Our universe is filled with things that go flicker, flare, and boom in the night. One of the most amazing events we catch are gamma-ray bursts. We didn’t know anything in the universe produced these high-energy light waves until they were accidentally discovered in the 1960s when politicians launched gamma-ray detecting spacecraft to monitor the planet for nuclear explosions. 

Today, we know they come in at least three different forms: two varieties of short bursts and longer bursts we’re still working out the details on. Recently, back in 2020, a long gamma-ray burst attempted to masquerade as a short gamma-ray burst. For just 0.65 seconds, the Fermi Gamma-Ray Space Telescope detected something. The Zwicky Transient Facility went on to detect a supernova explosion in the same part of the sky, and it’s now thought that this was a classic long-duration gamma-ray burst that, for some reason, had an abbreviated duration. 

Supernovae on their own don’t look like much because of their extreme distance, but if we could zoom in we’d see something pretty amazing.

It is believed that when some massive stars end their lives as supernovae, something happens that causes powerful jets to form, and those jets funnel gamma rays and other radiation into a narrow cone. When one of those cones happens to be directed at us, we get to see a long gamma-ray burst. These are generally powered for a noticeable period of time, up to hundreds of seconds in duration, and their duration is related to how long it takes whatever physics is driving them to be played out.

That is physics that should be something that can’t be completed in just 0.65 seconds, but the universe decided it likes variety.

The researchers behind this paper believe that the conditions in this event were at the border of what is necessary to form a gamma-ray burst, and what we saw was the system teetering out of the zone that would allow a normal, long-duration burst. This makes it clear that while all long-duration gamma-ray bursts are tied to supernovae, not all supernovae can support or sustain a gamma-ray burst. At a certain level, we knew that from statistics: there are too few gamma-ray bursts for their scarcity to be explained just by how often we are or aren’t in the cone of their jets. Now we have seen that transition case, where something tries really hard to be a gamma-ray burst and doesn’t quite make it.

You do you, Lil Gamma-Ray Burst. We understand that sometimes we don’t all get to scream into the void of the universe for as long as we’d like, and we respect your efforts.

More Information

Gemini Observatory press release

NASA press release

NOIRLab press release

“Discovery and confirmation of the shortest gamma ray burst from a collapsar,” Tomas Ahumada et al., to be published in Nature Astronomy (preprint on arxiv.org)