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Title: Possible Evolution of the Pulsar Braking Index from Larger than Three to About One

Abstract

The coupled evolution of pulsar rotation and inclination angle in the wind braking model is calculated. The oblique pulsar tends to align. The pulsar alignment affects its spin-down behavior. As a pulsar evolves from the magneto-dipole radiation dominated case to the particle wind dominated case, the braking index first increases and then decreases. In the early time, the braking index may be larger than three. During the following long time, the braking index is always smaller than three. The minimum braking index is about one. This can explain the existence of a high braking index larger than three and a low braking index simultaneously. The pulsar braking index is expected to evolve from larger than three to about one. The general trend is for the pulsar braking index to evolve from the Crab-like case to the Vela-like case.

Authors:
 [1];  [2]
  1. School of Physics and Electronic Engineering, Guangzhou University, 510006 Guangzhou (China)
  2. Xinjiang Astronomical Observatory, Chinese Academy of Sciences, Urumqi, Xinjiang 830011 (China)
Publication Date:
OSTI Identifier:
22661294
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 837; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; CRABS; DIPOLES; EVOLUTION; INCLINATION; PULSARS; ROTATION; SPIN; WIND

Citation Formats

Tong, H., and Kou, F. F., E-mail: htong_2005@163.com. Possible Evolution of the Pulsar Braking Index from Larger than Three to About One. United States: N. p., 2017. Web. doi:10.3847/1538-4357/AA60C6.
Tong, H., & Kou, F. F., E-mail: htong_2005@163.com. Possible Evolution of the Pulsar Braking Index from Larger than Three to About One. United States. doi:10.3847/1538-4357/AA60C6.
Tong, H., and Kou, F. F., E-mail: htong_2005@163.com. Fri . "Possible Evolution of the Pulsar Braking Index from Larger than Three to About One". United States. doi:10.3847/1538-4357/AA60C6.
@article{osti_22661294,
title = {Possible Evolution of the Pulsar Braking Index from Larger than Three to About One},
author = {Tong, H. and Kou, F. F., E-mail: htong_2005@163.com},
abstractNote = {The coupled evolution of pulsar rotation and inclination angle in the wind braking model is calculated. The oblique pulsar tends to align. The pulsar alignment affects its spin-down behavior. As a pulsar evolves from the magneto-dipole radiation dominated case to the particle wind dominated case, the braking index first increases and then decreases. In the early time, the braking index may be larger than three. During the following long time, the braking index is always smaller than three. The minimum braking index is about one. This can explain the existence of a high braking index larger than three and a low braking index simultaneously. The pulsar braking index is expected to evolve from larger than three to about one. The general trend is for the pulsar braking index to evolve from the Crab-like case to the Vela-like case.},
doi = {10.3847/1538-4357/AA60C6},
journal = {Astrophysical Journal},
number = 2,
volume = 837,
place = {United States},
year = {Fri Mar 10 00:00:00 EST 2017},
month = {Fri Mar 10 00:00:00 EST 2017}
}
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  • PSR J1846–0258 is an object that straddles the boundary between magnetars and rotation powered pulsars. Though behaving for many years as a rotation-powered pulsar, in 2006, it exhibited distinctly magnetar-like behavior—emitting several short hard X-ray bursts, and a flux increase. Here we report on 7 years of post-outburst timing observations of PSR J1846–0258 using the Rossi X-ray Timing Explorer and the Swift X-ray Telescope. We measure the braking index over the post-magnetar outburst period to be n = 2.19 ± 0.03. This represents a change of Δn = −0.46 ± 0.03 or a 14.5σ difference from the pre-outburst braking indexmore » of n = 2.65 ± 0.01, which itself was measured over a span of 6.5 years. A change to a pulsar braking index so large and long-lived is unprecedented and poses a significant challenge to models of pulsar spin-down.« less