Chandra によるSN1006 衝撃波面の詳細観測

馬場 彩、山崎 了、植野 優、小山 勝二( 京都大学 )

SN 1006 with ASCA

1. Introduction“How are cosmic rays accelerated up to TeV?”

Koyama et al.(1995)Discovery of synchrotron X-raysfrom the shell of SN 1006

Basic concept: Diffusive Shock Acceleration (DSA)(Bell 1978; Blandford & Ostriker 1978…)

Next problem: More realistic model

“How do the non-thermal electrons distribute on the shock?”

Spatial and spectral studies with Chandra

SN1006: type Ia d=1.8kpc

10´

1.2. Chandra の特長

1. 高空間分解能位置分解能 ～ 0.5″!

→ 衝撃波前後面の詳細構造が分かる

2. 低エネルギーまで感度あり 0.3 keV – 10.0 keV に感度 (ACIS-S)

→ 酸素のラインも見ることが出来る( 特に低温プラズマの診断に有利 )

Chandra ACIS-S で観測 (68 ksec)

2.1. Image and spectrum

How large are the scale length ofnon-thermal component? 0.3 – 2.0 keV

2.0 – 10.0 keV

inward= downstream

outward= upstream

SN1006 NE shell

Energy (keV)1 50.3

thermalextended

non-thermalsharp

2.2. Analyses method

We want to know:

the scale length of non-thermal component inupstreamdownstream

arcsec

outward= upstream

inward= downstream

wu wd

shock

cou

nts

0 20 40

020

40

2.0 – 10.0 keV

2.3. Fitting results

Mean value……………….Minimum value……….…..

Downstream0.2 pc0.05 pc

Upstream0.04 pc0.01 pc

0.01pc!

10´´ = 0.1 pc2 – 10 keV

3.1. Discussion (1)the observed and derived parameters

Observed parameters:

1. The wide band spectrum

2. The diffusion coefficient K

K = Emaxc3eB

~ > 1BB

EmaxBd0.5 = 0.37 erg G0.5

Derived parameters from DSA:

Emax

Bd> 6.4x106erg/G

wu = Ku

uuwd =

Kd

ud

3. The acceleration and loss

tacc = = 1010s 4(Ku+Kd)

us2

tsync= 6.3x102Emax-1Bd

-2

uu = 4ud = us = 2600 km/s(Winkler & Long 1997)

EmaxBd2 < 6.5x10-8 erg G2

tacc < tsync

Emax , Bd

break = 2.6 x1017 Hz+0.7-0.7

+0.04-0.06

3.2. Discussion (2)the Emax – Bd relation

Emax ~ 30 TeVBd ~ 30 Gd < 1.3

Highly turbulent magnetic field!

shock

downstream

?

Bd

e-

log (Emax/eV) 1413

log

(Bd/

G)

-6

-3from break

from Kd and

from tacc

3.3. Discussion (3)in upstream

Emax ~ 30 TeVBd ~ 30 G

Bd < Bu < Bd14

7 G < Bu < 30 G

The gyro radius in upstream rg:Emax

eBu0.001 pc < rg = < 0.005 pc ~ wu

min = 0.01 pc !

the magnetic field in upstream nearly parallel to shock planethe new acceleration mechanism e.g. Surfing acceleration (Hoshino & Shimada 2002)

shockBu

Bd

downstream

Conventional DSA cannot explain the result.

Further analyses of SN 1006 and other SNRs

4. Other SNRs (1) Young SNRsCas A Kepler Tycho

0.02pc0.04pc 0.007pc

0.02pc

0.06pc0.01pc

4. Other SNRs(2) middle aged SNRsRCW86 G347.3-0.5

0.5pc 0.1pc0.6pc0.08pc

5. Summary1. We resolved non-thermal emission

from thermal plasma in spatially and spectroscopically.

2. The non-thermal filaments havevery small scale length!

3. The conventional DSA should be revisedto explain the small scale le

ngth.the magnetic field parallel to shock plane in upstream?new acceleration mechanism?

or

4. The analyses of other SNRs is important!