Special Universe Talk: Multi-phase gaseous galaxy halos

by Ralph Tuellmann ((CfA Harvard))

Thursday 14 Jul 2011, 13:30 → 15:00 Europe/Berlin

seminar room (basement) (Cluster building, Garching)

Multi-phase gaseous galaxy halos are most frequently detected in actively star-forming late-type spiral galaxies and traced through their optical, radio, and X-ray emission. In all known cases, the presence of those multi-phase galaxy halos could be clearly attributed to stellar feedback processes in the disk. The halo appears to be very important during the evolution of a galaxy as this is the site where vast amounts of ionized gas (10^6 - 10^8 M_sol), produced by SNe, SNRs, and stellar winds, can be stored without disrupting the entire disk plane. Therefore, the halo serves as a pressure reservoir for the hot gas and thus as a 'coolant' for the disk. On the other hand, hierarchical galaxy formation models also predict the existence of extended gaseous halos as a consequence of gradual infall of primordial intergalactic gas onto the disk plane. Such continuing gas infall seems to be vital to explain the extended star formation histories of isolated spiral galaxies and the so called G-dwarf problem. Ralph will review our knowledge on the formation and evolution of those kinds of halos, outline the current limitations of existing observations and theoretical models, and point out some new aspects which may yield a more consistent picture on galaxy formation and evolution.

Slides GalaxyHaloes_IGM_TalkExcCl_Tuellmann2011.pdf