The Formation of Slow-Massive-Wide Jets

TL;DR

This paper presents a model explaining the formation of slow, massive, wide jets in astrophysical objects, where fast jets interact with surrounding gas to produce slower, more massive outflows, relevant to planetary nebulae and active galactic nuclei.

Contribution

The paper introduces a new model for SMW jet formation involving shock interactions of initial fast jets with surrounding gas, a process not previously detailed.

Findings

SMW jets are formed by shocks from fast jets interacting with surrounding gas.

The model requires sufficient surrounding gas and low radiative losses.

It explains observed SMW jets in planetary nebulae and active galactic nuclei.

Abstract

I propose a model for the formation of slow-massive-wide (SMW) jets by accretion disks around compact objects. This study is motivated by claims for the existence of SMW jets in some astrophysical objects such as in planetary nebulae (PNs) and in some active galactic nuclei in galaxies and in cooling flow clusters. In this model the energy still comes from accretion onto a compact object. The accretion disk launches two opposite jets with velocity of the order of the escape velocity from the accreting object and with mass outflow rate of ~1-20% of the accretion rate as in most popular models for jet launching; in the present model these are termed fast-first-stage (FFS) jets. However, the FFS jets encounter surrounding gas that originates in the mass accretion process, and are terminated by strong shocks close to their origin. Two hot bubbles are formed. These bubbles accelerate the surrounding gas to form two SMW jets that are more massive and slower than the FFS jets. There are two conditions for this mechanism to work. Firstly, the surrounding gas should be massive enough to block the free expansion of the FFS jets. Most efficiently this condition is achieved when the surrounding gas is replenished. Secondly, the radiative energy losses must be small.