RIKENMr. Teruyo EnokidoTheir international research group is about 6500 light-years away in the direction of Taurus.“Crab Pulsar”As a result of observing a pulsar called a pulsar (a type of neutron star in which periodic electromagnetic waves are observed to blink with high-speed rotation), a radio burst phenomenonBrightening of X-rays synchronized with “Giant Radio Pulse (GRP)”Announced the research results that was detected.
According to the research groupThe energy emitted from the “Crab Pulsar” when a huge radio pulse is generated greatly exceeds conventional expectations.It is said that this observation revealed that a strong radio wave is emitted for a very short time.“Fast Radio Burst (FRB)”It is said that it is an important knowledge to solve the mystery of.
■ First detection of brightening of X-rays synchronized with radio waves, energy amount is several hundred times more than previously expected
“Crab Pulsar” is a supernova remnant observed in 1054.“Crab Nebula”It is located inside and is believed to have been born with the explosion of a supernova that left the Crab Nebula.According to the research group, “Crab Pulsar”A huge radio pulse that makes the periodic radio pulse 10 to 1000 times stronger than usualIs said to be observed sporadically.Of the approximately 2,800 pulsars found in the Milky Way galaxy, theseOnly a dozen or so giant radio pulses are generated, including “Crab Pulsar”It has been with.
PulsarRadio waves, visible light, X-rays, gamma rayssuch asElectromagnetic waves of various wavelengthsHowever, since it was thought that the mechanism by which radio waves and other electromagnetic waves were emitted was different, the giant radio pulse was thought to be a brightening phenomenon of the pulsar observed only by radio waves. However,Visible light also brightens by a few percent when a giant radio pulse is generatedIt turned out in 2003 that the energy was even greater.Whether it is brightening even with X-rays and gamma raysIs said to have been attracting attention.
This time, the research group is from NASA, which is located outside the International Space Station (ISS).X-ray observation device “NICER”, Operated by Japan Aerospace Exploration Agency (JAXA)Usuda Deep Space Center 64m Radio Telescope, Operated by the National Institute of Information and Communications Technology (NICT)Kashima Space Technology Center’s 34m radio telescopeuse. About 2 years from 2017,Simultaneous observation of “Crab Pulsar” by X-ray and radio wavesWas carried out 15 times in total.
As a result of analyzing the observation dataX-rays brighten by about 4% in synchronization with a huge radio pulseIt became clear for the first time that I was doing it. According to the research group, X-rays release much more energy than radio waves, even with a brightening of only 4 percent.The amount of energy released when a huge radio pulse is generated is hundreds of times larger than previously expected.It is said to mean that.
■ Will it lead to the elucidation of the mysterious phenomenon “fast radio bursts”?
The research group has been revealed in recent yearsFast Radio Burst (FRB)Also mentions. Since high-speed radio bursts and giant radio pulses (GRP), which emit strong radio waves for only a few thousandths of a second, are similar phenomena, the theoretical model of giant radio pulses is a model that can explain high-speed radio bursts. It is said that it has been considered as one.
However, since this research revealed that a large amount of energy is emitted by X-rays when a huge radio pulse is generated,Difficult to explain fast radio bursts with a simple giant radio pulse modelIt is said that it turned out.
On the other hand, a type of neutron star with a strong magnetic field as a source of high-speed radio bursts.“Magnetar”Activities are becoming more promising, and in 2020Fast radio bursts were detected from the Milky Way galaxy magnetarToSandro Mereghetti 氏The results of their research have been announced.
The research group hopes that this achievement will provide important insights for observing the giant radio pulses of active young magnetars.
Image Credit: NASA, ESA and Allison Loll/Jeff Hester (Arizona State University)
Sentence / Takehiro Matsumura