The jet-disk symbiosis without maximal jets: 1-D hydrodynamical jets revisited

• Published in: arXiv.org 2017-03
• Main Authors: Crumley, Patrick, Ceccobello, Chiara, Connors, Riley M T, Cavecchi, Yuri
• Format: Article
• Language: English
• Subjects: Active galactic nuclei; Binary stars; Euler-Lagrange equation; Flux density; Internal energy; Jets; Lorentz factor; Luminosity; Radio spectra; Symbiosis; X ray binaries; X ray stars
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.1703.02842

In this work we discuss the recent criticism by Zdziarski of the maximal jet model derived in Falcke & Biermann (1995). We agree with Zdziarski that in general a jet's internal energy is not bounded by its rest-mass energy density. We describe the effects of the mistake on conclusions that have been made using the maximal jet model and show when a maximal jet is an appropriate assumption. The maximal jet model was used to derive a 1-D hydrodynamical model of jets in agnjet, a model that does multiwavelength fitting of quiescent/hard state X-ray binaries and low-luminosity active galactic nuclei. We correct algebraic mistakes made in the derivation of the 1-D Euler equation and relax the maximal jet assumption. We show that the corrections cause minor differences as long as the jet has a small opening angle and a small terminal Lorentz factor. We find that the major conclusion from the maximal jet model, the jet-disk symbiosis, can be generally applied to astrophysical jets. We also show that isothermal jets are required to match the flat radio spectra seen in low-luminosity X-ray binaries and active galactic nuclei, in agreement with other works.