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1881. BVR photometry of NGC 6584
ID:
ivo://CDS.VizieR/J/PAZh/21/596
Title:
BVR photometry of NGC 6584
Short Name:
J/PAZh/21/596
Date:
21 Oct 2021
Publisher:
CDS
Description:
Automatic stellar photographic BVR photometry reaching 1mag below the horizontal branch of NGC 6584, located at V~16.5mag, has been performed for this poorly studied globular cluster. One of the photoelectric standard stars used in our reductions appears to be variable. We also determined accurate coordinates of 52 variable stars in the cluster and around it.
1882. BVR photometry of NGC 4594 globular clusters
ID:
ivo://CDS.VizieR/J/AJ/132/1593
Title:
BVR photometry of NGC 4594 globular clusters
Short Name:
J/AJ/132/1593
Date:
21 Oct 2021
Publisher:
CDS
Description:
A detailed imaging analysis of the globular cluster (GC) system of the Sombrero galaxy (NGC 4594) has been accomplished using a six-image mosaic from the Hubble Space Telescope Advanced Camera for Surveys. The quality of the data is such that contamination by foreground stars and background galaxies is negligible for all but the faintest 5% of the GC luminosity function. This enables the study of an effectively pure sample of 659 GCs until ~2mag fainter than the turnover magnitude, which occurs at M^TOM^_V_=-7.60+/-0.06 for an assumed m-M=29.77. Two GC metallicity subpopulations are easily distinguishable, with the metal-poor subpopulation exhibiting a smaller intrinsic dispersion in color compared to the metal-rich subpopulation.
1883. byH{alpha} photometry in open clusters
ID:
ivo://CDS.VizieR/J/ApJS/161/118
Title:
byH{alpha} photometry in open clusters
Short Name:
J/ApJS/161/118
Date:
21 Oct 2021
Publisher:
CDS
Description:
Be stars are a class of rapidly rotating B stars with circumstellar disks that cause Balmer and other line emission. There are three possible reasons for the rapid rotation of Be stars: they may have been born as rapid rotators, spun up by binary mass transfer, or spun up during the main-sequence (MS) evolution of B stars. To test the various formation scenarios, we have conducted a photometric survey of 55 open clusters in the southern sky. Of these, five clusters are probably not physically associated groups and our results for two other clusters are not reliable, but we identify 52 definite Be stars and an additional 129 Be candidates in the remaining clusters.
1884. byH{alpha} photometry of NGC 3766
ID:
ivo://CDS.VizieR/J/ApJ/622/1052
Title:
byH{alpha} photometry of NGC 3766
Short Name:
J/ApJ/622/1052
Date:
21 Oct 2021
Publisher:
CDS
Description:
We describe a technique to identify Be stars in open clusters using Stroemgren b, y, and narrowband H{alpha} photometry. We first identify the B-type stars of the cluster using a theoretical isochrone fit to the (b-y, y) color-magnitude diagram. The strongest Be stars are easily identified in a (b-y, y-H{alpha}) color-color diagram, but those with weaker H{alpha} emission (classified as possible Be star detections) may be confused with evolved or foreground stars. Here we present such photometry plus H{alpha} spectroscopy of members of the cluster NGC 3766 to demonstrate the accuracy of our technique.
1885. Byurakan/Hamburg/ROSAT Catalog of Optical IDs
ID:
ivo://nasa.heasarc/bhrfscid
Title:
Byurakan/Hamburg/ROSAT Catalog of Optical IDs
Short Name:
BHROSATOpt.
Date:
25 Apr 2025
Publisher:
NASA/GSFC HEASARC
Description:
This table contains the Byurakan/Hamburg/ROSAT Catalog (BHRC) of the optical identifications of X-ray sources. The BHRC includes all 2791 X-ray sources from the ROSAT Faint Source Catalog (ROSAT-FSC, CDS Catalog <IX/29>) with galactic latitude |b| >= 30 degrees, declination >= 0 degrees, and ROSAT PSPC count rate CR > 0.04 ct/s. The optical identifications were carried out using the Hamburg Quasar Survey (HQS) digitized spectroscopic plates, the DSS1 and DSS2 (blue, red, and IR) images, the MAPS photometric data, the USNO-B1.0 (for proper motion), the NVSS and FIRST radio, and the IRAS and 2MASS infrared catalogs. From the DSS images, positional, brightness, color, extension, variability, and proper-motion information, the optical-to-X-ray positional offsets were obtained and a morphological classification was made. Available SIMBAD and NED data were also utilized. Cross-correlations were made with AGN, white dwarf, and cataclysmic variable catalogs (322, 8 and 7 associations, respectively). The authors managed to identify 97% of the sources (2696/2791 sources) that are associated with 3202 optical objects. 2248 X-ray sources have a single optical counterpart, 144 have a double or multiple optical counterpart (binaries, galaxy groups, etc.), and 304 have ambiguous identifications (some of the latter might actually be blends of two X-ray sources that were not resolved by ROSAT). The QSOs and AGN represent the largest group of X-ray counterparts (56.2%); bright stars (including late-type stars, but excluding WDs and CVs) are counterparts for 33.2% of the sources, and bright galaxies and groups of galaxies comprise 9.2%. A number of close galaxy pairs (possibly interacting/merging galaxies) are found as counterparts for X-ray sources (3.0%), as well as 1.0% WDs and 0.4% CVs. The BHRC may be used for the selection and study of samples of the various classes of X-ray emitters: the table gives all the available multiwavelength data for the identified sources. This table was created by the HEASARC in June 2006 based on CDS table J/A+A/449/425/table1.dat This is a service provided by NASA HEASARC .
