An anti-glitch in a magnetar

Area of Science:

• Astronomy
• Astrophysics
• Stellar Physics

Background:

• Magnetars are neutron stars with powerful magnetic fields, exhibiting X-ray and gamma-ray outbursts.
• Neutron stars, including magnetars and radio pulsars, experience 'glitches'—sudden spin-up events attributed to angular momentum transfer between the crust and superfluid interior.

Purpose of the Study:

• To investigate the phenomenon of magnetar glitches, specifically focusing on an unusual spin-down event.
• To analyze the accompanying X-ray variations and spin-down rate changes associated with the observed anti-glitch.

Main Methods:

• Conducted X-ray timing observations of the magnetar 1E 2259+586.
• Analyzed the timing data to detect and characterize spin-down events and associated radiative changes.

Main Results:

• Observed a distinct 'anti-glitch' event in magnetar 1E 2259+586, characterized by a sudden spin-down.
• The anti-glitch event was accompanied by multiple X-ray radiative changes and a significant alteration in the magnetar's spin-down rate.

Conclusions:

• The observed spin-down behavior challenges existing models of neutron star spin-down.
• This event suggests differential rotation within the magnetar, necessitating a reevaluation of glitch theory for all neutron stars.