Astro Seminar: "Mapping Magnetic Fields in Star Forming Regions with BLASTPol and BLAST-TNG "

Wed, 04/22/2015 - 14:00 - 16:00
Laura Fissel (Northwestern)

A key outstanding question in our understanding of star formation is
 whether magnetic fields provide support against the gravitational
 collapse of their parent molecular clouds and cores. Direct
 measurements of magnetic field strength using Zeeman splitting are
 extremely difficult and only a few clear detections have been made in
 high density molecular gas. Alternately, observations of polarized
 thermal emission from dust grains aligned with respect to the local
 cloud magnetic field can be used to measure magnetic field direction.
 I will discuss how a new generation of submillimeter polarimeters is
 providing detailed, sensitive maps of magnetic field morphology in
 star forming regions. These maps can then be compared with synthetic
 polarization maps derived from 3-D numerical simulations of star
 formation and used to constrain cloud magnetic field properties. As
 a case study I will discuss observations of Vela C from the 2012
 flight of the Balloon-borne Large Aperture Submillimeter Telescope
 for Polarimetry (BLASTPol). Our Vela C observations have been used
 to produce the most detailed sub-mm magnetic field maps ever made of
 a giant molecular cloud.  In depth studies of the polarized dust
 emission from Vela C highlight the need to understand how
 polarization efficiency varies within clouds and to study a large
 sample size of molecular clouds. Finally, I will discuss BLAST-TNG,
 a "next generation" polarimeter scheduled for a first science flight
 in late 2016. This new polarimeter will have an order of magnitude
 increase in spatial resolution and mapping speed and will map dozens
 of star forming regions, placing important constraints on the role
 magnetic fields play in regulating star formation. 

David Rittenhouse Laboratory, A6