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脉冲星辐射机制的探讨. 乔国俊 北京大学天文学系. 中子星如何产生辐射?. 引力 — 热运动 =》 中子星大气:几厘米. 脉冲星的 磁层 !. :. →. 辐射:高能粒子 + 曲线运动 ……. Goldreich & Julian, 1969; RS 1975. 如何产生观测到的 辐射 ?. 理论 :辐射区域 + 辐射机制 1 、 辐射区: 2 、边条件 3 、初条件 4 、足够的加速电势 观测 :观测与理论是否相符?. 可能的加速 + 辐射区 II. 内间隙模型 ● 表面束缚能: >10 keV

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slide2

中子星如何产生辐射?

引力 —热运动=》中子星大气:几厘米

slide3

脉冲星的磁层!

辐射:高能粒子+曲线运动……

Goldreich & Julian, 1969; RS 1975

slide4

如何产生观测到的辐射?

理论:辐射区域+辐射机制

1、辐射区:

2、边条件

3、初条件

4、足够的加速电势

观测:观测与理论是否相符?

slide5
可能的加速+辐射区

II.内间隙模型

● 表面束缚能:>10 keV

● 中子星?夸克星:OK;Core+Annular?

III. 外间隙模型

● 完全电荷分离?

● 回流加速?

IV. Slot Gap 模型: 加速电势?

V. 观测检验

脉冲星辐射机制的探讨

slide6

中子星的磁层

For Crab Pulsar:

slide7

Mono-generator

地球:

太阳:

For Crab Pulsar:

slide9

Outer gap model

polar cap model

slide10
环间隙模型

优点:

●靠近中子星也可产生很宽的辐射束

● 可同时给出射电和伽玛辐射!

Acomparison between the models

slide11
可能的加速+辐射区

II.内间隙模型

● 表面束缚能:>10 keV

● 中子星?夸克星:OK;Core+Annular?

III. 外间隙模型

● 完全电荷分离?

● 回流加速?

IV. Slot Gap 模型: 加速电势?

V. 观测检验

脉冲星辐射机制的探讨

slide13

漂移子脉冲

Backer (1973)

slide14
内间隙模型涉及三项重要内容

辐射机制:强磁场中的逆康普顿散射

表面束缚能:中子星、夸克星?

观测检验:空心束?中心、内环、外环?

Xia et al. AA.,1985, Qiao & Lin, 2001 Xu et al. Ch.Ph.Let. 1998, 1999,

Qiao et al. 2001, Zhang et al. 2007 Xu et al. ApJ, 1999, Xu et al., ApJ.,2001…

different gap heights mode changing
Different gap heights:mode changing

Rankin, 1986

Zhang,Qiao,Lin,Han,1997,ApJ.

slide16

原子吸收光子

强磁场中逆Compton散射

强磁场中电子的Landau能级:

Bohr原子:

.

.

电子处于量子化 Bohr能级上

B

电子处于量子化

Landau能级上

强磁场中共振逆Compton散射:

原子共振吸收光子:

Xia,Qiao,Wu,Hou,. 1985, A&A, 152, 93

mode changing
Mode changing

Zhang,Qiao,Lin,Han, 1997

slide18
环区与核区放电点反向漂移

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

slide19

The Annular Gap

The radio and gamma-ray can be understood by annular gap at same time.

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

slide20

Drifting sub-pulses

PULSE LONGITUDE

Drifting subpulses

Taylor et al. (1975)

Backer (1973)

bi drifting fitting
Bi-drifting: fitting

Mclaughlin 2003,astr-ph/0310454

Qiao,Lee,Zhang,Xu,Wang,2004b, ApJL

core and conal emission beams
Core and conal emission beams

Manchester,R.N. 1995

J. Astroph. Astr. 16,107

Rankin, 1983, ApJ,274,333

Core emission !

How to produce it?

slide23

Emission beams in RS model

Emission beams

Hollow cone only!

Ruderman & Sutherland, 1975

Low freq: wide beam!

Rankin, 1983, ApJ,274,333

inverse compton scattering ics model
Inverse Compton scattering (ICS) model

Qiao, 1992

Qiao & Lin, 1998, AA;

Qiao,Lin, Zhang,& Han, 2001,AA

slide25

?

Obs.

ICS model

RS model

The beaming frequency variation!

Qiao,Liu, Zhang,& Han, 2001,AA

Lyne & Manchester (1988) & Sieber et al. (1975),Kramer,(1994)

psr b2111 46 multi bands obs
PSR B2111+46: Multi-bands Obs.

Pulse profiles:

Gaussian fitting

Zhang, Qiao, Han, Lee, Wang , AA,2007

psr b2111 46 multi bands obs1
PSR B2111+46: Multi-bands Obs.

Light curves

Different components of same frequency come from different altitudes.

