1. 2010 Glitch in Vela Pulsar Sarah Buchner SKA Bursary conference Dec 2010

2. Observing Vela with XDM2 Neutron Stars and Pulsars

3. Observing Vela with XDM3 Pulsar Glitches –Very good clock but … –Sudden increase in frequency or “spin-up” –Frequency increases by few parts per million –In energy terms earthquake of 17 on Richter scale surface of the earth moves by 15 m.

4. Observing Vela with XDM4 Vela Pulsar PSR 0833-45 Vela supernova remnant About 10 000 years old P = 0.089 s = 11.2 Hz

5. Observing Vela with XDM5 Vela Glitches Vela glitches –Change in –Recovery contains exponential scales –16 large glitches since 1969 –Glitches every 1040 +- 326 days

6. Observing Vela with XDM6 Vela Glitches from HartRAO The Vela Pulsar is observed three or more times daily on most days from 1985-2008 using the HartRAO 26m antenna. Observations made at either S or L- band. Online glitch detection – if a glitch is detected then continuous observing begins to catch exponential recoveries. 10 large glitches observed

7. Observing Vela with XDM7 Vela Glitches From HartRAO

8. Observing Vela with XDM8 HartRAO bearing failure In October 2008 HartRAO 26m south polar bearing failed Started observing Vela with 15m XDM at HartRAO

9. Observing Vela with XDM9 XDM observations 26m pulsar timer was single channel pulsar timer. Produced a folded profile for each 55s observation On XDM multi-channel iBob Can access single pulse data

10. Observing Vela with XDM10 Began observing Vela with XDM for 14.7 hours per day First prize: Catch a glitch “in the act” Second Prize: Parameterize the recovery Free gift: –Pulsar timing provides exacting test of polarization and timing of XDM. –Soak test – continuous observing

11. Observing Vela with XDM11 XDM and HartRAO Use XDM to observe continuously (15 hour per day) Use HartRAO 26m to make transit observations

12. Observing Vela with XDM12 Waiting for Glitch

13. Observing Vela with XDM13 Observing Vela 22 July 2010 26m was repaired and begun normal observing once again Observed Vela approximately once hourly

14. Observing Vela with XDM14 10 days after 26m repaired…

15. Observing Vela with XDM15 Glitch Parameters Glitch epoch –MJD 55408.802 Vela was below horizon at the time Last pre-glitch observation –1.9 hour before glitch First post-glitch observation –7.4 hours after glitch Glitch size

16. Observing Vela with XDM16 Issued ATel

17. Observing Vela with XDM17 FERMI follow-up FERMI did not detect any increase of gamma-ray flux associated with the glitch FERMI timing detected the timing glitch – epoch not well constrained

18. Observing Vela with XDM18 Constraining Glitch Epoch Regular observing allows glitch epoch to be constrained 2006 Glitch observed with 26m Glitch occurred during a LIGO science run First direct search for grav waves assoc with glitch No grav wave seen

19. Observing Vela with XDM19 Post-glitch Observations

20. Observing Vela with XDM20 Determine nudot values

21. Observing Vela with XDM21 XDM data

22. Observing Vela with XDM22 Rotation Frequency

23. Observing Vela with XDM23 Nu dot from XDM

24. Observing Vela with XDM24 26 m data

25. Observing Vela with XDM25 Spin-down

26. Observing Vela with XDM26 The Standard Vela Glitch

27. Observing Vela with XDM27 Transients for Glitches 5 d 50 d 5d 0.5d 50d

28. Observing Vela with XDM28 Comparison with other Glitches

29. Observing Vela with XDM29 Comparison

30. Observing Vela with XDM30 Underlying Physics?

31. Observing Vela with XDM31 Neutron Star

32. Observing Vela with XDM32 Superfluid Rotation Core of neutron star is superfluid Rotates by means of array of quantised vortices For superfluid to slow down vortex lines must move outward

