NRAO/Socorro Colloquium Series

Charles J. Lada

CfA



Star Formation Rates in Nearby Molecular Clouds and the Nature of the Extragalactic Scaling Relations.

The star formation rate and its variation in time are intimately connected to the formation and evolution of galaxies from early cosmological epochs to the present era. Ever since the pioneering work of Schmidt a half-century ago there has been great interest in finding an appropriate physical relation that would directly link some physical property of interstellar gas with the rate of star formation in a galaxy. In this talk I will discuss how observations of nearby Galactic molecular clouds are now providing new insights into the nature of such
a physical link between the molecular ISM and the rate of star formation in a galaxy. In particular, I will describe wide-field infrared extinction mapping and Spitzer Space Telescope surveys that together have produced the first reasonably complete accountings of both star formation activity and molecular gas in the local Milky Way. These new observations indicate that the star formation rates in local molecular clouds are best correlated with the amount of dense gas that these clouds contain above a specific high density threshold. This correlation
appears to smoothly extend to galaxies of the nearby universe and may represent the underlying physical relationship or law that most directly connects star formation activity with the interstellar gas both within our Milky Way and within and between external galaxies. I will conclude the talk by showing how these observations enable the unification of the various extragalactic scaling relations (e.g., Kennicutt-Schmidt, Gao-Solomon) into a single framework that can connect star formation on local and cosmological scales.




March 23, 2012
11:00 am

Array Operations Center Auditorium

All NRAO employees are invited to attend via video, available in Charlottesville Room 230, Green Bank Room 137 and Tucson N525.

Local Host: Claire Chandler