The Chinese Insight-HXMT space observatory has recorded what would be the strongest magnetic field in the universe for now. The pulsar named Swift J0243.6+6124 has a magnetic field of 1.6 billion tesla , beating previous records of about 1 billion tesla discovered around the pulsars GRO J1008-57 and 1A 0535+262.
In 2020 the strongest magnetic field was determined to be approximately 1 billion tesla. Since then, the figure has been surpassed until reaching that of the Swift J0243.6+6124 pulsar and its 1600 tesla.
Swift J0243.6+6124 was already considered a star to watch out for. It is a pulsar, a rapidly rotating neutron star with a powerful magnetic field that is tilted with respect to the axis of rotation. The pulsar is positioned in space in such a way that bursts of radiation emitted by its magnetic field sweep over our planet with every spin.
Swift J0243.6+6124 is an X-ray pulsar , the only one in our galaxy that falls into the ultraluminous category. It is also the only example in the Milky Way of an X-ray pulsar with a Be-type companion star feeding it matter fast enough to generate radio-emitting jets of matter from its poles. These features, by themselves, provide a golden opportunity for studies carried out by astronomers.
However, measuring the magnetic field of a distant object is not an easy task , as no matter how strong the field is, at a distance of thousands of light years it weakens rapidly. This specifically is about 22,000 light years from Earth.
What can be done is to find clues in the way the ultra-bright X-ray glow scatters from electrons whizzing by the magnetic track, something known as a cyclotron resonance scattering feature .
In 2017, China launched an X-ray observatory, Insight-HXMT, which has since provided astrophysicists with a way to pick up signatures like these in distant emissions. It was what allowed the measurement in 2020 of the energies of the electrons in the field GRO J1008-57. Following the launch of Insight-HXMT , there was a burst of activity in Swift J0243.6+6124 and a glimpse of its high-strength magnetic field, with a cyclotron resonance scattering feature buried in its X-ray spectrum, was revealed. .
Researchers from the Chinese Academy of Sciences and the Sun Yat-Sen University, also in China, as well as the University of Tübingen (Germany), subsequently analyzed the characteristic to calculate the energy of its electrons, which reached a peak of 146 kiloelectronvolts. , surpassing the 90 and 100 kiloelectronvolts of the previous records.
Since Swift J0243.6+6124 is the only ultraluminous X-ray pulsar in our galaxy, having a precise measurement of its magnetic field can give an idea of what is happening near its surface.
As a type of neutron star, pulsars like Swift J0243.6+6124 are made of atoms smashed into configurations far beyond what we can create on Earth. Its magnetic properties help to support or not several models that explain how its highly compact crust behaves. In particular, the nature of the neutron star’s magnetism confirms the probability that its field is complex and made up of multiple poles.
Referencia: Ling-Da Kong et al. 2022. Insight-HXMT Discovery of the Highest-energy CRSF from the First Galactic Ultraluminous X-Ray Pulsar Swift J0243.6+6124. The Astrophysical Journal Letters.
