- ID:
- ivo://CDS.VizieR/J/A+AS/93/311
- Title:
- Relative proper motions in NGC 362
- Short Name:
- J/A+AS/93/311
- Date:
- 22 Feb 2022
- Publisher:
- CDS
- Description:
- Relative proper motions are determined for stars brighter than B~=17mag in a 1.5{deg}x1.5{deg} field centered on the globular cluster NGC 362. Proper motions and membership probabilities are tabulated for 488 stars within 10.2' of the cluster center. 14 astrographic plates with epoch differences up to 92 years were completely scanned, and each detectable object was stored. Proper motions were computed with an iterative central-overlap technique. A modal proper motion accuracy of 0.9 milliarcsec/year (mas/a) was achieved. NGC 362 appears projected onto the Small Magellanic Cloud (SMC), allowing to measure the proper motion of the cluster relative to extragalactic background stars. SMC stars were identified by position, proper motion and colour; the mean proper motion of these SMC candidates agrees well with the proper motions of SMC members known from the literature. The proper motion of NGC 362 relative to the SMC is +3.5+/-0.8mas/a in right ascension and -2.6+/-0.8mas/a in declination. For reasonable assumptions on the absolute proper motion of the SMC, the absolute proper motion and space motion of NGC 362 are computed. NGC 362 exhibits a highly eccentric orbit, typical for a member of the halo subgroup of the galactic globular cluster system. The perigalactic distance of NGC 362 is very small (<~1kpc), which raises the interesting question of how the cluster can survive the many passages near the galactic bulge over its lifetime.
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- ID:
- ivo://CDS.VizieR/V/143
- Title:
- Revised Bologna Catalog of M31 clusters, V.5
- Short Name:
- V/143
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The dataset lists all the confirmed globular clusters (GC), all the known candidates GCs, and also all the objects that were identified as candidate GCs in the past and were subsequently recognised not to be genuine clusters, each entry being properly classified (GC, candidate GC, foreground star, background galaxy, HII region, etc.). The latter entries are maintained in the catalogue to avoid re-discoveries of objects that may look like M31 GCs and have been already classified as non-GCs. Please take into account the classification flag(s) when you use the RBC.
- ID:
- ivo://CDS.VizieR/J/A+A/471/127
- Title:
- Revised Bologna Catalog of M31 clusters, V.3
- Short Name:
- J/A+A/471/127
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the first results of a large spectroscopic survey of candidate globular clusters located in the extreme outskirts of the nearby M 31 galaxy. The survey is aimed at ascertaining the nature of the selected candidates to increase the sample of confirmed M 31 clusters lying more that 2{deg} away from the center of the galaxy. We obtained low resolution spectra ({lambda}/{Delta}{lambda}~800-1300) of 48 targets selected from the Extended Source Catalogue of 2MASS, as in Galleti et al. (2005A&A...436..535G). The observed candidates have been robustly classified according to their radial velocity and by verifying their extended/point-source nature from ground-based optical images. We have also obtained a spectrum and a radial velocity estimate for the remote M 31 globular discovered by Martin et al. (2006MNRAS.371.1983M).
- ID:
- ivo://CDS.VizieR/J/A+A/416/917
- Title:
- Revised Bologna Catalog of M31 globular clusters
- Short Name:
- J/A+A/416/917
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have identified in the 2MASS database 693 known and candidate globular clusters in M31. The 2MASS J,H,K magnitudes of these objects have been transformed to the same homogeneous photometric system of existing near infrared photometry of M31 globulars, finally yielding J,H,K integrated photometry for 279 confirmed M31 clusters, 406 unconfirmed candidates and 8 objects with controversial classification. Of these objects 529 lacked any previous estimate of their near infrared magnitudes. The newly assembled near infrared dataset has been implemented into a revised version of the Bologna Catalogue of M31 globulars, with updated optical (UBVRI) photometry taken, when possible, from the most recent sources of CCD photometry available in the literature and transformed to a common photometric system. The final Revised Bologna Catalogue (table 2) most comprehensive list presently available of confirmed and candidate M31 globular clusters, with a total of 1164 entries. In particular, it includes 337 confirmed GCs, 688 GC candidates, 10 objects with controversial classification, 70 confirmed galaxies, 55 confirmed stars, and 4 HII regions. Using the newly assembled database we show that the V-K color provides a powerful tool to discriminate between M31 clusters and background galaxies, and we identify a sample of 83 globular cluster candidates, which is not likely to be contaminated by misclassified galaxies.
