- ID:
- ivo://CDS.VizieR/J/A+A/524/A44
- Title:
- CN and CH line strengths in 12 globulars
- Short Name:
- J/A+A/524/A44
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Globular clusters show star-to-star abundance variations for light elements that are not yet well understood. The preferred explanation involves a self-enrichment scenario, within which two subsequent generations of stars co-exist in globular clusters. Observations of chemical abundances in the main sequence and sub-giant branch stars allow us to investigate the signature of this chemically processed material without the complicating effects caused by stellar evolution and internal mixing. Our main goal is to investigate the carbon-nitrogen anti-correlation with low-resolution spectroscopy of 20-50 stars fainter than the first dredge-up in seven Galactic globular clusters (NGC288, NGC1851, NGC5927, NGC6352, NGC6388, and Pal12) with different properties. We complemented our observations with 47Tuc archival data, with four additional clusters from the literature (M15, M22, M55, NGC362), and with additional literature data on NGC288.
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+AS/109/487
- Title:
- Color-magnitude study of M 22
- Short Name:
- J/A+AS/109/487
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A new photographic C-M diagram for the globular cluster M 22 based on automatic plate measurements has been obtained. It reaches the main sequence turn-off at V=~17.1mag, (B-V)=~0.75.
- ID:
- ivo://CDS.VizieR/J/ApJ/743/149
- Title:
- Color-metallicity relations. II. M87 GCs
- Short Name:
- J/ApJ/743/149
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We here propose a new photometric technique to probe the possible nonlinear nature of globular clusters (GCs) color-metallicity relations (CMRs). In essence, a color distribution of GCs is a "projected" distribution of their metallicities. Since the form of CMRs hinges on which color is used, the shape of color distributions varies depending significantly on the colors. Among other optical colors, the u-band related colors (e.g., u-g and u-z) are theoretically predicted to exhibit significantly less inflected CMRs than other preferred CMRs (e.g., for g-z). As a case study, we performed the Hubble Space Telescope (HST)/WFPC2 archival u-band photometry for the M87 (NGC 4486) GC system with confirmed color bimodality. We show that the u-band color distributions are significantly different from that of g-z and consistent with our model predictions. With more u-band measurements, this method will support or rule out the nonlinear CMR scenario for the origin of GC color bimodality with high confidence.
- ID:
- ivo://CDS.VizieR/J/MNRAS/446/369
- Title:
- Colour and spectral index from the SLUGGS survey
- Short Name:
- J/MNRAS/446/369
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- As part of the SAGES Legacy Unifying Globulars and GalaxieS (SLUGGS) survey, we stack 1137 Keck DEIMOS (Deep Imaging Multi-Object Spectrograph) spectra of globular clusters from 10 galaxies to study their stellar populations in detail. The stacked spectra have median signal-to-noise ratios of ~90 {AA}^-1^. Besides the calcium triplet, we study weaker sodium, magnesium, titanium and iron lines as well as the H{alpha} and higher order Paschen hydrogen lines. In general, the stacked spectra are consistent with old ages and a Milky Way-like initial mass function. However, we see different metal line index strengths at fixed colour and magnitude, and differences in the calcium triplet-colour relation from galaxy to galaxy. We interpret this as strong evidence for variations in the globular cluster colour-metallicity relation between galaxies. Two possible explanations for the colour-metallicity relation variations are that the average ages of globular clusters vary from galaxy to galaxy or that the average abundances of light elements (i.e. He, C, N and O) differ between galaxies. Stacking spectra by magnitude, we see that the colours become redder and metal line indices stronger with brighter magnitudes. These trends are consistent with the previously reported `blue tilts' being mass-metallicity relations.
- ID:
- ivo://CDS.VizieR/J/A+AS/102/397
- Title:
- Colour magnitude diagram of M13
- Short Name:
- J/A+AS/102/397
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Two overlapping regions of M13 were observed on April 24, 1989 at the Loiano Observatory with a CDCD camera. A Colour-Magnitude diagram down to the main sequence was derived, as a preliminary search for the blue Horizontal Branch stars in this cluster.
