1. Anti-glitch induced by collision of a solid body with the magnetar 1E 2259+586 Y. F. Huang Collaborator: J. J. Geng Nanjing University

2. Outline 1. Background: glitches 2. Anti-glitch from 1E 2259+586 3. Our model: collision event 4. Discussion

3. Espinoza et al. 2011 MNRAS 30 years timing history of PSR B1930+22

4. Espinoza et al. 2011 MNRAS 4 large glitches in the Crab pulsar

5. Espinoza et al. 2011 MNRAS More glitches

6. Espinoza et al. 2011 MNRAS

8. Glitches of Magnetars RXS J170849.0-400910 and 1E 1841-045 Dib et al. 2008, ApJ

9. Shapiro & Teukolsky 2004

10. Explanations for glitches The origin is still debated: Superfluidity: interaction of quantized neutron vortex lines with the neutron-rich nuclear clusters in the inner crust (Pines & Alpar 1985; Negele & Vautherin 1973; Pizzochero 2011) Crust-cracking events (Ruderman et al. 1998) ? Pines & Alpar 1985 http://www.eskesthai.com/search/label/Bose%20Condensate

11. Outline 1. Background: glitches 2. Anti-glitch from 1E 2259+586 3. Our model 4. Discussion

12. The Magnetar 1E2259+586 P=6.979 s (v = 0.143 Hz) d = 4+/-0.8 kpc A few history glitches observed 1E 2259+586. Credit: ESA/XMM-Newton/M. Sasaki et al.

13. History glitches: 2002 outburst 2002 outburst On June 18 Woods et al. 2004

14. History glitches: 9 years overview Icdem et al. 2012 2002 glitch Possible micro anti-glitch?

15. An anti-glitch in April 2012 Archibald et al. 2013, Nat.

16. Timing events in around April 2012

17. Model 1: Model 2: + + x 2 =45.4/44 x 2 =38.1/44 Archibald et al. 2013, Nat.

18. Model 1: Model 2: + + x 2 =45.4/44 x 2 =38.1/44 Archibald et al. 2013, Nat.

19. Model 1: +x 2 =45.4/44 A hard X-ray burst: Exb=1.1e38 erg (36ms, Fermi/GBM,10-1000keV) An X-ray afterglow: Ex=2.1e41 erg (2-10 keV, Fx ~ t -0.38 ) Pulse profile: changed Foley et al. 2012

20. Possible models for anti-glitches Internal mechanisms Internal superfluid spins slower than the crust? (Thompson et al. 2000; Garcia & Ranea-Sandoval 2014, arXiv:1402.0848) External mechanisms Strong outflows (Tong 2013) Sudden twisting of magnetic fields (Lyutikov 2013) Accretion disk of retrograde matter (Katz 2013; Ouyed et al. 2013) Cannot explain the rarity or Not a sudden glitch, cannot explain the outburst.

21. Outline 1. Background: glitches 2. Anti-glitch from 1E 2259+586 3. Our model 4. Discussion

22. Our model: collision of a solid body with the magnetar Huang & Geng, ApJ, 2014, 782, L20 (arXiv:1310.3324)

23. Our model: collision of a solid body with the magnetar Huang & Geng, ApJ, 2014, 782, L20 (arXiv:1310.3324)

24. Colgate & Petschek 1981

26. Our model: collision process broken up distance: Collision duration: (Colgate & Petschek 1981) Huang & Geng, ApJ, 2014, 782, L20 (arXiv:1310.3324)

27. Consistency with observations Association with an outburst Duration of the outburst (36ms) Energy release in the afterglow (2.1e41 erg) Amplitude of the anti-glitch ( ) Huang & Geng, ApJ, 2014, 782, L20 (arXiv:1310.3324) Credit: NASA http://www.futuretimeline.net/blog/2013/06/2.htm#.U9Mhi7flpQI

28. Outline 1. Background: glitches 2. Anti-glitch from 1E 2259+586 3. Our model 4. Discussion

29. Discussion: more collision events are possible The capture radius could be as large as: 20R ns --- 80 R ns Tremaine & Zytkow 1986, ApJ

30. Collision possibility Asteroids disturbed by other planets? Oort-like cloud objects scatterd toward the NS? Collision of planets, generating small bodies? Neutron star escaping its original planet system? …… Collision rate: 1 per 5,000 --- 3e7 years for a single NS. (Mitrofanov & Sadgeev 1990)

31. Collision-induced glitches/anti-glitches Collision can produce either glitches or anti-glitches They can be either radiatively active or inactive Unlikely show any periodicity for a single NS More likely happen in young pulsars than old ones May have already been observed previously A new method to probe the capture events of neutron stars. Thank You!