- ID:
- ivo://CDS.VizieR/J/AJ/155/71
- Title:
- RGB & HB members of the bulge cluster NGC 6569
- Short Name:
- J/AJ/155/71
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Photometric and spectroscopic analyses have shown that the Galactic bulge cluster Terzan 5 hosts several populations with different metallicities and ages that manifest as a double red horizontal branch (HB). A recent investigation of the massive bulge cluster NGC 6569 revealed a similar, though less extended, HB luminosity split, but little is known about the cluster's detailed chemical composition. Therefore, we have used high-resolution spectra from the Magellan-M2FS and VLT-FLAMES spectrographs to investigate the chemical compositions and radial velocity distributions of red giant branch and HB stars in NGC 6569. We found the cluster to have a mean heliocentric radial velocity of -48.8 km/s ({sigma}=5.3 km/s; 148 stars) and <[Fe/H]>=-0.87 dex (19 stars), but the cluster's 0.05 dex [Fe/H] dispersion precludes a significant metallicity spread. NGC 6569 exhibits light- and heavy-element distributions that are common among old bulge/inner Galaxy globular clusters, including clear (anti)correlations between [O/Fe], [Na/Fe], and [Al/Fe]. The light-element data suggest that NGC 6569 may be composed of at least two distinct populations, and the cluster's low <[La/Eu]>=-0.11 dex indicates significant pollution with r-process material. We confirm that both HBs contain cluster members, but metallicity and light-element variations are largely ruled out as sources for the luminosity difference. However, He mass fraction differences as small as {Delta}Y~0.02 cannot be ruled out and may be sufficient to reproduce the double HB.
- ID:
- ivo://CDS.VizieR/J/A+A/590/A9
- Title:
- RGB stars in Galactic GC stellar parameters
- Short Name:
- J/A+A/590/A9
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Globular clusters trace the formation and evolution of the Milky Way and surrounding galaxies, and outline their chemical enrichment history. To accomplish these tasks it is important to have large samples of clusters with homogeneous data and analysis to derive kinematics, chemical abundances, ages and locations. We aim to obtain homogeneous metallicities and alpha-element enhancement for 51 Galactic bulge, disc, and halo globular clusters that are among the most distant and/or highly reddened in the Galaxy's globular cluster system. We also provide membership selection based on stellar radial velocities and atmospheric parameters. The implications of our results are discussed. We observed R~2000 spectra in the wavelength interval 456-586nm for over 800 red giant stars in 51 Galactic globular clusters. We applied full spectrum fitting with the code ETOILE together with libraries of observed and synthetic spectra. We compared the mean abundances of all clusters with previous work and with field stars. We used the relation between mean metallicity and horizontal branch morphology defined by all clusters to select outliers for discussion. [Fe/H], [Mg/Fe], and [alpha/Fe] were derived in a consistent way for almost one-third of all Galactic globular clusters. We find our metallicities are comparable to those derived from high-resolution data to within sigma=0.08dex over the interval -2.5<[Fe/H]<0.0. Further, a comparison of previous metallicity scales with ours yields sigma<0.16dex. We also find that the distribution of [Mg/Fe] and [alpha/Fe] with [Fe/H] for the 51 clusters follows the general trend exhibited by field stars. It is the first time that the following clusters are included in a large sample of homogeneous stellar spectroscopic observations and metallicity derivation: BH 176, Djorg 2, Pal 10, NGC 6426, Lynga 7, and Terzan 8. In particular, the first three clusters only had photometric metallicities previously and the available metallicity for NGC 6426 was based only on integrated spectroscopy and photometry. Two other clusters, HP 1 and NGC 6558, are confirmed as candidates for the oldest globular clusters in the Milky Way. Stellar spectroscopy in the visible at R~2000 for a large sample of globular clusters is a robust and efficient way to trace the chemical evolution of the host galaxy and to detect interesting objects for follow-up at higher-resolution and with forthcoming giant telescopes. The technique used here can also be applied to globular cluster systems in nearby galaxies with current instruments and to distant galaxies with the advent of ELTs.
- ID:
- ivo://CDS.VizieR/J/A+A/413/343
- Title:
- RGB stars in NGC 2808
- Short Name:
- J/A+A/413/343
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of the first observations, taken with FLAMES during Science Verification, of red giant branch (RGB) stars in the globular cluster NGC 2808. A total of 137 stars was observed, of which 20 at high resolution (R=47000) with UVES and the others at lower resolution (R=19000-29000) with GIRAFFE in MEDUSA mode, monitoring ~3mag down from the RGB tip. Spectra were taken of the H{alpha}, Na I D and Ca II H and K lines.
