Exploding Stars Create Massive Odd Radio Circles, Researchers Find

The discovery of Odd Radio Circles (ORCs) originating from outflowing galactic winds could provide new insights into galactic evolution.

Odd Radio Circles (ORCs), first detected in 2019, are believed to be the result of outflowing galactic winds from massive exploding stars, or supernovae, according to a team led by University of California San Diego Professor of Astronomy and Astrophysics Alison Coil.
These ORCs are so large they contain entire galaxies within their centers, and are formed when two large galaxies collide, causing an intense burst of star formation.
Starburst galaxies, which have an exceptionally high rate of star formation, can drive these ultra-fast outflowing winds. When enough stars explode near each other at the same time, the force of these explosions can push the gas out of the galaxy itself into outflowing winds, which can travel at up to 2,000 kilometers/second.
Coil's team used an integral field spectrograph at the W.M. Keck Observatory on Maunakea, Hawaii, to look at ORC 4, which revealed a tremendous amount of highly luminous, heated, compressed gas -- far more than is seen in the average galaxy.
Understanding the origins of ORCs can help astronomers understand outflowing winds and galactic evolution, including how common these extreme outflowing galactic winds are, what the wind life cycle is, and whether all massive galaxies go through an ORC phase.