Large Kinetic Power in FRII Radio Jets

TL;DR

This study estimates the kinetic powers and ages of four FR II radio jets, revealing they carry large amounts of energy, often exceeding minimum energy estimates, indicating significant invisible components like thermal leptons or protons.

Contribution

It provides detailed dynamical modeling of FR II radio sources, quantifying their kinetic powers and energies, and highlighting the presence of substantial invisible energy components.

Findings

Kinetic powers range from 0.02 to 10 times the Eddington luminosity.

Total cocoon energy exceeds minimum energy estimates by factors of 2 to 160.

Large kinetic powers suggest significant invisible components in jet composition.

Abstract

We investigate the total kinetic powers (L_{j}) and ages (t_{age}) of powerful jets of four FR II radio sources (Cygnus A, 3C 223, 3C 284, and 3C 219) by the detail comparison of the dynamical model of expanding cocoons with observed ones. It is found that these sources have quite large kinetic powers with the ratio of L_{j} to the Eddington luminosity (L_{Edd}) resides in $0.02 <L_{j}/L_{Edd} <10$. Reflecting the large kinetic powers, we also find that the total energy stored in the cocoon (E_{c}) exceed the energy derived from the minimum energy condition (E_{min}): $2< E_{c}/E_{min} <160$. This implies that a large amount of kinetic power is carried by invisible components such as thermal leptons (electron and positron) and/or protons.