33. Observing Vela with XDM33 Vortices in inner crust In inner crust vortices may pin to nuclei This region of superfluid is then unable to spin-down at same rate as crust Differential rotation develops At glitch vortices unpin and angular momentum is transferred from crustal superfluid to crust causing the spin-up

34. Observing Vela with XDM34 Two-component model

35. Observing Vela with XDM35 Alpar Vortex Creep Model Coupling between superfluid and the crust is a function of the lag between the velocities At the time of the glitch –the crust spins up –The lag decreases –Hence the coupling decreases –Superfluid “decouples” –Torque acting on smaller I so spin-down increases –Recovery as region of superfluid recouples

36. Observing Vela with XDM36 Non-linear coupling

37. Observing Vela with XDM37 Alpar Vortex Creep Model

38. Observing Vela with XDM38 But … Not all glitches are the same HartRAO archive data – 1994 double glitch

39. Observing Vela with XDM39 Overlaid Glitches with 1994

40. Observing Vela with XDM40 1994 glitch does not show transients Regions do not decouple? –Yet lag between superfluid and crust must change Different mechanism? Is the model correct?

41. Observing Vela with XDM41 Pulse Shape Changes Recent paper by Weltevrede et al suggests glitch induced magnetospheric changes Look for pulse shape changes Look for increase of single pulses

42. Observing Vela with XDM42 Conclusion Observing Vela with XDM First prize: Catch a glitch “in the act” –Vela was below horizon Second Prize: Parameterize the recovery –14.7 hours of observing enabled 0.5d time scale to be observed Free gift: –Pulsar timing provides exacting test of polarization and timing of XDM. –Soak test – continuous observing

43. Observing Vela with XDM43 Conclusion Work continues on modelling post-glitch recovery Can recovery be modelled by 3 distinct exponentials? What is the physical reason for this?

44. Observing Vela with XDM44 Thanks KAT team HartRAO staff

45. Observing Vela with XDM45 Questions / Thoughts?

46. Observing Vela with XDM46

47. Observing Vela with XDM47 Questions How fast does the crust spin-up? What is the recovery? –Interior of neutron star

48. Observing Vela with XDM48 Dedispersion and folding DBE DedisperseFoldFind TOA Barycentre Find residuals clock DMP Std Profile Pls position Timestamp Obs x,y,z

49. Observing Vela with XDM49 Arrival Times (TOA) 53075.8716014048 53076.6068099029 53076.6315093162 53076.6352589534 53076.6390085897 53076.7453055512 53076.7728053205 53076.8144370828 53076.8440091993

50. Observing Vela with XDM50 1 st order - frequency ‘early’ ‘late’ Observed - Predicted

51. Observing Vela with XDM51 2 nd order

52. Observing Vela with XDM52 2 nd order

53. Observing Vela with XDM53 Residuals 32.04 us

54. Observing Vela with XDM54 12 m @ Parkes 50.66 us Hobbs et al, 2009 0907.4847

55. Observing Vela with XDM55 Residuals 32.04 us

56. Observing Vela with XDM56 XDM prototype at HartRAO Kitty

57. Observing Vela with XDM57 KAT-7

58. Observing Vela with XDM58 KAT -> meerKAT

59. Observing Vela with XDM59 meerKAT

60. Observing Vela with XDM60

61. Observing Vela with XDM61 Neutron Stars and Pulsars

62. Observing Vela with XDM62 Observing Vela with XDM

63. 63 Waiting for Vela to glitch

64. Observing Vela with XDM64 Storm clouds over HartRAO

65. Observing Vela with XDM65 XDM Observations Observing Vela with XDM First prize: Catch a glitch “in the act” Second Prize: Parameterize the recovery Free gift: –Pulsar timing provides exacting test of polarization and timing of XDM. –Soak test – continous observing

66. Observing Vela with XDM66 Determine Glitch Epoch