- ID:
- ivo://CDS.VizieR/J/A+A/402/1157
- Title:
- Photometric standards around gravitational lenses
- Short Name:
- J/A+A/402/1157
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a catalog of secondary photometric standard stars in the neighborhood of 14 gravitationally lensed quasars. These stars were verified to be non variable using long-term monitoring. The instrumental magnitudes of the new standard stars have been transformed to the Johnson-Cousins BV(RI)c photometric system. For ten gravitational lenses (GLs) we also provide the BV(RI)c mean magnitudes of the integrated flux of all the lens components, for the epochs of the photometric calibration.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/II/50
- Title:
- Photometric Standard Stars
- Short Name:
- II/50
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The non-variable stars brighter than 5.0 mag in the equatorial zone between declinations +10{deg} and -10{deg} were adopted by IAU Commission 25 in 1970 as primary standards for the Johnson and Morgan UBV system of 1966. Fainter HR stars in the same zone were chosen as secondary standards. Data for the primary standards are taken from a Cape Royal Observatory Mimeogram and are presented in table2.dat. It gives the weighted mean V magnitudes and B-V colors based upon the best series available up to the end of 1966. The table is believed to provide a consistent UBV system over the southern sky. Most of the secondary standard star data, given in table4.dat, were published in Mon. Notes Astron. Soc. S. Afr. (22,23).
- ID:
- ivo://CDS.VizieR/J/PASP/106/967
- Title:
- Photometric Standard Stars
- Short Name:
- J/PASP/106/967
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- CCD photometry is presented for 119 stars observed in the Thuan-Gunn photometric system (the passbands vgr). The sample includes 82 stars for which magnitudes in this system have not previously been published. Photometry in the Johnson-Kron-Cousins photometric system (BV or UBV) has been obtained for a sub-sample of 85 of the stars. Of those stars which are not primary standard stars for the Thuan-Gunn system 70 observed in Gunn r, 48 observed in Gunn g, and 37 observed in Gunn v have sufficient repeat measurements that they may be used as secondary standard stars for CCD photometry. The typical uncertain- ties for the magnitudes of these stars are 0.006 mag.
- ID:
- ivo://CDS.VizieR/J/A+A/458/225
- Title:
- Photometric standard stars in the field of GR 290
- Short Name:
- J/A+A/458/225
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Understanding the origin of the instabilities of LBVs is important for shedding light on the late evolutionary stages of massive stars and on the chemical evolution of galaxies. To investigate the physical nature of variable stars in the upper H-R diagram, we performed a spectrophotometric study of the Romano's star GR 290 and the Hubble-Sandage variables A, B, and C in the close galaxy M 33. New spectroscopic and photometric data were employed in conjunction with already published data of these stars in order to derive spectral types, energy distribution and bolometric luminosities.
- ID:
- ivo://CDS.VizieR/J/AJ/154/30
- Title:
- Photometric study of fourteen low-mass binaries
- Short Name:
- J/AJ/154/30
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- New CCD photometric observations of fourteen short-period low-mass eclipsing binaries (LMBs) in the photometric filters I, R, and V were used for a light curve analysis. A discrepancy remains between observed radii and those derived from the theoretical modeling for LMBs, in general. Mass calibration of all observed LMBs was performed using only the photometric indices. The light curve modeling of these selected systems was completed, yielding the new derived masses and radii for both components. We compared these systems with the compilation of other known double-lined LMB systems with uncertainties of masses and radii less then 5%, which includes 66 components of binaries where both spectroscopy and photometry were combined together. All of our systems are circular short-period binaries, and for some of them, the photospheric spots were also used. A purely photometric study of the light curves without spectroscopy seems unable to achieve high enough precision and accuracy in the masses and radii to act as meaningful test of the M-R relation for low-mass stars.
- ID:
- ivo://CDS.VizieR/J/MNRAS/475/1633
- Title:
- Photometric study of globular clusters
- Short Name:
- J/MNRAS/475/1633
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this paper, we describe the photometric and spectroscopic properties of multiple populations in seven northern globular clusters. In this study, we employ precise ground-based photometry from the private collection of Stetson, space photometry from the Hubble Space Telescope (HST), literature abundances of Na and O, and Apache Point Observatory Galactic Evolution Experiment (APOGEE) survey abundances for Mg, Al, C, and N. Multiple populations are identified by their position in the C_U,B,I_-V pseudo colour-magnitude diagram (pseudo-CMD) and confirmed with their chemical composition determined using abundances. We confirm the expectation from previous studies that the red giant branches (RGBs) in all seven clusters are split and the different branches have different chemical compositions. The Mg-Al anticorrelations were well explored by the APOGEE and Gaia-ESO surveys for most globular clusters, some clusters showing bimodal distributions, while others continuous distributions. Even though the structure (i.e. bimodal versus continuous) of Mg-Al can greatly vary, the Al-rich and Al-poor populations do not seem to have very different photometric properties, agreeing with theoretical calculations. There is no one-to-one correspondence between the Mg-Al anticorrelation shape (bimodal versus continuous) and the structure of the RGB seen in the HST pseudo-CMDs, with the HSTphotometric information usually implying more complex formation/evolution histories than the spectroscopic ones. We report on finding two second-generation horizontal branch (HB) stars in M5, and five second-generation asymptotic giant branch (AGB) stars in M92, which is the most metal-poor cluster to date in which second-generation AGB stars have been observed.
