Magnetar formation through a convective dynamo in protoneutron stars.

Area of Science:

• Astrophysics
• Computational physics
• Stellar evolution

Background:

• Magnetars are theorized to power extreme explosive transients through spin-down energy release.
• Magnetar formation remains a theoretical challenge, lacking a firm observational or simulation basis.

Purpose of the Study:

• To investigate the generation of strong magnetic fields in protoneutron stars.
• To provide a theoretical basis for magnetar formation through simulations.

Main Methods:

• The study employed the first three-dimensional simulations of a convective dynamo.
• The simulations utilized a protoneutron star interior model.
• Analysis focused on dynamo instability saturation in the magnetostrophic regime.

Main Results:

• Sufficiently fast rotation rates consistently generate the required dipolar magnetic field.
• Dynamo instability saturates with magnetic energy up to 10 times kinetic energy.
• Generated magnetic field strengths align with observational constraints for galactic magnetars.

Conclusions:

• The findings provide strong theoretical support for millisecond protomagnetar models.
• These models are relevant for the central engines of gamma-ray bursts and superluminous supernovae.