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Published on November 14, 2007

Author: Junyo

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Qiao,G.J. Dept. of Astronomy, Peking Univ. :  Qiao,G.J. Dept. of Astronomy, Peking Univ. Radio and Gamma-ray emission from pulsars Slide2:  Collaborators: Zhang, B.(University of Nevada), Xu, R.X.(PKU), Han,J.L.(NAOC), Lin,W.P.(SHO), Liu,G.F.(CFA, Harvard) Xue,Y.Q.(Purdue Univ. ) Wang,H.G.(CFA , GuangzhouUniversity), Lee,K.J.(PKU) Slide3:  Pulsars are discovered 40 years Key problems: The nature of PSR:NS & Quark stars ? Radiation:radiation mechanisms? Polar gaps? Outer gaps? or … Annular gaps? Slide4:  Observations Radio Gamma-ray Annular gap Polar gap Theories Narrow Wide Outer gap Spect; Cut wide Plausible §1.Radio obs. & theories: Sparking; annular emission §2.The magnetosphere & acceleration polar gap; outer gap §3.Annular gap §4.Free flow: slot gap & Annular gap :  §1.Radio obs. & theories: Sparking; annular emission §2.The magnetosphere & acceleration polar gap; outer gap §3.Annular gap §4.Free flow: slot gap & Annular gap Radio and Gamma-ray radiation of pulsars Emission beams:  Emission beams Rankin, 1983, ApJ,274,333 Manchester,R.N. 1995 J. Astroph. Astr. 16,107 Core emission ! Slide7:  Emission beams in RS model Ruderman & Sutherland, 1975 Emission beams Hollow cone only! Low freq: wide beam! Slide8:  RS model Qiao,Liu, Zhang,& Han, 2001,AA Lyne & Manchester (1988) & Sieber et al. (1975),Kramer,(1994) There are various beam width- frequency relations, which can not be simple explained by RS model. ? ICS Model: emission beams ⇒ Core +cones:  ICS Model: emission beams ⇒ Core +cones Qiao, 1992 Qiao & Lin, A&A,1998 Slide10:  Zhang, Qiao, Han, Lee, Wang , AA,2007 Different components of same frequency come from different altitudes. Slide11:  Polarization: Beam shift→PA jumps Xu, Qiao & Han, 1997, AA Slide12:  Zhang,Qiao,Lin,Han, 1997 Rankin, 1986 Slide13:  Mode change pulsars Zhang,Qiao,Lin,Han, 1997,ApJ Zhang,Qiao, Han, 1997,ApJ §1.Radio obs. & theories: Sparking; annular emission §2.The magnetosphere & acceleration polar gap; outer gap §2.Annular gap §3.Free flow: slot gap & Annular gap :  §1.Radio obs. & theories: Sparking; annular emission §2.The magnetosphere & acceleration polar gap; outer gap §2.Annular gap §3.Free flow: slot gap & Annular gap Radio and Gamma-ray radiation of pulsars Slide15:  The magnetosphere of a NS For Crab Pulsar:  Goldreich & Julian, 1969,ApJ,157,869 1. Gap:inner gap & outer gap 2. Space Charge Limited Flow: Polar cap; Slot gap 3. Annular gap:  1. Gap:inner gap & outer gap 2. Space Charge Limited Flow: Polar cap; Slot gap 3. Annular gap The annular gap: the important region Basic Observational facts:  Basic Observational facts David J. Thompson:astro-ph/0312272 Slide18:  For inner gap Phase resolved spectrum, bridge is hard 1e1~1e3 Gev cut-off For outer gap Wide beams Thompson, astro-ph/0312272 , Kanbach, 2002,astro-ph/0209021 §1.Radio obs. & theories: Sparking; annular emission §2.The magnetosphere & acceleration polar gap; outer gap §3.Annular gap §4.Free flow: slot gap & Annular gap :  §1.Radio obs. & theories: Sparking; annular emission §2.The magnetosphere & acceleration polar gap; outer gap §3.Annular gap §4.Free flow: slot gap & Annular gap Radio and Gamma-ray radiation of pulsars Slide20:  Two polar cap regions Core region Annular