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Astronomers see signatures of a newborn black hole or neutron star

For the first time, astronomers have directly witnessed the birth of a super-tight object far beyond our galaxy – the…

For the first time, astronomers have directly witnessed the birth of a super-tight object far beyond our galaxy – the emergence of either a black hole or a collapsed star in real time. Up until now, we have only seen these objects many years after they first formed. But now we can study this creation in its early days, which gives us a new insight into what these mysterious phenomena look like when they first come into existence.

The discovery, named “The Cow,” came as a wonderful surprise during a routine night sky survey. Last year, a group of astronomers, using the Keck Observatory’s twin telescope in Hawaii, looked for transients &#821

1; astronomical explosions that suddenly appear with a flash in the sky and then fade away. On June 17, an incredibly bright one arose, and in just two days it had already peaked in shine. The result was a big event 10 to 100 times more light than your average star explosion or supernova.

First, astronomers were puzzled. They usually never look supernovae so bright. But on closer inspection they realized that they had something special on their hands. The radiation from the core of this blast shone through all the material that had been sprayed out during the explosion and revealed something incredibly tight that we usually can’t see.

Star explosions usually create giant bubbles of material around them, blocking anything within our point of view. But this time, astronomers could actually get a signal from deep inside the explosion. “Normally in a supernova, the compact object being formed is hidden. This is an unusual event that is very exciting,” Duncan Brown, a professor of physics at Syracuse University and a gravity wave researcher who was not involved in the study, says The Verge .


The Cow, Seen by Keck Observatory Raffaella Margutti / Northwestern University

It is too early to say whether the explosion resulted in a black hole. It is possible that it was formed in a type of star body, known as a neutron star, which is also incredibly dense. The good news is that we have found it, we can continue to observe it and see it develop, something we have not been able to do before. And how this creation changes can help transform our theories of what happens to black holes and neutron stars just after they are created. “We see them thousands of years afterwards, but we know nothing about what they do in the beginning,” says Rafaella Margutti, an astrophysicist at Northwestern University, who led the research to be published in the Astrophysical Journal The Verge .

We have long known that black holes and neutron stars are the remains of star explosions. When super-massive stars leave fuel, they burst out and throw out their outer layers of material. What remains is a dense core, something much smaller than our Sun in size, but filled with the same amount of material. We have also seen evidence of this process. When we look at the remains of the supernova, thousands of millions of years after they occurred, we see traces of these dense objects in their place. But the youngest black holes and neutron stars are always hidden by the outer layers of the exploding star shooting outwards.

The first big clue as Margutti and her team had something really unique came when they measured the X-rays originating from Kon. They found a variety of “hard” X-rays, which are 10 times more powerful than your average x-ray. This type of signal is what some astronomers call “hump”, and it is usually associated with black holes. This signal strongly suggests that something in the supernova sits up material, as black holes often do. “So there is something that lives in The Cow that produces these hard X-rays,” says Margutti. “It’s the important message from the observation.” She adds, “It’s something we’ve never seen in a transitory before. It’s totally unmatched. Margutti says the cow got her nickname because it was called AT2018cow as part of the team’s name order.


The placement of the cow in his host galaxy Image: Dustin Lang

Margutti and her team believe they could see this object because the star that exploded did not hide much material in the explosion, so there was not much stuff to protect the inner radiation from This can also explain why it became so bright so fast, normally supernovae take weeks to reach their maximum brightness, and the fact that it turned out to be light in just two days is really bizarre, and it may be because there was less material To block the light from our vision, for why this happened, the team does not know for sure, because most of the material from the blast may have fallen back in Black hole or neutron star. “We wondered, but I don’t quite know,” says Margutti. “We still don’t know.”

It also helped that this explosion happened relatively close – in the cosmic system of things – only 200 million light years away. It makes everything a little easier to observe. And to really understand this event in more detail, astronomers must keep track of it during the weeks and months ahead. Right now it’s too close to the sun in the sky to see. But after next week, it should be back in a good place to look at the first time.

And the details we get from this event can fill us in what happens to black holes and neutron stars when they are just newborns. How do they change in size? How do they rotate? With the cow, astronomers hope to come closer to answering these questions. “We’ve seen isolated neutron stars, neutron stars crashing into each other, and we’ve seen material falling into black holes,” Brown says. “This observation may well be that these things are born. It’s pretty cool.”

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