Evidence of the Gaia-VLBI position differences being related to radio source structure
| Autor: | Nataliya Zubko, Susanne Lunz, Harald Schuh, James M. Anderson, Tuomas Savolainen, Ming H. Xu |
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| Přispěvatelé: | Department of Electronics and Nanoengineering, GFZ German Research Centre for Geosciences, Technische Universität Berlin, Anne Lähteenmäki Group, Finnish Geospatial Research Institute, Aalto-yliopisto, Aalto University |
| Rok vydání: | 2021 |
| Předmět: |
010504 meteorology & atmospheric sciences
Astrophysics::High Energy Astrophysical Phenomena jets [galaxies] FOS: Physical sciences Context (language use) Astrophysics Astrophysics::Cosmology and Extragalactic Astrophysics 01 natural sciences Root mean square Position (vector) 0103 physical sciences Very-long-baseline interferometry reference systems 010303 astronomy & astrophysics Instrumentation and Methods for Astrophysics (astro-ph.IM) Astrophysics::Galaxy Astrophysics 0105 earth and related environmental sciences Physics Astrophysics::Instrumentation and Methods for Astrophysics Astronomy and Astrophysics Astrometry Geodesy Astrophysics - Astrophysics of Galaxies galaxies [radio continuum] Amplitude Space and Planetary Science Astrophysics of Galaxies (astro-ph.GA) active [galaxies] International Celestial Reference Frame astrometry Astrophysics - Instrumentation and Methods for Astrophysics Arc length |
| Zdroj: | Astronomy and Astrophysics |
| Popis: | We report the relationship between the $Gaia$--VLBI position differences and the magnitudes of source structure effects in VLBI observations. Because the $Gaia$--VLBI position differences are statistically significant for a considerable number of common sources, we attempt to discuss and explain these position differences based on VLBI observations and available source images at cm-wavelengths. Based on the derived closure amplitude root-mean-square (CARMS), which quantifies the magnitudes of source structure effects in the VLBI observations used for building the third realization of the International Celestial Reference Frame, the arc lengths and normalized arc lengths of the position differences are examined in detail. The radio jet directions and the directions of the $Gaia$--VLBI position differences are investigated for a small sample of sources. Both the arc lengths and normalized arc lengths of the $Gaia$ and VLBI positions are found to increase with the CARMS values. The majority of the sources with statistically significant position differences are associated with the sources having extended structure. Radio source structure is the one of the major factors of these position differences, and it can be the dominate factor for a number of sources. The vectors of the $Gaia$ and VLBI position differences are parallel to the radio-jet directions, which is confirmed with stronger evidence. Comment: 13 pages, 7 figures, and 5 tables. Accepted to be published in Astronomy & Astrophysics |
| Databáze: | OpenAIRE |
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