| Description: | Today's colloquium will be by Marco Spaans of the Kapteyn Astronomical Institute, Groningen. In the colloquium, high resolution 3D hydrodynamical simulations of the ISM within ~30 pc of a supermassive black hole (~107 Mo) are presented. The feedback from supernovae is included. An inhomogeneous disk is formed with a highly turbulent velocity field. An average supernova rate of ~5×10-5 yr-1 is large enough to maintain these structures. Gas column densities toward the nucleus larger than 1022 cm-2 are observed. However, the column densities are distributed over almost two orders of magnitude around the mean for any given viewing angle due to the clumpy nature of the torus. Black hole accretion drives the production of X-rays, which impinge on orbiting gas clouds. This strong X-ray irradiation causes the temperature of dense molecular gas to increase, even for columns larger than 1023 cm-2. This in turn leads to a top-heavy initial mass function through Jeans mass arguments. Consequences for galaxy evolution are explored. |
