How do black holes swallow stars?
I wake up to a chime from my smartphone. Bleary-eyed, I check it — and jolt awake upon seeing an automated email from the MeerKAT radio telescope in South Africa.
The subject line reads: “AT 2018xxx 2hr has been completed.” The message tells me that while I was sleeping, MeerKAT observed a target for two hours and, after some initial image processing, the observation is now ready for me in the archives. All that remains for me, half a world away in Cambridge, Massachusetts, to do is go online and download it.
The lure of potential discovery wakes me up more than a pot of coffee ever could. This could be it! A modern radio astronomer does not have to travel to faraway lands to collect the data herself — arguably less romantic. But the thrill of anticipation and discovery stays the same, no matter where on Earth you are.
I drum my fingers while waiting for my laptop to load the image, excitement mounting as I wonder what I’m about to see. There are a lot of stars and galaxies in this patch of sky, but that’s just window dressing. The real excitement would be overlooked by the untrained eye: a tiny collection of unobtrusive pixels in the middle of the image. It is light from a star’s final gasp as a supermassive black hole at the center of a galaxy gets violent, pulling the star apart and cannibalizing it. A tidal disruption event (TDE), as these occurrences are called, is one of the most energetic and luminous events in the universe. But few are easy to find, and even fewer emit the radio waves crucial to understanding them. Each new discovery is precious.
