- ID:
- ivo://CDS.VizieR/J/AJ/129/1596
- Title:
- BVI photometric variability survey of M3
- Short Name:
- J/AJ/129/1596
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have conducted a three-band (BVI) variability survey of the globular cluster M3. This is the first three-band survey of the cluster using modern image subtraction techniques. Observations were made over nine nights in 1998 on the 1.2m telescope at the F. L. Whipple Observatory in Arizona. We present photometry for 180 variable stars in the M3 field, 12 of which are newly discovered. New discoveries include six SX Phoenicis-type variables that all lie in the blue straggler region of the color-magnitude diagram, two new first-overtone RR Lyrae variables, a candidate multimode RR Lyrae variable, a detached eclipsing binary, and two unclassified variables. We also provide revised periods for 52 of the 168 previously known variables that we observe.
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- ID:
- ivo://CDS.VizieR/J/AJ/108/555
- Title:
- BVI photometry in globular cluster M68
- Short Name:
- J/AJ/108/555
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A total of 363 CCD frames in the B, V, and I passbands have been used to study the color-magnitude diagram (CMD) and the variable-star population of the metal-poor galactic globular cluster M68 (NGC 4590, C1236-264). Light curves have been prepared for 40 RR Lyrae variables, five of which are new discoveries, and for two probable SX Phe stars. The RR Lyraes have <V>=15.64+/-0.01, and via several methods E(B-V)=0.07+/-0.01. [Fe/H]=-2.1 is adopted. From a comparison with Sandage's data for M3 (NGC 5272, C1339+286), a period shift of Delta(logP)/Delta([Fe/H])=-0.11+/-0.02 is derived, and the mass-to-light parameter is found to be <A>=1.90. RR Lyrae masses are derived from Fourier fits to the light curves, from the RRd variables, and by comparison with HB (horizontal branch) evolutionary models calculated by Dorman. The light-curve structure agrees qualitatively with recent theoretical models. From short exposures, CMDs have been prepared that are complete from the tip of the red giant branch (RGB) to below the level of the HB, while from the long exposures a CMD to V~23 is provided for 7298 stars more than 158 arcsec distant from the cluster center. The HB is skewed to the blue with the eight bluest stars clearly separated from the remainder of the HB stars. This HB gap is at the identical color to that in M15 (NGC 7078, C2127+119), but M68 lacks the extensive population of the very blue HB stars present in M15. The total number of HB stars is deficient with respect to the RGB population, with the ratio of RGB to HB stars R=0.99. There are several likely blue stragglers identified on CMDs of inner annuli, but near to the cluster center photometric errors scatter stars off the main sequence (MS) into this region. The deep CMDs are in excellent agreement with existing CCD CMDs for M68, with the MS turnoff Delta(V)=3.42+/-0.10mag below the HB. Matching the M68 CMD to that for M15 in the subgiant-MS turnoff region shows that the age of M68 is identical to that for M15 to within +/-0.4Gyr.
- ID:
- ivo://CDS.VizieR/J/AJ/134/825
- Title:
- BVI photometry in M55 (NGC 6809)
- Short Name:
- J/AJ/134/825
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have compiled the asymptotic giant, horizontal, and upper red giant branch (AGB, HB, and RGB) stars in the globular cluster M55 (NGC 6809). Using the star counts and the R-parameter we compute the initial helium abundance Y=0.274+/-0.016.
- ID:
- ivo://CDS.VizieR/J/A+A/380/478
- Title:
- BVI photometry in NGC 6101
- Short Name:
- J/A+A/380/478
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We used HST-WFPC2 and the 1.54 Danish ESO-telescope at La Silla (Chile) to obtain photometry for stars located within 200 arcsec from the center of the cluster NGC 6101. HST-WFPC2 data for 1 field centered on the cluster, have been collected during HST-cycle 6. The resulting V, V-I photometry reach a limiting magnitude of V~25.5. Ground observations have been collected on July 1995. The resulting photometry containing the stars simultaneously detected in the V, B and I filters, is characterized by a limiting magnitude of V~22.5.
