ner_tags: O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B-Citation I-Citation I-Citation O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B-Citation I-Citation O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O
tokens: star formation rate per unit area , if we have one supernova per mass M SN of stars formed, then the supernova rate per unit area is . The momentum and energy injected per supernova are p SN and E SN , respectively, giving momentum and energy injection rates per unit area and . The energy injection rate into turbulent motions is (equation 17 ) and the ratio of this to the total supernova energy budget is where the numerical evaluation is for our canonical values p SN 310 5 M kms 1 and E SN 10 51 erg. Thus, for the values of found in our simulation, only a small portion of the supernova energy budget is consumed by driving turbulence. Similarly, the wind kinetic luminosity per unit area is of the order of and the ratio of this to the supernova energy injection rate is where the numerical evaluation is for M SN 100M and v esc 300kms 1 , and is the mass loading factor, which for our simulations is 1. Thus we conclude that neither launching the wind nor driving the turbulence consumes an appreciable fraction of the total supernova energy available. Instead, the energy released by supernovae must either be lost to radiation, or must go into a hot wind that carries it out. Unfortunately, our model does not allow computation of the partition between these two forms of energy loss, and the simulations that have been published to date are not helpful in addressing this question answering it correctly requires simulating with enough resolution to resolve the SedovTaylor phase of supernova remnant expansion, without using any artificial methods to lower the density in the vicinity of the supernovae. As we discuss in Section 4.6 , no published simulations meet these criteria. Observations of superbubbles away from galactic centres suggest that radiation cannot be the primary loss mechanism (Rosen etal. 2014 ), but it is unclear whether we can generalize these conclusions to the very different environment of the CMZ. If radiative losses do not dominate, then the hot wind must carry an energy flux of order , and given our result that 50percent of the incoming gas is converted to stars, this implies an energy flux ergs 1 . This material will mostly be launched from the star-forming ring at 100pc. The non-thermal particle energy injection rate should be 10percent of the hot gas energy budget, implying ergs 1 . Because non-thermal particle acceleration happens even if the hot gas does not vent, and because the non-thermal particles have long mean-free paths and thus should be able to escape the disc, this estimate should hold even if the primary loss mechanism is radiation rather than a hot wind. Cosmic ray escape is confirmed observationally (Crocker 2012 , and references therein): the diffuse non-thermal emission from the CMZ in radio continuum and -ray bands implies that only a small fraction (10percent) of the power injected into non-thermal particles accelerated in the CMZ is lost in situ radiatively; most of this power is carried off by escaping cosmic