Magnetar-powered Kilonova Blast. Credit: NASA, ESA, and DPlayer (STSCI)
Neutron-star Collision releases puzzle burst of infrared light
In our infinite universe, the stars can bump into the night. When this happens between a pair of crushed stars called neutron stars, the resulting fireworks show, called kilonova, is incomprehensible. Our collision-free light will shine 100 million times brighter than our sun.
What’s left of SmashUp? Especially more crushed object objects called Black hole. But in this case even after Hubble hit the head, forensic clues were found for something strange.
A sharp flood of gamma-rays signaling astronomers to this event has been seen before in other star smashups. But something unexpectedly came into Hubble’s near-infrared vision. Although the effect of radiation after explosion from X-rays to radio waves seemed typical, there was no flow of infrared radiation. It was 10 times brighter than the forecast for Kilonova. Without Hubble, gamma-ray explosions would have looked like many others, and scientists would not have been aware of the strange infrared component.
The most plausible understanding is that colliding neutron stars are formed on a much larger scale. Neutron star. It’s like breaking two Volkswagen Beatles together and getting a limousine. This new beast developed a powerful magnetic field, which made it a unique class of matter called a magnet. The magnet accumulates energy in the material that is ejected, causing it to glow brighter in infrared light than predicted. (If a magnet flew within 100,000 miles of the Earth, its intense magnetic field would erase the data of every credit card on our planet!)
This image shows the glow from kilonova due to the merger of two neutron stars. Kilonova, whose peak brightness reaches 10,000 times that of a classical nova, appears as a bright spot (indicated by an arrow) on the upper left of the host galaxy. The merger of neutron stars is believed to have produced a magnet that has an extremely powerful magnetic field. The energy radiation from that magnet made the material emitted from the explosion. Credit: NASA, ESA, W.C. Fong (Northwestern University), and t. Lashkar (University of Bath, UK)
With the explosion of so many gamma rays in the universe so long ago and so many times the sun would produce more power in half-a-second than it would during its entire 10-billion-year lifespan. In May 2020, light from a flash finally reached Earth and was first discovered NASANeil Gehrels Swift Observatory. Scientists quickly listed other telescopes – including NASA Hubble Space Telescope, A large array of radio observatories, the WM Cake Observatory and the Las Cambres Observatory Global Telescope Network, to study post-explosion and host galaxies. It was Hubble who provided the surprise.
Based on X-ray and radio observations from other observatories, astronomers were amazed by what they saw with Hubble: the nearby infrared emission was 10 times brighter than predicted. These results challenge the traditional theories of what happens after a short gamma-ray explosion. One possibility is that observations could point to the birth of a large, highly magnetic neutron star called a magnet.
“These observations do not fit into the traditional clarity for short gamma-ray explosions,” said study leader Wen-fi Fong. Northwestern University In Evanston, Illinois. “Looking at what we know about radio and X-rays from this explosion, it doesn’t match. The closest infrared emission path we are looking for with Hubble is very bright. In terms of trying to fit these gamma-ray puzzle pieces together, a puzzle piece is not exactly appropriate. ”
Bursting gamma-rays without Hubble would have looked like many others, and Fong and his team would not have been aware of the strange infrared behavior. “It’s amazing to me that after 10 years of studying a similar phenomenon, we can find unprecedented behavior like this,” Fong said. “It just shows the diversity of explosions that the universe is capable of producing, which is very exciting.”
Light Fantastic
The intense glare of gamma rays from these explosions emanates from a jet of material approaching the speed of light. Jets do not contain large amounts – perhaps the bulk of the Sun’s ten months – but because they are moving so fast, they release a huge amount of energy in all wavelengths of light. This particular gamma-ray explosion is a rare case in which scientists were able to detect light over the entire electromagnetic spectrum.
This illustration shows the sequence for forming a kilonova powered by a magnet, whose peak brightness reaches 10,000 times that of a classical nova. 1) Two orbiting neutron stars spiral closer and closer together. 2) They collide and merge, triggering an explosion that gives the sun more energy in half-seconds, during its entire 10-billion-year lifespan. )) The merger forms a much larger neutron star called a magnet, which has a stunningly powerful magnetic field. )) The magnet accumulates energy in the extracted material, causing it to become unexpectedly bright at infrared wavelengths. Credit: NASA, ESA, and DPlayer (STSCI)
“When the data came in, we created a picture of the mechanism that was producing the light we were looking at,” said Tanmoy Laskar, co-investigator of the study at the University of Bath in the United Kingdom. “As we received Hubble’s observations, we had to completely change the way we think, because the information Hubble added made us realize that we had to abandon our traditional thinking, and that a new phenomenon was emerging. So we had to find out what the physics behind these highly explosive explosions meant. “
Gamma-ray explosions – the most get-go, explosive events are known – live fast and die hard. They are divided into two classes based on the duration of their gamma rays.
