pulsar timing noises as evidence of hall drift and hall weves in crusts of isolated neutron stars

Pulsar timing noises as evidence of Hall drift and Hall Weves in cru

sts ofisolated neutron stars

Speaker ： Yi Xie

2014-04-30 Lunch Talk

Pulsars: The Most Stable Rotators

Observed pulse series

Irregular Period ChangesTwo Main Types of Irregularity ： Timing noise : low-frequency structures

Glitches:

classical glitches and slow glitches

Hobbs et al. 2010

Secular Period Changes

Zhang & Xie. 2012 a

Zhang & Xie. 2013

Xie & Zhang. 2013 submitted

Motivation: two issues in controversial

1. The long-term evolution of magnetic fields for individual pulsars?

Our model suggests that the evidence may probably be shown in pulsars with

2. The physical origin of pulsar timing noise?

The evidence for effective magnetic field evolution

Lyne et al. 2010

Lyne et al. 2010

VS ?

Sample selection

error:

rule out ！

reported:

B1828-11:

Theory :

Slope for

P. A. gives: Reported:

The allowed area in the Theta-Beta Plane

Xie & Zhang 2013 submitted.

Physical Implications

Reported:

The majority of dipolar magnetic field lines are restricted to their outer crusts!

Hall Drift

Magnetic field configuration

Hall Waves

Model: Hall wave induce changes of the areas of polar regions, producing pulse shape changes:

Assume:

Xie & Zhang 2013 submitted.

Observed and derived parameters for the pulsars:

2009-2-06

• This is the first time that the Hall drift and Hall waves are observationally identified in individual pulsars, which are responsible for the observed long-term evolution of the spin-down rates and their quasi-periodic modulations, respectively.

• The majority of dipolar magnetic field lines are restricted to their outer crusts.

• Millisecond pulsars have much weaker dipole magnetic fields, implying much smaller and , which is actually the basis for using them to detect gravitational waves.

Summary and discussion

2009-2-06

2009-2-06

Periodicity in Timing NoisePeriodicity in Timing Noise

• 1540-06 ： period 4.38 yr

Hobbs et al. 2010

脉冲到达时间：实测与模型之间的差值叫残差。残差不是白噪声：模型没有考虑到：自行、进动、伴

星、自转不稳定性（跃变和到达时间噪声）。

南山 25米

Mean Pulse Profiles Mean Pulse Profiles 脉冲星的平均轮廓脉冲星的平均轮廓

PSR B0329+54

P=0.7145 s

PSR B1937+21

P=1.557ms

每秒 642 转！

PSR 0437+4715

P=5.75ms

PSR B0531+21

P=33 ms （蟹状星云脉冲星）