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621. The Quintuplet cluster astrometry and photometry
ID:
ivo://CDS.VizieR/J/ApJ/789/115
Title:
The Quintuplet cluster astrometry and photometry
Short Name:
J/ApJ/789/115
Date:
21 Oct 2021
Publisher:
CDS
Description:
We investigate the orbital motion of the Quintuplet cluster near the Galactic center with the aim of constraining formation scenarios of young, massive star clusters in nuclear environments. Three epochs of adaptive optics high-angular resolution imaging with the Keck/NIRC2 and Very Large Telescope/NAOS-CONICA systems were obtained over a time baseline of 5.8 yr, delivering an astrometric accuracy of 0.5-1 mas/yr. Proper motions were derived in the cluster reference frame and were used to distinguish cluster members from the majority of the dense field star population toward the inner bulge. Fitting the cluster and field proper motion distributions with two-dimensional (2D) Gaussian models, we derive the orbital motion of the cluster for the first time. The Quintuplet is moving with a 2D velocity of 132+/-15 km/s with respect to the field along the Galactic plane, which yields a three-dimensional orbital velocity of 167+/-15 km/s when combined with the previously known radial velocity. From a sample of 119 stars measured in three epochs, we derive an upper limit to the velocity dispersion of {sigma}_1D_< 10 km/s in the core of the Quintuplet cluster. Knowledge of the three velocity components of the Quintuplet allows us to model the cluster orbit in the potential of the inner Galaxy. Under the assumption that the Quintuplet is located in the central 200 pc at the present time, these simulations exclude the possibility that the cluster is moving on a circular orbit. Comparing the Quintuplet's orbit with our earlier measurements of the Arches' orbit, we discuss the possibility that both clusters originated in the same area of the central molecular zone (CMZ). According to the model of Binney et al., two families of stable cloud orbits are located along the major and minor axes of the Galactic bar, named x1 and x2 orbits, respectively. The formation locus of these clusters is consistent with the outermost x2 orbit and might hint at cloud collisions at the transition region between the x1 and x2 orbital families located at the tip of the minor axis of the Galactic bar. The formation of young, massive star clusters in circumnuclear rings is discussed in the framework of the channeling in of dense gas by the bar potential. We conclude that the existence of a large-scale bar plays a major role in supporting ongoing star and cluster formation, not only in nearby spiral galaxies with circumnuclear rings, but also in the Milky Way's CMZ.
622. The revised orbit of the {delta} Sco system
ID:
ivo://CDS.VizieR/J/ApJ/729/L5
Title:
The revised orbit of the {delta} Sco system
Short Name:
J/ApJ/729/L5
Date:
21 Oct 2021
Publisher:
CDS
Description:
In anticipation of the possible collision between a circumstellar disk and the secondary star in the highly eccentric binary system {delta} Scorpii, high angular resolution interferometric observations have been acquired, aimed at revising the binary parameters. The Navy Prototype Optical Interferometer was used to spatially resolve the binary components in 2000 and over a period between 2005 and 2010. The interferometric observations are used to obtain the angular separations and orientations of the two stellar components at all epochs for which data have been obtained, including 2005 and 2006, for which, based on previous studies, there was some uncertainty as to if the signature of binarity can be clearly detected. The results of this study represent the most complete and accurate coverage of the binary orbit of this system to date and allow for the revised timing of the upcoming periastron passage that will occur in 2011 to be obtained.
623. The Sixth Fundamental Catalogue (FK6)
ID:
ivo://org.gavo.dc/fk6/q/collection
Title:
The Sixth Fundamental Catalogue (FK6)
Date:
06 Feb 2024 08:59:18
Publisher:
The GAVO DC team
Description:
Parts I and III of the sixth fundamental catalog, a catalog of high-precision astrometry for bright stars combining centuries of ground-based observations as reflected in FK5 with HIPPARCOS astrometry. The result contains, in particular for the proper motions, statistically significant improvements of the Hipparcos data und represents a system of unprecedented accuracy for these 4150 fundamental stars. The typical mean error in pm is 0.35 mas/year for 878 basic stars, and 0.59 mas/year for the sample of the 3272 additional stars.
624. The Sixth Fundamental Catalogue (FK6)
ID:
ivo://org.gavo.dc/fk6/q/cone
Title:
The Sixth Fundamental Catalogue (FK6)
Short Name:
FK6 cone
Date:
27 Dec 2024 08:31:03
Publisher:
The GAVO DC team
Description:
Parts I and III of the sixth fundamental catalog, a catalog of high-precision astrometry for bright stars combining centuries of ground-based observations as reflected in FK5 with HIPPARCOS astrometry. The result contains, in particular for the proper motions, statistically significant improvements of the Hipparcos data und represents a system of unprecedented accuracy for these 4150 fundamental stars. The typical mean error in pm is 0.35 mas/year for 878 basic stars, and 0.59 mas/year for the sample of the 3272 additional stars.
