Astronomers wander to explain this unusually bright Kilonova explosion


At a distance of 5.5 billion light-years from the universe, a series of telescopes have captured a bright flash of short gamma-ray explosions. It reminds us that we are reminded of the Kilonova explosion associated with the neutron star collision, which we discovered on the back of a historic history in 2017. Astronomers will be surprised to see that this is what we have just seen.

That 2017 discovery, known as GW 170817, was a great gift: a wealth of data in multiple signals to help us understand these events, and identify what we’re looking for or show someone again.

But with the new gamma-ray explosion there is something in Kilonova, called GRB 200522A, that is the opposite of a neutron star collision. The flash captured by the Hubble Space Telescope at near-infrared wavelengths was incredibly bright – 10 times brighter than the neutron star collision models predlo.

“These observations do not fit into the traditional explanation for short gamma-ray explosions,” said Wen-Fi Fong, an astronomer at Northwestern University.

“Looking at what we know about radio and X-rays from this explosion, it just doesn’t match. The near-infrared emission we’re looking for with Hubble is pretty bright.”

The light was first discovered by NASA’s Neil Garels Swift Observatory, a space telescope built to detect gamma-ray explosions as early as possible with its Burst Alert Telescope. Once the warning came, another space and terrestrial telescope came home to the scene of the explosion.

The very large array, the WM Cake Observatory, and the Las Cambres Observatory Global Telescope Network all worked to obtain an eventromagnetic profile ranging from radio wavelengths to X-rays. They showed that the event was a short gamma-ray burst – a type of dissolution, in less than two seconds of time associated with the merging of neutron stars.

But the Hubble Space Telescope, observing on near-infrared, would throw a spinner into the works.

“As soon as the data came out, we were creating a picture that produced the light of the mechanism we were seeing,” said Tanmoy Laskar, an astronomer at the University of Bath in the UK.

“We had to completely change our thinking process, because the information Hubble added made us realize that we had to abandon our traditional thinking and that a new phenomenon was emerging. Then we had to find out what physics meant behind these extremely explosive explosions. . “

The collision of two neutron stars – the debris cores of a dead star – is an important event. Neutron stars are small and ga ense, about 1.1 to 2.5 times the mass of the Sun, but they cover only 20 kilometers (12 miles).

When they collide, they emit a massive release of the Kilonova explosion, which is 1000 times brighter than the regular Nova. This is accompanied by an explosion of high-energy gamma-rays from a jet of expelled material traveling close to the speed of light.

Kilonova itself is a glow in optical and infrared wavelengths produced by the radioactive decay of heavy elements. Astronomers believe that in GW 170817 two neutron stars merged to form a black hole. GRB 200522 Infrared brightness near Kilonova, researchers believe, these two neutron stars merged to become something else: a magnet.

Magnetars are a kind of neutron star, but they are super virods, which have an extremely powerful magnetic field – about 1000 times more powerful than the average neutron star.

“You basically have these magnetic field lines that are anchored to a star that whips about 1000 times a second, and that produces a magnetic wind.”

“This spinning field is the rotational energy of the neutron star formed in the line merger and that energy accumulates in the ejecta from the eruption, making the material brighter.”

Magnets are also rare; Only 24 people have been confirmed in the galaxy. It makes it difficult for us to find out how we got it by accident. If the two neutron stars associated with GRB 200522A formed a magnet, it would give us a new way in which these extreme stars could exist.

“We know that magnets exist because we see them in our galaxy,” Fong said.

“We think that most of them are formed in the explosive death of giant stars, leaving behind this very magnetic neutron star. However, it is possible that the neutron star merger has a small fractional form. We have never seen evidence of it, let alone In infrared light, this makes the discovery special. “

It’s a little early to know for sure. To date only one kilonova has been confirmed and is well characterized; It is, of course, the Kilonova associated with GW 170817.

But the new discovery, with its near-infrared eccentricity, is a step towards listing possible variations in Kilonova and understanding the range of results when two neutron stars collide.

Research has been adapted Astrophysical Journal And available at Archive.

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