Speaker：Yi Xie 2014-04-30 Lunch Talk Pulsar timing noises as evidence of Hall drift and Hall Weves in crusts of isolated neutron stars Speaker：Yi Xie 2014-04-30 Lunch Talk

Pulsars: The Most Stable Rotators

Observed pulse series

Irregular Period Changes Two 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

B1828-11: rule out！ Theory : reported: Slope for error:

The allowed area in the Theta-Beta Plane Reported: P. A. gives:

Xie & Zhang 2013 submitted.

Physical Implications

Hall Drift Reported: The majority of dipolar magnetic field lines are restricted to their outer crusts!

Magnetic field configuration

Hall Waves

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

Observed and derived parameters for the pulsars: Xie & Zhang 2013 submitted.

Summary and discussion 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. 2009-2-06

2009-2-06

Periodicity in Timing Noise Hobbs et al. 2010 1540-06：period 4.38 yr 2009-2-06

南山 25米 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）。

Mean Pulse Profiles 脉冲星的平均轮廓 PSR B0329+54 P=0.7145 s PSR B0531+21 P=33 ms（蟹状星云脉冲星） PSR 0437+4715 P=5.75ms PSR B1937+21 P=1.557ms 每秒642转！