If the gamma-ray emission is more than two seconds, it is called a long gamma-ray explosion. This event is known for the direct result from the original fall of a big star. Scientists expect no supernova to accompany this long-term explosion.
If the gamma-ray emission lasts less than two seconds, it is considered a short burst. It is believed that the two neutron stars are due to the merging of extremely dense objects about the mass of the Sun, which is compressed in the amount of the city. The neutron star is so ga ense that on Earth, a spoon would weigh a billion tons! The merger of two neutron stars is generally thought to produce black holes.
Both images, taken on May 26 and July 16, 2020, show the fading light of Kilonova in the distant galaxy. Kilonova appears as a spot on the top left of the host galaxy. Glow is prominent in the May 26 image but fades into the July 16 image. The peak of the Kilonova reaches 10,000 times faster than that of the Classical Nova. The merging of two neutron stars – the source of Kilonova – is believed to have produced a magnet, which has an extremely powerful magnetic field. It illuminates the material emitted from the magnet radiation, causing it to become unusually bright in the infrared wavelength of light. Credit: NASA, ESA, W.C. Fong (Northwestern University), t. Lashkar (University of Bath), and a. Pagan (STSCI)
Neutron star mergers are very rare but important because scientists believe they are the main source of heavy elements in the universe, such as gold and uranium.
With a short gamma-ray eruption, scientists expect to see a “kilonova” whose top brightness is typically 1000 times that of a classical nova. Kilonova is an optical and infrared glow from the radioactive decay of heavy elements and is typical for the merging of two neutron stars or the merging of a neutron star with a small black hole.
Magnetic Monster?
Fong and his team discussed several possibilities to explain the unusual brilliance Hangle saw. When most of the short gamma-rays erupt probably result in a black hole, in this case the two merged neutron stars can come together to form a magnetar, a supermassive neutron star with a very powerful magnetic field.
“You basically have these magnetic field lines that are anchored to a star that whips about a thousand times a second, and this produces a magnetic wind,” Lascar explained. “This spinning field is the rotational extrusion of a neutron star formed in a line merger and that energy accumulates in the ejecta from the explosion, making the material brighter.”
This animation shows the sequence for forming a magnetar-powered kilonova, whose top brightness reaches 10,000 times that of a classical nova. In this order, two orbiting neutron stars spiral closer and closer to each other before colliding and merging. This triggers an explosion that releases more energy in half a second during the Sun’s entire 10-billion-year lifespan. The merger produces a much larger neutron star called a magnet, which has a stunningly powerful magnetic field. The magnet accumulates energy in the extracted material, causing it to become unexpectedly bright at infrared wavelengths. Credit: NASA, ESA, and DPlayer (STSCI)
If the extra brightness comes from a magnet that accumulates energy in the kilonova material, then in a few years, the team expects light to be emitted from the ejector fodder that appears on the radio wavelength. Subsequent radio observations may eventually prove that this was a magnet, and this may explain the origin of such objects.
“With its amazing sensitivity to near-infrared wavelengths, Hubble actually sealed the deal with this explosion,” Fong explained. “Surprisingly, Hubble was able to take an image only three days after the explosion. Through a series of subsequent images, Hubble showed that the source after the explosion was found. This is the opposite of having a static source that is unchanged. With these observations, we know that we have not only captured the source, but we have also discovered something very bright and very unusual. Hubble’s angular resolution was also important for directing the state of the explosion and accurately measuring the light coming from the merger. “
NASA’s next James Webb Web Space Telescope Particularly suitable for this type of inspection. “The web will revolutionize the study of similar phenomena,” said Edo Burger and chief investigator of the Hubble Program at Harvard University in Cambridge, Massachusetts. “With its incredible infrared sensitivity, it will not only be able to detect such emission at such large distances, but it will also provide detailed spectroscopic information that will solve the nature of the infrared emission.”
The team’s findings appear in the next issue Astrophysical Journal.
The Hubble Space Telescope is an international collaboration project between NASA and the ESA (European Space Agency). NASA’s Goddard Space Flight Center operates a telescope in Greenbelt, Maryland. The Hubble Science Institute operates the Space Telescope Science Institute (STSCI) in Baltimore, Maryland. STSCI for NASA by Astronomy University Research in Research in Washington DC.
