(ORDO NEWS) — The mysterious flash AT2018cow, which flared up much faster and brighter than any supernova, found another strange feature.
Unlike all similar cosmic explosions, this one did not expand in a symmetrical sphere, but was greatly flattened. In 2018, an unusually bright flash was seen in a distant galaxy, located almost 200 million light-years away.
It turned out to be an order of magnitude brighter and intensified much faster than ordinary supernovae, moreover, it had an unusual blue-shifted spectrum.
The event was named AT2018cow, or simply Cow, and since then astronomers have discovered several more similar outbreaks, which have continued to be called with references to various animals.
The nature of these fast blue optical transients ( FBOTs ) remains unknown.
A new work by scientists from the British University of Sheffield has revealed another oddity of the AT2018cow transient.
Unlike a “normal” explosion, whose front should expand more or less spherically, this one turned out to be strongly flattened. Perhaps this feature will finally make it possible to figure out what FBOT are.
Astronomers used data from the two-meter Liverpool telescope operating in the Canary Islands.
The instrument observed the AT2018cow for several days after its appearance and was able to register the polarization of radiation emanating from it.
Polarization made it possible to reconstruct the three-dimensional shape of the distant explosion and showed that it is very far from spherical, but strongly flattened.
“We never thought that explosions could be so non-spherical,” said Justin Mond.
“There are several explanations for this: maybe the stars create a flat disk even before they explode, or they are failed supernovae, in which the collapsing core of the star quickly turns into a black hole or a neutron star that absorbs the remains of the star.”
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