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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

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