- ID:
- ivo://CDS.VizieR/II/194A
- Title:
- Photometric study of IC 4665
- Short Name:
- II/194A
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- (no description available)
- ID:
- ivo://CDS.VizieR/J/AcA/58/23
- Title:
- Photometric survey for M33 stellar clusters
- Short Name:
- J/AcA/58/23
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a catalog of 4780 extended sources from the outer field of M33. The catalog includes 73 previously identified clusters or planetary nebulae, 1153 likely background galaxies, and 3554 new candidate stellar clusters. The survey is based on deep ground-based images obtained with the MegaCam instrument on the CFHT telescope. We provide g'r'i' photometry for detected objects as well as estimates of the FWHM and ellipticity of their profiles. The sample includes 122 new, relatively bright, likely globular clusters. Follow-up observations of fainter candidates from our list may extend the faint-end of the observed luminosity function of globular clusters in M33 by up to 3 magnitudes. The catalog includes several cluster candidates located in the outskirts of the galaxy. These objects are promising targets for deep photometry with the HST. We present a color-magnitude diagram for one detected object, showing that it is an extended and low-surface-brightness old cluster located at an angular distance of 27' from the center of M33.
- ID:
- ivo://CDS.VizieR/J/AJ/153/252
- Title:
- Photometric variability of BeSS-KELT stars
- Short Name:
- J/AJ/153/252
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Be stars have generally been characterized by the emission lines in their spectra, and especially the time variability of those spectroscopic features. They are known to also exhibit photometric variability at multiple timescales, but have not been broadly compared and analyzed by that behavior. We have taken advantage of the advent of wide-field, long-baseline, and high-cadence photometric surveys that search for transiting exoplanets to perform a comprehensive analysis of brightness variations among a large number of known Be stars. The photometric data comes from the KELT transit survey, with a typical cadence of 30 minutes, a baseline of up to 10 years, photometric precision of about 1%, and coverage of about 60% of the sky. We analyze KELT light curves of 610 known Be stars in both the northern and southern hemispheres in an effort to study their variability. Consistent with other studies of Be star variability, we find most of the stars to be photometrically variable. We derive lower limits on the fraction of stars in our sample that exhibit features consistent with non-radial pulsations (25%), outbursts (36%), and long-term trends in the circumstellar disk (37%), and show how these are correlated with spectral sub-types. Other types of variability, such as those owing to binarity, are also explored. Simultaneous spectroscopy for some of these systems from the Be Star Spectra database allow us to better understand the physical causes for the observed variability, especially in cases of outbursts and changes in the disk.
- ID:
- ivo://CDS.VizieR/J/PAZh/32/662
- Title:
- Photometric Variability of HD 51585
- Short Name:
- J/PAZh/32/662
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Photoelectric observations of HD 51585 (OY Gem), a B[e] star with an infrared excess and a candidate for protoplanetary nebulae, obtained with a 60-cm telescope at the Crimean Station of the Sternberg Astronomical Institute in 1992-2005 are presented. The star exhibited rapid irregular brightness variations with amplitudes from 0.1mag in the V band to 0.2mag in the U band within the observing season as well as slow systematic variations with amplitudes from 0.3mag in the V band to 0.65mag in the U band and with a quasi-period of ~2800days. The B-V color index varied within 0.1mag and did not follow the slow systematic brightness variations, while U-B correlated with the U brightness and varied between 0.7mag at maximum light and 0.35mag at minimum light. Our low-resolution spectroscopy performed in 1994-2005 has revealed significant variability of the Balmer and Paschen hydrogen emission lines as well as the He I and OI lines. Equivalent widths are given for the HI, He I, OI, and Fe II lines; a correlation has been found between the star's photometric variability and the hydrogen line intensities. Our joint analysis of the photometric and spectroscopic data suggests that variations in a strong stellar wind are responsible for the variability of the star.
