Department of Physics, Engineering Physics & Astronomy

Department of Physics, Engineering Physics & Astronomy
Department of Physics, Engineering Physics & Astronomy

SCUBA-Diving in Nearby Molecular Clouds: New Constraints

Dr. Doug Johnstone
NRC / Herzberg Institute, University of Victoria (Adjunct)

Thursday, January 9, 2003
2:30 PM @ Stirling C


I will present results from sub-millimetre surveys of the nearby molecular clouds. Combining large area JCMT continuum emission images at 450 and 850 microns, sensitive to ~ 0.1 Solar mass condensations, with molecular line data (CO isotopes, CS, formaldehyde, etc.) allows for a glimpse into the physical properties of molecular clouds on small scales. Both barely resolved condensations and large scale features are visible in the maps, revealing the variety of dynamical events which operate in star forming regions. I will discuss the important physics associated with these regions, as evidenced by the survey results: the formation of filamentary structures with threaded magnetic fields, sculpting of the medium by outflows, shocks in jets, and the temperature and dust emission properties of both large and compact structures. I will also present a model of the many compact clumps found in the dust continuum images in order to derive their physical properties - mass, temperature, and bounding pressure. The derived cumulative mass function for these clumps will be shown to be remarkably similar to the stellar IMF. I will close the talk with a discussion of how these observational clues may be used to solve the outstanding problem of how stars are formed.

Dr. Doug Johnstone is a candidate for the Observational-Experimental Astronomer position in the Department.

Refreshments will be available after the talk.