Measuring Cosmic Magnetism with the Low Frequency Radio Array

Arizona State University, Scottsdale AZ

Investigators

Abstract

Part 1 This proposal plans to carry out low-frequency radio measurements of cosmic magnetism through a collaboration between Arizona State University and the German Long Wavelength Consortium. Each year, the program will fund two first-year graduate students and five advanced undergraduates, who will carry out research with the Low Frequency Array (LOFAR), a remarkable new European radio telescope. Due to its sensitivity, resolution, and frequency coverage, LOFAR will allow for intergalactic magnetic field measurements orders of magnitude better than previously possible. Part 2 Magnetic fields thread the Universe, setting the criteria for star formation in galaxies, controlling the evolution of galaxy clusters, and altering the intergalactic medium from which all galaxies formed. Yet very little is known about their properties. LOFAR is the first of a new generation of telescopes that operates in the extremely low frequency range between 10 and 240 MHz. Magnetic fields are primarily detected by their interactions with cosmic rays, and only telescopes at these low frequencies, which correspond to low cosmic ray energies, are able to make sensitive measurements far away from cosmic ray sources and out in the depths of intergalactic space. With this remarkable new tool, the projects carried out by IRES students will help to open a new window on the magnetic universe. On galaxy scales, they will probe the connection between star formation and magnetism and the origin of the magnetic fields that surround galaxies. On galaxy cluster scales, they will probe the unknown physics of the hot intracluster medium and the evolution of the synchrotron emitting bubbles found within it. On cosmic scales they will uncover the magnetic properties of the web of gas that connects all galaxies. Together they will be filling in a key piece of the fundamental question: what is the structure of the Universe on the largest scales?