Dr. Simon Coudé (Harvard)

Title:

Revealing the dynamics of star-forming regions with far-infrared polarization

Abstract:

The polarization signature from dust thermal emission in the far-infrared is a powerful tool to study the physical properties of star-forming environments, and specifically to reveal the role of magnetic fields in slowing the gravitational collapse of interstellar filaments. With its multi-wavelength polarimetric capabilities, the High-resolution Airborne Wideband Camera Plus (HAWC+) aboard the Stratospheric Observatory for Infrared Astronomy (SOFIA) therefore opened a unique window into the dynamics of stellar nurseries during its lifetime. In particular, the Filaments Extremely Long and Dark: A Magnetic Polarization Survey (FIELDMAPS) with HAWC+ provided detailed maps of dust polarization at 214 µm in ten of the largest known filaments in the Milky Way galaxy. These observations provide the highest resolution measurements to date of the magnetic field in these dense filamentary structures, also described as the “bones” of our Galaxy. Using the Davis-Chandrasekhar-Fermi (DCF) technique and the Angular Dispersion Function (ADF), combined with ancillary spectroscopic data of dense gas tracers in each bone, to quantify the magnetic field amplitude across these filaments. Furthermore, polarization measurements at multiple wavelengths can also improve our understanding of dust physics by probing their alignment efficiency to interstellar magnetic fields, which emphasizes the importance of the synergy of HAWC+ observations with longer-wavelength data from other observatories.