On the nature of an ejection event in the jet of 3C111

TL;DR

This paper investigates the ejection event in the jet of galaxy 3C111, proposing a dense material perturbation model supported by hydrodynamics simulations, estimating the event's lifetime at about 36 days.

Contribution

It introduces a new perturbation model involving increased jet density to explain the ejection event, supported by relativistic hydrodynamics and emission simulations.

Findings

The perturbation is modeled as increased jet density without changing Lorentz factor.

An increase in Lorentz factor alone does not reproduce the observed flare evolution.

The ejection event's lifetime is estimated at 36±7 days.

Abstract

We present a possible scenario for the ejection of a superluminal component in the jet of the Broad Line Radio Galaxy 3C111 in early 1996. VLBI observations at 15 GHz discovered the presence of two jet features on scales smaller than one parsec. The first component evolves downstream, whereas the second one fades out after 1 parsec. We propose the injection of a perturbation of dense material followed by a decrease in the injection rate of material in the jet as a plausible explanation. This scenario is supported by 1D relativistic hydrodynamics and emission simulations. The perturbation is modeled as an increase in the jet density, without modifying the original Lorentz factor in the initial conditions. We show that an increase of the Lorentz factor in the material of the perturbation fails to reproduce the observed evolution of this flare. We are able to estimate the lifetime of the ejection event in 3C111 to be 36\pm7 days.