The maximum dipole moments of neutron stars implied by the Barrow-Gibbons conjecture

Abstract

The maximum magnetic moment to angular momentum conjecture, recently posed by Barrow \& Gibbons, is in tension with the generally accepted parameters of magnetars. According to the conjecture the dimensionless Schuster-Wilson-Blacket number, $c\mu /J\sqrt{G}$ where $\mu$ is the magnetic moment and $J$ is the angular momentum, should be of order unity. A resolution is to assume that not only the low-magnetic field magnetars, but all magnetars have their super-critical fields in the higher multipoles. This requires the presence of external torques other than the magnetic dipole torque, such as from fallback disks or winds, on these systems to yield the measured high spin-down rates.

5 pages, no figures, typos corrected

References in corpus (7)

• An Ultraluminous X-ray Source Powered by An Accreting Neutron Star
• An accreting pulsar with extreme properties drives an ultraluminous x-ray source in NGC 5907
• A Debris Disk Around An Isolated Young Neutron Star
• The Prelude to and Aftermath of the Giant Flare of 2004 December 27: Persistent and Pulsed X-ray Properties of SGR 1806-20 from 1993 to 2005
• The ultra luminous X-ray source NuSTAR J095551+6940.8: A magnetar in a high mass X-ray binary
• A Mid-Infrared Counterpart to the Magnetar 1E 2259+586
• The Anomalous X-Ray Pulsar 4U 0142+61: A Neutron Star with a Gaseous Fallback Disk