- ID:
- ivo://CDS.VizieR/J/A+A/565/A8
- Title:
- Stroemgren photometry near NGC 6528
- Short Name:
- J/A+A/565/A8
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present Stroemgren and near-infrared (NIR) photometry of the bulge cluster NGC 6528 and its surrounding field in Baade's Window. uvby images were collected with EFOSC2 on the New Technology Telescope (NTT, La Silla, ESO). The NIR catalogs are based on J,K-band VIRCAM at VISTA (Paranal, ESO) and SOFI at NTT photometry. We matched the aforementioned data sets with Hubble Space Telescope photometry to obtain proper-motion-cleaned samples of NGC 6528 and bulge stars. Furthermore, we were able to correct the Stroemgren-NIR photometry for differential reddening. The huge color sensitivity of the Stroemgren-NIR color-magnitude-diagrams (CMDs) helped us in separating age and metallicity effects.
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- ID:
- ivo://CDS.VizieR/J/MNRAS/474/4438
- Title:
- Stroemgren photometry of M13
- Short Name:
- J/MNRAS/474/4438
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a photometric study of M13 multiple stellar populations over a wide field of view, covering approximately 6.5 half-light radii, using archival Isaac Newton Telescope observations to build an accurate multiband Stroemgren catalogue. The use of the Stroemgren index cy permits us to separate the multiple populations of M13 on the basis of their position on the red giant branch. The comparison with medium and high resolution spectroscopic analysis confirms the robustness of our selection criterion. To determine the radial distribution of stars in M13, we complemented our data set with Hubble Space Telescope observations of the cluster core, to compensate for the effect of incompleteness affecting the most crowded regions. From the analysis of the radial distributions, we do not find any significant evidence of spatial segregation. Some residuals may be present in the external regions where we observe only a small number of stars. This finding is compatible with the short dynamical time-scale of M13 and represents, to date, one of the few examples of fully spatially mixed multiple populations in a massive globular cluster.
- ID:
- ivo://CDS.VizieR/J/AJ/119/1225
- Title:
- Stroemgren photometry of Omega Cen and NGC 6397
- Short Name:
- J/AJ/119/1225
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have observed (with vby filters) a field north of the core of the most massive globular cluster in our galaxy, {omega} Centauri. We have found a correlation of age and metallicity in a region that avoids the dense core and the inhomogeneous foreground dust emission shown by IRAS. Our observations show that the comparatively metal-rich stars (as defined by the b-y and m_1_ colors) are younger than the metal-poor stars by at least 3 Gyr.
- ID:
- ivo://CDS.VizieR/J/ApJ/706/1277
- Title:
- Stromgren photometry in {omega} Cen
- Short Name:
- J/ApJ/706/1277
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new intermediate-band Stromgren photometry based on more than 300 u, v, b, y images of the Galactic globular cluster {omega} Cen. Optical data were supplemented with new multiband near-infrared (NIR) photometry (350 J, H, Ks images). The final optical-NIR catalog covers a region of more than 20x20arcmin squared across the cluster center. We use different optical-NIR color-color planes together with proper-motion data available in the literature to identify candidate cluster red-giant (RG) stars. By adopting different Stromgren metallicity indices, we estimate the photometric metallicity for ~4000 RGs, the largest sample ever collected. We identify four distinct subpopulations, namely, MP ([Fe/H]<=-1.49), metal-intermediate (MI; -1.49<[Fe/H]<=-0.93), metal-rich (MR; -0.95<[Fe/H]<=-0.15), and solar metallicity ([Fe/H]~0). The last group includes only a small fraction of stars (~8%+/-5%) and should be confirmed spectroscopically. Moreover, using the difference in metallicity based on different photometric indices, we find that the 19%+/-1% of RGs are candidate CN-strong stars.
- ID:
- ivo://CDS.VizieR/J/MNRAS/458/4162
- Title:
- Stromgren photometry of M3 (NGC5272)
- Short Name:
- J/MNRAS/458/4162
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present Stroemgren photometry of the Galactic Globular Cluster M3 to study its multiple generations phenomenon. The use of different colour-magnitude diagrams (CMDs) and especially of the notoriously efficient c_y_ index allowed us to detect a double red giant branch in the cluster CMD. After decontamination from fore- and background sources, the two sequences turned out to be equally populated. The two components also show a bimodal radial distribution well corresponding to that predicted by numerical simulations for clusters living in an intermediate dynamical evolutive state and with a population with modified chemical composition that was born more centrally concentrated than the primordial. The analysis of high-resolution spectra quantitatively demonstrates that the two detected sequences correspond to the first (Na-poor) generation and the second (Na-rich) generation, thus confirming the importance of synergy between photometry and spectroscopy.
