1. Multiband observation and theory of magnetars H. Tong ( 仝号 ) Xinjiang Astronomical Observatory, CAS 2013.8 For 2013 Pulsar summer school @Beijing

2. Contents Introduction Radio observations of magnetars Soft X-ray observations of magnetars Optical/IR/HX/gamma observations Magnetar/PWN/SNR system Summary

3. Where are they?

4. What's AXPs & SGRs AXPs: anomalous X-ray pulsars Lx>Edot (not necessary!) No binary signature SGRs: soft gamma-ray repeaters Soft: typical photon energy is lower Repeater: recurrent bursts The same class!

5. Critical magnetic field Cyclotron energy = electron rest mass Microscopic process: QED

6. Traditional magnetar model (2008) Magnetar = 1.young NS (SNR & MSC) 2.B_dip> B _ QED = 4.4*10^13 G (braking) 3.B_mul=10^14-10^15 G (burst and super-Eddington luminosity and persistent emission)

7. prehistory of magnetars 1932: Chadwick, discovery of neuton 1932: Landau, celestial objects with nuclear density 1934: Baade & Zwicky, NSs born in SNe 1939: Oppenheimer & Volkoff, NS structure M_sun, 10 km 1967: Hewish & Bell, discovery of (rotation- powered) pulsars 1971: Giacconi et al., discovery of accretion- powered X-ray pulsars

8. A brief history of magnetars 1979: giant flare of SGR 0526-66 1981: anomalous X-ray pulsars 1992: “magnetars” 1998: Timing of SGR 1806-20 giant flare of SGR 1900+14 2006-: multiwave era (radio, IR, HX) 2010: “low magnetic field” magnetar (B<7.5*10^12 G)

9. The magnetar model 1. Duncan & Thompson 1992: 1.Dynamo 2.spin-down 2. Usov 1992: millisecond magnetar as central engine for GRBs 3. Paczynski 1992: super-Eddington luminosity 1992: “magnetar”

10. Magnetar timing Kouveliotou et al. (1998) SGR 1806-20: P=7.47s Pdot= 8.24*10^-11 tau=1500 yr B=8*10^14. G (assuming magnetic dipole braking!)

11. Giant flare (Hurley et al. 1999) 1998: SGR 1900+14 Modeling: Yu+ 2013

12. Other observations Burst from one AXP 1E 1048.1-5937 (2002) Glitches during outburst of 1E 2259+586 (2003) Intermediate flare from 1E 1547.0-5408 (2009) AXPs & SGRs belong to the same class!

13. Observations for the magnetar model (Tong & Xu 2011) 1. B from P and Pdot 2. Cyclotron lines (?) 3. Pulsating tail 4. Super-Eddington luminosity 5. SGR-like bursts from HBPSR 6....(other more model dependent ones)

14. Failed predictions 1. SNe more energetic (2006) 2. A larger kick velocity (2007) 3. No radio emissions (2006) 4. High-energy gamma-ray detectable by Fermi/LAT (2010) 5. B>B QED (2010) 6. Always a large L x (L x >E dot ): transients & HBPSRs 7.Precession

15. 3+1 things to do 1.Origin of strong-B 2.Emission mechanisms in the magnetar domain 3.Alternative models of AXPs/SGRs 4.Relation between magnetars and other pulsar-like objects (XDINSs, CCOs, HBPSRs, and normal pulsars)

16. Various alternatives 1. NS+twisted magnetosphere (Thompson et al. 2002; Beloborodov+ 2007, 2009) 2. Wind braking of magnetars (Tong et al. 2013) 3. Fallback disk model (Alpar 2001) 4. Accretion induced star quake model (Xu et al. 2006) 5. Quark nova remnant (Ouyed et al. 2007) 6. Accreting WD model (Malheiro et al. 2011)

17. No radio emissions from magnetars? No radio emissions from magnetars (QED calculations, Baring & Harding 1998) Transient pulsed radio emssions from AXP XTE J1810-197 (Camilo et al. 2006) Peculiarities (Mereghetti 2008) : variable flux and pulse profile Flat spectra Transient in nature

