- ID:
- ivo://CDS.VizieR/J/AJ/123/279
- Title:
- VI Photometry and Variables in NGC 3201
- Short Name:
- J/AJ/123/279
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Globular Cluster NGC 3201 was monitored for the existence of variable stars with 16.5<V<20 and 0.2days<period<5days. The files v*.dat contain time-series photometry data in V and I for the 14 variables detected in the field of NGC 3201. Only V6 (a blue straggler contact binary) is a member of the cluster. Due to its low-latitude position, interstellar extinction is present across the field of the cluster. The file phot.dat contains VI photometry data on the monitored stars. These data are NOT corrected for extinction. The variables V7, V8, and V9 were discovered during a follow-up observing run with a different telescope and therefore do not lie in the field covered by phot.dat. Variables V1-V9 are contact system eclipsing binaries, V10 is an RR Lyrae, V11 a semi-detached Algol type binary, V12 a detached binary system, and V13 and V14 are unclassified variable systems.
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- ID:
- ivo://CDS.VizieR/J/A+A/533/A36
- Title:
- VI photometry and velocity map of NGC 6388
- Short Name:
- J/A+A/533/A36
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present results from ground based VLT/FLAMES spectroscopy in combination with HST data for the globular cluster NGC 6388. The aim of this work is to probe whether this massive cluster hosts an intermediate-mass black hole at its center and to compare the results with the expected value predicted by the M-{sigma} scaling relation.
- ID:
- ivo://CDS.VizieR/J/AJ/109/1086
- Title:
- VI Photometry in M54 and Sgr Dwarf Galaxy
- Short Name:
- J/AJ/109/1086
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present VI CCD color-magnitude diagrams for the globular cluster M54 and the Sagittarius dwarf galaxy. These are used to derive the following quantities: [Fe/H] = -1.79 +/- 0.08 for M54 and [Fe/H] = -0.52 +/- 0.09 for Sagittarius. We find a metallicity dispersion of +/- 0.16 dex in M54, and we infer the possible existence of a [Fe/H] ~ -1.3 component in Sagittarius, which may have a metallicity dispersion as well. The mean reddening in the direction of M54 is E(B-V) = 0.13 +/- 0.02. The distances to M54 and Sagittarius, determined using their horizontal branch magnitudes, are identical to within the uncertainties of existing RR Lyrae luminosity-abundance relations. This, together with positional and radial velocity arguments, suggests that M54 is physically associated with Sagittarius. We note that M54 is substantially brighter than the globular cluster members of the Fornax dwarf spheroidal galaxy, and that the metal abundance of Sagittarius is quite high for its estimated absolute magnitude.
- ID:
- ivo://CDS.VizieR/J/AJ/128/224
- Title:
- VI photometry in M33 outer regions
- Short Name:
- J/AJ/128/224
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present deep CCD photometry in the VI passbands using the WIYN 3.5m telescope of a field located approximately 20 southeast of the center of M33; this field includes the region studied by Mould & Kristian in 1986ApJ...305..591M. The color-magnitude diagram (CMD) extends to I~25 and shows a prominent red giant branch (RGB), along with significant numbers of asymptotic giant branch and young main-sequence stars.
- ID:
- ivo://CDS.VizieR/J/A+AS/106/161
- Title:
- (V,I) photometry in NGC 6356 and 47 Tuc
- Short Name:
- J/A+AS/106/161
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- CCD photometry in the VRI and Gunn z bands was obtained for the populous bulge globular cluster NGC 6356. The analysis of the red giant branch indicates that it is metal-rich, intermediate between 47 Tuc and NGC 6528; we estimate [Fe/H]=~-0.4. The red giant clump is clearly detected. The horizontal branch morphology is red and compact. We derive a reddening of E(B-V)=0.2410.04 and a distance d=15.010.4kpc from the Sun. We also present VI colour magnitude diagrams of 47 Tuc for comparison. NGC 6356 and 47 Tuc are important reference objects for studies of more reddened metal-rich bulge clusters.
- ID:
- ivo://CDS.VizieR/J/AJ/112/772
- Title:
- VI photometry in South Galactic Pole
- Short Name:
- J/AJ/112/772
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Catalogs of V and I photometry for two 20 square degree regions near the South Galactic Pole, containing 30,000 and 19,000 stars, have been constructed using a CCD in time delay integration mode. Internal and external comparisons indicate a characteristic photometric accuracy ranging from 0.02mag at V~12 to 0.05 at V~18-18.5.
