Starbursts: Musings on the astrophysics of runaway star formation
Tuesday 14 October 2014
to 14:30 at
Jay Gallaghar (U Wisconsin-Madison)
Star formation in the disks of most galaxies, including the neighborhood of the Sun, proceeds slowly such that the available gas supplies can support current rates for thousands of millions of years. This lazy star formation mode evidently results from a combination of limited gas supplies and the negative feedback from young massive stars that can impede further star formation. Starburst galaxies, however, have star formation rates that are factors of 10-100 times higher, producing huge populations of short-lived massive stars. Despite the presence of the high mass stars and their negative feedback via ionizing radiation and supernovae, starbursts can be sustained over the lifetimes of multiple generations of massive stars. The environments of starbursts thus differ substantially from those in normal disks, and resemble conditions in rapidly evolving young galaxies. This talk will review conditions that lead to starbursts in nearby galaxies and consider the astrophysical consequences. These include high internal energy densities, galactic winds, and intense fluxes of cosmic rays. Cosmic rays, in particular, are key factors in the radio synchrotron and gamma ray emission from starburst galaxies, while also potentially playing a role in the production of high energy cosmic neutrinos.
(host: A. Adamo)