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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
Wednesday, October 17, 2012
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
Wednesday, October 17, 2012
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
Wednesday, October 17, 2012
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
Wednesday, October 17, 2012
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
Wednesday, October 17, 2012
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
Wednesday, October 17, 2012
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
Wednesday, October 17, 2012
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
Wednesday, October 17, 2012
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
Wednesday, October 17, 2012
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)
Wednesday, October 17, 2012
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
Wednesday, October 17, 2012
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
Wednesday, October 17, 2012
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.
Wednesday, October 17, 2012
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.
Wednesday, October 17, 2012