Physics of the central region in the quasar 0850+581

TL;DR

This study investigates the frequency-dependent core shift in the quasar 0850+581 using multi-frequency VLBA observations, revealing insights into the jet's physical conditions and geometry at parsec scales.

Contribution

It provides the first detailed analysis of the core shift in quasar 0850+581 across multiple frequencies, improving understanding of jet physics.

Findings

Detected large core shift between 2 and 8 GHz

Estimated the absolute geometry of the jet origin

Constrained physical conditions in the parsec-scale jet

Abstract

The apparent position of the origin (core) of extragalactic radio jets shifts with the observing frequency, owing to synchrotron self-absorption and external absorption. One of the largest core shifts was detected by us in the quasar 0850+581 between 2 and 8 GHz. We have followed this up recently by a dedicated VLBA experiment at 5, 8, 15, 24, and 43 GHz. First results from this study enabled estimating the absolute geometry and physical conditions in the parsec-scale jet origin.