Completing the Galactic Plane Infrared Polarization Survey (GPIPS)

Trustees Of Boston University, Boston

Investigators

Abstract

The magnetic field threading the Galaxy's interstellar medium (ISM) is poorly revealed and its roles in cloud and star formation are unclear. Dr. Dan Clemens (Boston University) and his team are addressing these problems using a powerful instrument (Mimir, a near-infrared wide-field imaging polarimeter) coupled with substantial observing time (about 50 nights per year, with key project status) on the 1.8-meter Perkins telescope outside Flagstaff, Arizona. Presently, the team is about midway through the telescopic observations comprising the Galactic Plane Infrared Polarization Survey (GPIPS) and, through this award, will complete all GPIPS observations over the next four years. GPIPS expands existing optical/infrared (OIR) probes of the ISM magnetic field by four to five orders of magnitude, to about 500,000 stellar polarizations, and reveals the field five times more distant than seen before using OIR methods, to and beyond the nearest spiral arm and through dark clouds to a visual extinction of 25 magnitudes. GPIPS represents a huge increase in the data available for probing the Milky Way's magnetic field. The inner midplane region offers a wealth of correlative data concerning the stellar targets, as well as revealing a wide variety of distinctly different environments in the diffuse and dense ISM. The new magnetic field insight GPIPS will uncover will help test models across many size scales to gauge the role of the magnetic field in a wide range of ISM environments in the Galaxy. The public release of high-quality, well-calibrated data products will allow other astronomers to mine the transformative GPIPS data for new discoveries, and to bring vital insight to other studies. The methods and approaches pioneered by GPIPS will guide future large-scale and follow-up studies. During the first three years of the survey, GPIPS and Mimir have had major impacts on the career development of research students, comprising the capstone astronomical experience for about 30 Boston University students to date, and enabling visitors and collaborators to obtain new data for a wide variety of projects. The team's suite of publically-available software tools and web sites make access to, and science with, Mimir data easy and efficient. Over the next four years, the team will leverage this base to higher levels of impact by developing and serving out a series of webcasts and podcasts, both for the general public on topics such as infrared astronomy, polarimetry, and magnetic fields, and for the research community (the GPIPS data products, the Mimir instrument and software). Finally, members of the team will work with the Boston University Scientific Visualization Center to develop exportable tools and/or shows to view and interact with the three-dimensional decomposition of the GPIPS data set and its relationships to other tracers of the ISM.