|22nd of March 2018|
|Revealing the Galactic Magnetic Field with Radio Polarization|
|by Tom Landecker (DRAO)|
It is over fifty years since the polarization of the Galactic radio
emission was discovered, but only in the last few years has technology
allowed us to observe Galactic polarized emission with the tools that
we need to understand it. Wideband feeds, wideband digital signal
processing, and Rotation Measure Synthesis are three tools that have
come together to help us open up the Faraday depth spectrum.
In this talk I will describe GMIMS, the Global Magneto-Ionic Medium Survey. GMIMS sets out to map the entire sky, North and South, using big single-antenna telescopes, spanning 300 to 1800 MHz with thousands of frequency channels. We have completed a survey of the Northern sky with the DRAO 26-m Telescope covering 1270 to 1750 MHz. We have completed a survey with the Parkes 64-m Telescope of the Southern sky, covering 300 to 480 MHz, and we have completed a second Parkes survey from 1300 to 1800 MHz. I will discuss results from these surveys.
The goal of GMIMS is to map the three-dimensional structure of the magnetic field, and to help understand the role of the field in the Galaxy. The magnetic field is the hidden constituent of the Interstellar Medium, it carries significant energy, it "stiffens" the interstellar plasma and pushes back against every force, and so plays a significant role in most ISM processes. (Image credit: http://astroherzberg.org/projects/)