A team of astronomers has detected the strongest magnetic field ever observed in the universe. It was precisely the Insight-HXMT team of researchers who, studying the powerful X-ray signals that come from a neutron star, calculated that its magnetic field is tens of millions of times stronger than any other created in a laboratory here. on earth.
Compared with other X-ray satellites, Insight-HXMT has outstanding advantages in the detection of cyclotron lines (especially at high energies) due to its broadband spectral coverage (1-250keV), large effective area at high energies or effects of negligible build-up for bright fonts.
Where does this powerful magnetic field come from?
Its name is GRO J1008-57 , a neutron star belonging to a very specific subtype: a growing X-ray pulsar. As a pulsar, it emits powerful beams of electromagnetic radiation that periodically sweep across the Earth like a beam of light. The neutron star accumulates matter and forms a surrounding accretion disk. If the magnetic field is strong, the accumulated matter is channeled through magnetic lines towards the surface of the neutron star, which produces X-ray radiation . The description of “accumulated X-rays” comes from the fact that the material falls regularly on its surface, causing periodic bursts of energetic X-rays that can be detected by telescopes. And it is precisely astronomers from the Chinese Academy of Sciences and the Eberhard Karls University in Tübingen who have been able to detect and study one of these bursts to calculate the strength of the pulsar’s magnetic field.
We have to go back to an outbreak in August 2017; astronomers observed the pulsar using the Hard X-Ray Modulation Telescope (Insight-HXMT) or simply the Insight telescope, launched in 2017 to observe black holes, neutron stars and similar phenomena. The experts noted a particular signature called the cyclotron resonant scattering characteristic (CRSF), a pattern that occurs when X-ray photons scatter from plasma electrons on the surface.
This CRSF was measured at an energy of 90 keV at a significance level of> 20σ. (Note that the scientific community confirms a new scientific discovery when its significance level is greater than 5σ); Using this data, the team calculated that the pulsar’s magnetic field was as high as a billion Tesla . It is by far the most powerful magnetic field ever detected in the universe. For context, for reference, the strongest magnetic field created in the lab has so far been “just” 1,200 Tesla.
While this is the strongest that has been directly detected, it is theorized that even more intense versions of neutron stars, called magnetars, can have magnetic fields of up to 100 billion Tesla. Magnetars or magnetars are versions of neutron stars powered by an incredibly strong magnetic field. They are super-dense remnants of supernova explosions. We could say that the most powerful images known in our universe.
Referencia: M. Y. Ge et al. Insight-HXMT Firm Detection of the Highest-energy Fundamental Cyclotron Resonance Scattering Feature in the Spectrum of GRO J1008-57, The Astrophysical Journal (2020). DOI: 10.3847/2041-8213/abac05
