Evidence of the Gaia-VLBI position differences being related to radio source structure

Minghui Xu, Susanne Lunz, James M. Anderson, Tuomas Savolainen, Nataliya Zubko, Harald Schuh

Research output: Contribution to journalArticleScientificpeer-review

2 Citations (Scopus)
5 Downloads (Pure)

Abstract

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.
Original languageEnglish
Article numberA189
Number of pages13
JournalAstronomy & Astrophysics
Volume647
DOIs
Publication statusPublished - 1 Mar 2021
MoE publication typeA1 Journal article-refereed

Keywords

  • galaxies: active
  • galaxies: jets
  • astrometry
  • reference systems
  • radio continuum: galaxies

Fingerprint

Dive into the research topics of 'Evidence of the Gaia-VLBI position differences being related to radio source structure'. Together they form a unique fingerprint.

Cite this