Why the braking indices of young pulsars are less than 3?

Abstract

In this letter we discuss two possible reasons which cause the observed braking indices n of young radio pulsars to be smaller than 3: (a) the evolving spin-down model of the magnetic field component $B_{\perp }$ increases with time; (b) the extrinsic braking torque model in which the tidal torques exerted on the pulsar by the fallback disk, and carries away the spin angular momentum from the pulsar. Based on some simple assumptions, we derive the expression of the braking indices, and calculate the spin-down evolutionary tracks of pulsars for different input parameters.

4 pages, 3 figures, accepted for publication in A&A Letters

References in corpus (1)

• Radio pulsars as progenitors of AXPs and SGRs: magnetic field evolution through pulsar glitches

Cited by in corpus (10)

• 45 Years of Rotation of the Crab Pulsar
• Multipolar electromagnetic fields around neutron stars: exact vacuum solutions and related properties
• Rotational evolution of the Crab pulsar in the wind braking model
• Determining the efficiency of converting magnetar spin-down energy into gamma-ray burst X-ray afterglow emission and its possible implications
• What can the braking indices tell us about pulsars' nature?
• A Generalized Semi-Analytic Model for Magnetar-Driven Supernovae
• Braking Index of Isolated Pulsars II: A novel two-dipole model of pulsar magnetism
• Evolution of Spin Period and Magnetic Field of the Crab Pulsar: Decay of the Braking Index by the Particle Wind Flow Torque
• Astrophysics in 2006
• Constraints on Undetected Long-Period Binaries in the Known Pulsar Population