- ID:
- ivo://CDS.VizieR/J/AJ/126/237
- Title:
- BV photometry of LW 55 in LMC
- Short Name:
- J/AJ/126/237
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The field of the moderately old open cluster LW 55 in the outer parts of the Large Magellanic Cloud disk was monitored for detection of short-period variable stars over two nights. Eight variables were found; all but one (a detached eclipsing binary) are small-amplitude ({Delta}V<=0.1mag) pulsating stars of the {delta} Scuti, SX Phoenicis, or Doradus type. The BV color-magnitude diagram extends down to the solar-type stars at V=24 (M_V_~5.2). The cluster age is estimated at 1.5Gyr for Z=0.004 ([Fe/H]=-0.67); the surrounding stellar field is older, with an age greater than 4Gyr.
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142. BV photometry of M71
- ID:
- ivo://CDS.VizieR/J/A+AS/144/227
- Title:
- BV photometry of M71
- Short Name:
- J/A+AS/144/227
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- File table2 contains coordinates (J2000) and B,V magnitudes and B-V colours with corresponding errors of 4450 stars in a 20'x20' region centered on the globular cluster M 71 (NGC 6838). The limiting magnitude of the catalogue is about V=18.0 The observations were made in 1995 at Calar Alta Observatory.
- ID:
- ivo://CDS.VizieR/J/A+A/459/321
- Title:
- BV photometry of M31 eclipsing binaries
- Short Name:
- J/A+A/459/321
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Broad band photometry (in Johnson B and V) has been obtained in a region (34'x34') at the North-Eastern quadrant of M31 over 5 years (1999-2003) at the Isaac Newton Telescope (La Palma, Spain). The data, containing more than 250 observations per filter, have been reduced by means of the so-called difference image analysis technique and the DAOPHOT program. A catalog with 236238 objects with photometry in both B and V passbands has been obtained. The catalog is the deepest (V<25.5mag) obtained so far in the studied region and contains 3964 identified variable stars, with 437 eclipsing binaries and 416 Cepheids.
- ID:
- ivo://CDS.VizieR/J/PASP/119/1233
- Title:
- BV photometry of M11 stars
- Short Name:
- J/PASP/119/1233
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- V-band time-series CCD photometric observations of the intermediate-age open cluster M11 were performed to search for variable stars.
- ID:
- ivo://CDS.VizieR/J/AJ/118/2839
- Title:
- BV photometry of NGC 1866
- Short Name:
- J/AJ/118/2839
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a new deep (down to V~24) photometry of a wide region (~6'x6') around the Large Magellanic Cloud globular cluster NGC 1866. Our sample is much larger (by more than a factor of 3) than any previous photometry and with a main sequence (MS) that may be considered complete, down to at least 3 mag below the brightest MS star; such an occurrence allows a meaningful and robust comparison with various theoretical scenarios produced by means of models computed with the evolutionary code FRANEC.
- ID:
- ivo://CDS.VizieR/J/A+A/431/1189
- Title:
- BV photometry of NGC 6822 variables
- Short Name:
- J/A+A/431/1189
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Deep B, V time-series photometry obtained with the ESO Very Large Telescope has been used to identify variable stars in the dwarf irregular galaxy NGC 6822. We surveyed a 6.8x6.8 arcmin area of the galaxy and detected a total number of 390 candidate variables with the optimal image subtraction technique (Alard C., 2000A&AS..144..363A). Light curves on a magnitude scale were obtained for 262 of these variables. Differential flux light curve are available for the remaining sample. We were able to determine periods and pulsation characteristics for 69 out of the 262 variables with light curves in magnitude scale, they include: 18 RR Lyrae stars (16 ab-type and 2 c-type), 45 Cepheids and 6 binary systems. We also tentatively calibrated 8 of the 128 objects with light curves on a differential flux scale on the assumption that they are ab-type RR Lyrae stars.
- ID:
- ivo://CDS.VizieR/J/MNRAS/350/679
- Title:
- BV photometry of NGC 300 variables
- Short Name:
- J/MNRAS/350/679
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have performed a search for variable stars in the Sculptor Group spiral galaxy NGC 300 using wide-field multi-epoch BV photometry up to a limiting magnitude V~23. Apart from the Cepheid variables in this galaxy already reported in an earlier paper by Pietrzynski et al. (2002, Cat. <J/AJ/123/789>) and the variable blue supergiants reported by Bresolin et al. (2002ApJ...567..277B), we have identified 26 additional periodic variables, with periods ranging from 0.2 to 190d, and 121 slow variables. Two of these newly discovered variables are Galactic foreground stars (one of them is a W UMa system), and three correspond to previously identified Wolf-Rayet stars. 16 stars are new Cepheids, and the other objects span a huge range in colours and represent a mixture of different types of luminous variables.
