Seminar:- Composition and Alignment of Interstellar Dust Grains
Astronomers have known about interstellar dust particles for almost a century, and for most of this time we have also known that these spinning grains somehow become aligned with respect to the ambient galactic magnetic field. However, our knowledge of the grains’ composition is very incomplete, as is our understanding of the grain alignment mechanism. Such information is needed if we are to (a) efficiently exploit polarimetry of aligned grains to study the role of magnetic fields in star/planet formation, and (b) remove the contaminating dust signal from cosmological observations of gravity waves from the inflationary epoch. The speaker will review established facts and knowledge gaps in these areas, and show how measurements of the polarization spectrum of dust emission are allowing us to make progress in filling in the gaps. As an example, the speaker will discuss the first measurement of the submillimeter polarization spectrum of a translucent molecular cloud, made using BLASTPol, a balloon-borne telescope flown over Antarctica in 2012.
時間：2017.09.26(二) 14:30 ~ 15:30
講者：Professor Giles NOVAK (Department of Physics and Astronomy Northwestern University, USA)