18. Levin et al. 2010

19. Levin et al. 2012

20. “Fundamental plane” of magnetar radio emissions (Rea et al. 2012)

21. “Fundamental plane” of magnetar radio emissions (Rea+ 2012) A magnetar is radio-loud if and only if: Rotation-powered

22. Failed predictions Failed in one new source Swift J1834.9-0856 (Tong, Yuan & Liu 2013, RAA, 13, 835; obs 2012.5/6) GBT nondetection (Esposito+ arXiv:1212.1079; obs 2011.8-11) GMRT nondetection (obs: 2013.1)

23. Alternative idea of magnetar radio emissions “Low luminosity magnetars are more likely to have radio emissions” magnetism-powered

24. Interesting application VLBI measurement of magnetar kick velocity: Failed predictions XTE J1810-197: Helfand+ 2007 1E 1547.0-5408: Deller+ 2012 J1622-4950: ?

25. 4 th radio-loud magnetar at the Galatic Center: Rea et al. 2013

27. Espinoza et al. 2011: From normal pulsars to magnetars? Relations with radio pulsars Modeling: Liu+ 2012

28. Soft X-ray observations Timing P & Pdot measurement (1998) Glitch (2000) Low-B magnetars (2010) Anti-glitch (2013) Outbursts, transient Relations with other pulsar-like objects (XDINSs, CCOs etc)

29. Magnetar timing Kouveliotou et al. (1998) SGR 1806-20: P=7.47s Pdot= 8.24*10^-11 tau=1500 yr B=8*10^14. G (assuming magnetic dipole braking!) Problems: 1. the existence of HBPSRs, 2. the Pdot variations of magnetars, 3. Low-B magnetars (2010)!

30. Glitches in magnetars Glitch in AXP 1E 2259+586 (Kaspi+ 2003) 1.Large amplitude: 2.Accompanied by outburst 3.Increase in spindown rate: 2 times larger

31. Outburst of 1E 2259+586 Kaspi et al. (2003)

32. Summary of glitches in magnetars (Dib+ 2008) 1.Most AXPs show glitches 2.Some (and only some) are associated with radiative events 3.Large recoveries (Q>1): superfluid of magnetars rotates slower than the crust?

33. Low-B magnears: two sources (-2013.7) 1. SGR 0418+5729 (Rea+2010) 2. Swift J1822.3-1606 (Rea+2012)

34. SGR 0418+5729 Bursts detected by Fermi-GBM, 2009/6/5 (van der Horst et al. 2010) Early X-ray and optical obs: Pdot<1.1*10^-13 B dip <3*10^13 G (Esposito et al. 2010) One year obs: Pdot<6.0*10^-15 (P=9.1sec) B dip <7.5*10^12 G (Rea et al. 2010, Science)

35. Implications Assuming magnetic dipole braking: B dip <7.5*10^12 G tau_c>2.4*10^7 yr Rotational energy: E dot <3.1*10^29 erg s^-1 X-ray luminosity: Lx=6.2*10^31 erg s^-1

36. Implications-II Assuming B-powered: B mul >5*10^14 G

37. Problems? Magnetar = young NS (SNR etc) B dip > 4.4*E13 G (braking) B mul =10^14-10^15 G (burst and persistent emission and super-Eddington luminosity)

38. “Old magnetars” Turolla et al. (2011) Magnetars: strong internal toroidal field

40. Alternatives Old magnetars (Turolla+2011) Wind braking (Tong& Xu 2013) Disk spindown (Alpar+2011) Quark-Nova remnant (Ouyed+2011) White dwarf model (Malheiro+2012)

41. Wind braking of magnetars Tong+2013, ApJ

43. Wind braking of SGR 0418+5729 Tong & Xu 2012, ApJL

45. Anti-glitch of magnetar 1E 2259+586 ● Archibald+ (2013), Nature

46. Anti-glitch in SGR 1900+14 ● Woods+ (1999)

47. Net spindown of PSR J1846-0258 ● Livingstone+ (2010) Q=8.7

48. Modeling anti-glitch 1.Lyutikov (arXiv:1306.2264): corona-mass- eruption-like model 2.Tong (arXiv:1306.2445): wind braking 3.Katz (arXiv:1307.0586): retrograde accretion 4.Ouyed+ (arXiv:1307.1386): retrograde accreting quark-nova

