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A new version of the Optical Characteristics of Astrometric Radio Sources (OCARS) catalog is presented. This compiled catalog includes radio sources observed in different VLBI programs and experiments that result in source position determination, their redshift, and photometry in the visible and near-infrared bands. A cross-identification table between the OCARS and other catalogs is also provided. The status of the catalog as of 2018 September 7 is described in this paper. The OCARS catalog currently contains 6432 sources, of which 3895 have redshift data and 5479 have photometric data. Compared with the previous version, the current version has been enriched with extended redshift and photometry information, and cross-identification with several catalogs in radio, optical, infrared, ultraviolet, X-ray, and gamma-ray bands. The OCARS catalog is updated every few weeks on average to incorporate new data that appear in the NASA/IPAC Extragalactic Database (NED), SIMBAD database, and in the literature.
A comparison was made between $Gaia$ magnitudes and magnitudes obtained from ground-based observations for astrometric radio sources . The comparison showed that these magnitudes often not agree well. There may be several reasons for this disagreemen
The Hubble Source Catalog is designed to help optimize science from the Hubble Space Telescope by combining the tens of thousands of visit-based source lists in the Hubble Legacy Archive into a single master catalog. Version 1 of the Hubble Source Ca
We present a catalog of Faraday rotation measures (RMs) and redshifts for 4003 extragalactic radio sources detected at 1.4 GHz, derived by identifying optical counterparts and spectroscopic redshifts for linearly polarized radio sources from the NRAO
We compiled a catalog of Faraday rotation measures (RMs) for 4553 extragalactic radio point sources ublished in literature. These RMs were derived from multi-frequency polarization observations. The RM data are compared to those in the NRAO VLA Sky S
URAT1 is an observational, astrometric catalog covering most of the Dec >= -15 deg area and a magnitude range of about R = 3 to 18.5. Accurate positions (typically 10 to 30 mas standard error) are given for over 228 million objects at a mean epoch ar