Science & Technology

Sudden Spin-Down Event Illuminates Magnetar Mystery

Magnetars are a type of neutron star that are characterized by their incredibly strong magnetic fields. These fields are estimated to be a thousand billion times stronger than the magnetic field of the Earth, making magnetars some of the most magnetic objects in the universe. They emit intense bursts of X-rays and gamma rays, which can last from a fraction of a second to several minutes, and are thought to be caused by the release of energy stored in their magnetic fields. In addition, magnetars also emit a continuous low-level emission of X-rays.

A recent publication in the journal Nature Astronomy is offering new insights into magnetars, whose characteristics are still not well understood. A magnetar is a type of neutron star with a magnetic field that is extremely strong and rotates once every two to ten seconds.

Researchers observing the magnetar SGR 1935+2154 detected a sudden slowing of the star’s angular momentum, often referred to as a spin-down glitch, on October 5, 2020. In the following days, the magnetar emitted three Fast Radio Burst-like radio bursts followed by a month-long episode of pulsed radio emission, despite there being no signs of variation in the X-ray emission behavior in the star or evidence of a strong X-ray burst.

Due to the rarity of spin-down glitches and radio signals from magnetars, the research team says the synchronicity of these events suggests an association, offering clues to their origin and triggering mechanisms.

The researchers point to plasma shedding close to the magnetic pole, which generated a wind that impacted the star’s momentum and magnetic field and created the combination needed to trigger radio emission.

Reference: “Magnetar spin-down glitch clearing the way for FRB-like bursts and a pulsed radio episode” by G. Younes, M. G. Baring, A. K. Harding, T. Enoto, Z. Wadiasingh, A. B. Pearlman, W. C. G. Ho, S. Guillot, Z. Arzoumanian, A. Borghese, K. Gendreau, E. Göğüş, T. Güver, A. J. van der Horst, C.-P. Hu, G. K. Jaisawal, C. Kouveliotou, L. Lin and W. A. Majid, 12 January 2023, Nature Astronomy.
DOI: 10.1038/s41550-022-01865-y

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