- ID:
- ivo://CDS.VizieR/J/AJ/149/99
- Title:
- VVV globulars. I. 2MASS-GC 02, Terzan 10
- Short Name:
- J/AJ/149/99
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The VISTA Variables in the Via Lactea (VVV) ESO Public Survey is opening a new window to study inner Galactic globular clusters (GCs) using their variable stars. These GCs have been neglected in the past due to the difficulties caused by the presence of elevated extinction and high field stellar densities in their lines of sight. However, the discovery and study of any present variables in these clusters, especially RR Lyrae stars, can help to greatly improve the accuracy of their physical parameters. It can also help to shed some light on the questions raised by the intriguing Oosterhoff dichotomy in the Galactic GC system. In a series of papers we plan to explore variable stars in the GCs falling inside the field of the VVV survey. In this first paper, we search for and study the variables present in two highly reddened, moderately metal-poor, faint, inner Galactic GCs: 2MASS-GC 02 and Terzan 10. We report the discovery of sizable populations of RR Lyrae stars in both GCs. We use near-infrared period-luminosity relations to determine the color excess of each RR Lyrae star, from which we obtain both accurate distances to the GCs and the ratios of the selective-to-total extinction in their directions. We find the extinction toward both clusters to be elevated, non-standard, and highly differential. We also find both clusters to be closer to the Galactic center than previously thought, with Terzan 10 being on the far side of the Galactic bulge. Finally, we discuss their Oosterhoff properties, and conclude that both clusters stand out from the dichotomy followed by most Galactic GCs.
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Search Results
- ID:
- ivo://CDS.VizieR/J/AJ/128/712
- Title:
- Washington Photometry in NGC 5128
- Short Name:
- J/AJ/128/712
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- To investigate the global properties of the globular cluster system (GCS) around NGC 5128, the central giant elliptical galaxy in the nearby Centaurus group, we have obtained deep CCD imaging for an area of almost 2{deg}^2^ centered on the galaxy. Our data, in the CMT_1_ Washington photometric system, reach an approximate limiting magnitude of T_1_~R~22 and contain magnitudes, colors, and coordinates for more than 100,000 objects. Of these, the vast majority (about 99%) are either foreground stars or faint background galaxies; the old-halo globular clusters make up the remaining tiny fraction of the sample. Our database, however, provides the material for understanding the large-scale features of the GCS, including its metallicity distribution (MDF), luminosity distribution, and spatial structure.
- ID:
- ivo://CDS.VizieR/J/AJ/128/723
- Title:
- Washington Photometry in NGC 5128. II
- Short Name:
- J/AJ/128/723
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Building on the CMT_1_ photometric database presented in Paper I (Cat. <J/AJ/128/712>), in this paper we derive the large-scale properties of the globular cluster system (GCS) in NGC 5128, the nearest giant elliptical and the dominant galaxy in the Centaurus group. Using the metallicity-sensitive C-T_1_ color index, we discuss the metallicity distribution function (MDF) for a subsample of 211 previously identified clusters, all on a homogeneous photometric system. We find the MDF to be strongly bimodal, with metallicity peaks at [Fe/H]=-1.55 and -0.55 and with nearly equal numbers of clusters in each of the metal-poor and metal-rich modes. Finally, we present a list of 327 new cluster candidates not identified in any previous surveys; most of these are in the less well studied bulge region of the galaxy and along the minor axis.
- ID:
- ivo://CDS.VizieR/J/AJ/119/1748
- Title:
- WFPC 2 imaging of young LMC clusters
- Short Name:
- J/AJ/119/1748
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have carried out Wide Field Planetary Camera 2 (WFPC2) F160BW, F555W, and F656N imaging of four young populous clusters: NGC 330, in the Small Magellanic Cloud, and NGC 1818, 2004, and 2100, in the Large Magellanic Cloud. We report photometric results for these four clusters, including identification using photometric colors of the cluster Be star population. We present theoretical WFPC2 and broadband colors and bolometric corrections for LMC and SMC metallicities. The use of the far-UV F160BW filter enables accurate determination of the effective temperatures for stars in the vicinity of the main-sequence turnoff and on the unevolved main sequence.
