Date/Time Date(s) - 26/03/20143:30 pm - 4:30 pm
Title: Schmidt’s Conjecture and The Nature of Star Formation from Nearby Molecular Clouds to Distant Galaxies.
Speaker: Dr. Charles Lada
Institute: Harvard Smithsonian
Location: ABB 102
Description:
The star formation rate and its variation in time are intimately connected to our understanding of the formation and evolution of the Milky Way and external galaxies from early cosmological epochs to the present era. Ever since the pioneering work of Martin Schmidt a half-century ago there has been great interest in finding an appropriate empirical relation that would directly link some property of interstellar gas with the physical process of star formation within it. Schmidt conjectured that this might take the form of a scaling relation between the rate of star formation and the surface density of the interstellar gas. In this colloquium I will describe how modern observations of nearby Galactic molecular clouds are now providing new insights into this relationship. These new observations suggest that the star formation rates in interstellar molecular clouds are directly controlled by the amount of dense molecular gas contained within the clouds. This correlation between the mass of dense gas and the total star formation rate differs in a number of respects from the original Schmidt scaling law but it likely represents the underlying physical relationship that most directly connects star formation activity with interstellar gas both within our Milky Way and within external galaxies. Finally, I will discuss the implications of these results for assessing the physical relevance of the original Schmidt law to the process of star formation.