Zhang, Qiao, Han, Lee, Wang , AA,2007

spark model
Spark Model

Polar cap region

Gil & Sendyk, 2000

slide29

关于强磁场中的你康普顿(谐振)散射

Harding et al. (1998):“张乔等(1996,1997)最先研究了…逆康普顿散射光子产生电子对的效应,他们发现…极冠区加速的标准模型需要进行实质性的修改”。Hibschman & Arons(2001)指出,“在过去25年中, 基本模型未发生实质性的变化。然而,最近有两项重要的进展,一个是Muslimov …发现的广义相对论…产生的加速电势,…另一个是… Zhang et al. 1997提出的逆康普顿散射…”。

gil sendyk 2000 0437 10 0031 07 rs

关于强磁场中的你康普顿(谐振)散射

Gil 和 Sendyk (2000)指出, “…新近关于0437+10 和0031+07漂移子脉冲的文章强烈显示极冠区RS型真空间隙的存在,徐等强调如果脉冲星(至少那些具有漂移子脉冲的)是夸克星,束缚能问题可以完全解决…”。
slide31

关于环间隙&漂移子脉冲

Weltevrede et al.(2006)指出:“对脉冲星子脉冲漂移现象解释的最好的模型是真空间隙(gap)放电模型(…Qiao et al.2004)…脉冲的双向漂移就可以解释(Qiao et al.2004)…双向漂移可以做为一个迹象,表明这些脉冲星既有环间隙也有中心间隙(Qiao et al.2004)”。

slide32
可能的加速+辐射区

II.内间隙模型

● 表面束缚能:>10 keV

● 中子星?夸克星:OK;Core+Annular?

III. 外间隙模型

● 完全电荷分离?

● 回流加速?

IV. Slot Gap 模型: 加速电势?

V. 环间隙模型

脉冲星辐射机制的探讨

slide33
外间隙模型涉及的三项重要内容

Cheng & Ruderman, 1976

向内流动的粒子?次级中性等离子体?

磁层:是否完全电荷分离?

向内流动的粒子:是否会加速?

观测检验:是否在零电荷面外?

why the ag plays a important role
Why the AG plays a important role?

Theory:●outer gap <=> annular

Observations:● very wide emission beams

● Bi-drifting sub-pulses…

Qiao,Lee,Zhang,Wang, Xu, 2007,ChJAA

Du, Han, Qiao, Chou, 2010, ApJ.

free flow slot gap annular gap
Free flow: slot gap & Annular gap

Qiao,Lee,Zhang,Wang, Xu, 2007,ChJAA

the annular gap qiao lee zhang wang xu 2007 chjaa
The annular gap Qiao,Lee,Zhang,Wang, Xu, 2007,ChJAA

the acceleration effect of AG is much higher efficiency!

slide37
可能的加速+辐射区

II.内间隙模型

● 表面束缚能:>10 keV

● 中子星?夸克星:OK;Core+Annular?

III. 外间隙模型

● 完全电荷分离?

● 回流加速?

IV. Slot Gap 模型: 加速电势?

V.观测检验

脉冲星辐射机制的探讨

slot gp
Slot GP模型涉及的三项重要内容

⊙ 初条件?(从中子星表面流出粒子等于当地磁层密度?)

⊙是否可以忽略环间隙区域?

⊙ 加速电势是否足够?

Favorable

region

(Muslimov & Harding, 2004)

Arons,J. 1983, ApJ

slide39

Mono-generator

地球:

太阳:

For Crab Pulsar:

slide40
可能的加速+辐射区

II.内间隙模型

● 表面束缚能:>10 keV

● 中子星?夸克星:OK;Core+Annular?

III. 外间隙模型

● 完全电荷分离?

● 回流加速?

IV. Slot Gap 模型: 加速电势?

V. 观测检验

脉冲星辐射机制的探讨

position angle sweep fit with rotation vector model
Position angle sweep fit with Rotation Vector Model

Viewing Angle

z

Inclination Angle

a

Double-pole origin

W

~157o

z

m

a

MP

Pole B

(IP)

IP

Pole A

(MP)

Line of Sight

Wang et al.2006

Lyne & Manchester 1988

slide43

射电+伽玛==》辐射区域

Radio

Gamma-ray

Thompson et al. 1992

Wang.Qiao,Xu,Liu, 2006,MN

From observation, the radiation location can be determined uniquely for this star.

slide45

偏振位置角的突跳

Xu, Qiao & Han, 1997, AA

fermi lat
FERMI/LAT

FERMI Observatory:

Launch date: 11 June 2008

Two instruments:

GBM: 8 keV – 40 MeV

GRBs, transient sources

LAT: main telescope

20 MeV to > 300 GeV

Great improvements:

8000 cm2 at 1 GeV

0.8o at 1 GeV

Large FOV -

cover all sky in two orbits 3 hr

slide47

Where we are…

Pulses at

1/10th true rate

slide49

Millisecond pulsars: pulse profiles in the Annular gap

Du, Qiao, Han, Lee, Xu 2010, MN

slide50

Modeled radio and Gamma-ray light curves for PSR J0034-0534

Gamma-ray

Obs.

Radio Obs.

Du, Qiao, Chen 2012

slide51

Vela: pulse profiles in the Annular gap

Du et al. 2010

Du, Han, Qiao, Chou,2011, ApJ.

wide radio beams from ray pulsars ravi manchester hobbs 2010
WIDE RADIO BEAMS FROM γ -RAY PULSARS Ravi, Manchester & Hobbs,2010

G-Gamma-ray

R-radio

Θc-common

Θg-gamma

Θr-radio