UBC Okanagan Researchers Map Milky Way's Complex Magnetic Field
A team led by UBC Okanagan has produced the first broadband map of the Milky Way's magnetic field, revealing unexpected complexity and providing new insights into galactic evolution.
Researchers from the University of British Columbia Okanagan (UBCO) have created the first broadband map of the Milky Way's magnetic field, uncovering a level of complexity previously unobserved. The study, led by Dr. Alex Hill, Assistant Professor in the Irving K. Barber Faculty of Science at UBCO, utilized data from the Dominion Radio Astrophysical Observatory's (DRAO) 15-meter telescope near Penticton, British Columbia.
The project, known as the Dominion Radio Astrophysical Observatory GMIMS of the northern sky (DRAGONS), is part of the Global Magneto-Ionic Medium Survey (GMIMS). This initiative aims to measure the three-dimensional structure of galactic magnetic fields. Dr. Anna Ordog, a former UBCO postdoctoral researcher, led the DRAGONS project, which captures polarized radio emissions across a wide range of frequencies, allowing astronomers to detect previously invisible magnetic structures.
"With our new dataset, we can look at the polarized emissions from within the galaxy itself, and we see that the magnetic field has a lot of structure to it," Dr. Ordog explained. The research builds on a theoretical insight from 1966, which proposed that observing polarized radio waves at multiple frequencies enables measurements of the Milky Way's magnetic field in three dimensions. Modern broadband telescopes, such as the DRAO 15-meter telescope, have now made this research feasible.
The study, recently published in The Astrophysical Journal Supplement Series, tracks how polarized radio waves twist as they travel through the galaxy, revealing the strength, structure, and direction of magnetic fields along the line of sight. The survey indicates that more than half the sky contains complex magnetic structures rather than simple, uniform fields.
Dr. Tom Landecker, an astronomer emeritus at DRAO and adjunct professor at both UBCO and the University of Calgary, noted the significance of these findings. "DRAGONS is like a compass, telling us how matter and magnetic fields in the galaxy are organized and how the magnetic field interacts with bubbles created by supernova explosions, spiral arms, and other parts of the galaxy in ways that have never been possible before," he said.
Understanding the Milky Way's magnetic field is crucial for comprehending star formation and galactic evolution. Dr. Hill emphasized, "For decades, we could only measure the Milky Way's magnetic field in a very averaged, simplified way. But its magnetic field is an important piece of the puzzle when it comes to understanding how the universe and everything in it operates and came into being."
The DRAGONS data have already been utilized in a study of a large-scale reversal in the galactic magnetic field, led by University of Calgary doctoral student Rebecca Booth and published in an accompanying paper in The Astrophysical Journal. Dr. Ordog highlighted the dataset's potential for ongoing research, stating, "DRAGONS is part of a new generation of radio surveys that allow scientists to map the Milky Way's three-dimensional magnetic field structure in the space between the stars. It is an important Canadian contribution to the global astronomical community."