On the long nulls of psrs j1738 2330 and j1752 2359
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On the long nulls of PSRs J1738-2330 and J1752+2359. Vishal Gajjar (NCRA-TIFR) Bhal Chandra Joshi (NCRA-TIFR) Geoffrey Wright (Uni. Sussex) MWSKY, 2013. Absence of pulses : Pulsar Nulling. Absence of pulses : Pulsar Nulling. PSR J1738-2330. PSR J1752+2359. Motivations.

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On the long nulls of PSRs J1738-2330 and J1752+2359

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On the long nulls of psrs j1738 2330 and j1752 2359

On the long nulls of PSRs J1738-2330 and J1752+2359

VishalGajjar

(NCRA-TIFR)

Bhal Chandra Joshi (NCRA-TIFR)

Geoffrey Wright (Uni. Sussex)

MWSKY, 2013


Absence of pulses pulsar nulling

Absence of pulses : Pulsar Nulling


Absence of pulses pulsar nulling1

Absence of pulses : Pulsar Nulling


On the long nulls of psrs j1738 2330 and j1752 2359

PSR J1738-2330

PSR J1752+2359


Motivations

Motivations

  • Compare and contrast nulling behavior of similar but high NF viz. 85%.

    PSR J1738-2330 (Gajjar et al. 2012)

    PSR J1752+2359 (Lewandowski et al. 2004).

  • Scrutinize the quasi-periodic oscillation between the null and burst phases.

  • Investigate the Big Burst Bunches (BBB).

  • Validate the long null phases.


On the long nulls of psrs j1738 2330 and j1752 2359

PSR J1738-2330

PSR J1752+2359


Psr j1738 2330

PSR J1738-2330


Psr j1752 2359

PSR J1752+2359


Fourier spectrum

Fourier spectrum


Pair correlation function

Pair Correlation Function

Periodic BBB PCF 


Pair correlation function1

Pair Correlation Function

J1738-2330 J1752+2359


Big burst bunches bbb

Big Burst Bunches : BBB


On the long nulls of psrs j1738 2330 and j1752 2359

Average BBB

PSR J1738-2330 average BBB OPE pattern after adding 12 observed BBBs

PSR J1752+2359 average BBB OPE pattern after adding 12 observed BBBs


Bbb modeling

BBB Modeling


Psr j1752 2359 bbb parameters peak and decay relation

PSR J1752+2359 : BBB parametersPeak (α) and Decay (τ) relation

Slope : -0.74 +/- 0.04

Kendall’s Tau

correlation : -0.67

(< 10-7 Probability of random chance)

Energy release during each BBB is constant


On the long nulls of psrs j1738 2330 and j1752 2359

Emission in the null region of PSR J1738-2330?


Emission in the null region of psr j1752 2359

Emission in the null region of PSR J1752+2359


On the long nulls of psrs j1738 2330 and j1752 2359

Intermediate Burst Pulses (IBPs)

Arecibo Observations @ 325 MHz


Polarization profiles of j1752 2359

Polarization profiles of J1752+2359


On the long nulls of psrs j1738 2330 and j1752 2359

J1502-5653

Li et al. 2012

B0823+26

(Young et al. 2012)

J0941-39 (Burke-Spolaor & Bailes 2010)

B0818-41

(Bhaswatiet al. 2009)


On the long nulls of psrs j1738 2330 and j1752 2359

Why ??


P diagram

P-Ṗ Diagram


P diagram1

P-Ṗ Diagram


P diagram2

P-Ṗ Diagram


P diagram3

P-Ṗ Diagram


Nulling mechanism

Nulling Mechanism

  • Cessation of sparking (Sturrock 1971; Kramer et al. 2006)

  • Continuous supply of particle (Filippenko and Radhkrishnan 1982)

  • Switching between CR/ICS (Zhang et al. 1997)

  • Surface composition changes (Bartel et al. 1982)

  • Magnetic field instabilities (Geppert et al. 2003)

  • Partial screen gap (Gil et al. 2003)

  • Reversal of the emission beam (Dyks 2005)

  • Orbital companions (Cordes and Shannon 2008)

  • Missing line-of-sight (Herfindal and Rankin 2007; 2008)

  • Time dependent pair cascade (Timokhin 2010)


Summary

Summary

  • Both pulsars show quasi-periodic fluctuations with J1752+2359 showing loss of coherence.

  • An exponential decline is seen during a BBB for PSR J1752+2359, while PSR J1738-2330 exhibits flickering emission process.

  • PSR J1752+2359 shows switching between IBP and BBB state, where IBP rate is independent of the BBB separations.

  • Comparison of BBB and IBP polarization profiles shows distinct shift towards the leading edge.

  • The energy release during the BBBs is approximately constant for PSR J1752+2359.

  • Hence, both pulsars with similar NF (around 85%) show very distinct emission modulations.


On the long nulls of psrs j1738 2330 and j1752 2359

Null length correlation with the preceding and succeeding BBB parameters


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