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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. 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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  1. 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

  2. Absence of pulses : Pulsar Nulling

  3. Absence of pulses : Pulsar Nulling

  4. PSR J1738-2330 PSR J1752+2359

  5. 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.

  6. PSR J1738-2330 PSR J1752+2359

  7. PSR J1738-2330

  8. PSR J1752+2359

  9. Fourier spectrum

  10. Pair Correlation Function Periodic BBB PCF 

  11. Pair Correlation Function J1738-2330 J1752+2359

  12. Big Burst Bunches : BBB

  13. 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

  14. BBB Modeling

  15. 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

  16. Emission in the null region of PSR J1738-2330?

  17. Emission in the null region of PSR J1752+2359

  18. Intermediate Burst Pulses (IBPs) Arecibo Observations @ 325 MHz

  19. Polarization profiles of J1752+2359

  20. J1502-5653 Li et al. 2012 B0823+26 (Young et al. 2012) J0941-39 (Burke-Spolaor & Bailes 2010) B0818-41 (Bhaswatiet al. 2009)

  21. Why ??

  22. P-Ṗ Diagram

  23. P-Ṗ Diagram

  24. P-Ṗ Diagram

  25. P-Ṗ Diagram

  26. 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)

  27. 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.

  28. Null length correlation with the preceding and succeeding BBB parameters

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