SN-SNR 2012 Suzaku Observations of W28cosmic.riken.jp/snsnr2012/presen/day3/sawada.pdfSN-SNR 2012...

Makoto Sawada

Thanks to ...K. Koyama, K. Masai, H. Yamaguchi, H. Uchida, T. Shimizu, T. Ohnishi, M. Ozawa, J. Kaastra, J. de Plaa, Y. Fukui, C. Brogan, Y. Ohira, T. Inoue, R. Yamazaki, and A. Bamba.

from Aoyama Gakuin University

SN-SNR 2012

Suzaku Observations of W28Formation & Evolution of Recombining Plasma

Probed by the Spatial Distribution

Wednesday, October 17, 2012

Do all SNRs have shell/ionizing plasma?-No.

Both X/Radio are Shell-like Ionizing (Tz < Te)

Thermal StructureSpatial Structure

Evolution of Standard (Shell) SNRsAssuming SNe in uniform ISM

SNR E0102 Time after shock passage

Ion T

Elec. T (Te)Ioni. T (Tz)Te

mpe

ratu

re

Equipartition>100 yr

Ioni. eq.~3e4 yr

Radio/X-ray


Both the Spatial and Thermal Structures cannot be realized by Standard Evolution.

Mixed Morphology= Central X-rays + Radio Shell

Some of MM SNRs have Recombining Plasma (Tz > Te)!

Thermal StructureSpatial Structure

Non-Standard SNRs

Radio/X-ray

MM SNR IC 443

Si e

e

Strong free-bound X-rays


Any Scenario would be related to the environments of SNe/SNRs.

What makes Tz > Te?

How Recombining Plasma formed?

Age

Te

Tz

Tem

pera

ture

External Ionization?

Rapid Cooling?

• Photo-ionization

• Supra-thermal Electrons

• Conduction to Cold Clouds

• Rarefaction (adiabatic cooling) due to Shock Break-out of Dense CSM of Massive Progenitor

Possible Scenarios

Yamaguchi+09,12, Shimizu+11, Moriya+12

Kawasaki+02,05

Kawasaki+02,05

Ohnishi+11


Study spatial distribution of RP on W28

Motivation & Target

Morph Gal. Lat. MC γ-rays Size discov. of RP

IC 443

W49B

G359.1

W28

W44

MM +3.0 OH-m, CO GeV/TeV 45’ Yamaguchi+09

MM -0.2 H2 GeV/TeV 4’ Ozawa+09

MM -0.5 OH-m, CO TeV ? 20’ Ohnishi+11

MM -0.1 OH-m, CO GeV/TeV 50’ Sawada+12

MM -0.4 OH-m, CO GeV 30’ Uchida+12

Common features of Recombining SNRs

SN Recombining Plasma+ environment

evolve to

can probe


70+100+150 ks observations.Analyzed coaxially divided 1.2-5.0 keV spectra.

X-ray map with Suzaku + Radio contours

Mixed-Morphology SNR W28

0.5-2 keV2-5 keV5-8 keV

d~2 kpc

age~30 kyr


0

45135

180

225 315

510

1520

25

Ionization temperature (keV)

0.20

0.30

0.40

0.50

0.60

0.70

0.80

0.90

1.00

1.10

1.20

0

45135

180

225 315

510

1520

25

Electron temperature (keV)

0.20

0.30

0.40

0.50

0.60

0.70

0.80

0.90

1.00

1.10

1.20

Both are highest at central region and decrease outward.

Tz of SiTe

Spatial Distribution of RP


0.0 5.0 10.0 15.0 20.0 25.0 30.0Distance from TeV -ray peak (pc)

0.0

0.5

1.0

1.5

2.0

Ioni

zatio

n te

mpe

ratu

re

(keV

)

01 02 08

0309

0410

0511

121314

06 07

15

1920211617

18

23

2224 25

Correlation coeff.=0.60

ESNRCTSW

0

45135

180

225 315

510

1520

25

Ionization temperature (keV)

0.20

0.30

0.40

0.50

0.60

0.70

0.80

0.90

1.00

1.10

1.20

No evidence supporting ionization by supra-thermal electrons.