region Outer gap Slide21:  The Inner Annular Gap Qiao,Lee,Wang,Xu, 2004a, ApJL The radio and gamma-ray can be understood by annular gap at same time. Slide22:  Mclaughlin 2003,astr-ph/0310454 Bi-drifting: Obs. Slide23:  Accelerators: Inner vacuum gap (Ruderman & Sutherland 1975) requiring high binding energy of charges on stellar surface Drifting sub-pulses Xu,Qiao Zhang, 1999,ApJL,522,L112 Deshpannde & Rankin, 1999,ApJ, 524,1008 Inner Annular Gap ::  Inner Annular Gap : Bi-drifting: fitting:  Bi-drifting: fitting Mclaughlin 2003,astr-ph/0310454 Qiao,Lee,Zhang,Xu,Wang,2004b, ApJL §1.The magnetosphere & acceleration polar gap: phase resolute spectrum,cut off outer gap: gamma-ray wide beam §2.Annular gap §3.Free flow: slot gap & Annular gap §4.Radio obs. & theories: Sparking; annular emission :  §1.The magnetosphere & acceleration polar gap: phase resolute spectrum,cut off outer gap: gamma-ray wide beam §2.Annular gap §3.Free flow: slot gap & Annular gap §4.Radio obs. & theories: Sparking; annular emission Radio and Gamma-ray radiation of pulsars The annular flow accelerator --Can particles be accelerated in the annular region (the non-vacuum gap cases)?:  The annular flow accelerator --Can particles be accelerated in the annular region (the non-vacuum gap cases)? Qiao,Lee,Zhang,Wang,Xu, astro-ph/0704.3801 The annular gap:  The annular gap the annular gap must be taking into account! ⇒ Slide29:  Pulsars: NS or Quark stars ? Free flow: sparking or not ? Free flow: can produce drifting sub-pulse? Annular gap & others: Obs. Test? Future obs. & theories Slide30:  PSR B1055-52 : observational constraints Position angle sweep fit with Rotation Vector Model:  ~157o Position angle sweep fit with Rotation Vector Model Lyne & Manchester 1988 Inclination Angle a Viewing Angle z a Line of Sight W m z Pole A (MP) Pole B (IP) MP IP Double-pole origin Wang et al.2005 Slide32:  PSR B1055-52 : observational constraints 1). Inclination angle a=74.7 dgree 2). Viewing angle z =114 dgree Slide33:  Thompson et al. 1992 Radio Observed emission beams Gamma-ray Slide34:  Observed emission beams Wang et al.2005 From observation, the radiation location can be determined uniquely for this star. Slide35:  Annular emission model Wang et al.2005 The observations show that the radiation position locates in the annular region. Slide36:  Thank you ! Spark Model:  Spark Model Gil & Sendyk, 2000 Qiao & Lin, A&A,1998:  Qiao & Lin, A&A,1998 ICS: shift of emission beams Different emission location→shift of the emission beams Slide39:  ω=2γ2ω0(1-βCosθi) The Inverse Compton Scattering (ICS) model Qiao & Lin,1998, A&A Slide40:  Polarization of integrated pulse in ICS (Xu et al. ApJ.2000 ) V—circular poln L—Linear poln I—Total Intensity Position angle Slide41:  Polarization: PA jump Xu, Qiao & Han, 1997, AA Xu et al. ApJ. 2000:  Polarization of Individual pulses in ICS model Xu et al. ApJ. 2000 Pulsar radiation :  Pulsar radiation Radio: w/P∼3-4% Gamma-ray: Two pulses & very wide Slide44:  “S” shape PA & Obs. → The radiation location: near surface The annular gap:  The annular gap Slide46:  Drifting subpulses PULSE LONGITUDE Drifting subpulses Taylor et al. (1975) Backer (1973) Slide47:  Slot gap Slot gap model:  Slot gap model Arons,J. 1983, ApJ Slide49:  McCullon et al. 1976 Observation at radio band Slide50:  Obs. Obs.

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