- ID:
- ivo://CDS.VizieR/J/AJ/120/3111
- Title:
- Stromgren photometry of NGC 6397
- Short Name:
- J/AJ/120/3111
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- CCD photometry extending below the turnoff of the globular cluster NGC 6397 on the uvbyH{beta} system is presented and analyzed. Restricting the sample to stars with small photometric errors and highly probable cluster membership, the reddening from approximately 1500 stars at the turnoff is E(b-y)=0.127+/-0.002 (standard error of the mean), equivalent to E(B-V)=0.179+/-0.003. The photometric abundance for the same sample, on the revised spectroscopic scale for globular clusters, is [Fe/H]=-1.82+/-0.04 (standard error of the mean). From 220 cluster red giants, well-defined relations are established for m_1_ and c_1_ as a function of b-y.
- ID:
- ivo://CDS.VizieR/J/AJ/146/20
- Title:
- Structural parameters for 79 globular clusters in M31
- Short Name:
- J/AJ/146/20
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this paper, we present surface brightness profiles for 79 globular clusters in M31, using images observed with the Hubble Space Telescope, some of which are from new observations. The structural and dynamical parameters are derived from fitting the profiles to several different models for the first time. The results show that in the majority of cases, King models fit the M31 clusters just as well as Wilson models and better than S\'ersic models. However, there are 11 clusters best fitted by Sersic models with the Sersic index n>2, meaning that they have cuspy central density profiles. These clusters may be the well-known core-collapsed candidates. There is a bimodality in the size distribution of M31 clusters at large radii, which is different from their Galactic counterparts. In general, the properties of clusters in M31 and the Milky Way fall in the same regions of parameter spaces. The tight correlations of cluster properties indicate a "fundamental plane" for clusters, which reflects some universal physical conditions and processes operating at the epoch of cluster formation.
- ID:
- ivo://CDS.VizieR/J/AJ/131/414
- Title:
- Structural parameters of SMC star clusters
- Short Name:
- J/AJ/131/414
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present structural parameters for 204 stellar clusters in the Small Magellanic Cloud derived from fitting King and Elson, Fall, and Freeman (EFF, 1987ApJ...323...54E) model profiles to the V-band surface brightness profiles as measured from the Magellanic Clouds Photometric Survey images.
- ID:
- ivo://CDS.VizieR/VII/151
- Title:
- Structure Parameters of Galactic Globular Clusters
- Short Name:
- VII/151
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This catalog contains observed and derived structure parameters for 154 galactic globular clusters, 7 dwarf spheroidal satellites of the Galaxy, and 6 globular clusters in the Fornax dwarf spheroids, respectively, in six different files. Files 1-3 (table1a, table1b, & table1c) list observed parameters, including cluster designation in order of right ascension, equatorial coordinates (B1950), apparent level of the cluster horizontal branch, reddening, subgiant branch color, limiting and core angular radii, ellipticities (only for table1b), integrated magnitude and central surface brightness. Files 4-6 (table2a, table2b, & table2c) contain positional and structural data derived from the observational data of table1. These include, for instance, galactic and galactocentric or Cartesian coordinates, heliocentric and galactocentric distances, or angular and projected linear distances, position angle, metallicity, limiting and core radii, central relaxation time scale, central mass density, central velocity dispersion, and central escape velocity. The references (all columns which label start by r_) are not available in electronic form.
- ID:
- ivo://CDS.VizieR/J/AJ/106/604
- Title:
- Study of globular cluster NGC 6366
- Short Name:
- J/AJ/106/604
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The nearby, metal-rich, halo globular cluster NGC 6366 has been observed in order to obtain its color-magnitude diagram and to search for variable stars. THE color-magnitude diagram indicates that the cluster has a reddening E(B-V) of 0.80 (higher than most previous determinations) and a distance of 3.0kpc. The cluster has numerous blue straggler stars.
