天文系A类岗位考核聘任汇报 - 致密天体与弥漫介质研究团组.ppt

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1、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,Radio and Gamma-ray emission of pulsars,I. Radio emission (Inverse Compton scattering model: ICS )II. In

2、ner annular gap & gamma-ray emission Radio + Gamma ray emissionIII. Pulsar: Neuron stars or Strange stars?,Core beamBeam-frequencyMode changing,Bi-drifting,Gamma-ray,Core gap,Annular gap,Strange stars,Pulsar emission beams,Observations,Emission beams,Rankin, 1983, ApJ,274,333,Theories,Ruderman & Sut

3、herland (RS) Model,Ruderman & Shutherland,1975, ApJ,196,51,Emission beams in RS model,Ruderman & Sutherland, 1975,Emission beams,Hollow cone only!,Obs. & Theory(ICS),(1) Core + Cones (2) Different components come from different locations (3) Pulse profile shapes changing with freq. (4) Mode changing

4、 (5) Bi-drifting Pulsars: NS or Strange stars?,ICS Model: emission beams Core +cones,Qiao, 1992,ICS: shift of emission beams,Different emission locationshift ofthe emission beams,Qiao & Lin, 1998, A&A,333,172,Poln: Beam shiftPA jumps,Xu, Qiao & Han, 1997, AA,Poln: PA jump,Xu, Qiao & Han, 1997, AA,IC

5、S model: inner gap sparking 0,=220(1-Cosi),Qiao & Lin, 1998, A&A,Core beamBeam-frequencyMode changing,Bi-drifting,Gamma-ray,Core gap,Annular gap,Strange stars,RS model,Qiao,Liu, Zhang,& Han, 2001,AA,Lyne & Manchester (1988) & Sieber et al. (1975),Kramer,(1994),“S” shape PA & Obs.,Poln of integrated

6、pulse in ICS,Vcircular poln,LLinear poln,ITotal Intensity,Position angle,Xu,Liu,Han,Qiao, 2000, ApJ,Core beamBeam-frequencyMode changing,Bi-drifting,Gamma-ray,Core gap,Annular gap,Strange stars,Mode changing of pulsars,Rankin, 1986,Zhang,Qiao,Lin,Han, 1997,Tree mode of sparking,Thermal ICS,Curvature

7、 radiation,Resonant ICS,Mode change pulsars,Zhang,Qiao,Lin,Han, 1997,ApJZhang,Qiao, Han, 1997,ApJ,Core beamBeam-frequencyMode changing,Bi-drifting,Gamma-ray,Core gap,Annular gap,Strange stars, Polar cap (polar gap),Basic Observational facts vs Theories,Radio- Gamma-rays: Obs.,Outer gap,Gamma-ray,Rad

8、io,The magnetosphere of a NS,+,Inner annular gap,Inner annular gap,Qiao,Lee,Wang,Xu, Han, 2004a,ApJL,Inner annular gap,Qiao,Lee,Wang,Xu, 2004a, ApJL,Inner Annular Gap,Qiao,Lee,Wang,Xu, 2004a, ApJL,Core beamBeam-frequencyMode changing,Bi-drifting,Gamma-ray,Core gap,Annular gap,Strange stars,Mclaughli

9、n 2003,astr-ph/0310454,Bi-drifting: Obs.,Drifting subpulses,PULSE LONGITUDE,Drifting subpulses,Taylor et al. (1975),Backer (1973),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

10、Deshpannde & Rankin,1999,ApJ, 524,1008,Inner Annular Gap : V= c E x B / B2,Bi-drifting: fitting,Mclaughlin 2003,astr-ph/0310454,Qiao,Lee,Zhang,Xu,Wang,2004b, ApJL,Neutron stars: Binding energy 10 KeV no gap can be formed! Binding energy 10 KeV only one gap cab be formed: core or annular gapStrange s

11、tars: both core & annular gap can be Formed !, 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?,Conclusion and discussion,Core beamBeam-frequencyMode changing,Bi-drifting,Gamma-ray,Cor

