It’s a discovery of cosmic proportions: a never-before-seen look into the magnetic structure of the Milky Way galaxy.
The celestial breakthrough was made by two University of Calgary students, Russell Shanahan and Stephen Lemmer, who at first thought their findings were a mistake.
Lemmer described the magnetic field in the galaxy as the muscles of the body.
“The first reaction was disbelief, kind of skeptical if this was a real signature or was some false detection of some noise,” U of C PhD student Shanahan said.
The pair was working with data from an international survey called the THOR project, a comprehensive survey of data of interstellar gas in the Milky Way.
Lemmer was an astrophysics undergraduate in the radio astronomy group at the time who noticed the unusually high values.
“The structure that we have is a combination of a magnetic field of the galaxy as well as plasma inside the galaxy, and what we saw was a spike in data that we didn’t expect so this is occurring in a place we hadn’t expected before,” he said.
But the math checks out. What Shanahan and Lemmer found was an invisible magnetic field in the Sagittarius arm of the galaxy.
Astro scientists said the discovery is significant because it maps out a clearer picture of our galaxy’s composition and has astronomical implications in understanding how stars are formed.
“How star formations are formed is still kind of unknown. This discovery of peak and rotation measure can indicate that magnetic fields play a more significant role in star formations,” Shanahan said.
The pair’s discovery happened while working with radio astronomer and associate professor Jereon Stil on a research project. Stil has been a radio astronomer for 30 years and has been doing survey work for about 15 years.
The advancements in technology made this discovery possible. Since the 1980s, scientists have been looking in this area but telescopes were unequipped — until now.
“The radio telescopes were not equipped to detect this high, strong effect,” Shanahan said.
The five-year research finally paid off. The finding was published in the Astrophysical Journal, sparking more international interest and kicking off additional research. Shanahan and Stil even went to Germany to present their findings.
“We met in Berlin and shared what we were doing and what we found. When we presented this result to our colleagues, there was an audible gasp, like what is this? Because the thought wasn’t that we would find something like that. It was shocking,” Shanahan said.
Stil said the discovery spurred a lot of follow-up.
“People think scientific discovery is like something like eureka and what we did in the last five minutes. This is a long process. Russell has been working on this for the past five years, and a lot of nitty-gritty data processing and making the images and technical analysis. What was special about here, there was this point where we said, ‘What is this?’
“The true surprise and the eureka moment was when we thought, ‘This must be the arm.’ It’s very exciting.”