625. The solar neighborhood.XLVI. New M dwarf binaries
ID:
ivo://CDS.VizieR/J/AJ/160/215
Title:
The solar neighborhood.XLVI. New M dwarf binaries
Short Name:
J/AJ/160/215
Date:
21 Oct 2021
Publisher:
CDS
Description:
We use 20yr of astrometric data from the REsearch Consortium On Nearby Stars (RECONS) program on the Cerro Tololo Inter-American Observatory/SMARTS 0.9m telescope to provide new insight into multiple star systems in the solar neighborhood. We provide new and updated parallaxes for 210 systems and derive nine high-quality astrometric orbits with periods of 2.49-16.63yr. Using a total of 542 systems parallaxes from RECONS, we compare systems within 25pc to Gaia DR2 to define criteria for selecting unresolved astrometric multiples from the DR2 results. We find that three out of four unresolved multistar red dwarf systems within 25pc in DR2 have parallax_error >=0.32mas, astrometric_gof_al>=56, astrometric_excess-noise_sig>=108.0, ruwe>=2.0, and parallaxes more than ~10% different from the long-term RECONS results. These criteria have broad applications to any work targeting nearby stars, from studies seeking binary systems to efforts targeting single stars for planet searches.
626. The Southern SHARC catalogue
ID:
ivo://CDS.VizieR/J/MNRAS/341/1093
Title:
The Southern SHARC catalogue
Short Name:
J/MNRAS/341/1093
Date:
21 Oct 2021
Publisher:
CDS
Description:
The Southern Serendipitous High-redshift Archival Cluster (SHARC) catalogue is a X-ray selected catalogue of galaxy clusters detected in deep ROSAT observations. The survey area is 17.7deg^2^ and is selected from long (greater than 10ks) ROSAT exposures with a declination <+20deg and excluding the Galactic plane (excluding galactic latitudes within the range [-20,20]deg). Optical follow-up was performed to confirm the presence of a galaxy cluster and measure its redshift. The final catalogue contains 32 galaxy clusters with redshifts between 0.05 and 0.70 and X-ray luminosities between 7x10^35^W and 4x10^37^W. Above a redshift of 0.3 - which forms the primary subsample of the survey - there are 16 clusters; the X-ray luminosities of these clusters are all greater than 2x10^36 W. All X-ray luminosities are quoted in the 0.5-2.0keV band and were calculated using an Einstein-de Sitter cosmology with H_0_ set to 50km/s/Mpc.
627. The star catalogue of Wilhelm IV
ID:
ivo://CDS.VizieR/J/A+A/649/A112
Title:
The star catalogue of Wilhelm IV
Short Name:
J/A+A/649/A112
Date:
22 Feb 2022
Publisher:
CDS
Description:
We analyse a manuscript star catalogue by Wilhem IV, Landgraf von Hessen-Kassel from 1586. From measurements of altitudes and of angles between stars, given in the catalogue, we find that the measurement accuracy averages 26 arcsec for eight fundamental stars, compared to 49 arcsec of the measurements by Brahe. The computation in converting altitudes to declinations and angles between stars to celestial position is very accurate, with errors negligible with respect to the measurement errors. Due to an offset in the position of the vernal equinox the positional error of the catalogue is slightly worse than that of Brahe's catalogue, but when correction is made for the offset -- which was known to 17th century astronomers -- the catalogue is more accurate than that of Brahe. We provide machine-readable Tables of the catalogue.
628. The 90000 stars Supplement to the PPM Catalogue
ID:
ivo://CDS.VizieR/I/208
Title:
The 90000 stars Supplement to the PPM Catalogue
Short Name:
I/208
Date:
21 Oct 2021
Publisher:
CDS
Description:
Since its appearance in 1966, the SAO Catalogue (SAO, 1966) has been the primary source for stellar positions and proper motions. Typical values for the rms errors are 1 arcsec in the positions at epoch 1990, and 1.5 arcsec/century in the proper motions. The corresponding figures for the AGK3 (Heckmann et al., 1975) on the northern hemisphere are 0.45 arcsec and 0.9 arcsec/century. Common to both catalogues is the fact that proper motions area derived from two observational epochs only. Both catalogues are nominally on the B1950/FK4 coordinate system. The PPM Star Catalogue (Roeser and Bastian, 1991, Bastian et al., 1993; for a short description see Roeser and Bastian, 1993) effectively replaced these catalogues by providing more precise astrometric data for more stars on the J2000/FK5 coordinate system. Compared to the SAO Catalogue the improvement in precision is about a factor of 3 on the northern and a factor of 6 to 10 on the southern hemisphere. In addition, the number of stars is increased by about 50 percent. Typical values for the rms errors on the northern hemisphere are 0.27 arcsec in the positions at epoch 1990, and 0.42 arcsec/century in the proper motions. On the southern hemisphere PPM is much better, the corresponding figures being 0.11 arcsec and 0.30 arcsec/century. The improvement over the SAO Catalogue was made possible by the advent of new big catalogues of position measurements and by the inclusion of the century-old Astrographic Catalogue (AC) into the derivation of proper motions (for a description of AC see Eichhorn, 1974). But even PPM does not fully exploit the treasure of photographic position measurements available in the astronomical literature of the last 100 years. The Astrographic Catalogue contains roughly four million stars that are not included in PPM. For most of them no precise modern-epoch position measurements exist. Thus it is not yet possible to derive proper motions with PPM quality for all AC stars. But among the 4 million there is a subset of some 100,000 CPC-2 stars that are not included in PPM. These stars constitute the 90,000 Stars Supplement to PPM. See file "desc.txt" for complete explanations provided by the authors.
