Pulsar’s Multi-Accelerator Ra

diation model

李柯伽导师：乔国俊

Peking University

Outline

The difficulties of present pulsar models

The apocalypse from observation & theoretical research

A new acceleration region and a new model

Properties of this model Comparing to observations

Pulsars

+

- -

+

Null surface

1. Strong magnetic field

2. Rapidly rotation

Pulsar

NullSurface :W.B=0

Difficulties of present modelThere are two kinds of models

For Polar Gap Model(Muslimov & Harding 2003)

• Require small inclination angle and impact angle

For Outer Gap Model(Cheng et al 1986, 1994, 2000...)

No off-pulse emission No Tev cut-off Too sharp rise of pulse profile

We will solve these problem here.

Observation Note

•The radio pulse is narrow.

•The gamma-ray pulse is wide.

•Bridge emission

•Off pulse emission

Spectra

Observation

Cut-Off

The apocalypse from observation

Pulse profile show: The radio radiation comes from a c

ompact region while gamma-ray radiation comes from a wide region

Spectra show Tev cut-off require the radiation loc

ation not far from the pulsar

The theory of pulsar radiation

Polar Gap Model Radiation locates at the

magnetic pole of the pulsar

Outer Gap Model Radiation locates outside

the null surface,far from the pulsar

Reasons for Difficulties

of Present Model

For Polar Gap ModelRequire small inclination angle and impact angle

ReasonToo near

For Outer Gap ModelNo off-pulse emission

No Tev cut-off

Too sharp rise of pulse profile

Reason

Too far

New Radiation Location

We note the so called “Mid-Gap”

It locates near than Outer Gap

Farther than Polar Gap

Input Physics

1. The radiation direction

2. The intensity of radiation

3. NOTE: only at this time! We will calculate the physics very soon.

Determine the Radiation Geometry

Abbreviation Correction

The abbreviation will affect the direction of radiation.

V

c

c

o o’

tg Hj 'L= Sin HjLg@Cos HjL- bD

The Calculation for the Radiation Map

Relative intensity

dEdtdW

µàhnn HnL Rcur ân

Radio?

We also consider the radio radiation in this region

Take the Inverse Compton Scatter model to calculate the radio radiation

Have the intrinsic

Beauty of

Unification! Not a machine made model

ICS model sketch map

Calculation for Radio Radiation

Unified Results

Gamma

Radio1Radio2

The result of our model1.Beam patterns

2.Pulse profile

We have

•Bridge Emission

•Off-pulse Emission

•Soft rise and down

0 50 100 150 200 250 300 3500

50

100

150

=45o,=5o =0.8,=0.5

-400 -300 -200 -100 0 100 200 300 4000

0.2

0.4

0.6

0.8

1

Phase(Deg)

Flu

x

=45 = =0.5 =0.8

Sight

Line

Vela

Vision

Multi-bands Fitting of

ObservationsVela

Crab

Geminga

• ICS model is used to give radio results

Gamma-ray

Radio

Predictions

1. Some pulsar could be only observed at certain bands

2. Some pulsar can be observed at many bands

3. Three components pulsar

Gamma-B Process

Gamma-B process1.If the photons fly with some angle respect to the magnetic field

2.The photons have enough energy

3.Strong enough magnetic field

The absorption ratio is

Cm^-1

k =106 B12 Sinqã-60

Emev B12 Sinq

e®Emit =

dxdq

i®

+dydq

j®

+dzdq

k®

where

x=R0Sin@qsourceD3 Cos@j SourceD+ dxdqsourcedrdqsource l ;

y=R0Sin@qsourceD2 Sin@qsourceDSin@j SourceD+ dydqsourcedrdqsource l ;

z=R0Sin@qsourceD2 Cos@qsourceD+ dzdqsourcedrdqsource l

Geometry Condition

The Equation and Numeric Method

0 20 40 60 80 1000

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

2x 10

-51

Distance form source(Km)

Ab

sorp

tion

Km

^-1

k-L

Mu=1850 ThetaS=0.07

Nu=10 R0=1595

The Radiation Transfer Equation is rather hard to integrate.

Delta like and infinite integration

The Escape Membrane of the Photons

Solve:

To get the location of source

Spectra Result

Tev cut-off

Solve the spectra problem of outer gap

Fit the crab

Our Work•Study a new gamma-ray pulsar model with a new accelerator

•Investigate the possible acceleration mechanisms

•Discuss the physical and geometrical conditions of this region

•Discuss the spectra properties induced by gamma-B process

•Give the last escape membrane of photons.

•Compare our model with observation

Further Work

Dynamic & Kinetic

Thanks