- ID:
- ivo://CDS.VizieR/J/A+A/483/253
- Title:
- BV photometry of NGC 2099 variables
- Short Name:
- J/A+A/483/253
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Rotation and solar-type magnetic activity are closely related to each other in main-sequence stars of G or later spectral types. The presence and level of magnetic activity depend on star's rotation, and rotation itself is strongly influenced by strength and topology of the magnetic fields. Open clusters represent especially useful targets to investigate the connection between rotation and activity. The open cluster NGC 2099 has been studied as a part of the RACE-OC project (Rotation and ACtivity Evolution in Open Clusters), which is aimed at exploring the evolution of rotation and magnetic activity in the late-type members of open clusters of different ages. We collected time series CCD photometric observations of this cluster in January 2004, and we determined the presence of periodicities in the flux variation related to the stellar rotation by Fourier analysis. We investigate the relations between activity manifestations, such as the light curve amplitude, and global stellar parameters. We have discovered 135 periodic variables, 122 of which are candidate cluster members. Determination of rotation periods of G- and K-type stars has allowed us to better explore the evolution of angular momentum at an age of about 500Myr. In our analysis, we have also identified 3 new detached eclipsing binary candidates among cluster members. A comparison with the older Hyades cluster (~625Myr) shows that the newly-determined distribution of rotation periods is consistent with the scenario of rotational braking of main-sequence spotted stars as they age. However, a comparison with the younger M34 cluster (~200Myr) shows that the G8-K5 members of these clusters have the same rotation period distribution. That is, G8-K5 members in NGC 2099 seem to have experienced no significant braking in the age range from ~200 to ~500Myr. Finally, NGC 2099 members have a smaller level of photospheric magnetic activity, as measured by light curve amplitude, than in younger stars of the same mass and rotation, suggesting that the activity level also depends on some other age-dependent parameters.
- ID:
- ivo://CDS.VizieR/J/A+A/561/A106
- Title:
- BV photometry of 6 SMC stellar clusters
- Short Name:
- J/A+A/561/A106
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Stellar clusters in the Small Magellanic Cloud (SMC) are useful probes to study the chemical and dynamical evolution of this neighbouring dwarf galaxy, enabling inspection of a large period covering over 10Gyr. The main goals of this work are the derivation of age, metallicity, distance modulus, reddening, core radius and central density profile for six sample clusters, in order to place them in the context of the Small Cloud evolution. The studied clusters are: AM 3, HW 1, HW 34, HW 40, Lindsay 2, and Lindsay 3, where HW 1, HW 34, and Lindsay 2 are studied for the first time. Optical Colour-Magnitude Diagrams (V, B-V CMDs) and radial density profiles were built from images obtained with the 4.1m SOAR telescope, reaching V~23. The determination of structural parameters were carried out applying King profile fitting. The other parameters were derived in a self-consistent way by means of isochrone fitting, which uses the likelihood statistics to identify the synthetic CMDs that best reproduce the observed ones. Membership probabilities were determined comparing the cluster and control field CMDs. Completeness and photometric uncertainties were obtained performing artificial star tests. The results confirm that these clusters (except HW 34, identified as a field fluctuation) are intermediate-age clusters, with ages between 1.2Gyr (Lindsay 3) and ~5.0Gyr (HW 1). In particular HW 1, Lindsay 2, and Lindsay 3 are located in a region that we called West Halo, where studies on ages and metallicity gradients are still lacking. Moreover Lindsay 2 was identified as a moderately metal-poor cluster with [Fe/H]=-1.4+/-0.2dex, lower than expected from the age-metallicity relation by Pagel & Tautvaisiene (1998MNRAS.299..535P). We also found distances varying from ~53 to 66kpc, compatible with the large depth of the SMC.
- ID:
- ivo://CDS.VizieR/J/AcA/59/193
- Title:
- BV photometry of stars in NGC 6866
- Short Name:
- J/AcA/59/193
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the discovery of 19 variable stars and two blue stragglers in the field of the open cluster NGC 6866. Three of the variable stars we classify as delta Sct, two as g Dor, four as WUMa, two as ellipsoidal variables, and one as an eclipsing binary. Seven stars show irregular variability. Two of the pulsators, delta Sct star NGC 6866-29 and gamma Dor star NGC 6866-21, are multiperiodic.
