Results 111 to 120 of about 11,793 (207)

Precise absolute astrometry from the VLBA imaging and polarimetry survey at 5 GHz

, 2011
We present in this paper accurate positions of 857 sources derived from the astrometric analysis of 16 eleven-hour experiments from the Very Long Baseline Array imaging and polarimetry survey at 5 GHz (VIPS).
Abdo, Adelman-McCarthy, Beasley, Fomalont, G. B. Taylor, Healey, Helmboldt, Kovalev, L. Petrov, Lindegren, Linford, Lister, Ma, Marscher, Petrov, Petrov, Petrov, Petrov, Ros, Schaer, Taylor, Taylor, York   +22 more
core   +1 more source

Precise optical and radio astrometry of the quasar 1928 + 738

The Astronomical Journal, 1987
Precise optical and radio positions of the quasar 1928 + 738 have been obtained in the FK4 system from direct photography and VLA astrometry. In addition, for the first time, precise astrometric positions have been obtained from CCD frames related to the FK4 system by faint reference stars derived from the photographic plates.
C. de Vegt, J. Schramm, K. J. Johnston
openaire   +1 more source

VLBI observations of weak extragalactic radio sources for the alignment of the future GAIA frame with the ICRF

, 2007
The space astrometry mission GAIA will construct a dense optical QSO-based celestial reference frame. For consistency between the optical and radio positions, it will be important to align the GAIA frame and the International Celestial Reference Frame ...
G. Bourda, P. Charlot, Perryman, R. Porcas, S. Garrington, Véron-Cetty   +5 more
core   +2 more sources

87th Annual Meeting of the Meteoritical Society 2025: Abstracts

Meteoritics &Planetary Science, Volume 60, Issue S1, Page 30-350, August 2025.
wiley   +1 more source

First Detection of CH3OD in Prestellar Cores

The Astrophysical Journal
The isotopic ratios of deuterated methanol derived around protostars are commonly used to infer the physical conditions under which they formed in the earlier prestellar stage.
Beatrice M. Kulterer, Asunción Fuente, Maria N. Drozdovskaya, Silvia Spezzano, Gisela Esplugues, David Navarro-Almaida, Marina Rodríguez Baras, Angèle Taillard, Karin Öberg   +8 more
doaj   +1 more source

Origin and Evolution of Enceladus's Tidal Dissipation. [PDF]

Space Sci Rev, 2023
Nimmo F, Neveu M, Howett C.
europepmc   +1 more source

Innovative approach for modelling gravity-induced signal path variations of VLBI radio telescopes

Earth, Planets and Space
Gravitationally induced deformation of the receiving unit of radio telescopes used for Very Long Baseline Interferometry (VLBI) distorts the observations and biases the deduced products.
Michael Lösler, Cornelia Eschelbach, Ansgar Greiwe, Boye Zhou, Lucia McCallum   +4 more
doaj   +1 more source

Fermi Unassociated Sources in the MeerKAT Absorption Line Survey

The Astrophysical Journal
Over 2000 γ -ray sources identified by the Large Area Telescope on NASA's Fermi Gamma-ray Space Telescope are considered unassociated, meaning that they have no known counterparts in any other frequency regime.
Morgan Himes, Preshanth Jagannathan, Dale A. Frail, Frank Schinzel, Neeraj Gupta, S. A. Balashev, F. Combes, P. P. Deka, H.-R. Klöckner, E. Momjian, J. D. Wagenveld   +10 more
doaj   +1 more source

Radio Astronomical Antennas in the Central African Region to Improve the Sampling Function of the VLBI Network in the SKA Era? [PDF]

Sensors (Basel), 2022
Atemkeng M, Okouma P, Maina E, Ianjamasimanana R, Zambou S.   +4 more
europepmc   +1 more source

Metrics of Astrometric Variability in the International Celestial Reference Frame. I. Statistical Analysis and Selection of the Most Variable Sources

The Astrophysical Journal Supplement Series
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 astrometric ...
Phil Cigan, Valeri V. Makarov, Nathan J. Secrest, David Gordon, Megan C. Johnson, Sebastien Lambert   +5 more
doaj   +1 more source