- ID:
- ivo://CDS.VizieR/J/A+A/503/469
- Title:
- Compact clusters in LMC catalogue of stars
- Short Name:
- J/A+A/503/469
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The LMC is an ideal environment for studying stellar MFs, because it contains a large population of compact clusters at different evolutionary stages. We aim to obtain constraints on the initial MFs (IMFs) of our sample clusters on the basis of their present-day MFs, combined with our understanding of their dynamical and photometric evolution. We use Hubble Space Telescope photometry for six rich, compact star clusters in the Large Magellanic Cloud (LMC), with ages ranging from 0.01 to 1.0Gyr, to derive the clusters' stellar mass functions (MFs) at their half-mass radii.
- ID:
- ivo://CDS.VizieR/J/PASJ/56/1025
- Title:
- Compact star clusters in SW field of M31
- Short Name:
- J/PASJ/56/1025
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A survey for compact clusters with a dimension of 10pc order was conducted in an area of about 500 square arc-minutes of the south-west part of the M31 disk, making use of the high-resolution capability of Suprime-Cam. Photometry in the B, V and R broad-bands, and in the R* medium-band centered around H{alpha} with varying apertures was carried out for about 1200 targets, which are related to about 300 compact objects detected in the survey. The results for 101 prominent compact objects are presented as photometric catalogues and morphological atlases, separately for samples with and without strong H{alpha} emission.
- ID:
- ivo://CDS.VizieR/J/ApJ/703/1872
- Title:
- Compact star clusters in the M31 disk
- Short Name:
- J/ApJ/703/1872
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have carried out a survey of compact star clusters (apparent size <~3") in the southwest part of the M31 galaxy, based on the high-resolution Suprime-Cam images (17.5'x28.5'), covering ~15% of the deprojected galaxy disk area. The UBVRI photometry of 285 cluster candidates (V<~20.5mag) was performed using frames of the Local Group Galaxies Survey. The final sample, containing 238 high probability star cluster candidates (typical half-light radius r_h_~1.5pc), was selected by specifying a lower limit of r_h_>~0.15" (>~0.6pc). We derived cluster parameters based on the photometric data and multiband images by employing simple stellar population models. The clusters have a wide range of ages from ~5Myr (young objects associated with 24um and/or H{alpha} emission) to ~10Gyr (globular cluster candidates), and possess mass in a range of 3.0<~log(m/m_{sun}_)<~4.3 peaking at m~4000m_{sun}_. Typical age of these intermediate-mass clusters is in the range of 30Myr<~t<~3Gyr, with a prominent peak at ~70Myr. These findings suggest a rich intermediate-mass star cluster population in M31, which appears to be scarce in the Milky Way galaxy.
- ID:
- ivo://CDS.VizieR/J/MNRAS/403/1592
- Title:
- Cool stars in galactic clusters
- Short Name:
- J/MNRAS/403/1592
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have investigated the relevant trend of the bolometric correction (BC) at the cool-temperature regime of red giant stars and its possible dependence on stellar metallicity. Our analysis relies on a wide sample of optical-infrared spectroscopic observations, along the 3500{AA}=>2.5um wavelength range, for a grid of 92 red giant stars in five (three globular + two open) Galactic clusters, along the full metallicity range covered by the bulk of the stars, -2.2<=[Fe/H]<=+0.4.
- ID:
- ivo://CDS.VizieR/J/A+A/529/A104
- Title:
- Coordinates for Arp's Baade's Window stars
- Short Name:
- J/A+A/529/A104
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Identifications and coordinates for all stars in Arp's (1965ApJ...141...43A) finding chart for Baade's Window. For each star Arp's ID is presented, as are 2MASS and OGLE IDs when matches were found. All OGLE sources are in the BUL SC45 field. Coordinates are from 2MASS when available; for the remaining stars coordinates are calculated as described in the paper. All coordinates are in J2000. We include photometry and photometric errors from 2MASS (JHKs) and OGLE-II (VI); certain flags regarding the quality of the 2MASS photometry are also listed.
