Expect the unexpected from the big-data boom in radio astronomy.
We dubbed them ORCs, which stands for “odd radio circles�
But we soon confirmed they are real, using other radio telescopes?
The rings of radio emission are probably caused by clouds of electrons, but why don’t we see anything in visible wavelengths of light.
Could they be supernova remnants, the clouds of debris left behind when a star in our galaxy explodes.Could they be the rings of radio emission sometimes seen in galaxies undergoing intense bursts of star formation.Could they be the giant lobes of radio emission we see in radio galaxies, caused by jets of electrons squirting out from the environs of a supermassive black hole.Not likely, because the ORCs are very distinctly circular, unlike the tangled clouds we see in radio galaxies.
Could they be Einstein rings, in which radio waves from a distant galaxy are being bent into a circle by the gravitational field of a cluster of galaxies.Such explosions may have something to do with fast radio bursts, or the neutron star and black hole collisions that generate gravitational waves?
How we closed in on the location of a fast radio burst in a galaxy far, far away.