49. Wind braking Particle wind luminosity:

50. Anti-glitch in the wind braking scenario 1.Due to an enhanced particle wind 2.Anti-glitch always accompanied by radiative events 3.No anti-glitch, but an enhanced period of spindown ● Future anti-gltich without radiative event or a very small timescale can rule out the wind braking model

51. Other observations A debris disk around one AXP (Wang et al. 2006) QPOs (Israel et al. 2005): magnetar seismology “free oscillation of the central star”

52. Summary: multiband observations transient radio emissions Soft X-ray activities (timing, radiative) Optical/IR: fallback disk (Wang+ 2006) Hard X-ray: burst (& giant flares) & persistent Gamm-ray: nondetection by Fermi (Failed predictions) PWN/SNR: normal SNe energies (failed predictions) & possible PWN

53. Summary: Magnetars in astrophysics (Kaspi 2010) 1.AXP/SGR 2.XDINSs: dead magnetar 3.CCO: magnetar-in-waiting /disk braked down magnetar 4.HBPSR: magnetar activities also seen (PSR J1846-0258) 5.Low B SGR: magnetar activities in normal pulsars in the future! 6.Magnetars in binary system?

54. Thanks!

55. Failed predictions I: SNe energy Vink & Kuiper (2006)

56. Possible solution Spin-down time scale: Wind braking of magnetars (Tong+ 2012) : a dipole field 10 times lower A high dipole field, magnetic dipole braking

57. Failed predictions II: kick velocity Helfand et al. (2007) (VLBA)

58. VLBI obs of the second radio-loud magnetar: AXP 1E 1547.0-5408 Deller et al. 2012

59. Proper motion of SGR 1806-20 and SGR 1900+14 through NIR astrometry (arXiv:1210.8151)

60. Failed predictions III: No radio emissions No radio emissions from magnetars (QED calculations, Baring & Harding 1998) Transient pulsed radio emssions from AXP XTE J1810-197 (Camilo et al. 2006) Peculiarities (Mereghetti 2008) : variable flux and pulse profile Flat spectra Transient in nature

61. “Fundamental plane” of magnetar radio emissions (Rea et al. 2012)

62. “Fundamental plane” of magnetar radio emissions A magnetar is radio-loud if and only if: Failed in one new source (Tong, Yuan & Liu 2013) “Low luminosity magnetars are more likely to have radio emissions”

63. Failed prediction IV: Fermi/LAT obs of 4U 0141+61 (Sasmaz Mus & Gogus 2010; Tong, Song, & Xu 2010) Exposure: 31.7 Ms No detection!

65. Fermi/LAT observation of all magnetars (Fermi-LAT collaboration 2010; Tong, Song, & Xu 2011)

66. Possible solutions 1. Accretion model for AXPs and SGRs 2. Wind braking of magnetars: a different magnetospheric structure

67. Failed predictions V: Low-B SGR (Rea et al. 2010)

68. Problems of SGR 0418 1. B_mul>>B_dip? 2. Burst-active at 10^6-10^7 yr? Too many SGR in our Galaxy (Muno et al. 2008) 3. What about XDINSs?

69. Another possibility (Tong & Xu 2012) A normal magnetar Instead of a low-B magnetar

70. Failed predictions VI: A radio loud magnetar (Levin et al. 2010) PSR J1622-4950 Discovered 2009/04 HRTU survey, Parkes Edot=8.5*10^33 erg s^-1 Lx=2.5*10^33 erg s^-1 (Chandra)

71. P-Pdot diagram

72. Why Lx so low? Also transient magnetars, e.g., XTE J1810-197 and HBPSRs Corona model is not the full story!

73. Failed predictions: VII free precession of magnetars Prolate in shape Free precession (Thompson et al. 2000) :