Extragalactic Radio Sources with Large Changes in Their Apparent Coordinates

Abstract

We have analyzed the time series of coordinates for 5468 radio sources obtained from geodetic VLBI observations in 1993–2024. We have identified 49 objects whose coordinates change within the range from 6 to 143 mas. We have revealed several types of astrometric instability probably associated with different astrophysical processes in active galactic nuclei. In some cases, the coordinates change rapidly over a relatively short time interval (1–3 years). These peculiarities should be taken into account while compiling the next fundamental astrometric ICRF catalogue.