Multi-epoch radio source structure analysis of 11 calibrators at 2.3 and 8.4 GHz in the south

TL;DR

This study analyzes the multi-epoch radio structures of 11 calibrator sources in the Southern Hemisphere at 2.3 and 8.4 GHz, revealing jet-structures and potential core-shift phenomena through VLBI data and flux comparisons.

Contribution

It provides a detailed multi-epoch VLBI analysis of southern calibrators, highlighting structural variability and flux behavior at two radio frequencies.

Findings

Jet-like structures observed in most sources

Structural variability evident in S/X-band analysis

Indications of core-shift phenomenon

Abstract

We present the source structure analysis of 11 calibrator sources in the Southern Hemisphere at 2.3 (S-band) and 8.4 GHz (X-band). We used multi-epoch very long baseline interferometry source maps available in the radio fundamental catalog to analyse jet-structure variability and also used fluxes from the Goddard Space Flight Center database to see whether these two complement each other or not. Also, total fluxes from the maps were plotted with the fluxes from the database. The S/X-band light curve analysis provides a more clear picture of the structural variability at the S/X-band also indicates the possibility of the "core-shift" phenomenon. We found jet-like structures in the majority of the sources in the sample.