- ID:
- ivo://CDS.VizieR/J/A+AS/116/403
- Title:
- VRI photometry of stars in 12 BL Lac objects
- Short Name:
- J/A+AS/116/403
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present VR_cI_c Johnson-Cousins magnitudes of field comparison stars for twelve BL Lacertae objects belonging to the more large sample of blazars which is monitored at Perugia Astronomical Observatory. These comparison stars can be used in the long-term CCD photometric monitoring of BL Lac objects aimed to understand the characteristics of their variability. Finding charts for all of these comparison sequences are also included in this paper. For a description of the (RI)c photometric system, see e.g. the General Catalog of Photometric Data <GCPD/54>
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/464/373
- Title:
- VRIZJHK photometry around Alpha Cen
- Short Name:
- J/A+A/464/373
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Thanks to its proximity, alpha Centauri is an outstanding target for an imaging search for extrasolar planets. We searched for faint comoving companions to alpha Cen located at angular distances of a few tens of arcseconds, up to 2-3 arcmin. We obtained CCD images from the NTT-SUSI2 instrument in the Bessel V, R, I, and Z bands, and archive data from 2MASS.
- ID:
- ivo://CDS.VizieR/J/A+A/489/571
- Title:
- VRizK photometry of RDCSJ0910+54 cluster
- Short Name:
- J/A+A/489/571
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report on the environmental dependence of properties of galaxies around the RDCSJ0910+54 cluster at z=1.1. We obtained multi-band wide-field images of the cluster with Suprime-Cam and MOIRCS on Subaru and WFCAM on UKIRT. Also, an intensive spectroscopic campaign was carried out using LRIS on Keck and FOCAS on Subaru. We collected 161 spectra with secure redshifts, with which we calibrated a larger sample of photometric redshifts.
- ID:
- ivo://CDS.VizieR/J/MNRAS/365/1392
- Title:
- VRi'z' phot. & redshifts around RX J0152.7-1352
- Short Name:
- J/MNRAS/365/1392
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a discovery of definitive large-scale structures around RX J0152.7-1352 at z=0.83 based on spectroscopic redshifts. In our previous papers, we reported a photometric identification of the large-scale structures at z~0.8. A spectroscopic follow-up observation was carried out on eight selected regions covering the most prominent structures to confirm their association to the main cluster. In six out of the eight fields, a well-isolated peak is identified in the distribution of spectroscopic redshifts at or near the cluster redshift. This is strong evidence for the presence of large-scale structures associated to the main cluster at z=0.83.
- ID:
- ivo://CDS.VizieR/J/AJ/137/4598
- Title:
- VR light curve of ASAS-North Cepheids
- Short Name:
- J/AJ/137/4598
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have obtained VR photometry of 282 Cepheid variable star candidates from the northern part of the All Sky Automated Survey (ASAS). These together with data from the ASAS and the Northern Sky Variability Survey (NSVS) were used to redetermine the periods of the stars.
- ID:
- ivo://CDS.VizieR/J/MNRAS/372/69
- Title:
- VR light curves of M2 variables
- Short Name:
- J/MNRAS/372/69
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the results of CCD V and R photometry of the RR Lyrae stars in M2. The periodicities of most variables are revised and new ephemerides are calculated. Light-curve decomposition of the RR Lyrae stars was carried out and the corresponding mean physical parameters [Fe/H]=-1.47, Teff=6276K, logL=1.63L_{sun}_ and M_V_=0.71 from nine RRab and [Fe/H]=-1.61, M=0.54M_{sun}_, Teff=7215K, logL=1.74L_{sun}_ and M_V_=0.71 from two RRc stars were calculated. A comparison of the radii obtained from the above luminosity and temperature with predicted radii from non-linear convective models is discussed. The estimated mean distance to the cluster is 10.49+/-0.15kpc. These results place M2 correctly in the general globular cluster sequences for Oosterhoff type, mass, luminosity and temperature, all as a function of the metallicity. Mean relationships for M, logL/L_{sun}_, Teff and MV as a function of [Fe/H] for a family of globular clusters are offered. These trends are consistent with evolutionary and structural notions on the horizontal branch. Eight new variables are reported.
