Radio and Gammaray emission of pulsars Qiao G

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 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 Core gap Bi-drifting Annular gap Strange stars Gamma-ray

Pulsar emission beams

Observations

Emission beams Rankin, 1983, Ap. J, 274, 333

Theories

Ruderman & Sutherland (RS) Model Ruderman & Shutherland, 1975, Ap. J, 196, 51

Emission beams in RS model Emission beams Ruderman & Sutherland, 1975 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 →ω0 ω=2γ 2ω0(1 -βCosθi) Qiao & Lin, 1998, A&A

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

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

“S” shape PA & Obs.

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

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

Mode changing of pulsars Rankin, 1986

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

Mode change pulsars Zhang, Qiao, Lin, Han, 1997, Ap. J Zhang, Qiao, Han, 1997, Ap. J

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

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

The magnetosphere of a NS +

Inner annular gap

Inner annular gap Qiao, Lee, Wang, Xu, Han, 2004 a, Ap. JL

Inner annular gap Qiao, Lee, Wang, Xu, 2004 a, Ap. JL

Inner Annular Gap Qiao, Lee, Wang, Xu, 2004 a, Ap. JL

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

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

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

Drifting sub-pulses Accelerators: • Inner vacuum gap (Ruderman & Sutherland 1975) requiring high binding energy of charges on stellar surface Xu, Qiao Zhang, 1999, Ap. JL, 522, L 112 Deshpannde & Rankin, 1999, Ap. J, 524, 1008

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

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

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

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?

Core beam Beam-frequency Mode changing Bi-drifting ? Gamma-ray ? Core 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!

? 100 m at Effelsberg Jodrell Bank New Green Bank Telescope Ka. Shi, China ?

Thank you !

Multi-cones in the ICS model Qiao, Wang, Xu, 2002, Ch. JAA

Multi-frequency fitting of PSR J 0437 -4715 Qiao, Wang, Xu, 2002, Ch. JAA

Magnetosphere of pulsars Goldreich & Julian (1969)

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

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

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

Strange stars: binding energy << 10 Ke. V 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 ? ? ?

The “Death line” of radio pulsars Daugherty & Lerche, 1975

The Death line of radio pulsars

Death and appearance line Sparking condition ! Does not Hubble line! Qiao et al. , 2003

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

Slot gap model Muslimov & Harding, 2003

Beams in ICS model Type II Type I Qiao, Liu, Zhang & Han, 2001

Obs. & ICS : Type I a Obs. Lyne & Manchester (1988) & Sieber et al. (1975) ICS Qiao, Liu, Zhang, & Han, 2001, AA

Obs. & ICS: Type Ib Obs. Kramer (1994). ICS Qiao, Liu, Zhang, & Han, 2001, AA

Obs. & ICS : Type IIa Obs. Phillips & Wolszczan (1992). ICS Qiao, Liu, Zhang, & Han, 2001, AA

Magnetospere of pulsars Inner gap Outer gap, 1 Space charge limited flow Am--mass of ion, Z-charge of ion

Holloway 1975 MN

Poln. of Individual pulses in ICS model Xu, Liu, Han, Qiao, 2000, Ap. J

Radio emission of pulsars Observations & Theories ☆ Emission beams: Core+Cones Emission locations ☆ Polarization: linear, circular, “orthogonal mode” ☆ Pulse profiles changing with frequencies

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

ICS model: The low frequency wave can Propagate near the surface ω=2γ 2ω0(1 -βCosθi) 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

Pulsar Gaps • Pulsars are broad-band emitters (gamma-ray, Xray, optical, radio) • Pulsars must be particle accelerators • Two preferred acceleration regions: --- Polar cap region --- Outer gap region

Gamma-ray OBS. Of Radio Pulsars ●

Janssenet al. astr-ph/0406484: PSR B 1818 -13