China News Service, Beijing, September 4 (Reporter Sun Zifa) The reporter learned from the Institute of High Energy Physics of the Chinese Academy of Sciences (Institute of High Energy Physics, Chinese Academy of Sciences) on the 4th that the HXMT satellite team passed the X-ray accretion pulsar GRO J008-57. The detailed observation of the pulsar using direct measurement method to obtain the surface magnetic field intensity of the pulsar is about 1 billion Tesla, which is by far the strongest magnetic field in the universe that has been directly and very reliably measured by humans.

  This major astronomical scientific research paper, which is mainly completed by the Institute of High Energy Research of the Chinese Academy of Sciences and the University of Tubingen in Germany, has recently been published in the internationally renowned journal Astrophysical Journal Letters (ApJL).

Artistic imagination of the "Wisdom Eye" satellite in space.

Photo courtesy of the "Wise Eye" satellite team of the Institute of High Energy, Chinese Academy of Sciences

  According to the Institute of High Energy, Chinese Academy of Sciences, in August 2017, researchers used the Smarteye satellite to make detailed observations of an outbreak of the X-ray accretion pulsar GRO J1008-57, and for the first time in its X-ray energy spectrum the standard deviation was higher than 20 times. With high confidence (the scientific community confirms that the standard of scientific discovery is generally 5-20 times the standard deviation), a cyclotron absorption line was found near 90 kiloelectron volts (keV).

According to theoretical inference, the surface magnetic field intensity of the neutron star corresponding to the cyclotron absorption line is as high as about 1 billion Tesla, which is tens of millions of times higher than the strongest magnetic field of tens of Tesla that can be generated in the current earth laboratory.

  "Smart Eye" is China's first X-ray astronomical satellite, equipped with high-energy, medium-energy, and low-energy X-ray telescopes, three scientific payloads and space environment monitors, with an observation energy range of 1-250keV.

Compared with foreign X-ray satellites, "Huiyan" satellites have a wide range of energy coverage, the largest effective area in the high-energy X-ray energy range, high time resolution, small detection dead time, and no photon accumulation effect for observation of strong sources. Advantages, so it has the unique ability to detect high-energy cyclotron absorption lines.

  A neutron star is the celestial body with the strongest magnetic field in the universe. Its X-ray binary star system is composed of a neutron star and its accompanying stars. The gas accompanying the star falls to the neutron star under the strong gravitational action of the neutron star, forming a gas disk rotating around the neutron star at high speed, which is called accretion. plate.

If the magnetic field is strong, the plasma on the accretion disk will fall to the surface of the neutron star along the lines of magnetic force and emit strong X-ray radiation.

  The scientific research team pointed out that due to the rotation of the neutron star, the X-ray emission area rotates with it, forming periodic X-ray pulse signals. Therefore, such celestial bodies are also called "X-ray accretion pulsars."

A large number of observations have found that this type of celestial body will have a "sink" structure in the X-ray radiation energy spectrum. The theory is that this is caused by the cyclotron resonance scattering of electrons in a magnetic field, so it is called cyclotron absorption line, and the energy at the absorption line corresponds to Magnetic field strength, which can be used to directly measure the magnetic field strength near the surface of a neutron star.

  It is understood that the "Wisdom Eye" satellite was first proposed in 1993 by Li Tibei, Wu Mei and others from the Institute of High Energy of the Chinese Academy of Sciences. It was launched in June 2017. The Institute of High Energy of the Chinese Academy of Sciences is responsible for satellite payloads, ground application systems and scientific research.

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