Physics

More Than 1.6 Billion Tesla

Insight-HXMT Strongest Magnetic Field in Universe

Insight-HXMT’s discovery of the fundamental electron cyclotron absorption line near 146 keV for the first Galactic ultraluminous X-ray pulsar Swift J 0243.6+6124. Credit: Image by IHEP

Insight-HXMT Breaks Own Measurement Record for Strongest Magnetic Field in Universe

Neutron stars generate the strongest magnetic fields in the universe. However, the only way we have to measure their surface magnetic field directly is to observe the cyclotron absorption lines in their X-ray energy spectra. Recently, the Insight-HXMT team discovered a cyclotron absorption line with an energy of 146 keV in the neutron star X-ray binary Swift J0243.6+6124, which translates to a surface magnetic field of more than 1.6 billion Tesla.

After direct measurement of the strongest magnetic field in the universe at about 1 billion Tesla in 2020, the world records for the highest energy cyclotron absorption line and direct measurement of the strongest magnetic field in the universe have been smashed by a large margin.

The findings, which were published on June 28, 2022, in Astrophysical Journal Letters (ApJL), were obtained jointly by the Key Laboratory for Particle Astrophysics at the Institute of High Energy Physics (IHEP) of the Chinese Academy of Sciences and the Institute for Astronomy and Astrophysics, Kepler Center for Astro and Particle Physics, University of Tübingen ( IAAT). Dr. Lingda Kong, Professor Shu Zhang, and Professor Shuangnan Zhang from IHEP are the corresponding authors of the paper. Dr. Victor Doroshenko and Professor Andrea Santangelo from the University of Tübingen significantly contributed to the discovery.

or[{” attribute=””>neutron star X-ray binary system consists of a neutron star and its companion star. Under the strong gravitational force of the neutron star, the gas of the companion star falls towards the neutron star, forming an accretion disk. The

Insight HXMT Fundamental Electron Cyclotron Absorption Line

Insight-HXMT’s discovery of the fundamental electron cyclotron absorption line near 146 keV for the first Galactic ultraluminous X-ray pulsar Swift J 0243.6+6124. Credit: Image by IHEP

Ultraluminous X-ray pulsars are a class of objects whose X-ray luminosity far exceeds that of canonical X-ray accreting pulsars. They have previously been discovered in several galaxies far from the

This time, the direct magnetic field measurement by Insight-HXMT based on the cyclotron absorption line is about an order of magnitude greater than that estimated using indirect means. This serves as the first concrete evidence that a neutron star’s magnetic field structure is more complex than that of a traditional symmetric dipole field, and it also provides the first measurement of the nonsymmetric component of a neutron star’s magnetic field.

Reference: “Insight-HXMT Discovery of the Highest-energy CRSF from the First Galactic Ultraluminous X-Ray Pulsar Swift J0243.6+6124” by Ling-Da Kong, Shu Zhang, Shuang-Nan Zhang, Long Ji, Victor Doroshenko, Andrea Santangelo, Yu-Peng Chen, Fang-Jun Lu, Ming-Yu Ge, Peng-Ju Wang, Lian Tao, Jin-Lu Qu, Ti-Pei Li, Cong-Zhan Liu, Jin-Yuan Liao, Zhi Chang, Jing-Qiang Peng and Qing-Cang Shui, 28 June 2022, Astrophysical Journal Letters.
DOI: 10.3847/2041-8213/ac7711

Hard X-ray Modulation Telescope (HXMT)

The Hard X-ray Modulation Telescope (HXMT), also known as Insight, is a Chinese X-ray observatory launched on June 15, 2017 aboard a Long March 4B rocket from the Jiuquan Satellite Launch Center. The mission provides high resolution imagery across a wide spectrum of X-ray energies.

Insight-HXMT is the first Chinese X-ray astronomy satellite. It comprises scientific payloads including a high-energy telescope, medium-energy telescope, low-energy telescope, and a space environment monitor. Insight-HXMT has advantages over other X-ray satellites in terms of broadband (1-250 keV) spectral coverage, large effective area at high energies, high time resolution, low dead-time, and no pile-up effects for bright sources, thus opening up a new window for observing black holes, neutron stars with hard X-ray fast transitions, and energy spectrum studies.

In 2020, the Insight-HXMT team reported the detection of a 90 keV cyclotron absorption line from a neutron star in the X-ray binary system GRO J1008-57, corresponding to a surface magnetic field of 1 billion Tesla, which set a world record for direct measurement of the universe’s strongest magnetic field at the time. Later, a new record for a cyclotron absorption line—with its highest energy around 100 keV—was detected by Insight-HXMT from another neutron star in 1A 0535+262. Insight-HXMT has demonstrated its exceptional capacity to explore the energy spectrum by breaking its own records for cyclotron absorption line discoveries.

Insight-HXMT was proposed by Professor Tipei Li and Professor Mei wu in 1993 at IHEP and was successfully launched on June 15, 2017. Its development is supported by the China National Space Administration and CAS. IHEP was responsible for satellite payloads, ground segments, and scientific research for this mission. The China Academy of Space Technology was responsible for the satellite system. Tsinghua University participated in the development of payload and ground segments. The National Space Science Center and Beijing Normal University were also involved in the mission. The calibration of the detectors on board Insight-HXMT was supported by the National Institute of Metrology, Ferrara University in Italy, and the Max Planck Institute for Extraterrestrial Physics.

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