As much as we may know about our universe, there is even more that we know that we don’t know than. Gamma-ray bursts, the random flashes of some distant something we think are associated with supernovae, fall into the category of things we know we don’t fully understand, and every piece of data we can get is welcomed gladly. 

As Pamela has experienced, if you’re using a telescope that might be able to see the optical counterpoint to a gamma-ray burst, you may get asked to stop what you’re doing and move the telescope to look for that brief optical afterglow. For one telescope, however, no repointing was required. The Transiting Exoplanet Survey Satellite (TESS) spacecraft just happened to be looking for planets in the part of the sky where a distant gamma-ray burst was spotted by the Swift-BAT satellite. Normally, this telescope can look for afterglows on its own, but with its super-wide field of view and a photobombing Moon, this time, it couldn’t. 

The lucky coincidence that TESS and its smaller field of view were looking at just the right place meant that data was collected. The optical afterglow was at its brightest 1000-2600 seconds after the gamma rays were spotted, and within 7000 seconds, the glow had faded beyond TESS’s ability to see it. We don’t yet know what new science may have been learned, but this is such a cool coincidence, we had to share.

Telescopes like Swift and TESS do their jobs by systematically surveying the sky, over and over and over, looking for things that change. Their repeating series of images means we can easily see when something flickers or flares in the night, and we can go back and see what was there prior to the flash.

More Information

Southern Methodist University press release

“GRB 191016A: A Long Gamma-Ray Burst Detected by TESS,” Krista Lynne Smith et al., 2021 April 14, The Astrophysical Journal