How can newly born rapidly rotating neutron stars become magnetars?

Abstract

In a newly born (high-temperature and Keplerian rotating) neutron star, r-mode instability can lead to stellar differential rotation, which winds the seed poloidal magnetic field ($\sim 10^{11}$ G) to generate an ultra-high ($\sim 10^{17}$ G) toroidal field component. Subsequently, by succumbing to the Tayler instability, the toroidal field could be partially transformed into a new poloidal field. Through such dynamo processes, the newly born neutron star with sufficiently rapid rotation could become a magnetar on a timescale of $\sim 10^{2-3}$ s, with a surface dipolar magnetic field of $\sim 10^{15}$ G. Accompanying the field amplification, the star could spin down to a period of $\sim 5$ ms through gravitational wave radiation due to the r-mode instability and, in particular, the non-axisymmetric stellar deformation caused by the toroidal field. This scenario provides a possible explanation for why the remnant neutron stars formed in gamma-ray bursts and superluminous supernovae could be millisecond magnetars.

5 pages, 2 figures, published in ApJL

References in corpus (7)

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• X-Ray Flares from Postmerger Millisecond Pulsars
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• Thermonuclear Explosions and Accretion-induced Collapses of White Dwarfs in Active Galactic Nucleus Accretion Disks
• X-ray transients from the accretion-induced collapse of white dwarfs
• The effects of a magnetar engine on the gamma-ray burst-associated supernovae: Application to double-peaked SN 2006aj
• On the initial spin periods of magnetars born in weak supernova explosions and their gravitational wave radiation
• A Target Search for Fast Radio Bursts Associated with Two Fast Blue Optical Transients: AT2018cow and CSS161010
• Could the stochastic gravitational wave background from newborn magnetars be detected by the advanced LIGO and Einstein Telescope?
• Evolution of Crab Pulsar: Magnetic Inclination Angle and Spin