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- ID:
- ivo://CDS.VizieR/J/A+A/543/A75
- Title:
- Near-IR spectra of LMC globular clusters
- Short Name:
- J/A+A/543/A75
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The rest-frame near-IR spectra of intermediate age (1-2Gyr) stellar populations are dominated by carbon based absorption features offering a wealth of information. Yet, spectral libraries that include the near-IR wavelength range do not sample a sufficiently broad range of ages and metallicities to allow for accurate calibration of stellar population models and thus the interpretation of the observations. In this paper we investigate the integrated J- and H-band spectra of six intermediate age and old globular clusters in the Large Magellanic Cloud (LMC).
- ID:
- ivo://CDS.VizieR/J/ApJ/578/405
- Title:
- Neutron stars in NGC 5139
- Short Name:
- J/ApJ/578/405
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Chandra/ACIS-I detectors observed NGC 5139 in imaging mode for two continuous periods (2000 January 24 02:15-09:46 and January 25 04:33-17:24 TT) for a total exposure of ~68.6ks. We combined the two observations and analyzed them as one. We searched for point sources using CELLDETECT, using only the 0.1-2.5keV energy range, excluding regions less than 16 pixels from the detector edges and keeping only sources with signal-to-noise ratio (S/N)>5.0. We find 40 X-ray point sources over the four ACIS-I chips and chip S2 of ACIS-S, which are numbered in order of decreasing S/N in Table 1.
- ID:
- ivo://CDS.VizieR/J/AJ/143/84
- Title:
- New candidate globular clusters in NGC 5128
- Short Name:
- J/AJ/143/84
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have used new wide-field imaging with the Magellan IMACS camera to search for globular cluster (GC) candidates around NGC 5128, the nearest giant E galaxy. The imaging data are in the B and R broadband filters and cover a 1.55 deg^2^ field centered on the galaxy, corresponding to an area about 90*90kpc^2^ at the distance of NGC 5128. All the fields were taken under exceptionally high-quality seeing conditions (FWHM=0.4-0.5" in R). Using this material we are able, for the first time in the literature, to construct a homogeneous list of GC candidates covering a wide span of the NGC 5128 halo and unusually free of field contaminants (foreground stars and faint background galaxies). Selecting the measured objects by color, magnitude, ellipticity, and profile size gives us a final catalog of 833 new high-quality GC candidates brighter than R=21 (0.8mag fainter than the standard GC luminosity function turnover point). The measured positions have better than 0.2" precision in both coordinates.
- ID:
- ivo://CDS.VizieR/J/A+A/590/A13
- Title:
- New candidate members in young associations
- Short Name:
- J/A+A/590/A13
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The young associations offer us one of the best opportunities to study the properties of young stellar and sub-stellar objects and directly image planets thanks to their proximity (<200pc) and age (5-150Myr). However, many previous works have been limited to identifying the brighter, more active members (1Msun) due to photometric survey sensitivities limiting the detections of lower-mass objects. We search the field of view of 542 previously identified members of the young associations to identify wide / extremely wide (1000-100,000au in physical separation) companions. Methods. We have combined 2MASS near-infrared photometry (J, H, K) with proper motion values (from UCAC4, PPMXL, NOMAD) to identify companions in the field of view of known members. We collated further photometry and spectroscopy from the literature and conducted our own high-resolution spectroscopic observations for a sub-sample of candidate members. This complementary information allowed us to assess the efficiency of our method. We identified 84 targets (45:0.2-1.3M_{sun}_, 17:0.08-0.2M_{sun}_, 22:<0.08M_{sun}_) in our analysis, 10 of which have been identified from spectroscopic analysis in previous young association works. For 33 of these 84 we were able to further assess their membership using a variety of properties (X-ray emission, UV excess, H{alpha}, lithium and KI equivalent widths, radial velocities, and CaH indices). We derive a success rate of 76-88% for this technique based on the consistency of these properties. Once confirmed, the targets identified in this work would significantly improve our knowledge of the lower-mass end of the young associations. Additionally, these targets would make an ideal new sample for the identification and study of planets around nearby young stars. Given the predicted sub-stellar mass of the majority of these new candidate members and their proximity, high-contrast imaging techniques would facilitate the search for new low-mass planets.
- ID:
- ivo://CDS.VizieR/J/AJ/134/706
- Title:
- New globular clusters in M 31
- Short Name:
- J/AJ/134/706
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the result of a wide-field survey of globular clusters (GCs) in M31 covering a 3{deg}x3{deg} field centered on M31. We have searched for GCs on CCD images taken with Washington CMT1 filters at the KPNO 0.9m telescope using the following steps: (1) inspection of morphological parameters given by the SExtractor package such as stellarity, full width at half-maximum, and ellipticity; (2) consulting the spectral types and radial velocities obtained from spectra taken with the Hydra spectrograph at the WIYN 3.5m telescope; and (3) visual inspection of the images of each object. We have found 1164 GCs and GC candidates, of which 605 are newly found GCs and GC candidates and 559 are previously known GCs. Among the new objects there are 113 genuine GCs, 258 probable GCs, and 234 possible GCs, according to our classification criteria. Among the known objects there are 383 genuine GCs, 109 probable GCs, and 67 possible GCs. In total there are 496 genuine GCs, 367 probable GCs, and 301 possible GCs. Most of these newly found GCs have T1 magnitudes of 17.5-19.5mag [17.9<V<19.9mag assuming (C-T1)~1.5], and (C-T1) colors in range 1-2.
