Collaborative Research: Using Observations and Models to Study How Dust Grains Between the Stars Align

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This astronomy project aims at improving our understanding of the gas and dust that exists in interstellar space, i.e., in the space between the stars in our Galaxy. The team has developed their own theory about how elongated grains of dust in this "interstellar medium" are lined up. This rather complex process involves magnetic forces or "fields"---which are known to exist in space---and starlight. The theory will be tested using observations from a range of telescopes, including the Herschel and Planck space telescopes, the airborne Stratospheric Observatory for Infrared Astronomy (SOFIA), and the ground-based Sloan Digital Sky Survey (SDSS), James Clerk Maxwell Telescope (JCMT), and Multi-Mirror Telescope (MMT), among others. Magnetic fields affect the way gas moves through space, and particularly the way clouds collapse under their own weight to form stars. Understanding magnetic fields is therefore hugely important when trying to understand how stars and planets like Earth are formed. Graduate and undergraduate students from Santa Clara University and the University of Wisconsin will be heavily involved in this project. A young post-doctoral researcher will also take a leading role in this effort.This tri-institute collaborative project will develop an analytical version of the Radiative Alignment Torque (RAT) theory for the alignment of irregular, paramagnetic dust grains in the Interstellar Medium (ISM). The theory has already had some qualitative successes in interpreting past observations. The awardees now aim to quantitatively test the theory against a range of observations using an analytical version of the theory that incorporates realistic source structures. When combined with optical and infrared polarization measurements, the RAT theory may be a powerful diagnostic tool for studying interstellar magnetic fields in a variety of environments (Giant Molecular Clouds, Accretion Disks, etc.). Dust-induced polarization provides a relatively straightforward probe of the magnetic field if a reliable understanding of grain alignment is available. Understanding foreground dust polarization is also crucial to studies of the cosmic microwave background. The recipients of this award will provide classroom and hands-on training to students at Santa Clara University and the University of Wisconsin (UW), developing "polarization classes (schools)" that may also be used by non-affiliated undergraduate students. The award also supports outreach aimed at the general public, including programs at the Lick Observatory and as part of the Lassen Dark Sky Festival. Popular science content will be pursued through drafted magazine articles, as well as student involvement in popular astronomy broadcasting in Spanish at UW.