The jet feedback mechanism (JFM) in stars, galaxies and clusters

Abstract

I review the influence jets and the bubbles they inflate might have on their ambient gas as they operate through a negative jet feedback mechanism (JFM). I discuss astrophysical systems where jets are observed to influence the ambient gas, in many cases by inflating large, hot, and low-density bubbles, and systems where the operation of the JFM is still a theoretical suggestion. The first group includes cooling flows in galaxies and clusters of galaxies, star-forming galaxies, young stellar objects, and bipolar planetary nebulae. The second group includes core collapse supernovae, the common envelope evolution, the grazing envelope evolution, and intermediate luminosity optical transients. The suggestion that the JFM operates in these four types of systems is based on the assumption that jets are much more common than what is inferred from objects where they are directly observed. Common to all eight types of systems reviewed here is the presence of a compact object inside an extended ambient gas. The ambient gas serves as a potential reservoir of mass to be accreted on to the compact object. If the compact object launches jets as it accretes mass, the jets might reduce the accretion rate as they deposit energy to the ambient gas, or even remove the entire ambient gas, hence closing a negative feedback cycle.

Mass Distribution in Galaxy Cluster Cores

“…In the standard picture, radio-mechanical feedback from AGN jets hosted by the central brightest cluster galaxy (BCG) provides the required energy by inflating cavities in the X-ray atmosphere, which rise buoyantly and subsequently drive turbulence, weak shocks, and sound waves. Exactly how this feedback energy couples to the ICM is unclear (see review by Soker 2016), with recent work suggesting that gas mixing may be the dominant heating mechanism alongside contributions from turbulence and shock heating (Hillel & Soker 2016a, 2016bYang & Reynolds 2016). Indeed the relative importance of these mechanisms may change during episodes of AGN activity (Li et al 2015), though the time-averaged energy output of the AGN is more than sufficient to counteract the expected ICM cooling (see McNamara & Nulsen 2007, 2012Fabian 2012 for reviews).…”

AGN jet-driven stochastic cold accretion in cluster cores

“…There is a general consensus that the intracluster medium (ICM) in low-entropy galaxy cluster cores is able to remain in rough global thermal equilibrium because the powerful jets from the central AGN inject sufficient energy to compensate for radiative losses (for a review, see McNamara & Nulsen 2007, 2012Fabian 2012;Soker 2016). There are, however, a number of key issues associated with this "radio feedback" schema that have yet to be firmly pinned down, one of which is: how is the central supermassive black hole (SMBH) able to transport sufficient energy to the cluster core (∼ 10s of kpc) at a timescale shorter than the core cooling time ( 0.5 Gyr).…”

Core collapse supernova remnants with ears

“…There are three lines of arguments to support the operation of the JFM in the explosion of massive stars (Soker 2016b). (1) Observations show that most CCSNe explode with a typical energy (mainly the kinetic energy), that is about equal to and up to several times the binding energy of the ejected mass, E explosion ≃ few × E bind ≈ 10 51 erg.…”