- ID:
- ivo://CDS.VizieR/J/ApJ/900/95
- Title:
- New M87 GCs metallicities from Keck & MMT sp.
- Short Name:
- J/ApJ/900/95
- Date:
- 13 Jan 2022 00:22:24
- Publisher:
- CDS
- Description:
- We present an extensive study of spectroscopically derived chemical abundances for M87 and its globular cluster (GC) system. Using observations from the Mitchell spectrograph at McDonald, LRIS at Keck, and Hectospec on the MMT, we derive new metallicity gradients from ~2 to 140kpc. We use a novel hierarchical statistical framework to simultaneously separate the GC system into subpopulations while measuring the metallicity gradients of those subpopulations. We create physically motivated spectral stacks of the GC subpopulations by leveraging the output of this statistical framework to perform the first application of abundance tagging in a massive early-type galaxy to better constrain the origins of the GC subpopulations and thus the assembly history of M87. We find a metal-poor, {alpha}-enhanced population of GCs in both the inner and outer halos unanticipated by current cosmological simulations of galaxy evolution. We use the remarkably flat metallicity gradients we find for both the metal-rich and metal-poor GC subpopulations in the inner halo as tentative evidence that some amount of the metal-poor GCs formed directly in the halo of M87 at high redshift.
- ID:
- ivo://CDS.VizieR/J/AJ/154/57
- Title:
- New SDSS and Washington photometry in Segue 3
- Short Name:
- J/AJ/154/57
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new SDSS and Washington photometry of the young outer-halo stellar system Segue 3. Combined with archival VI-observations, our most consistent results yield Z=0.006+/-0.001, log(Age)=9.42+/-0.08, (m-M)_0_=17.35+/-0.08, and E(B-V)=0.09+/-0.01, with a high binary fraction of 0.39+/-0.05 derived using the Padova models. We confirm that mass-segregation has occurred, supporting the hypothesis that this cluster is being tidally disrupted. A three-parameter King model yields a cluster radius of r_cl_=0.017{deg}+/-0.007{deg}, a core radius of r_c_=0.003{deg}+/-0.001{deg}, and a tidal radius of r_t_=0.04{deg}+/-0.02{deg}. A comparison of Padova and Dartmouth model-grids indicates that the cluster is not significantly {alpha}-enhanced, with a mean [Fe/H]=-0.55_-0.12_^+0.15^dex, and a population age of only 2.6+/-0.4Gyr. We rule out a statistically significant age spread at the main-sequence turnoff because of a narrow subgiant branch, and discuss the role of stellar rotation and cluster age, using Dartmouth and Geneva models: approximately 70% of the Seg 3 stars at or below the main-sequence turnoff have enhanced rotation. Our results for Segue 3 indicate that it is younger and more metal-rich than all previous studies have reported to date. From colors involving Washington C and SDSS-u filters, we identify several giants and a possible blue straggler for future follow-up spectroscopic studies, and we produce spectral energy distributions of previously known members and potential Segue 3 sources with Washington (CT_1_), Sloan (ugri), and VI-filters. Segue 3 shares the characteristics of unusual stellar systems that have likely been stripped from external dwarf galaxies as they are being accreted by the Milky Way, or that have been formed during such an event. Its youth, metallicity, and location are all inconsistent with Segue 3 being a cluster native to the Milky Way.
- ID:
- ivo://CDS.VizieR/J/A+A/373/899
- Title:
- New variables in M22 globular cluster
- Short Name:
- J/A+A/373/899
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- File table1 contains equatorial coordinates for 36 newly identified variables from the central field of the globular cluster M22. File table2 contains basic photometric data for SX Phe stars reported in the paper. File table3 contains magnitudes and colors for selected sample of new variables. Files table4-39 contain V-band time-series photometry for 36 newly identified variables from the central field of the globular cluster M22. Individual finding charts for new variables are in fig directory; each chart is 33arcsec on a side with north up and east to the left.
- ID:
- ivo://CDS.VizieR/J/other/IBVS/6137
- Title:
- New variables in M5 (NGC 5904)
- Short Name:
- J/other/IBVS/613
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report twelve variables not previously detected in the globular cluster M5 (NGC 5904); one SX Phe and eleven semi-regular variables (SR). Their identifications, equatorial coordinates, ephemerides, and light curves are given. Furthermore, we have explored the light curves of a group of stars whose variability has not been confirmed and that are marked as probable non-variables in the CVSGC. Finally, we offer detailed identifications for some of the known variables in crowded regions that were misidentified in previous studies. We shall also address the cases of the cataclysmic variable or U Gem type V101 and of the variable blue straggler V159.