TeV peak at northeast edge. Tz near TeV peak is not high.

No correlationTeV peak on Tz map

Ext. Ionization by Supra-thermals?

TeV peak


0

45135

180

225 315

510

1520

25

/

1.00

1.20

1.40

1.60

1.80

2.00

2.20

2.40

2.60

2.80

3.00

Widely distributed RP across ~30 pc does NOT prefer GRB photo-ionization scenario.

Entire SNR is RP (Tz/Te>1)

Photo-ionization by GRB/afterglow?

• No bright X-ray source.

• Past GRB can ionize.

• Beaming make narrow photo-ionized “cone”.

• Photo-ionized cone→RP

• Outside of the cone→IP


0.2 0.4 0.6 0.8 1.0 1.2CO ratio

0.0

0.2

0.4

0.6

0.8

1.0

Elec

tron

tem

pera

ture

(k

eV)

0102

08

03 0904 10

05 11

12

13 14

06

07

1519

2021

1617 18

23

22

2425

Correlation coeff.=-0.72

ESNRCTSW

0

45135

180

225 315

510

1520

25

Electron temperature (keV)

0.20

0.30

0.40

0.50

0.60

0.70

0.80

0.90

1.00

1.10

1.20

Conduction may play a role, but hard to make the entire SNR recombining.

CO data provided by NANTEN group.Excited CO clouds founds near

low-Te regions.

Possible correlation found.12CO J=2-1 clouds on Te map

Conduction cooling to shocked MCs?

~10^5 yr


2e-14 1e-13 2e-13Surface brightness (erg s cm arcmin )

0.1

0.2

0.5

1.0

Elec

tron

tem

pera

ture

(k

eV)

010208

0309 0410

0511

12

1314

0607

1519

2021

16 1718

23

22

2425

Correlation coeff.=0.46

ESNRCTSW

Radial position (pc)

Surfa

ce b

right

ness

(erg

s ar

cmin

)

01

02

08

03

09

04

10

05

11

1213

14

0607

15

19

20

21

16

17

1823

2224

25

(Roughly) consistent with rarefaction.

Surface brightness and density is higher near the center.

Basically tenuous region has low electron temperature.

Correlation with TeSB/density pro!le

Rarefaction (adiabatic cooling)

ne∝ r^(-1)


Consistent with rarefaction scenario.

Rec. timescale ~ 20 kyr ~ SNR ageCooling occurred in early stage. Type-II like pattern.

Abundance patternThermal History (netrec)

Further Supports for Rarefaction

• Ne/CN ~ 0.2 solar

• Mg/CN ~ 0.4 solar

• Si/CN ~ 0.3 solar

• S/CN ~ 0.2 solar

• Fe/CN ~0.1 solar


Similar center-!lled Hα emission also found in the recombining SNRs G359.1 and W44.

Filled-center Hα = CSM tracer?

Evidence of dense CSM+Cavity Wall?

HαX-rayRadio


Evidence of dense CSM+Cavity Wall?

Before rarefaction Evolved (~1e4 yr later?)

Dense clumps (>103/cm3) in RSG wind (~102-5/cm3) can survive forward shock.

Interaction btw rare!ed plasma and cavity wall may produced partial shells.


Thank you for your attention.

SN-SNR 2012

Summary• Obtained spatial distribution of RP on W28.

• Examined the origin of RP by comparing it to structures in other wavelength.

• External-ionization and conduction cooling scenarios are not favorable.

• Long recombination time (~age), abundances and centrally-!lled X/Hα morphologies are consistent with the rarefaction scenario.


SN-SNR 2012 Suzaku Observations of W28cosmic.riken.jp/snsnr2012/presen/day3/sawada.pdfSN-SNR 2012...

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