THE BICONICAL KILOPARSEC STRUCTURE GENERATED BY NUCLEAR STARBURSTS

Two-dimensional calculations of the hydrodynamics produced by nuclear starbursts, taking into consideration the accretion or infall of disc matter on to the heart of the starburst, are here shown to lead to sta tionary solutions that naturally account for the kpc-scale biconical X -ray and optically detected filamentary structure. The calculated flow s are critically compared with former models and with observations of nuclear starbursts. For the infall models, we find that the mechanical energy power of the nuclear cluster must exceed a threshold value, im posed by the rate of disc mass accretion, to undergo blowout. This, co mbined with an initial mass function (IMF), is shown to regulate the m inimum amount of mass that a starburst needs to generate kpc-scale out flows.