- ID:
- ivo://CDS.VizieR/J/ApJ/632/266
- Title:
- WFPC2 photometry of the globular cluster M5
- Short Name:
- J/ApJ/632/266
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present deep VI photometry of stars in the globular cluster M5 (NGC 5904) based on images taken with the Hubble Space Telescope. The resulting color-magnitude diagram reaches below V~7mag, revealing the upper 2-3mag of the white dwarf cooling sequence and main-sequence stars 8mag and more below the turnoff.
- ID:
- ivo://CDS.VizieR/J/AJ/143/50
- Title:
- White dwarfs in 47 Tuc (NGC 104) with HST
- Short Name:
- J/AJ/143/50
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a new distance determination to the Galactic globular cluster 47 Tucanae (47 Tuc, NGC 104) by fitting the spectral energy distributions of its white dwarfs (WDs) to pure hydrogen atmosphere WD models. Our photometric data set is obtained from a 121-orbit Hubble Space Telescope program using the Wide Field Camera 3 UVIS/IR channels, capturing F390W, F606W, F110W, and F160W images. These images cover more than 60 arcmin^2^ and extend over a radial range of 5-13.7arcmin (6.5-17.9pc) within the globular cluster. Using a likelihood analysis, we obtain a best-fitting unreddened distance modulus of (m-M)_o_=13.36+/-0.02+/-0.06 corresponding to a distance of 4.69+/-0.04+/-0.13kpc, where the first error is random and the second is systematic. We also search the WD photometry for infrared excess in the F160W filter, indicative of low-mass companions, and find no convincing cases within our sample.
- ID:
- ivo://CDS.VizieR/J/A+A/563/A80
- Title:
- Wide field imagers ground-based astrometry. V.
- Short Name:
- J/A+A/563/A80
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- High-precision astrometry requires accurate point-spread function modeling and accurate geometric-distortion corrections. This paper demonstrates that it is possible to achieve both requirements with data collected at the High Acuity Wide-field K-band Imager (HAWK-I); a wide-field imager installed at the Nasmyth focus of UT4/VLT ESO 8m telescope. Our final astrometric precision reaches ~3mas per coordinate for a well exposed star in a single image, with a systematic error less than 0.1mas. We constructed calibrated astro-photometric catalogs and atlases of 7 fields: the Baade's window, NGC 6656, NGC 6121, NGC 6822, NGC 6388, NGC 104, and the James Webb Space Telescope calibration field (in the LMC). We make these catalogs and images electronically available to the community. Furthermore, as a demonstration of the efficacy of our approach, combining archival material taken with the optical wide-field imager at the MPI/ESO 2.2m with HAWK-I observations, we are able to achieve an excellent separation between cluster members and field objects for NGC 6656 and NGC 6121 with a time base-line of about 8 years. Using both HST and HAWK-I data, we also study the radial distribution of the SGB populations in NGC 6656 and conclude that the radial trend is flat, within our uncertains. We also provide membership probabilities for most of the stars in NGC 6656 and NGC 6121 catalogs and estimate membership for the published variable stars in these two fields.