629. The third realization of the ICRF, ICRF3
ID:
ivo://CDS.VizieR/J/A+A/644/A159
Title:
The third realization of the ICRF, ICRF3
Short Name:
J/A+A/644/A159
Date:
21 Oct 2021
Publisher:
CDS
Description:
A new realization of the International Celestial Reference Frame (ICRF) is presented based on the work achieved by a working group of the International Astronomical Union (IAU) mandated for this purpose. This new realization follows the initial realization of theICRF completed in 1997 and its successor, ICRF2, adopted as a replacement in 2009. The new frame, referred to as ICRF3, is based on nearly 40 years of data acquired by very long baseline interferometry at the standard geodetic and astrometric radio frequencies (8.4 and 2.3GHz), supplemented with data collected at higher radio frequencies (24GHz and dual-frequency 32 and 8.4GHz) over the past 15 years. State-of-the-art astronomical and geophysical modeling has been used to analyze these data and derive source positions. The modeling integrates, for the first time, the effect of the galactocentric acceleration of the solar system (directly estimated from the data) which, if not considered, induces significant deformation of the frame due to the data span. The new frame includes positions at 8.4GHz for 4536 extragalactic sources. Of these, 303 sources, uniformly distributed on the sky, are identified as "defining sources" and as such serve to define the axes of the frame. Positions at 8.4GHz are supplemented with positions at 24GHz for 824 sources and at 32GHz for 678 sources. In all, ICRF3 comprises 4588 sources, with three-frequency positions available for 600 of these. Source positions have been determined independently at each of the frequencies in order to preserve the underlying astrophysical content behind such positions. They are reported for epoch 2015.0 and must be propagated for observations at other epochs for the most accurate needs, accounting for the acceleration toward the Galactic center, which results in a dipolar proper motion field of amplitude 0.0058 milliarcsecond/yr (mas/yr). The frame is aligned onto the International Celestial Reference System to within the accuracy of ICRF2 and shows a median positional uncertainty of about 0.1mas in right ascension and 0.2 mas in declination, with a noise floor of 0.03mas in the individual source coordinates. A subset of 500 sources is found to have extremely accurate positions, in the range of 0.03 to 0.06mas, at the traditional 8.4GHz frequency. Comparing ICRF3 with the recently released Gaia Celestial Reference Frame 2 in the optical domain, there is no evidence for deformations larger than 0.03 mas between the two frames, in agreement with the ICRF3 noise level. Significant positional offsets between the three ICRF3 frequencies are detected for about 5% of the sources.Moreover, a notable fraction (22%) of the sources shows optical and radio positions that are significantly offset. There are indications that these positional offsets may be the manifestation of extended source structures. This third realization of the ICRF was adopted by the IAU at its 30th General Assembly in August 2018 and replaced the previous realization, ICRF2, on January 1, 2019.
630. The Tycho-2 Catalogue
ID:
ivo://CDS.VizieR/I/259
Title:
The Tycho-2 Catalogue
Short Name:
I/259
Date:
21 Oct 2021
Publisher:
CDS
Description:
The Tycho-2 Catalogue is an astrometric reference catalogue containing positions and proper motions as well as two-colour photometric data for the 2.5 million brightest stars in the sky. The Tycho-2 positions and magnitudes are based on precisely the same observations as the original Tycho Catalogue (hereafter Tycho-1; see Cat. <I/239>)) collected by the star mapper of the ESA Hipparcos satellite, but Tycho-2 is much bigger and slightly more precise, owing to a more advanced reduction technique. Components of double stars with separations down to 0.8 arcsec are included. Proper motions precise to about 2.5 mas/yr are given as derived from a comparison with the Astrographic Catalogue and 143 other ground-based astrometric catalogues, all reduced to the Hipparcos celestial coordinate system. Tycho-2 supersedes in most applications Tycho-1, as well as the ACT (Cat. <I/246>) and TRC (Cat. <I/250>) catalogues based on Tycho-1. Supplement-1 lists stars from the Hipparcos and Tycho-1 Catalogues which are not in Tycho-2. Supplement-2 lists 1146 Tycho-1 stars which are probably either false or heavily disturbed. For more information, please consult the Tycho-2 home page: http://www.astro.ku.dk/~erik/Tycho-2

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