- ID:
- ivo://CDS.VizieR/J/ApJ/801/69
- Title:
- Iron EWs for 21 giant star members of NGC3201
- Short Name:
- J/ApJ/801/69
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- NGC 3201 is a globular cluster suspected to have an intrinsic spread in the iron content. We re-analyzed a sample of 21 cluster stars observed with UVES-FLAMES at the Very Large Telescope and for which Simmerer et al. (2013ApJ...764L...7S) found a 0.4dex wide [Fe/H] distribution with a metal-poor tail. We confirmed that when spectroscopic gravities are adopted, the derived [Fe/H] distribution spans ~0.4dex. On the other hand, when photometric gravities are used, the metallicity distribution from Fe I lines remains large, while that derived from Fe II lines is narrow and compatible with no iron spread. We demonstrate that the metal-poor component claimed by Simmerer et al. (2013ApJ...764L...7S) is composed by asymptotic giant branch stars that could be affected by non-local thermodynamical equilibrium effects driven by iron overionization. This leads to a decrease of the Fe I abundance, while leaving the Fe II abundance unaltered. A similar finding has been already found in asymptotic giant branch stars of the globular clusters M5 and 47 Tucanae. We conclude that NGC 3201 is a normal cluster, with no evidence of intrinsic iron spread.
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- ID:
- ivo://CDS.VizieR/J/MNRAS/351/1204
- Title:
- IR Photometry of 10 Galactic Globular Clusters
- Short Name:
- J/MNRAS/351/1204
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The IR catalogs of the observed clusters are based on ground-based observations using the near-IR camera IRAC2@ESO/MPI 2.2m equipped with a NICMOS-3 256x256 array detector. By using two different magnifications: 0.28"/pix and 0.51"/pix a total FoV of 4'x4' has been covered. The instrumental magnitudes have been calibrated into the 2MASS photometric system and astrometrically corrected by using 2MASS catalogs, with an accuracy of <0.2arcsec.
- ID:
- ivo://CDS.VizieR/J/AJ/131/1416
- Title:
- IR Photometry of nearby globular clusters
- Short Name:
- J/AJ/131/1416
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We compare the near-infrared (JHK) globular cluster luminosity functions (GCLFs) of the Milky Way, M31, and the Sculptor Group spiral galaxies. We obtained near-infrared photometry with the Persson's Auxiliary Nasmyth Infrared Camera on the Baade Telescope for 38 objects (mostly globular cluster candidates) in the Sculptor Group. We also have near-infrared photometry from the Two Micron All Sky Survey (2MASS)-6X database for 360 M31 globular cluster candidates and aperture photometry for 96 Milky Way globular cluster candidates from the 2MASS All-Sky and Second Incremental Release databases.
- ID:
- ivo://CDS.VizieR/J/AJ/109/1131
- Title:
- JHK Photometry in Metal Rich Globulars.
- Short Name:
- J/AJ/109/1131
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- As a first step in investigating the properties of heavily reddened, metal-rich globular clusters, we present JHK colors and magnitudes for four objects: NGC 5927, NGC 6712, NGC 6838 (M71), and Terzan 2. These data begin near the top of the giant branch (GB) and extend to stars six magnitudes fainter, reaching below the horizontal branch (HB). We use our sample and previously published data for two other clusters, 47 Tucanae and M69, to develop techniques for deriving basic properties such as metallicity and distance modulus from observable parameters of cluster color-magnitude diagrams (CMDs) in the near-IR. We also analyze the horizontal branches of the clusters in an attempt to set constraints on mass loss for first-ascent giants. We find that the slope of the linear fit to the GB stars brighter than the HB can be used to predict metallicity to an accuracy of +/- 0.25 dex for clusters with [Fe/H] between -1.0 and -0.3. There appears to be no significant dependence on [Fe/H] for other reddening-free indices measured from the CMD, including the width of the HB and the separation between the GB and HB at the level of the HB. Using the clusters in our sample that have known distances, we derive a value of <M_K0(HB)> = -1.15 +/- 0.10 for the extinction-corrected absolute K magnitude of the HB. This provides a means of determining the distance to clusters for which only infrared CMDs are available. We derive a distance modulus to Terzan 2 of 14.37 +/- 0.2 which places it within a few hundred parsecs of the galactic center. In the J-H,H-K diagram, Terzan 2 giants are located near the Baade's Window giants rather than in the region populated by nearly all other globular cluster stars. The GB of stars in the field around Terzan 2 has a slope that implies [Fe/H] = +0.1, comparable to that in Baade's Window.
- ID:
- ivo://CDS.VizieR/J/MNRAS/402/1729
- Title:
- JHK photometry of 36 Galactic globular clusters
- Short Name:
- J/MNRAS/402/1729
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present near-infrared colour-magnitude diagrams and physical parameters for a sample of 12 galactic globular clusters located towards the inner bulge region. For each cluster we provide measurements of the reddening, distance and photometric metallicity and of the luminosity of the horizontal branch red clump and the red giant branch bump and tip. The sample discussed here, together with that presented in Valenti, Ferraro & Origlia (2007, Cat. J/AJ/133/1287), represents the largest homogeneous catalogue of bulge globular clusters (comprising ~80 per cent of the entire bulge cluster population) ever studied. The compilation is available in electronic form on the World Wide Web (http://www.bo.astro.it/~GC/ir_archive).