- ID:
- ivo://CDS.VizieR/J/ApJ/704/750
- Title:
- Rotational behavior of metal-poor stars
- Short Name:
- J/ApJ/704/750
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This paper describes the behavior of the rotational velocity in metal-poor stars ([Fe/H]<=-0.5dex) in different evolutionary stages, based on vsini values from the literature. Our sample is comprised of stars in the field and some Galactic globular clusters, including stars on the main sequence, the red giant branch (RGB), and the horizontal branch (HB). The metal-poor stars are, mainly, slow rotators, and their vsini distribution along the HR diagram is quite homogeneous. Nevertheless, a few moderate to high values of vsini are found in stars located on the main sequence and the HB. We show that the overall distribution of vsini values is basically independent of metallicity for the stars in our sample. We present an extensive tabulation of all quantities discussed in this paper, including rotation velocities, temperatures, gravities, and metallicities [Fe/H], as well as broadband magnitudes and colors.
- ID:
- ivo://CDS.VizieR/J/AJ/152/170
- Title:
- RRLs in globulars. IV. UBVRI photometry in Omega Cen
- Short Name:
- J/AJ/152/170
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- New accurate and homogeneous optical UBVRI photometry has been obtained for variable stars in the Galactic globular cluster {omega} Cen (NGC 5139). We secured 8202 CCD images covering a time interval of 24 years and a sky area of 84x48arcmin. The current data were complemented with data available in the literature and provided new, homogeneous pulsation parameters (mean magnitudes, luminosity amplitudes, periods) for 187 candidate {omega} Cen RR Lyrae (RRLs). Among them we have 101 RRc (first overtone) and 85 RRab (fundamental) variables, and a single candidate RRd (double-mode) variable. Candidate Blazhko RRLs show periods and colors that are intermediate between the RRc and RRab variables, suggesting that they are transitional objects. A comparison of the period distribution and the Bailey diagram indicates that RRLs in {omega} Cen show a long-period tail not present in typical Oosterhoff II (OoII) globulars. The RRLs in dwarf spheroidals and in ultra-faint dwarfs have properties between Oosterhoff intermediate and OoII clusters. Metallicity plays a key role in shaping the above evidence. These findings do not support the hypothesis that {omega} Cen is the core remnant of a spoiled dwarf galaxy. Using optical period-Wesenheit relations that are reddening-free and minimally dependent on metallicity we find a mean distance to {omega} Cen of 13.71+/-0.08+/-0.01mag (semi-empirical and theoretical calibrations). Finally, we invert the I-band period-luminosity-metallicity relation to estimate individual RRLs' metal abundances. The metallicity distribution agrees quite well with spectroscopic and photometric metallicity estimates available in the literature.
- ID:
- ivo://CDS.VizieR/J/AJ/155/137
- Title:
- RRLs in globulars. V.{omega} Centauri NIR photometry
- Short Name:
- J/AJ/155/137
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a new complete near-infrared (NIR, JHK_s_) census of RR Lyrae stars (RRLs) in the globular {omega} Cen (NGC 5139). We collected 15472 JHK_s_ images with 4-8 m class telescopes over 15 years (2000-2015) covering a sky area around the cluster center of 60x34 arcmin^2^. These images provided calibrated photometry for 182 out of the 198 cluster RRL candidates with 10 to 60 measurements per band. We also provide new homogeneous estimates of the photometric amplitude for 180 (J), 176 (H) and 174 (K_s_) RRLs. These data were supplemented with single-epoch JK_s_ magnitudes from VHS (Mcmahon et al. 2013Msngr.154...35M) and with single-epoch H magnitudes from 2MASS (Cat. VII/233). Using proprietary optical and NIR data together with new optical light curves (ASAS-SN) we also updated pulsation periods for 59 candidate RRLs. As a whole, we provide JHK_s_ magnitudes for 90 RRab (fundamentals), 103 RRc (first overtones) and one RRd (mixed-mode pulsator). We found that NIR/optical photometric amplitude ratios increase when moving from first overtone to fundamental and to long-period (P>0.7 days) fundamental RRLs. Using predicted period-luminosity-metallicity relations, we derive a true distance modulus of 13.674+/-0.008+/-0.038 mag (statistical error and standard deviation of the median) based on spectroscopic iron abundances, and of 13.698+/-0.004+/-0.048 mag based on photometric iron abundances. We also found evidence of possible systematics at the 5%-10% level in the zero-point of the period-luminosity relations based on the five calibrating RRLs whose parallaxes had been determined with the HST.