12、e flow,Annular flow,Neutron stars,?,?,?,Qiao,Lee,Zhang,Wang & Xu,2005,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!,?,100m at Effels

13、berg,New Green Bank Telescope,Jodrell Bank,KaShi,China ?,Thank you !,Multi-cones in the ICS model,Qiao,Wang,Wang,Xu, 2002,ChJAA,Multi-frequency fitting of PSR J0437-4715,Qiao,Wang,Wang,Xu, 2002,ChJAA,Magnetosphere of pulsars,Goldreich & Julian (1969),Charge density GJ(Goldreich & Julian 1969 ),Accel

14、eration electric field,Inner annular gap,Qiao,Lee,Wang,Xu, Han, 2004,Ruderman & Sutherland, 1975,Neutron stars: binding energy 10KeV,Cant form core and annular gap at the same time!,Strange stars: binding energy 10KeV,Can form core and annular gap at the same time!,Interstellar Dispersion,Ionised ga

15、s 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-periodDM-dispersion measure,C

16、rab pulsar,Vela Pulsar,Geminga,Inner annular gap,Qiao,Lee,Wang,Xu, 2003,PA jumps: individual pulses ?,Stinebring et at. 1984,OPM Depolarization (Xu.R.X), Orthogonal Poln Mode (OPM) Depolarization (Low LP ?Or Low LP OPM ?,Daugherty & Lerche, 1975,The “Death line” of radio pulsars,The Death line of ra

17、dio pulsars,Death and appearance line,Qiao et al.,2003,Sparking condition !,Does not Hubble line!,The Death line of radio pulsars,Qiao & Zhang,1996,The magnetosphere of a NS,Critical field line,NCS,Low L PolnOPM ?,Xu & Qiao, 2000, Science in China,Outer Gap Model,Emission beams:1 &4：toward out side2

18、 & 3：toward inside,Muslimov & Harding, 2003,Slot gap model,Beams in ICS model,Type I,Type II,Qiao,Liu,Zhang & Han, 2001,Obs. & ICS : Type I a,Obs.,ICS,Qiao,Liu, Zhang,& Han, 2001,AA,Lyne & Manchester (1988) & Sieber et al. (1975),Obs. & ICS: Type Ib,Obs.,ICS,Qiao,Liu, Zhang,& Han, 2001,AA,Kramer (19

19、94).,Obs. & ICS : Type IIa,ICS,Obs.,Qiao,Liu, Zhang,& Han, 2001,AA,Phillips & Wolszczan (1992).,Magnetospere of pulsars,Am-mass of ion, Z-charge of ion,Outer gap, 1,Space charge limited flow,Inner gap,Holloway 1975 MN,Poln. of Individual pulses in ICS model,Xu,Liu,Han,Qiao, 2000, ApJ,Radio emission

20、of pulsars,Observations & Theories Emission beams: Core+Cones Emission locations Polarization: linear, circular, “orthogonal mode” Pulse profiles changing with frequencies,Rankin (1983, 1993),Gil ,Gangadhara & Gupta 2001,Lyne & Manchester 1988,Han & Manchester 2001,Core and Cones,=220(1-Cosi),ICS mo

21、del: The low frequency wave can Propagate near the surface,Qiao & Lin, 1998, AA,Polar Cap Model,Inner annular gap,Qiao,Lee,Wang,Xu, 2003,Gamma-ray +radio emission,Radio + Gamma ray emission model Basic picture Pulse profiles fitting: radio + Gamma-rays,Gamma-ray emission of pulsars,Current models Po

22、lar cap model Outer gap model Radio + Gamma ray emission model Basic picture Pulse profiles fitting: radio + Gamma-rays,Pulsars are broad-band emitters (gamma-ray, X-ray, optical, radio)Pulsars must be particle acceleratorsTwo preferred acceleration regions: - Polar cap region - Outer gap region,Pulsar Gaps,Gamma-ray OBS. Of Radio Pulsars,Janssenet al. astr-ph/0406484: PSR B1818-13,