- ID:
- ivo://CDS.VizieR/J/AJ/133/1287
- Title:
- JHK photometry of 24 Galactic globular clusters
- Short Name:
- J/AJ/133/1287
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present near-IR color-magnitude diagrams and physical parameters for a sample of 24 Galactic globular clusters toward the bulge. In this paper we discuss the properties of 12 new clusters (out of the 24) in addition to those previously studied and published by our group. The compilation includes measurements of the cluster reddening, distance, photometric metallicity, horizontal branch red clump, and red giant branch morphological (e.g., mean ridgelines) and evolutionary (e.g., bump and tip) features. The compilation is available in electronic form on the World Wide Web, and it will be updated regularly.
- ID:
- ivo://CDS.VizieR/J/AJ/110/2844
- Title:
- JHK photometry of globular clusters. III.
- Short Name:
- J/AJ/110/2844
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new JHK photometry for the disk globular clusters NGC 6440 and NGC 6624. These data are initially used to confirm and refine several important results from Kuchinski et al. (1995AJ....109.1131K) for other disk globular. First, we again demonstrate the ability to derive a reddening-independent estimate for the [Fe/H] of a cluster from the slope if its giant branch (GB) in a K, J-K color magnitude diagram (CMD). Second, the reddening corrected J-K color and K magnitude of the center of the horizontal branch (HB) and the J-K color of its red edge are confirmed to be independent of [Fe/H] for these clusters. Thus these parameters can be used to estimate E(J-K) of metal-rich clusters with no knowledge of distance or [Fe/H] and to estimate (m-M) if one can first estimate the reddening. We also confirm that the reddening-independent quantities, the half width of a cluster's horizontal branch (HB), and the color difference between the center of the HB and the GB at the level of the HB, both appear to be insensitive to metallicity. The JHK colors of NGC 6440 are similar to those of Liller 1; in both cases these colors are unlike those seen for other globular clusters, field giants, or bulge giants. We have not been able to identify any other cluster parameter that would help to explain these anomalous colors. We have assembled V photometry from the literature for the clusters in our sample and VK photometry for two additional disk globular clusters from Davidge et al. (1992ApJS...81..251D). We conclude that K, J-K CMDs are preferable to K, V-K CMDs as tools to study basic cluster properties. Finally, we compare our data with theoretical isochrones for metal-rich clusters and present observational evidence that the dependence of the V-K color of the GB on [Fe/H] may be different for halo and disk globular clusters. This difference may be related to differences in the [O/Fe] values for the two cluster systems.
- ID:
- ivo://CDS.VizieR/J/AJ/148/4
- Title:
- JHK photometry of 913 globular clusters in M31
- Short Name:
- J/AJ/148/4
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present Two Micron All Sky Survey JHK_s_ photometry for 913 star clusters and candidates in the field of M31, which are selected from the latest Revised Bologna Catalog of M31 globular clusters (GCs) and candidates. The photometric measurements in this paper supplement this catalog, and provide the most comprehensive and homogeneous photometric catalog for M31 GCs in the JHK_s_bandpasses. In general, our photometry is consistent with previous measurements. The globular cluster luminosity function (GCLF) peaks for the confirmed GCs derived by fitting a t_5_distribution using the maximum likelihood method are J_0_=15.348_-0.208_^+0.206^, H_0_=14.703_-0.180_^+0.176^, and K_s0_=14.534_-0.146_^+0.142^, all of which agree well with previous studies. The GCLFs are different between metal-rich (MR) and metal-poor (MP), and between inner and outer subpopulations, as MP clusters are fainter than their MR counterparts and the inner clusters are brighter than the outer ones, which confirm previous results. The NIR colors of the GC candidates are on average redder than those of the confirmed GCs, which leads to an obscure bimodal distribution of color indices. The relation of (V-K_s_)_0_ and metallicity shows a notable departure from linearity, with a shallower slope toward the redder end. The color-magnitude diagram (CMD) and color-color diagram show that many GC candidates are located out of the evolutionary tracks, suggesting that some of them may be false M31 GC candidates. The CMD also shows that the initial mass function of M31 GCs covers a large range, and the majority of the clusters have initial masses between 10^3^ and 10^6^M_{sun}_.
- ID:
- ivo://CDS.VizieR/J/AJ/109/1154
- Title:
- JHK Photometry of Liller 1
- Short Name:
- J/AJ/109/1154
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the first color-magnitude diagram of Liller 1, a globular cluster with an angular separation of only 5 deg from the galactic center and a latitude of 0.2 deg. We estimate a metallicity for this cluster of [Fe/H] = +0.25 +/- 0.3 based on the slope of Liller 1's giant branch in the near-infrared. This implies that Liller 1 is the most metal rich galactic globular cluster known. Any reasonable uncertainty in the age of the cluster will not affect our method for deriving the metallicity. We also conclude that for Liller 1 E(J-K) = 1.70 +/- 0.06 (or A_V ~ 9.5) and (m-M)0 = 14.68 +/- 0.23. The atypical JHK colors of the Liller 1 stars, the extreme slope of its giant branch, and its physical closeness to the galactic center raise the question of whether it is a normal globular cluster or if its formation and evolution have been strongly influenced by its proximity to the galactic center.
- ID:
- ivo://CDS.VizieR/J/AJ/129/2714
- Title:
- JHK photometry of M92 variable stars
- Short Name:
- J/AJ/129/2714
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present near-infrared (NIR) J-, H-, and K-band time series observations of the Galactic globular cluster (GGC) M92.
