Structure of the Radio Source 3C 120 at 8.4 GHz from VLBA+ Observations in 2002

TL;DR

This study presents high-resolution VLBA+ observations of the radio source 3C 120 at 8.4 GHz, revealing superluminal jet motions and their deceleration over distance, indicating jet-medium interactions.

Contribution

First detailed VLBA+ imaging of 3C 120 at multiple epochs showing jet knot motions and their deceleration, providing insights into jet dynamics and interactions.

Findings

Jet knots exhibit superluminal speeds decreasing from 5.40c to 2.00c.

Jet deceleration suggests interaction with surrounding medium.

Observations support models of jet-medium interaction affecting jet propagation.

Abstract

Maps of the radio source 3C 120 obtained from VLBA+ observations at 8.4 GHz at five epochs in January - September 2002 are presented. The images were reconstructed using the maximum entropy method and the Pulkovo VLBImager software package for VLBI mapping. Apparent superluminal motions of the brightest jet knots have been estimated. The speeds of jet knots decreases with distance from the core, changing from 5.40+-0.48c $ to 2.00+-0.48c over 10 mas (where c is the speed of light) for a Hubble constant of 65 km/s/Mpc. This can be explained by interaction of the jet with the medium through which it propagates.