Theory and Models of the Disk-Halo Connection

Modelling the Disk-Halo Interaction in Galaxies

¹ Zentrum für Astronomie und Astrophysik, Technische Universität Berlin, Hardenbergstr. 36, 0623 Berlin, Germany
² Department of Mathematics, University of Évora, R. Romão Ramalho 59, 7000 Évora, Portugal
³ Institut für Astronomie, University of Vienna, Türkenschanzstr. 17, 1180 Vienna, Austria
⁴ P.N. Lebedev Institute, Leninskii pr, 53, 119991 Moscow, Russia

Abstract

We review the evolution of the interstellar medium in disk galaxies, and show, both analytically and by numerical 3D hydrodynamic simulations, that the disk-halo connection is an essential ingredient in understanding the evolution of star forming galaxies. Depending on the star formation rate of the underlying gaseous disk, a galactic fountain is established. If the star formation rate is sufficiently high and/or cosmic rays are well coupled to the thermal plasma, a galactic wind will be formed and lead to a secular mass loss of the galaxy. Such a wind leaves a unique imprint on the soft X-ray spectra in edge-on galaxies, with delayed recombination being one of its distinctive features. We argue that synthetic spectra, obtained from self-consistent dynamical and thermal modeling of a galactic outflow, should be treated on an equal footing as observed spectra. We show that it is thus possible to successfully fit the spectrum of the starburst galaxy NGC 3079