- ID:
- ivo://CDS.VizieR/J/other/RMxAA/40.209
- Title:
- VR light curves of 15 RR Lyrae in NGC 4147
- Short Name:
- J/other/RMxAA/40
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the results of CCD V and R photometry of the RR Lyrae stars known in NGC 4147. The periodicities of most variables are revised and new ephemerides are calculated. The Blazhko effect has been detected in V2 and V6. Three previously reported variables; V5, V9, and V15 are found to be non-variable. A new variable V18 was discovered with a period of 0.49205-days and an amplitude of 0.15mag. Using the approach of Fourier decomposition of the light curves, the physical parameters of the RRab and RRc variables were estimated. The cluster is of the Oosterhoff type I. With the newly values [Fe/H]=-1.22+/-0.31 and 16.8+/-1.3kpc, the cluster fits very well into the Oosterhoff type-metallicity and metallicity-temperature sequence found in globular clusters. A comparison with ZAHB models indicates that the RRab stars have not yet evolved off the horizontal branch, a result consistent with the mean period of the RRab variables and with the metallicity of the cluster derived in this work.
- ID:
- ivo://CDS.VizieR/J/AJ/152/129
- Title:
- VR photometry for 914 stars in NGC 188
- Short Name:
- J/AJ/152/129
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We used the newly commissioned 50cm Binocular Network telescope at Qinghai Station of Purple Mountain Observatory (Chinese Academy of Sciences) to observe the old open cluster NGC188 in V and R as part of a search for variable objects. Our time-series data span a total of 36 days. Radial velocity and proper-motion selection resulted in a sample of 532 genuine cluster members. Isochrone fitting was applied to the cleaned cluster sequence, yielding a distance modulus of (m-M)_V_^0^=11.35+/-0.10mag and a total foreground reddening of E(V-R)=0.062+/-0.002mag. Light-curve solutions were obtained for eight W Ursae Majoris eclipsing binary systems (W UMas), and their orbital parameters were estimated. Using the latter parameters, we estimate a distance to the W UMas that is independent of the host cluster's physical properties. Based on combined fits to six of the W UMas (EP Cep, EQ Cep, ES Cep, V369 Cep, and-for the first time-V370 Cep and V782 Cep), we obtain an average distance modulus of (m-M)_V_^0^=11.31+/-0.08mag, which is comparable to that resulting from our isochrone fits. These six W UMas exhibit an obvious period-luminosity relation. We derive more accurate physical parameters for the W UMa systems and discuss their initial masses and ages. The former show that these W UMa systems have likely undergone angular momentum evolution within a convective envelope (W-type evolution). The ages of the W UMa systems agree well with the cluster's age.
- ID:
- ivo://CDS.VizieR/J/AJ/122/714
- Title:
- VR photometry of Century Survey galaxies
- Short Name:
- J/AJ/122/714
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We use 64{deg}^2^ of deep V and R CCD images to measure the local V- and R-band luminosity functions of galaxies. The V_0_<16.7 and R_0_<16.2 redshift samples contain 1255 and 1251 galaxies and are 98.1% and 98.2% complete, respectively.
- ID:
- ivo://CDS.VizieR/J/AJ/128/1748
- Title:
- VR photometry of type II Cepheids
- Short Name:
- J/AJ/128/1748
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present 1256 new photometric observations of 36 Cepheids with periods longer than 8 days. The majority are likely type II Cepheids, but we have included about a dozen classical Cepheids for comparison purposes, a few stars of uncertain type, and one putative RV Tauri star. We discuss the appearance of the light curves, the Fourier parameters, and the light-curve stability in terms of differentiation between type I and type II Cepheids. Although we encounter the same difficulties as previous investigators in using these parameters for this purpose, we are able to identify some stars of particular interest, including several likely type I Cepheids at large distances from the Galactic plane. Six stars with especially large period changes are identified and discussed.
