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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