NRAO/Socorro Colloquium Series
Karl Gordon
STScI
Extragalactic Dust Mass Determinations in the Iptical and Infrared: Duest Emissivity Variations
Infrared dust mass and associated measurements are used to study the
properties of the ISM(structure, radiation field, grain compostions,
total gas mass) in many astrophysical objects, including galaxies. It
is often assumend that the far-IR dust grain properites are well
described by a single emissivity law that does no tdepend on
enviroment. I will discuss an investigation using the HERITAGE Herschek
Key Project far-IR/submm observations of the Magellanic Clouds that
indicate there are wavelenght dependent variations in the dist
emissivity law with enivronment. Then, I will show that an independent
traceer of the dust column and grain size is possible using
measurements of a large number of stars in M31 from PHAT Hubble Multi
Cycle Program. Combining the PHAT measurements with Herschel far-IR
submm observations of M31 gives strong evidence that the overall dust
emissivity is also dependent on environment. The combination of these
two investigatiosn gives strong evidence that far-IR/submm dist
emissivity is varying significantly with environment. These results
provide constraints on dust grain properties and indicate more
realistic dust models should be used in interpreting far-IR/submm
observatiosn of galaxies. December 7, 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: Juergen Ott
