Particle Outflow and Pulsar Timing Noise

Particle Outflow and Pulsar Timing Noise

Xiong Wei Liu

2011-05-09

Based on: Chin. Phys. Lett. Vol. 28, No. 1 (2011) 019701

Department of Astronomy, Peking University

Outline

•Background;

•Our Model;

•Observational Checking;

•Discussion.

Background

Theoretically, pulsars spin stably

Standard Clock

GW detection

Observationally, timing niose exist everywhere

Explainations for timing noise:

a. unmodelled companions;

b. gravitational waves;

c. free-precession of neutron star.

...

But, timing noise still can’t be eliminated completely, especially the noise in long timescale of years.

Background

Our Model

Main Idea: A new kind of intrinsic Timing Noise of pulsar

Theoretical Basis: The Partical outflow from a pulsar should be unstable ， so is the spin of the pulsar

(Xu & Qiao 2001 ApJL. 561 L85)

dE

uE is the power carried away by relativistic particles which rise from unipolar induction, and is the power of magnetic dipole radiation. is the variation.

Observational Clue: Variations of flux density may indicate

the variations of particle outflow

Our Model

Theoretical Result: The relationship between variations of particle outflow and Timing Noise

The longer, the stronger the noise!

Our Model

Variations of particle outflow Timing noise

140 0 0(1 ) 0.1 , 1 10Take n P s P

Simulation:

Our Model

Resemble with observations: Profile feature, range feature and time dependence

Our Model

Estimate from

Observational Checking

Checking 1: Relationship between Timing Noises and distribution of pulsars

Ryan M. et al. (arXiv:1010.4794v1)Statistics from approximately 450 distinct pulsars

Checking 2: Relationship between spin frequency, frequency derivative and Timing Noise

Observational Checking

Cordes & Downs (1985) and D’Alessandro et al.(1995)

Ryan M. et al. (arXiv:1010.4794v1)

Checking 3: Random walks in frequency and frequency derivative–Phenomenon and the essence

Observational Checking

Discussion

New mechanism of TN: The fluctuation of particle outflow can lead to significant timing noise in long time span of years.

New Challenges: Intrinsic Timing Noise, unavoidable!

The millisecond pulsars chose to detecting GW or act as Standard Clock, which haven’t found signigicant long time span TNs, will effect by their intrinsic TNs in longer time

New Question: How to avert the bad effect of this kind of TNs?