The bizarre space explosion that stunned scientists in 2018 just got weirder.A New Analysis of Polarization from the First Recorded Fast Blue Light Transient (FBOT) Outburst (Officially Known as His AT2018cow) Nicknamed “cow” — The blast was the most asymmetrical explosion astronomers have ever seen, revealing it to explode into space in a flattened pancake-like shape instead of the typical sphere.
The shape of an explosion roughly the size of our solar system and occurring 180 million light-years from Earth could challenge scientists’ understanding of how eruptive events like FBOT occur. There is a nature.
“This finding shows that these explosions are not spherically symmetrical. In fact, the discs we think we have observed are really flat.” Justin Mound (opens in new tab)A senior lecturer in astrophysics at the University of Sheffield, UK, and lead author of the new study, told Live Science via email. “This means that any model who wants to explain these FBOTs of his will have to face the fact that these are not round events.”
A cow-like FBOT was already a major puzzle for scientists. Little is known about FBOT and its causes, as only four other similar transients have been identified since the discovery of the cow in 2018. But one thing is clear. typical supernovais the most common type of cosmic explosion that occurs when a massive star runs out of nuclear fuel and collapses under its own gravity.
“FBOT is bright. It’s very bright, brighter than an ultra-bright supernova, but then it suddenly appears and its brightness drops like a stone!” Mound said. “Unlikely, there are no radioactive elements that produce brightness, so the energy must come from somewhere else.”
In their new study, Mound and his team looked again at the light from cows first recorded in June 2018. This time, we investigated how light was polarized, that is, how the oscillations of light waves traveled in a single plane. This analysis of the cow does not yet reveal the origin of the FBOT, but the flatness of the cow indicates that his FBOT is even more different from a supernova than scientists previously thought.
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“On the first night we saw a big spike in polarization and then a drop,” Mound said. “The spike on the first night he hit 7%. I’ve never seen such a rapidly evolving high level of polarization or polarization for a supernova. So this is something we’re not used to at all.” Thing.”
These polarized observations allowed the team to identify the cow’s odd shape. Light from Kau was measured using the Liverpool Telescope, which has a primary mirror that is only 2 meters in diameter. The team used these data to create his 3D model of the explosion, which, using polarized light, was reconstructed as if it had been discovered with a telescope about 388 miles (625 kilometers) in diameter. This allowed us to map the explosion to its edges, revealing just how flat it really is.
“Based on previous research on supernovae, we’re looking at something that looks a little flattened, like a hamburger or a little flattened like a rugby ball, but not so spherical,” Mound said. “So when this number came out of our analysis, me and my co-authors did all the data reduction and analysis over and over again to make sure!”
The team now plans to search more FBOTs to see how many exhibit similar polarization to Cow’s and determine if they are also pancake-like disks. Researchers will collect these data through space and time legacy surveys conducted by the Vera Rubin Observatory in Chile.
The team hopes that deeper observations of this cow will shed light on these rare and powerful events. increase.
“FBOT can be caused by disruptions as the star passes through the black hole, or by a failed supernova where the core collapses and does not cause a supernova. Black Hole again neutron star And it starts chewing on the inside, which powers what we see as FBOT,” Mound said.
The team’s work was published March 30 in the monthly journal of the Royal Astronomical Society. (opens in new tab).