- ID:
- ivo://CDS.VizieR/J/ApJ/819/1
- Title:
- Wide-field photometry of the GC Palomar 5
- Short Name:
- J/ApJ/819/1
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an analysis of wide-field photometric surveys of the Palomar 5 globular cluster and its stellar stream, based on g- and r-band measures together with narrow-band DDO 51 photometry. In this first study, we use the deep (g, r) data to measure the incidence of gaps and peaks along the stream. Examining the star-counts profile of the stream plus contaminating populations, we find no evidence for significant underdensities, and find only a single significant overdensity. This is at odds with earlier studies based on matched-filter maps derived from shallower SDSS data if the contaminating population possesses plausible spatial properties. The lack of substantial substructure along the stream may be used in future dynamical simulations to examine the incidence of dark matter sub-halos in the Galactic halo. We also present a measurement of the relative distances along the stream, which we use to create the deepest wide-field map of this system to date. Universe}
- ID:
- ivo://CDS.VizieR/J/ApJ/835/212
- Title:
- Wide-field spectrosc. survey of GCs in Virgo cluster
- Short Name:
- J/ApJ/835/212
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of a wide-field spectroscopic survey of globular clusters (GCs) in the Virgo cluster. We obtain spectra for 201 GCs and 55 ultracompact dwarfs (UCDs) using Hectospec on the Multiple-Mirror Telescope and derive their radial velocities. We identify 46 genuine intracluster GCs (IGCs), not associated with any Virgo galaxies, using the 3D GMM test on the spatial and radial velocity distribution. They are located at a projected distance 200kpc<~R<~500kpc from the center of M87. The radial velocity distribution of these IGCs shows two peaks, one at v_r_=1023km/s, associated with the Virgo main body, and another at v_r_=36km/s, associated with the infalling structure. The velocity dispersion of the IGCs in the Virgo main body is {sigma}_GC_~314km/s, which is smoothly connected to the velocity dispersion profile of M87 GCs but is much lower than that of dwarf galaxies in the same survey field, {sigma}_dwarf_~608km/s. The UCDs are more centrally concentrated on massive galaxies-M87, M86, and M84. The radial velocity dispersion of the UCD system is much smaller than that of dwarf galaxies. Our results confirm the large-scale distribution of Virgo IGCs indicated by previous photometric surveys. The color distribution of the confirmed IGCs shows a bimodality similar to that of M87 GCs. This indicates that most IGCs are stripped off dwarf galaxies and some off massive galaxies in the Virgo.
- ID:
- ivo://CDS.VizieR/J/ApJS/245/25
- Title:
- WISE Extended Source Catalog (WXSC). I.
- Short Name:
- J/ApJS/245/25
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present mid-infrared photometry and measured global properties of the 100 largest galaxies in the sky, including the well-studied Magellanic Clouds, Local Group galaxies M31 and M33, the Fornax and Virgo galaxy cluster giants, and many of the most spectacular Messier objects (e.g., M51 and M83). This is the first release of a larger catalog of extended sources as imaged in the mid-infrared, called the Wide-field Infrared Survey Explorer (WISE) Extended Source Catalog (WXSC). In this study, we measure their global attributes, including integrated flux, surface brightness, and radial distribution. The largest of the large are the LMC, SMC, and Andromeda galaxy, which are also the brightest mid-infrared galaxies in the sky. We interrogate the large galaxies using WISE colors, which serve as proxies for four general types of galaxies: bulge-dominated spheroidals, intermediate semi-quiescent disks, star-forming (SF) spirals, and AGN-dominated. The colors reveal a tight "sequence" that spans 5 mag in W2-W3 color, ranging from early to late types and low to high SF activity; we fit the functional form given by (W1-W2)=[0.015*e^(W2-W3)/1.38^]-0.08. Departures from this sequence may reveal nuclear, starburst, and merging events. Physical properties and luminosity attributes are computed, notably the diameter, aggregate stellar mass, and dust-obscured star formation activity. To effectively study and compare these galaxy characteristics, we introduce the "pinwheel" diagram, which depicts physical properties with respect to the median value observed for WISE galaxies in the local universe. Utilized with the WXSC, this diagram will delineate between different kinds of galaxies, identifying those with similar star formation and structural properties. Finally, we present the mid-infrared photometry of the 25 brightest globular clusters in the sky, of which many are also the largest and brightest objects orbiting the Milky Way, including Omega Centauri, 47 Tucanae, and a number of famed night-sky targets (e.g., M13).