- ID:
- ivo://CDS.VizieR/J/AJ/110/638
- Title:
- BVI photometry in NGC 1866
- Short Name:
- J/AJ/110/638
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A photometric sequence consisting of 53 stars measured in the V, B, and I bands has been set up in the vicinity of the rich, young Large Magellanic Cloud cluster, NGC 1866. Many of these stars are relatively isolated and are thus suitable for use as local standard stars for photometric studies of the cluster. Color magnitude diagrams to a limit of V=20.5 for various parts of the 13x13arcmin field, centered on the cluster, show that NGC 1866 is embedded in a mix of populations which includes stars younger than the cluster itself, the dominant 0.5-3Gyr population, plus some very old stars represented by four RR Lyrae variables.
- ID:
- ivo://CDS.VizieR/J/MNRAS/349/1278
- Title:
- BVI photometry of M22
- Short Name:
- J/MNRAS/349/1278
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present wide field photometry of the Galactic Globular Cluster M 22 in the B, V and I passbands for more than 186,000 stars. The study is complemented by the photometry in two narrowband filters centered on H{alpha} and the adjacent continuum, and by infrared J, H and K magnitudes derived from the 2 MASS survey for ~2000 stars. Profiting from this huge database, we completely characterized the evolved stellar sequences of the cluster by determining a variety of photometric parameters, including new photometric estimates of the mean metallicity, reddening and distance to the cluster. In particular, from our multi-wavelength analysis, we re-examined the long-standing metallicity spread problem in M 22. According to our dataset, we conclude that most of the observed width of the red giant branch must be due to differential reddening, which amounts to a maximum of {Delta}E(B-V)~0.06, although the presence of a small metallicity spread cannot be completely ruled out. More specifically, the maximum metallicity spread allowed by our data is of the order of {Delta}[Fe/H]~0.1-0.2dex, i.e., not much more than what allowed by the photometric errors. Finally, we identified most of the known variable stars and peculiar objects in our field of view. In particular, we find additional evidence supporting previous optical identifications of the central star of the Planetary Nebula IRAS 18333-2357, which is associated with M 22.
- ID:
- ivo://CDS.VizieR/J/ApJ/611/323
- Title:
- BVI photometry of M5 giant branch stars
- Short Name:
- J/ApJ/611/323
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have tabulated lists of upper red giant, horizontal-, and asymptotic giant branch (RGB, HB, and AGB) stars in the globular cluster M5 that are complete to over 10' from the core for the RGB and AGB samples, and 8' for the HB sample. The large samples give us the most precise value of R_2_=N_AGB_/N_HB_ to date for a single globular cluster (0.176+/-0.018).
- ID:
- ivo://CDS.VizieR/J/PASP/126/733
- Title:
- BVI photometry of M15 stars
- Short Name:
- J/PASP/126/733
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new BVI photometry containing 40,000 stars of the Galactic globular cluster M15 (NGC 7078), covering a 25'x25' area centered on the cluster with a magnitude range from the tip of the red giant branch to 3 mag below the main sequence turnoff. Using {alpha}-enhanced Dartmouth Stellar Evolution Program models, we find an age of 13.0+/-1.0Gyr and distance modulus of (m-M)_V_=15.4+/-0.1 through isochrone fitting. Unlike previous works, we find good agreement between the observed completeness-corrected stellar luminosity function and models.
- ID:
- ivo://CDS.VizieR/J/MNRAS/421/2872
- Title:
- BVI photometry of NGC 4261 globular clusters
- Short Name:
- J/MNRAS/421/2872
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an analysis of the globular cluster (GC) population of the elliptical galaxy NGC 4261 based on Hubble Space Telescope Wide Field Planetary Camera 2 data in the B, V and I bands. We study the spatial distribution of the GCs in order to probe the anisotropy in the azimuthal distribution of the discrete X-ray sources in the galaxy revealed by Chandra images.
- ID:
- ivo://CDS.VizieR/J/MNRAS/357/265
- Title:
- BVI photometry of omega Cen red giants
- Short Name:
- J/MNRAS/357/265
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This catalogue of omega Cen is based on ground-based observations using FORS1@VLT and contains more than 100,000 stars covering an area of 9"x9" around the center of the cluster. The limiting magnitude is V>=21mag and the positional accuracy is better than 0.2" .
