty of 1.1mas. The parallaxes show reasonable agreement with the Tycho-Gaia Astrometric Solution, though caution is advised for data with modest significance. The SQL data base housing the data is made available via the web. We give example applications for studies of Galactic structure, nearby objects (low-mass stars and brown dwarfs, subdwarfs, white dwarfs) and kinematic distance measurements of young stellar objects. Nearby objects discovered include LTT 7251 B, an L7 benchmark companion to a G dwarf with over 20 published elemental abundances, a bright L subdwarf, VVV 1256-6202, with extremely blue colours and nine new members of the 25pc sample. We also demonstrate why this catalogue remains useful in the era of Gaia. Future versions will be based on profile fitting photometry, use the Gaia absolute reference frame and incorporate the longer time baseline of the VVV extended survey.
- ID:
- ivo://CDS.VizieR/J/AJ/108/1598
- Title:
- Virgo cluster ellipticals. III.
- Short Name:
- J/AJ/108/1598
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have used the Planetary Camera on the Hubble Space Telescope to study the morphology and surface brightness parameters of a luminosity- limited sample of fourteen elliptical galaxies in the Virgo cluster. The total apparent blue magnitudes of the galaxies range between 9.4 and 13.4. In this paper, the core brightness profiles are presented, while the overall morphology and the isophotal shapes are discussed in two companion papers [Jaffe et al. AJ, 108, 1567 (1994); van den Bosch et al. AJ, 108, 1579 (1994)]. We show that, in spite of the spherical aberration affecting the HST primary mirror, deconvolution techniques allow recovery of the brightness profile up to 0.2arcsec from the center of the galaxies. We find that none of the galaxies has an isothermal core. On the basis of their morphological and photometrical properties, the galaxies can be divided in two physically distinct groups, referred to as Type I and Type II. All of the Type I galaxies are classified as E1 to E3 in the Revised Shapley Ames Catalog (Sandage & Tammann 1981), while Type II galaxies are classified as E5 to E7. The characteristics of Type II galaxies are explained by the presence of disks component on both the 1 arcsec and the 10 arcsec scales, while Type I galaxies correspond to the classical disk-free ellipticals.
- ID:
- ivo://CDS.VizieR/J/ApJ/806/133
- Title:
- Virgo cluster ETGs: GC and galaxy diffuse light
- Short Name:
- J/ApJ/806/133
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a kinematic analysis of the globular cluster (GC) systems and diffuse stellar light of four intermediate luminosity (sub-L*) early-type galaxies in the Virgo cluster based on Gemini Multi-Object Spectrographs (GMOS) data. Our galaxy sample is fainter (-23.8<M_K_<-22.7) than most previous studies, nearly doubling the number of galaxies in this magnitude range that now have GC kinematics. The data for the diffuse light extends to 4R_e_, and the data for the GCs reaches 8-12R_e_. We find that the kinematics in these outer regions are all different despite the fact that these four galaxies have similar photometric properties, and are uniformly classified as "fast rotators" from their stellar kinematics within 1R_e_. The GC systems exhibit a wide range of kinematic morphology. The rotation axis and amplitude can change between the inner and outer regions, including a case of counter-rotation. This difference shows the importance of wide-field kinematic studies, and shows that stellar and GC kinematics can change significantly as one moves beyond the inner regions of galaxies. Moreover, the kinematics of the GC systems can differ from that of the stars, suggesting that the formation of the two populations are also distinct.
- ID:
- ivo://CDS.VizieR/J/ApJS/111/143
- Title:
- Virgo cluster ultraviolet sources
- Short Name:
- J/ApJS/111/143
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We analyze three UV images covering a ~100 square degree field toward the Virgo cluster, obtained by the FAUST space experiment. We detect 191 sources to a signal-to-noise ratio of 4.4 and identify 94% of them. Most sources have optical counterparts in existing catalogs, and about half are identified as galaxies. Some sources with no listed counterpart were observed at the Wise Observatory. We present the results of low-resolution visible spectrophotometry and discuss the foreground 101 stellar sources and the 76 detected galaxies, both in the cluster and in the foreground or background. We derive conclusions on star formation properties of galaxies and on the total UV flux from discrete and diffuse sources in the cluster. We test for the presence of intracluster dust, determine the clustering properties of UV emitting galaxies, and derive the UV luminosity function of Virgo galaxies.
- ID:
- ivo://CDS.VizieR/J/A+A/538/A69
- Title:
- Virgo early-type galaxies optical properties
- Short Name:
- J/A+A/538/A69
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Studies of dwarf spheroidal (dSph) galaxies with statistically significant sample sizes are still rare beyond the Local Group, since these low surface brightness objects can only be identified with deep imaging data. In galaxy clusters, where they constitute the dominant population in terms of number, they represent the faint end slope of the galaxy luminosity function and provide important insight on the interplay between galaxy mass and environment. In this study we investigate the optical photometric properties of early-type galaxies (dwarf ellipticals (dEs) and dSphs) in the Virgo cluster core region, by analysing their location on the colour magnitude relation (CMR) and the structural scaling relations down to faint magnitudes, and by constructing the luminosity function to compare it with theoretical expectations.
