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391. Pulkovo Visual Double Star Catalogue
ID:
ivo://CDS.VizieR/I/292
Title:
Pulkovo Visual Double Star Catalogue
Short Name:
I/292
Date:
21 Oct 2021
Publisher:
CDS
Description:
Into the present catalogue the seasonal mean relative positions (rho and theta 2000) are included for 234 visual double stars observed at Pulkovo with 26-inch refractor from 1960 through 2001. This catalogue is a successor of the catalogue dated 1986 [1]. Epoch of equinox is 2000.0. The main aim of these observations is to create the data base for the double star orbit and mass determinations [2]. The stars with the great orbital motion, having longer observation series, were measured in the first line. The photographic and CCD observations of visual double stars are being continued now. The results will be included into the future catalogue. Some stars are accompanied with notes. More full information about visual double stars investigations in the Pulkovo Observatory may be obtained from the articles, the list of references being enclosed.
392. Pulkovo visual double stars photographic obs.
ID:
ivo://CDS.VizieR/J/PAZh/42/46
Title:
Pulkovo visual double stars photographic obs.
Short Name:
J/PAZh/42/46
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the results of determining the relative positions of the 359 pairs of stars. More then six thousands of plates had been obtained in 1960-2007 years using the 26-inch Zeiss refractor(D=650mm, F=10413mm, scale is 19.80-arcsec/mm) at Pulkovo (code is 084). The plate digitization was carried out using a digital camera Canon EOS 5D Mark II and the lens 21M Jupiter, the scale was 21um/pixel. The measurements were calibrated using a template which was digitized by means of the Belgian high-precision scanner ROB Digitizer. Results were thoroughly examined for the systematic errors.
393. Pulsar timing at UAO
ID:
ivo://CDS.VizieR/J/MNRAS/328/855
Title:
Pulsar timing at UAO
Short Name:
J/MNRAS/328/855
Date:
21 Oct 2021
Publisher:
CDS
Description:
A pulsar timing system has been operating in the 18-cm band at the Urumqi Astronomical Observatory 25-m telescope since mid-1999. Frequency resolution allowing de-dispersion of the pulsar signals is provided by a 2x128x2.5MHz filterbank/digitizer system. Observations of 74 pulsars over more than 12 months have resulted in updated pulsar periods and period derivatives, as well as improved positions. Comparison with previous measurements showed that the changes in period and period derivative tend to have the same sign and to be correlated in amplitude. A model based on unseen glitches gives a good explanation of the observed changes, suggesting that long-term fluctuations in period and period derivatives are dominated by glitches. In 2000 July, we detected a glitch of relative amplitude {Delta}{nu}/{nu}~24x10^-9^in the Crab pulsar. The post-glitch decay appears similar to other large Crab glitches.
394. Quasars in ESO/SERC field 927
ID:
ivo://CDS.VizieR/J/MNRAS/266/317
Title:
Quasars in ESO/SERC field 927
Short Name:
J/MNRAS/266/317
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the spectroscopic observations of 56 quasars that were discovered by AQD (Automated Quasar Detection) in a field of ~25.3deg2, centred at (1950) RA l0h40m00s, Dec. 05deg00'00". These observations, with the CTIO 4-m telescope, led to the discovery by Clowes & Campusano of a large group of quasars with size ~100-200h^-1^Mpc at z~1.3. Quasars of particular interest are noted, including one that is a BAL quasar with z~1.78.
395. QUEST RR Lyrae survey. II. Halo overdensities
ID:
ivo://CDS.VizieR/J/AJ/132/714
Title:
QUEST RR Lyrae survey. II. Halo overdensities
Short Name:
J/AJ/132/714
Date:
21 Oct 2021
Publisher:
CDS
Description:
The first catalog of the RR Lyrae stars (RRLSs) in the Galactic halo by the Quasar Equatorial Survey Team (QUEST) has been searched for significant overdensities that may be debris from disrupted dwarf galaxies or globular clusters. These RRLSs are contained in a band 23 wide in declination that spans 165{deg} in right ascension and lie 4 to 60kpc from the Sun. Away from the major overdensities, the distribution of these stars is adequately fitted by a smooth halo model, in which the flattening of the halo decreases with increasing galactocentric distance (as reported by Preston et al., 1991ApJ...375..121P). This model was used to estimate the background of RRLSs on which the halo overdensities are overlaid. A procedure was developed for recognizing groups of stars that constitute significant overdensities with respect to this background. To test this procedure, a Monte Carlo routine was used to make artificial RRLS surveys that follow the smooth halo model but with Poissondistributed noise in the numbers of RRLSs and, within limits, random variations in the positions and magnitudes of the artificial stars. The 104 artificial surveys created by this routine were examined for significant groups in exactly the same way as the QUEST survey.
