Special seminar

Speaker: Elizabeth Tasker (University of Florida/NAOJ)
Title: The Evolution of Giant Molecular Clouds in Global Disk Galaxy Simulations
Date (JST): Fri, Oct 02, 2009, 13:30 - 15:00
Place: Seminar Room at IPMU Prefab. B
Abstract: The formation of stars from gas in disk galaxies is one of the most
basic processes controlling galactic evolution. While there are many
other important effects, such as galaxy interactions and infall of
diffuse gas, ultimately a large fraction of the gas settles into a
rotationally supported disk where the majority of the stellar
population is born. Due to restrictions in resolution, galactic-scale
simulations have largely modeled star formation using empirical
correlations between the gas density and star formation rate. While
useful, these methods are unable to tell us about the early stages of
star formation and the evolution of the interstellar medium (ISM). In
this talk, I will show results from a set of high adaptive mesh
resolution (15 - 10 pc) global galaxy simulations (32 kpc) that
follows the birth, evolution and death of star-forming clouds in the
ISM. I'll present a technique to track the clouds through their life
and compare the properties of clouds at different ages. The clouds
are defined with a density threshold that should give them similar
properties to giant molecular clouds, and this allows us to make
detailed comparison of our simulation results to observations of the
Milky Way and other galaxies. I will compare the results of including
star formation and the effect of photoelectric heating from dust grains.
Since even at these high resolutions, the star formation prescription
is inevitably sub-grid, I will also present results from
investigating GMC evolution in a pseudo-shearing box simulation with
resolutions extending down to sub-parsec scales.