Related papers: How accurate are SuperCOSMOS positions?

In this pilot investigation, precise optical positions in the FK5 system are presented for a set of 16 compact extragalactic radio sources, which will be part of the future radio--optical reference frame. The 0.9 m KPNO and CTIO telescopes…

Using the adaptive optics facilities at the 200-in Hale and 10-m Keck II, we observed in the near infrared a sample of 12 binary and multiple stars and one open cluster. We used the near diffraction limited images of these systems to…

We compare cosmic microwave background lensing convergence maps derived from South Pole Telescope (SPT) data with galaxy survey data from the Blanco Cosmology Survey, the Wide-field Infrared Survey Explorer, and a new large Spitzer/IRAC…

Reference systems and frames are crucial for high precision absolute astrometric work, and their foundations must be well-defined. The current frame, the International Celestial Reference Frame, will be discussed: its history, the use of…

The second release of Gaia data (Gaia DR2) contains the astrometric parameters for more than half a million quasars. This set defines a kinematically non-rotating reference frame in the optical domain referred to as the Gaia-CRF2. The…

We investigate a sample of 3412 {\it International Celestial Reference Frame} (ICRF3) extragalactic radio-loud sources with accurate positions determined by VLBI in the S/X band, mostly active galactic nuclei (AGN) and quasars, which are…

The Low Frequency Array (LOFAR) Two-metre Sky Survey (LoTSS) is a sensitive, high-resolution 120-168 MHz survey split across multiple tiers over the northern sky. The first LoTSS Deep Fields data release consists of deep radio continuum…

The alignment between the radio-based International Celestial Reference Frame (ICRF) and the optical Gaia Celestial Reference Frame (Gaia-CRF) is critical for multi-waveband astronomy, yet systematic offsets at the optical bright end (G<13)…

Using very long baseline interferometry data for the sources that comprise the third International Celestial Reference Frame (ICRF3), we examine the quality of the formal source position uncertainties of ICRF3 by determining the excess…

A possible method for linking the optical Gaia Celestial Reference Frame (GCRF) to the VLBI-based International Celestial Reference Frame (ICRF) is to use radio stars in a manner similar to that in the linking of the Hipparcos Celestial…

We report redshifts, magnitudes and morphological classifications for 5369 galaxies with $m_B \leq 15.5$ and 57 galaxies fainter than this limit, in two regions covering a total of 1.70 steradians in the southern celestial hemisphere. The…

We present the COSMOS2015 catalog which contains precise photometric redshifts and stellar masses for more than half a million objects over the 2deg$^{2}$ COSMOS field. Including new $YJHK_{\rm s}$ images from the UltraVISTA-DR2 survey,…

It is expected that the European Space Agency mission Gaia will make possible to determine coordinates in the optical domain of more than 500000 quasars. In 2006, a radio astrometry project was launched with the overall goal to make…

We present an updated K band (24 GHz) celestial reference frame (CRF) constructed from 3.5 million Very Long Baseline Interferometry (VLBI) observations collected during 211 observing epochs between May 2002 and December 2025 using the Very…

The second data release of the LOFAR Two-Metre Sky Survey (LoTSS) covers 27% of the northern sky, with a total area of $\sim 5,700$ deg$^2$. The high angular resolution of LOFAR with Dutch baselines (6 arcsec) allows us to carry out optical…

We have conducted a widefield, wideband, snapshot survey using the Australian SKA Pathfinder (ASKAP) referred to as the Rapid ASKAP Continuum Survey (RACS). RACS covers $\approx$ 90% of the sky, with multiple observing epochs in three…

The most precise realization of inertial reference frame in astronomy is the catalogue of 212 defining extragalactic radiosources with coordinates obtained during VLBI observation runs in 1979-1995. IAU decided on the development of the…

We measure photometric redshifts and spectral types for galaxies in the COSMOS survey. We use template fitting technique combined with luminosity function priors and with the option to simultaneously estimate dust extinction (i.e. E(B-V))…

We present the astrometric calibration of the Beijing-Arizona Sky Survey (BASS). The BASS astrometry was tied to the International Celestial Reference Frame via the \emph{Gaia} Data Release 2 reference catalog. For effects that were stable…

The second IBIS/ISGRI survey has produced a catalogue containing 209 hard X-ray sources visible down to a flux limit of around 1 milliCrab. The point source location accuracy of typically 1-3 arcminutes has allowed the counterparts for most…