Friday 16 February at 2pm
Doug Johnstone - University of Toronto
"SCUBA-Diving in Nearby Molecular Clouds More
Clues to the Physical Process of Star Formation"
ABSTRACT: "I will present results from sub-millimetre surveys of the
nearby molecular clouds rho Oph, Orion A and Orion B. Combining large area
JCMT continuum emission images at 450 and 850 microns, sensitive to ~ 0.01
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 the clumps in both Orion
and rho Oph 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."
http://www.astro.utoronto.ca/~johnstone
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