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Main Title: Evidence of the Gaia–VLBI position differences being related to radio source structure
Author(s): Xu, Ming H.
Lunz, Susanne
Anderson, James M.
Savolainen, Tuomas
Zubko, Nataliya
Schuh, Harald
Type: Article
Abstract: Context. We report the relationship between the Gaia–VLBI position differences and the magnitudes of source structure effects in VLBI observations. Aims. Because the Gaia–VLBI position differences are statistically significant for a considerable number of common sources, we discuss and attempt to explain these position differences based on VLBI observations and available source images at centimeter wavelengths. Methods. 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. Results. 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 dominant 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 via stronger evidence.
Subject(s): galaxies
reference systems
radio continuum
Issue Date: 2-Apr-2021
Date Available: 13-Apr-2021
Language Code: en
DDC Class: 520 Astronomie und zugeordnete Wissenschaften
Journal Title: Astronomy and Astrophysics
Publisher: EDP Sciences
Volume: 647
Article Number: A189
Publisher DOI: 10.1051/0004-6361/202040168
EISSN: 1432-0746
ISSN: 0004-6361
TU Affiliation(s): Fak. 6 Planen Bauen Umwelt » Inst. Geodäsie und Geoinformationstechnik » FG Satellitengeodäsie
Appears in Collections:Technische Universität Berlin » Publications

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