Posted on by Evan Gough

Can a Dead Star Keep Exploding?

This is an artist’s representation of AT2022tsd, an explosion in a distant galaxy. The image shows one possible explanation for the strange object. It could be a black hole accreting matter from a disk and powering a jet. Variation in the jet's direction could produce the observed rapid flashes. Image Credit: Robert L. Hurt/Caltech/IPAC

In September 2022, an automated sky survey detected what seemed to be a supernova explosion about one billion light-years away. The Zwicky Transient Facility (ZTF) spotted it and gave it the name AT2022tsd. But something was different about this supernova. Supernovae explode and shine brightly for months, while AT2022tsd exploded brightly and then faded within days.

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Posted on by Evan Gough

Astronomers See the Exact Moment a Supernova Turned into a Black Hole (or Neutron Star)

A look at The Cow (approximately 80 days after explosion) from the W.M. Keck Observatory in Maunakea, Hawaii. The Cow is nestled in the CGCG 137-068 galaxy, 200 million light years from Earth. Image Credit:Raffaella Margutti/Northwestern University
A look at The Cow (approximately 80 days after explosion) from the W.M. Keck Observatory in Maunakea, Hawaii. The Cow is nestled in the CGCG 137-068 galaxy, 200 million light years from Earth. Image Credit:Raffaella Margutti/Northwestern University

On June 17th 2018, the ATLAS (Asteroid Terrestrial-impact Last Alert System) survey’s twin telescopes spotted something extraordinarily bright in the sky. The source was 200 million light years away in the constellation Hercules. The object was given the name AT2018cow or “The Cow.” The Cow flared up quickly, and then just as quickly it was gone.

What was it?

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