396. QUEST RR Lyrae Survey III. Low Galactic latitude
ID:
ivo://CDS.VizieR/J/MNRAS/427/3374
Title:
QUEST RR Lyrae Survey III. Low Galactic latitude
Short Name:
J/MNRAS/427/3374
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present results for the QUEST RR Lyrae Survey at low Galactic latitude, conducted entirely with observations obtained with the QUEST mosaic camera and the 1.0/1.5-m Jurgen Stock Schmidt telescope at the National Observatory of Venezuela. The survey spans an area of 476deg^2^ on the sky, with multi-epoch observations in the V, R and I photometric bands for 6.5x10^6^ stars in the Galactic latitude range -30{deg}<=b<=+25{deg}, in a direction close to the Galactic anticentre 190{deg}<=l<=230{deg}. The variability survey has a typical number of 30 observations per object in V and I and ~25 in R, with up to ~120-150 epochs in V and I and up to ~100 in R in the best sampled regions. The completeness magnitudes of the survey are V=R=18.5mag, and I=18.0mag. We identified 211 RR Lyrae stars, 160 bona fide stars of type ab and 51 candidates of type c, ours being the first deep RR Lyrae survey conducted at low Galactic latitude, in the Galactic disc. The completeness of the RR Lyrae survey was estimated in >~95 and ~85 per cent for RRab and RRc stars, respectively. Photometric metallicities were computed based on the light curves and individual extinctions calculated from minimum light colours for each RRab star. Distances were obtained with typical errors ~7 per cent. The RR Lyrae survey simultaneously spans a large range of heliocentric distances 0.5<=R_hel_(kpc)<=40 and heights above the plane -15<=z(kpc)<=+20, with well-known completeness across the survey area, making it an ideal set for studying the structure of the Galactic thick disc.
397. Radial Velocities of Stars in M4
ID:
ivo://CDS.VizieR/J/ApJ/443/124
Title:
Radial Velocities of Stars in M4
Short Name:
J/ApJ/443/124
Date:
21 Oct 2021
Publisher:
CDS
Description:
The internal stellar velocity distribution of the globular cluster M4 is evaluated from nearly 200 new radial velocity measurements good to 1 km/s and a rederivation of existing proper motions. The mean radial velocity of the cluster is 70.9 +/- 0.6 km/s. The velocity dispersion is 3.5 +/- 0.3 km/s at the core, dropping marginally towards the outskirts. Such a low internal dispersion is somewhat at odds with the cluster's orbit, for which the perigalacticon is sufficiently close to the galactic center that the probability of cluster disruption is high; a tidal radius two-thirds the currently accepted value would eliminate the discrepancy. The cluster mass-to-light ratio is also small, M/L_V = 1.0 +/- 0.4 in solar units. M4 thus joins M22 as a cluster of moderate mass and concentration with a mass-to-light ratio among the lowest known. The astrometric distance to the cluster is also smaller than expected, 1.72 +/- 0.14 kpc. This is only consistent with conventional estimates of the luminosity of horizontal branch stars provided an extinction law R = A_V/E(B-V) ~ 4 is adopted, as has been suggested recently by several authors.