1886. Byurakan-IRAS galaxies (BIG) with SDSS spectra
ID:
ivo://CDS.VizieR/J/PAZh/44/383
Title:
Byurakan-IRAS galaxies (BIG) with SDSS spectra
Short Name:
J/PAZh/44/383
Date:
21 Oct 2021
Publisher:
CDS
Description:
The sample of Byurakan-IRAS galaxies (BIG) has been created based on optical identifications of IRAS Point Source Catalog (PSC) at high galactic latitudes. As a result, 1178 galaxies have been identified. 172 of them have been observed spectroscopically with Byurakan Astrophysical Observatory (BAO, Armenia) 2.6m, Special Astrophysical Observatory (SAO, Russia) 6m and Observatoire de Haute Provence (OHP, France) 1.93m telescopes. Later on, spectra were obtained for more 83 BIG objects in Sloan Digital Sky Survey (SDSS). We have extracted and studied these spectra, classified them and measured spectral features. Diagnostic diagrams have been built to distinguish starbursts (SB), LINERs and Seyfert galaxies. Cross-correlations were made for these objects with multiwavelength (MW) catalogues and their physical properties were studied. Among these 83 objects, 55 HII, 8 Seyfert galaxies, 2 LINERs, 4 other AGN, 6 composite spectrum objects, and 8 other emission-line galaxies have been revealed. Three of these objects are Ultra-Luminous InfraRed Galaxies (ULIRG).
1887. BzJK observations around radio galaxies
ID:
ivo://CDS.VizieR/J/A+A/507/131
Title:
BzJK observations around radio galaxies
Short Name:
J/A+A/507/131
Date:
21 Oct 2021
Publisher:
CDS
Description:
We explore the environments of two radio galaxies at z~1.5, 7C 1751+6809 and 7C 1756+6520, using deep optical and near-infrared imaging. Our data cover 15x15arcmin^2^ fields around the radio galaxies. We develop and apply BzK color criteria to select cluster member candidates around the radio galaxies and find no evidence of an overdensity of red galaxies within 2Mpc of 7C 1751+6809. In contrast, 7C 1756+6520 shows a significant overdensity of red galaxies within 2Mpc of the radio galaxy, by a factor of 3.1+/-0.8 relative to the four MUSYC fields. At small separation (r<6"), this radio galaxy also has one z>1.4 evolved galaxy candidate, one z>1.4 star-forming galaxy candidate, and an AGN candidate (at indeterminate redshift).
1888. Ca abundance for Omega Cen red giants
ID:
ivo://CDS.VizieR/J/ApJ/462/241
Title:
Ca abundance for Omega Cen red giants
Short Name:
J/ApJ/462/241
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present an unbiased catalog of calcium abundances for 517 red giants brighter than M_V_~-1 in the chemically inhomogeneous globular cluster omega Centauri. The basic features of the abundance distribution are as follows: (1) few, if any, stars exist on the giant branch of omega Cen with [Ca/H] less than -1.6; (2) there is a well-defined peak in the distribution at [Ca/H]=-1.4, with a long tail stretching up to ~[Ca/H]~-0.3; and (3) the distribution is bimodal with a second smaller peak in the distribution at [Ca/H]=-0.9.
1889. C abundances in G and K nearby stars
ID:
ivo://CDS.VizieR/J/A+A/526/A71
Title:
C abundances in G and K nearby stars
Short Name:
J/A+A/526/A71
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present a determination of photospheric parameters and carbon abundances for a sample of 172 G and K dwarf, subgiant, and giant stars with and without detected planets in the solar neighbourhood. The analysis was based on high signal-to-noise ratio and high resolution spectra observed with the ELODIE spectrograph (Haute Provence Observatory, France) and for which the observational data were publicly available. We intend to contribute precise and homogeneous C abundances in studies that compare the behaviour of light elements in stars with and without planets. This will bring new arguments to the discussion of possible anomalies that have been suggested and will contribute to a better understanding of different planetary formation process.
1890. Ca,by photometry in globular clusters. I. M22
ID:
ivo://CDS.VizieR/J/ApJS/219/7
Title:
Ca,by photometry in globular clusters. I. M22
Short Name:
J/ApJS/219/7
Date:
21 Oct 2021
Publisher:
CDS
Description:
We investigate the multiple stellar populations in one of the peculiar globular clusters (GCs), M22, using new ground-based wide-field Ca by and Hubble Space Telescope Wide-Field Camera 3 photometry with equivalent passbands, confirming our previous result that M22 has a distinctive red giant branch (RGB) split mainly due to the difference in metal abundances. We also make use of radial velocity measurements by others of the large number of cluster membership stars. Our main results are the following. (1) The RGB and the subgiant branch number ratios show that the calcium-weak (Ca-w) group is the dominant population of the cluster. However, an irreconcilable difference can be seen in the rather simple classification into two horizontal branches by others. (2) Each group has its own CN-CH anticorrelation. However, the alleged CN-CH positive correlation is likely illusory. (3) The location of the RGB bump of the calcium-strong (Ca-s) group is significantly fainter, which may pose a challenge to the helium enhancement scenario in the Ca-s group. (4) The positions of the centers are similar. (5) The Ca-w group is slightly more centrally concentrated, whereas the Ca-s is more elongated at larger radii. (6) The mean radial velocities for both groups are similar, but the Ca-s group has a larger velocity dispersion. (7) The Ca-s group rotates faster. The plausible scenario for the formation of M22 is that it formed via a merger of two GCs in a dwarf galaxy environment and accreted later to our Galaxy.

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