When the magnetosphere in the Milky Way galaxy produced extremely powerful radio waves in 2020, scientists finally had solid evidence to clarify the origin of the explosion. radio speed.
A new mind-stimulating study has reduced the machine. By studying the bright light of a fast radio burst detected in 2022, a team of astronomers has discovered a source of gravity around a magnetar, in a galaxy light-years away. 200 million.
It is the first solid evidence that fast radio bursts can originate from the magnetospheres of magnetars.
Astronomer Kenzie Nimmo of the Massachusetts Institute of Technology (MIT) says: “In these neutron star environments, the magnetic field is at the limit of what the Universe can produce.
“There has been a lot of debate about whether this bright radio could even escape that extreme plasma.”
Fast radio bursts (FRBs) have puzzled scientists since they were first discovered in 2007. They are, as the name suggests, very short bursts of radio emission, which last only seconds. They are also very powerful, sometimes giving off more than 500 million times the energy of the Sun in a short blink.
FRBs are difficult to study because they usually only burst once. This makes it impossible to predict, and tricky – but impossible – to get back to the source. Several single-emitting FRBs have been traced to galaxies across millions to billions of light-years of space.
Astronomers can also examine the characteristics of the radio beam, such as its polarization, to determine what kind of environment it traveled through on its way to Earth. Which types of stars can emit FRBs is still a mystery, but growing evidence implicates magnetism.
Magnetaras are rare neutron stars, which are themselves very dense remnants of the core left after a massive star has gone supernova. But the magnets have a stronger external magnetic field than ordinary neutron stars – about 1,000 times stronger. It is the strongest gravitational force in the Universe.
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“Near these very powerful neutron stars, also known as magnetars, atoms cannot exist – they can be pulled apart by gravity,” says physicist Kiyoshi Masui of MIT.
“The exciting thing here is, we find that the energy stored in those magnetic fields, close to the source, distorts and rearranges itself so that it can be released as radio waves that we can see. half of the Universe.”
To trace the origin of the FRB, Nimmo and his colleagues studied a feature known as scintillation in the event known as FRB 20221022A, which was first detected in 2022 and later followed the galaxy 200 million light-years away. Scintillation is what makes stars twinkle – the bending of light’s path as it travels through gas in space. The longer the distance, the stronger the blink.
FRB 20221022A is pretty bog-standard, as far as FRBs go. It was moderately long, about 2 milliseconds, and of moderate intensity. This makes it an excellent subject for trying to understand the properties of other FRBs, too.
A companion paper studying the polarization of light from FRB 20221022A – the degree to which its wavelengths are distorted – found an S-shaped wave associated with a rotating object, a first for an FRB . This suggested that the signal originated very close to the rotating object.
Nimmo and colleagues found that, if they could determine the amount of scintillation in FRB 20221022A, they could calculate the size of the region where it originated. The light from the FRB showed strong scintillation, leading the researchers to the region of gas that distorted the signal. Using that gas field as a lens, they narrowed down the FRB source to a distance of 10,000 kilometers (6,213 miles) from the magnetic source.
“Getting close to 10,000 km, from a distance of 200 million light years, is like being able to measure the diameter of a DNA helix, which is about 2 nanometers across, on the Moon ,” Masui said. “There’s an incredible range of scales involved.”
It is the first solid evidence that extragalactic FRBs can originate in the magnetosphere of high-energy neutron stars. But more than that. The methods used by the team show that scintillation may be a powerful probe for other FRBs, so astronomers can try to understand how different they are – and what other types of stars can also emit powerful eruptions.
“These bursts are always happening,” says Masui. “There can be many different types of how and where they happen, and this scintillation pattern will be very useful in helping to disentangle the different physics driving these explosions.”
Research published in Nature.
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