- 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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- ID:
- ivo://CDS.VizieR/J/A+A/493/317
- Title:
- Radio source selection for the ICRF
- Short Name:
- J/A+A/493/317
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The most accurate realization of a quasi inertial reference frame, the International Celestial Reference Frame (ICRF), is made of 212 defining extragalactic radio sources whose coordinates are determined using VLBI observations. Recent studies demonstrated however that using other sets of sources could improve the frame stability. This study examines a simple radio source selection scheme to define celestial reference frame axes more stable than the ones as currently defined by the ICRF. After having derived source coordinate time series from 26 years of VLBI observations, we select the most suitable sources on the basis of their positional variability (rms and slope), and observational history. We determine the axis stability of the frame defined by the selection, as well as its suitability for global geodetic VLBI analyses, i.e., determination of Earth orientation parameters and source and station coordinates.
- ID:
- ivo://CDS.VizieR/J/A+A/425/367
- Title:
- REFLEX Galaxy Cluster Survey catalogue
- Short Name:
- J/A+A/425/367
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the catalogue of the REFLEX Cluster Survey providing information on the X-ray properties, redshifts, and some identification details of the clusters in the REFLEX sample. The catalogue describes a statistically complete X-ray flux-limited sample of 447 galaxy clusters above an X-ray flux of 3x10^-12^erg/s/cm^2^ (0.1 to 2.4keV) in an area of 4.24ster in the southern sky. The cluster candidates were first selected by their X-ray emission in the ROSAT-All Sky Survey and subsequently spectroscopically identified in the frame of an ESO key programme. Previously described tests have shown that the sample is more than 90% complete and there is a conservative upper limit of 9% on the fraction of clusters with a dominant X-ray contamination from AGN. In addition to the cluster catalogue we also describe the complete selection criteria as a function of the sky position and the conversion functions used to analyse the X-ray data. These are essential for the precise statistical analysis of the large-scale cluster distribution. This data set is at present the largest, statistically complete X-ray galaxy cluster sample. Together with these data set we also provide for the first time the full three-dimensional selection function. The sample forms the basis of several cosmological studies, one of the most important applications being the assessment of the statistics of the large-scale structure of the universe and the test of cosmological models. Part of these cosmological results have already been published.
- ID:
- ivo://CDS.VizieR/I/100A
- Title:
- Results of obs with the 6-inch transit circle
- Short Name:
- I/100A
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This catalog is a compilation of seven catalogs of positions derived from observations with the six-inch transit circle of the U. S. Naval Observatory. The observations were obtained between 1911 and 1971 and were published in the catalogs: W210, W025, W150, W250, W350, W450, and W550. Proper motions and, in most catalogs, spectral types were added from other sources.
- ID:
- ivo://CDS.VizieR/VII/110A
- Title:
- Rich Clusters of Galaxies
- Short Name:
- VII/110A
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This is an all-sky catalog of 4073 rich clusters of galaxies, each having at least 30 members within the magnitude range m_3_ to m_3_ + 2 (m_3_ is the magnitude of the third brightest cluster member) and each with a nominal redshift less than 0.2. The southern data have been collected from a survey of UK 1.2 m Schmidt telescope IIIa-J plates and films and have been reduced to the systems defined by the northern data previously published by G.O. Abell. A revised northern catalog, including Bautz-Morgan types and redshifts where known, is also included.
- ID:
- ivo://CDS.VizieR/I/222
- Title:
- San Fernando AC Zone Data Reduced to ACRS
- Short Name:
- I/222
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The U.S. Naval Observatory is in the process of making new reductions of the Astrographic Catalogue (AC) using a modern reference system, the ACRS, which represents the system of the FK5. The data from the San Fernando Zone, whose plates are centered between declinations -3 and -9 degrees (eq. 1900), have been analyzed for scale, rotation, tilt, coma, magnitude equation, radial distortion and distortions introduced by the use of reseaux in the Carte du Ciel program. The result is a positional catalog of over 225,000 stars on eq. J2000.0, epoch of observation. Additionally, all stars have been matched with the Tycho Input Catalog (revised); those numbers have been added for additional identification purposes.
- ID:
- ivo://CDS.VizieR/J/A+AS/95/355
- Title:
- Santiago catalogue of 1105 FK5 stars
- Short Name:
- J/A+AS/95/355
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The positions in right ascension and declination of 1105 FK5 stars, observed with a Meridian Circle during the period 1979 to 1991, are given. The average mean square error of a position, for the whole catalog, is +/-0.009s in right ascension and +/-0.10arcsec in declination. The mean epoch of the catalog is 1983.148.
- ID:
- ivo://CDS.VizieR/J/A+A/645/A76
- Title:
- Saturnian satellites in the Gaia ref. frame
- Short Name:
- J/A+A/645/A76
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a remeasurement of old photographic plates, providing important raw data for dynamical studies of the Saturnian satellite system. The unprecedentedly accurate realization of the Gaia reference frame allows us to make a precise calibration of digitized astronegatives of the Saturnian satellite images. We reprocessed 357 astronegatives taken with the 26-inch refractor and the normal astrograph of the Pulkovo Observatory between 1972 and 2007 to obtain the positions of the main Saturnian moons in the second Gaia data release (Gaia DR2) system. Photographic plates were digitized with the Pulkovo Mobile Digitizing Device (MDD) scanner. The New Astrometric Reduction of Old Observations (NAROO) digitizer at the Paris Observatory was used to calibrate the scanned images. Satellite image centering and astrometric reduction were performed. In total, 6487 positions (equatorial coordinates) have been determined with an accuracy of 50mas. This is confirmed by a comparison of our data with modern ephemerides. The verification of the results was performed using data from past close approaches by Saturnian satellites to Gaia reference stars, showing the adequacy of the current residual analysis. A joint review of the Pulkovo and the United States Naval Observatory (USNO) intersatellite positions allows us to conclude about the existence of faint systematic effects in the satellite theories of motions at the 10mas level.
- ID:
- ivo://CDS.VizieR/I/44
- Title:
- Second Cat of Fundamental Stars (SPF2)
- Short Name:
- I/44
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Catalogue SPF2 was obtained from observations of the fundamental FK4 stars as a reference stars for SRS, BS and DS star. Observations were made by Pulkovo observers in the declination zone -42 to -90 and +16 to -16 degrees using Repsold Meridian Circle of the Cerro Calan Observatory (Santiago, Chile) from 1963 to 1968.
- ID:
- ivo://CDS.VizieR/J/A+AS/103/427
- Title:
- Second Quito Astrolabe Catalogue
- Short Name:
- J/A+AS/103/427
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The paper contains 515 individual corrections {DELTA}{alpha} and 235 corrections {DELTA}{delta} to FK5 and FK5Supp. stars and 50 corrections to their proper motions computed from observations made with the classical Danjon astrolabe OPL-13 at Quito Astronomical Observatory of Ecuador National Polytechnical School during a period from 1964 to 1983. These corrections cover the declination zone from -30{deg} to +30{deg}. Mean probable errors of catalogue positions are 0.047" in {alpha}cos{delta} and 0.054" in {delta}. The systematic trends of the catalogue {DELTA}{alpha}{alpha}cos{delta}, {DELTA}{alpha}{delta}cos{delta}, {DELTA}{delta}{alpha}, {DELTA}{delta}{delta} are presented for the observed zone.