- ID:
- ivo://CDS.VizieR/J/AJ/116/469
- Title:
- VI photometry of galactic cepheids
- Short Name:
- J/AJ/116/469
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present results of a survey of a 6deg^2^ region near l=60{deg}, b=0{deg} to search for distant Milky Way Cepheids. Few such Cepheids are known at distances >~ R_0_, limiting large-scale Milky Way disk models derived from Cepheid kinematics; this work was designed to find a sample of distant Cepheids for use in such models. The survey was conducted in the V and I bands over eight epochs, to a limiting I~=18, with a total of almost 5 million photometric observations of over 1 million stars. We present a catalog of 578 high-amplitude variables discovered in this field. Cepheid candidates were selected from this catalog on the basis of variability and color change and observed again the following season. We confirm 10 of these candidates as Cepheids with periods from 4 to 8 days, most at distances greater than 3kpc. Many of the Cepheids are heavily reddened by intervening dust, some with implied extinction A_V_>10mag. With a future addition of infrared photometry and radial velocities, these stars alone can provide a constraint on R_0_ to 8% and in conjunction with other known Cepheids should provide good estimates of the global disk potential ellipticity.
- ID:
- ivo://CDS.VizieR/J/A+A/581/A13
- Title:
- VI photometry of globular ESO 37-1
- Short Name:
- J/A+A/581/A13
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In the Milky Way, most globular clusters are highly conspicuous objects that were found centuries ago. However, a few dozen of them are faint, sparsely populated systems that were identified largely during the second half of the past century. One of the faintest is ESO 37-1 (E 3) and as such it remains poorly studied, with no spectroscopic observations published so far although it was discovered in 1976. We investigate the globular cluster E3 in an attempt to better constrain its fundamental parameters. Spectroscopy of stars in the field of E3 is shown here for the first time. Deep, precise VI CCD photometry of E3 down to V~26mag is presented and analysed. Low-resolution, medium signal-to-noise ratio spectra of nine candidate members are studied to derive radial velocity and metallicity. Proper motions from the UCAC4 catalogue are used to explore the kinematics of the bright members of E3. Isochrone fitting indicates that E3 is probably very old, with an age of about 13Gyr; its distance from the Sun is nearly 10kpc. It is also somewhat metal rich with [Fe/H]=-0.7. Regarding its kinematics, our tentative estimate for the proper motions is ({mu}_{alpha}*cos{delta}, {mu}_{delta}_=(-7.0+/-0.8, 3.5+/-0.3)mas/yr (or a tangential velocity of 382+/-79km/s) and for the radial velocity 45+/-5km/s in the solar rest frame. E3 is one of the most intriguing globular clusters in the Galaxy. Having an old age and being metal rich is clearly a peculiar combination, only seen in a handful of objects like the far more conspicuous NGC 104 (47 Tucanae). In addition, its low luminosity and sparse population make it a unique template for the study of the final evolutionary phases in the life of a star cluster. Unfortunately, E3 is among the most elusive and challenging known globular clusters because field contamination severely hampers spectroscopic studies.
- ID:
- ivo://CDS.VizieR/J/AJ/122/2569
- Title:
- VI photometry of NGC 288, 362 and 1851
- Short Name:
- J/AJ/122/2569
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present deep V, I photometry of the globular clusters NGC 288, 362, and 1851 obtained during a single observational run under strictly homogeneous conditions. We use the bimodal horizontal branch (HB) of NGC 1851 as a "bridge" to obtain the optimum relative match between the HBs of NGC 288 and NGC 362. In this way we can effectively remove the uncertainties associated with distance, reddening, and inhomogeneities in the absolute calibration, thus obtaining a very robust, purely differential estimate of the age difference between these two clusters. According to the bridge test, NGC 288 is found to be older than NGC 362 by 2+/-1Gyr. The observations were carried out during the nights of 1997 January 2 and 3 at the 2.2 m ESO/MPI telescope at La Silla (Chile), with the EFOSC2 camera equipped with a Loral/Lesser 2048x2048 pixel CCD. The pixel scale is 0.26"/pix, and the effective field of view is 8x8arcmin^2^. The gain is 1.63 e^-^ADU^-^, and the readout noise is 6.3 e^-^rms. The seeing conditions were average during the January 2 night (~1.3") when the NGC 1851 and NGC 288 observations were carried out, and they worsened (~2") during the second night when we observed NGC 362.
- ID:
- ivo://CDS.VizieR/J/ApJS/116/263
- Title:
- VI photometry of open clusters
- Short Name:
- J/ApJS/116/263
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- New CCD VI photometric data for 10 template open clusters with accurately determined fundamental parameters are presented. From the observed V versus V-I diagrams of the clusters, fiducial sequences have been defined and transformed into the M_v_ versus (V-I)_0_ diagram by averaging sequences of template open clusters with similar ages. The resulting composite Mv versus (V-I)_0_ diagram presents a homogeneous set of empirical isochrones in the age range between 5Myr and 4Gyr. These empirical isochrones show an overall very good agreement with those computed from stellar evolutionary models. Theoretical isochrones with moderate overshooting fit the observed main sequences better than the canonical ones for clusters older than 600Myr. The present set of empirical isochrones will be useful for the study of faint reddened open clusters
