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Radio and Gamma-ray emission of pulsars

Radio and Gamma-ray emission of pulsars. Qiao,G.J. Dept. of Astronomy, Peking Univ. Collaborators: Zhang, B.( University of Nevada ), Xu, R.X.(PKU), Han,J.L.(NAOC), Lin,W.P.(SHO),Lee,K.J.(PKU) Xia,X.Y. Radio and Gamma-ray emission of pulsars.

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Radio and Gamma-ray emission of pulsars

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  1. Radio and Gamma-ray emission of pulsars Qiao,G.J. Dept. of Astronomy, Peking Univ.Collaborators:Zhang, B.(University of Nevada), Xu, R.X.(PKU), Han,J.L.(NAOC), Lin,W.P.(SHO),Lee,K.J.(PKU)Xia,X.Y.

  2. Radio and Gamma-ray emission of pulsars I. Radio emission(Inverse Compton scattering model: ICS )II. Inner annular gap & gamma-ray emission Radio + Gamma ray emissionIII. Pulsar: Neuron stars or Strange stars?

  3. Core beam Beam-frequency Mode changing Bi-drifting Gamma-ray Core gap Annular gap Strange stars

  4. Pulsar emission beams

  5. Observations

  6. Emission beams Rankin, 1983, ApJ,274,333

  7. Theories

  8. Ruderman & Sutherland (RS) Model Ruderman & Shutherland,1975, ApJ,196,51

  9. Emission beams in RS model Emission beams Hollow cone only! Ruderman & Sutherland, 1975

  10. Obs. & Theory(ICS) (1) Core + Cones (2) Different components come from different locations (3) Pulse profile shapes changing with freq. (4) Mode changing (5) Bi-drifting  Pulsars: NS or Strange stars?

  11. ICS Model: emission beams ⇒Core +cones Qiao, 1992

  12. ICS: shift of emission beams Different emission location→shift of the emission beams Qiao & Lin, 1998, A&A,333,172

  13. Poln: Beam shift→PA jumps Xu, Qiao & Han, 1997, AA

  14. Poln: PA jump Xu, Qiao & Han, 1997, AA

  15. ICS model: inner gap sparking→ω0 ω=2γ2ω0(1-βCosθi) Qiao & Lin, 1998, A&A

  16. Core beam Beam-frequency Mode changing Bi-drifting Gamma-ray Core gap Annular gap Strange stars

  17. RS model Lyne & Manchester (1988) & Sieber et al. (1975),Kramer,(1994) Qiao,Liu, Zhang,& Han, 2001,AA

  18. “S” shape PA & Obs.

  19. Poln of integrated pulse in ICS Position angle I—Total Intensity L—Linear poln V—circular poln Xu,Liu,Han,Qiao, 2000, ApJ

  20. Core beam Beam-frequency Mode changing Bi-drifting Gamma-ray Core gap Annular gap Strange stars

  21. Mode changing of pulsars Rankin, 1986

  22. Tree mode of sparking Curvature radiation Thermal ICS Resonant ICS Zhang,Qiao,Lin,Han, 1997

  23. Mode change pulsars Zhang,Qiao,Lin,Han, 1997,ApJZhang,Qiao, Han, 1997,ApJ

  24. Core beam Beam-frequency Mode changing Bi-drifting Gamma-ray Core gap Annular gap Strange stars

  25. Basic Observational facts vs Theories ☆Radio--- Gamma-rays: Obs. ☆Polar cap (polar gap) Gamma-ray Radio Outer gap

  26. The magnetosphere of a NS +

  27. Inner annular gap

  28. Inner annular gap Qiao,Lee,Wang,Xu, Han, 2004a,ApJL

  29. Inner annular gap Qiao,Lee,Wang,Xu, 2004a, ApJL

  30. Inner Annular Gap Qiao,Lee,Wang,Xu, 2004a, ApJL

  31. Core beam Beam-frequency Mode changing Bi-drifting Gamma-ray Core gap Annular gap Strange stars

  32. Bi-drifting: Obs. Mclaughlin 2003,astr-ph/0310454

  33. Drifting subpulses PULSE LONGITUDE Drifting subpulses Taylor et al. (1975) Backer (1973)

  34. Drifting sub-pulses Accelerators: • Inner vacuum gap (Ruderman & Sutherland 1975) requiring high binding energy of charges on stellar surface Xu,Qiao Zhang, 1999,ApJL,522,L112 Deshpannde & Rankin, 1999,ApJ, 524,1008

  35. Inner Annular Gap : V= c E x B / B^2

  36. Bi-drifting: fitting Mclaughlin 2003,astr-ph/0310454 Qiao,Lee,Zhang,Xu,Wang,2004b, ApJL

  37. Neutron stars: Binding energy ≤ 10 KeV no gap can be formed!!! Binding energy > 10 KeV only one gap cab be formed: core or annular gap Strange stars: both core & annular gap can be Formed !

  38. Conclusion and discussion ● Annular Gap mole: different Gamma-ray pulsars can be fitted ● Pulsars: Strange stars?● Observational check: Polarization at high energy bands● Theory: two caps=two gap? 

  39. Core beam Beam-frequency Mode changing Bi-drifting Gamma-ray ? ? Core flow Annular flow ? Neutron stars Qiao,Lee,Zhang,Wang & Xu,,2005,

  40. • Can free flow produce drifting pulses? • If not, can we distinguish NS from SS? ♣ More drifting phenomena need to be obs. ♣ Sub-millisecond pulsar need to be found? 100 m telescope will be helpful for the research above! 

  41. ? 100m at Effelsberg New Green Bank Telescope Jodrell Bank KaShi,China?

  42. Thank you !

  43. Multi-cones in the ICS model Qiao,Wang,Wang,Xu, 2002,ChJAA

  44. Multi-frequency fitting of PSR J0437-4715 Qiao,Wang,Wang,Xu, 2002,ChJAA

  45. Magnetosphere of pulsars Goldreich & Julian (1969)

  46. Acceleration electric field Charge density—ρGJ (Goldreich & Julian 1969 )

  47. Inner annular gap Qiao,Lee,Wang,Xu, Han, 2004

  48. Neutron stars: binding energy > 10KeV Can’t form core and annular gap at the same time! Ruderman & Sutherland, 1975

  49. Strange stars: binding energy << 10KeV Can form core and annular gap at the same time!

  50. Interstellar Dispersion Ionised gas in the interstellar medium causes lower radio frequencies to arrive at the Earth with a small delay compared to higher frequencies. Given a model for the distribution of ionised gas in the Galaxy, the amount of delay can be used to estimate the distance to the pulsar. P--period DM--dispersion measure

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