398. Radial velocities & orbital data, 5 triple stars
ID:
ivo://CDS.VizieR/J/AJ/160/251
Title:
Radial velocities & orbital data, 5 triple stars
Short Name:
J/AJ/160/251
Date:
21 Oct 2021
Publisher:
CDS
Description:
Joint analysis of radial velocities and position measurements of five hierarchical stellar systems is undertaken to determine elements of their inner and outer orbits and, whenever possible, their mutual inclinations. The inner and outer periods are 12.9 and 345yr for HD12376 (ADS1613), 1.14 and ~1500yr for HD19971 (ADS2390), 8.3 and 475yr for HD89795 (ADS7338), 1.11 and 40yr for HD152027, 0.69 and 7.4yr for HD190412. The latter system with its coplanar and quasi-circular orbits belongs to the family of compact planetary-like hierarchies, while the orbits in HD12376 have a mutual inclination of 131{deg}.
399. Radial Velocities with Astrometric Data
ID:
ivo://CDS.VizieR/III/239
Title:
Radial Velocities with Astrometric Data
Short Name:
III/239
Date:
21 Oct 2021
Publisher:
CDS
Description:
The catalogue of radial velocities of Galactic stars with high precision astrometric data (CRVAD) is the result of a merging of star lists from the General Catalog of Mean Radial Velocities (GCRV, Cat. III/213) and from the All-sky Compiled Catalogue of 2.5 Million Stars (ASCC-2.5, Cat. I/280). The cross identification of GCRV and ASCC-2.5 objects was carried out with help of coordinate, magnitude, colour and/or spectral type criteria. Data from the Catalogue of Components of Double and Multiple Stars (CCDM, Cat. I/274) were taken into account for the identification of multiple system components. 34553 stars of the ASCC-2.5 were identified with 33509 stars of the GCRV, i.e. 33509 stars of the GCRV have one entry in the ASCC-2.5, and 1044 objects have two entries. The catalogue includes accurate equatorial coordinates J2000, proper motions and trigonometric parallaxes in the Hipparcos system, B and V magnitudes in Johnson system, spectral classes, multiplicity and variability flags from the ASCC-2.5, and radial velocities, stellar magnitudes and spectra from the GCRV. Stars are sorted in right ascension J2000 order. 3967 stars were selected as radial velocity standard candidates (file rv_std.dat). These stars: - do not have any multiplicity and/or variability flags both in the GCRV and ASCC-2.5; - have standard errors of equatorial coordinates e <= 40 mas; - have standard errors of proper motions e_pm <= 4 mas/yr; - have standard errors of V magnitude e_V <= 0.05 mag and (B-V) colour e_(B-V) <= 0.07 mag; - have standard errors of radial velocity e_RV <= 2 km/s or quality index A or B, which corresponds to e_RV 0.74 and 1.78 km/s; - have at least four RV observations N_RV.
400. Radio-optical reference frame link
ID:
ivo://CDS.VizieR/I/325
Title:
Radio-optical reference frame link
Short Name:
I/325
Date:
21 Oct 2021
Publisher:
CDS
Description:
Between 1997 and 2004 several observing runs were conducted mainly with the CTIO 0.9m to image ICRF counterparts (mostly QSOs) in order to determine accurate optical positions. Contemporary to these deep CCD images the same fields were observed with the USNO astrograph in the same bandpass. These provide accurate positions on the Hipparcos/Tycho-2 system for stars in the 10 to 16 magnitude range used as reference stars for the deep CCD imaging data. Here we present final optical position results of 413 sources based on astrograph data reductions using UCAC2 and UCAC4 type reference stars. These optical positions are compared to radio VLBI positions. The current optical system is not perfectly aligned to the ICRF radio system with rigid body rotation angles of 3 to 5 mas (3{sigma}) found between them for all 3 axes. Furthermore, statistically, the optical-radio position differences are found to exceed the total, combined, known errors in the observations. Systematic errors in the optical reference stars as well as physical offsets between the centers of optical and radio emissions are both identified as likely causes. A detrimental, astrophysical, random noise (DARN) component is postulated to be on about the 10mas level. If confirmed by future observations, this could severely limit the Gaia to ICRF reference frame alignment accuracy to an error of about 0.5mas per coordinate axis with the current number of sources envisioned to provide the link. A list of 36 ICRF sources without the detection of an optical counterpart to a limiting magnitude of about R=22 is provided as well.

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