my country’s “Huiyan” satellite once again refreshed the record of direct measurement of the strongest magnetic field in the universe

IT House July 6 news, according to the website of the Institute of High Energy Physics, Chinese Academy of Sciences, neutron stars are celestial bodies with the strongest magnetic fields in the universe. method.Recently, the “Huiyan” satellite team has been working on the neutron star X-ray binary star numbered Swift J0243.6+6124.Discovery of cyclotron absorption lines with energies up to 146 keV, corresponding to the surface magnetic field of neutron stars exceeding 1.6 billion Teslafollowing the direct measurement of the strongest magnetic field in the universe of about 1 billion Tesla in 2020,The world record for the direct measurement of the highest energy cyclotron absorption line and the strongest magnetic field in the universe has once again been greatly refreshed. The research work was mainly completed by the Institute of High Energy Physics (IHEP) of the Chinese Academy of Sciences in cooperation with The University of Tübingen, Germany. Recently, it was published online in the internationally renowned journal “Astrophysical Journal Letters (ApJL)” published.

▲ Art image of accretion pulsar observed by Huiyan satellite | Source: website of Institute of High Energy Physics, Chinese Academy of Sciences

Neutron star X-ray binary system consisting of a neutron star and its companion star, the gas accompanying the star falls to the neutron star under the strong gravitational action of the neutron star, forming a gas disk that rotates at a high speed around the neutron star, called an accretion disk. The material on the accretion disk will fall to the surface of the neutron star along the magnetic field lines of the neutron star, and emit strong X-ray radiation. X-ray accretion pulsars”. observation found,This type of celestial body will have a “sag” structure in the X-ray radiation energy spectrum, which is caused by the absorption of X-ray photons by resonant scattering of electrons whirling in the magnetic field, known as the cyclotron absorption line. The magnetic field strength corresponding to the energy at the cyclotron absorption line is the magnetic field strength on the surface of the neutron star, which is currently the only method to directly measure the magnetic field strength near the surface of the neutron star.

Ultra-bright X-ray pulsars are special X-ray accretion pulsars with unusually bright X-ray luminosity. They have been found in many galaxies outside the Milky Way before. Astronomers speculate that their pulsars have a high magnetic field strength, but have not measured them directly. evidence.“Huiyan” satellite made detailed wide-energy band observations of the first ultra-bright X-ray pulsar in the Milky Way, Swift J0243.6+6124this time, a cyclotron absorption line with an energy as high as 146 keV was found in its energy spectrum with extremely high significance (about 10 times the standard deviation), corresponding to the surface magnetic field of the neutron star exceeding 1.6 billion Tesla.This is not only the highest record of direct measurement of the magnetic field of a cosmic celestial body so far, but also the first direct measurement of the surface magnetic field of a neutron star in an ultra-bright X-ray source..

It is generally believed that the surface magnetic field of a neutron star has a complex structure, including a dipole magnetic field with a large extension range and a multipole magnetic field limited to the surface of the neutron star. Previously, various indirect methods could only estimate the dipole magnetic fields of neutron stars that extend farther away. The “Huiyan” satellite directly measured the surface magnetic field strength of Swift J0243.6+6124,about an order of magnitude higher than the dipole magnetic field strength given by indirect methods, indicating that it corresponds to the multipole magnetic field near the surface of the neutron star. This is the first direct observation that neutron stars do have a more complex asymmetric magnetic field structure in addition to the bipolar symmetric dipole magnetic field.

IT Home understands that,Huiyan satellite is my country’s first X-ray astronomical satellite, carrying three scientific payloads and space environment monitors, the high-energy X-ray telescope, the medium-energy X-ray telescope and the low-energy X-ray telescope, with an observation energy range of 1-250 keV. Compared with foreign X-ray satellites, Huiyan satellites have outstanding advantages such as wide coverage of energy range, largest effective area in high-energy X-ray energy range, high time resolution, small detection dead time, and no photon accumulation effect for observation of strong sources. A new window has been opened for the observation of black holes, hard X-ray fast light changes of neutron stars and energy spectrum research. In 2020, the “Huiyan” satellite detected a cyclotron absorption line of 90 keV in the neutron star numbered GRO J1008-57, corresponding to the surface magnetic field of the neutron star of 1 billion Tesla, which was the world record for direct measurement of the cosmic magnetic field at that time. Subsequently, the “Smart Eye” team also detected a cyclotron absorption line of about 100 keV on the energy spectrum of another neutron star (1A 0535+262). The “Huiyan” satellite has set the highest record in the measurement of cyclotron absorption line energy for three consecutive times, showing its unique ability to detect the high-energy X-ray energy spectrum of celestial bodies in the world.