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

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

Core beam Beam-frequency Mode changing Bi-driftingGamma-ray Core gapAnnular gap Strange stars

Pulsar emission beams

Observations

Emission beams Rankin, 1983, ApJ,274,333

Theories

Ruderman & Sutherland (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 (5) Bi-drifting  Pulsars: NS or Strange stars?

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

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

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

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

ICS model: inner gap sparking → ω 0 ω=2γ 2 ω 0 (1-βCosθ i ) Qiao & Lin, 1998, A&A

Core beam Beam-frequency Mode changing Bi-driftingGamma-ray Core gapAnnular 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 pulse in ICS V —circular poln L —Linear poln I —Total Intensity Position angle Xu,Liu,Han,Qiao, 2000, ApJ

Core beam Beam-frequency Mode changing Bi-driftingGamma-ray Core gapAnnular gap Strange stars

Mode changing of pulsars Rankin, 1986

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

Mode change pulsars Zhang,Qiao,Lin,Han, 1997,ApJ Zhang,Qiao, Han, 1997,ApJ

Core beam Beam-frequency Mode changing Bi-driftingGamma-ray Core gapAnnular gap Strange stars

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

The magnetosphere of a NS +

Inner annular gap

Qiao,Lee,Wang,Xu, Han, 2004a,ApJL

I nner annular gap Qiao,Lee,Wang,Xu, 2004a, ApJL

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

Core beam Beam-frequency Mode changing Bi-driftingGamma-ray Core gapAnnular gap Strange stars

Mclaughlin 2003,astr-ph/ 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 Deshpannde & Rankin, 1999,ApJ, 524,1008

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

Bi-drifting: fitting Mclaughlin 2003,astr-ph/ 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 gap Strange stars: 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 beam Beam-frequency Mode changing Bi-driftingGamma-ray Core flowAnnular 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 Effelsberg 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 J Qiao,Wang,Wang,Xu, 2002,ChJAA

Magnetosphere of pulsars Goldreich & Julian (1969)

Charge density — ρ GJ (Goldreich & Julian 1969 ) Acceleration electric field Acceleration electric field

I nner annular gap Qiao,Lee,Wang,Xu, Han, 2004

Ruderman & Sutherland, 1975 Neutron stars: binding energy > 10KeV Can’t 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 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

Crab 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 radio 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 Poln→OPM ? Xu & Qiao, 2000, Science in China

Outer Gap Model Emission beams: 1 &4 ： toward out side 2 & 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 (1994).

Obs. & ICS : Type IIa ICS Obs. Qiao,Liu, Zhang,& Han, 2001,AAPhillips & 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 of pulsars Observations & Theories ☆ Emission beams: Core+Cones Emission locations ☆ Polarization: linear, circular, “orthogonal mode” ☆ Pulse profiles changing with frequencies

Rankin (1983, 1993) Gil & Krawczyk 1996; Mitra & Deshpande 1999; Gangadhara & Gupta 2001,  Lyne & Manchester 1988 Han & Manchester 2001  Core and Cones

ω=2γ 2 ω 0 (1-βCosθ i ) ICS model: 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 ☆ Polar 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 accelerators Two preferred acceleration regions: --- Polar cap region --- Outer gap region Pulsar Gaps

● Gamma-ray OBS. Of Radio Pulsars

Janssenet al. astr-ph/ : PSR B