In the fast-paced world of transient astronomy, the CIFAR Azrieli Global Scholar makes quick decisions to catch the Universe’s most extreme events.
At any time of day or night, Raffaella Margutti’s phone might ping with the gentle knock of a Slack notification. The Universe is calling.
Margutti is an associate professor of astronomy at Northwestern University, where she studies the extreme events that occur when large stars die. She is particularly interested in the rare and exotic systems that rip themselves apart, release huge jets of energy, and make ripples in the fabric of space and time itself. These are exactly the types of events that are the focus of CIFAR’s Gravity & the Extreme Universe program, which Margutti joined in 2019.
These explosions release enough energy to outshine galaxies, but they last only a short time. So Margutti has to act quickly if she wants to repoint a telescope to catch them in action. Every minute counts because these explosions last minutes or hours, not the billions of years that most astronomers are used to working with.
To make sure she catches these spectacular events, Margutti is plugged in to a web of telescopes set up all over the world as well as in orbit. They monitor for changes in the night’s sky, but they aren’t sensitive enough to really tell Margutti about the physics of the explosions. They are also prone to sending alerts for mundane changes like regular supernova or star births. What Margutti really wants to study are the extreme events that seem to break the laws of physics.
So when a notification from one of these survey telescopes alerts her that there is something in the sky that wasn’t there last night, she has only a short time to decide whether to act on the notification. If she takes more than a few minutes to decide, the event might already be over by the time she can point the right kind of telescope at it.
The vast majority of notifications are spurious. “I tell my students that we will fail a lot,” says Margutti. “We don’t have a discovery every day.”
There are needles to be found in the haystack, however. In 2018, for example, Margutti repointed a NASA telescope called NuSTAR to follow up on a strange stellar explosion called AT2018cow, leading to unique x-ray data that helped astronomers narrow in on the cause of the unusually powerful explosion. These kinds of insights about the causes of extreme events shed light on how our Universe works at a fundamental level.
Repointing a telescope, like how Margutti commandeered NuSTAR, comes at a cost. It interrupts whatever studies the telescope was already doing. “Even if you have the power to interrupt other astronomers’ programs, it’s always better to have a personal contact,” says Margutti. “There is a sociology to this work, otherwise you create too many enemies and then you’re doomed.”
The sociology of science
The politics of interrupting other astronomers isn’t the only way Margutti sees social dynamics impacting science. “Because time-domain astronomy is so fast-paced, being able to put your stamp on something [by sending out an Astronomer’s Telegram] is extremely important,” says Margutti. “If I observe something half an hour before someone else and I send out a telegram, I can claim discovery. But am I really a better astronomer than someone else because I had access to a telescope where the night was happening 30 minutes earlier?”
To explore these philosophical and sociological questions, she recently collaborated with CIFAR Azrieli Global Scholar Joshua Shepherd, a philosopher in CIFAR’s Brain, Mind & Consciousness program, to host a cross-program workshop on the nature of discovery. At the workshop, which took place in February 2021, astronomers, neuroscientists, philosophers, and physicists from two seemingly disparate CIFAR programs (Gravity & the Extreme Universe and Brain, Mind & Consciousness) compared notes on how discovery and credit operate in their respective fields, striving to find better ways to reward good science.
The experience turned Margutti’s opinion of interdisciplinarity. “I always had a little bit of skepticism about interdisciplinary projects,” she says. “This effort now with Josh and philosophy is the first time that it’s worked out. I’m extremely pleased and surprised. Whatever CIFAR is doing, it’s doing it right.”