?????????????RCW86??? Suzaku Observations of Supernova Remnant RCW86

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?????????????RCW86???Suzaku Observations of
Supernova Remnant RCW86

• ?? ?? (??)
• Hiroya Yamaguchi (RIKEN)

? Preliminary image of the Suzaku mapping
observation
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1. Introduction
RCW86 (G315.4 -2.3) SN185 ? Age 1800 yr D 2.8
kpc (Rosado1996)
ASCA Discovered synchrotron X-rays
(Bamba2000 Borkowski2001) Chandra, XMM-Newton
Revealed the detailed structure Northeast
rim soft-thermal and non-thermal emission
filament join smoothly along the outer shell
XMM-Newton
Chandra
Red0.5-1 keV (thermal plasma) Blue2-6 keV
(synchrotron X-ray) Vink2006
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1. Introduction
Another remarkable results of ASCA Detection
of Fe-Ka line at 6.4keV( corresponds to neutral
Fe) ? Fluorescent by supra-thermal electrons ??
(Vink1997) ? Fluorescent by synchrotron X-rays
?? (Tomida1999) However, following Chandra and
XMM-Newton observations failed to detect Fe-K
emission from this region. ? So, the origin of
Fe-K emission is still unknown
Scientific goal of the Suzaku observation -
To reveal the reason for the separation of the
thermal and non-thermal filament - To reveal
the origin of Fe-K emission ? Investigation of
the morphology and ionization state of Fe-K
emission is necessary
The merit of Suzaku high sensitivity and good
spectral resolution in the energy range above
5keV where Fe-K is included.
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2. Suzaku Image
Red 0.5-1 keV (thermal) Blue 3-6 keV
(non-thermal) Green 6.3-6.5 keV (Fe-Ka)
No spatial correlation between the Fe-Ka and the
hard X-ray
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3.1 Hard Band Spectrum
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3.2 Full-Band Spectrum
East Non equilibrium ionization (NEI) plasma2
power-law Low temperature component kTe 0.3
keV, subsolar elemental abundances High
temperature component kTe 1.8 keV, Fe-rich (
gtgt solar abundance) plasma age (ionization
timescale) lt 380 yr ( ltlt the SNR
age of 1800 yr) NE Low temperature component
power-law (power-law dominant)
East
NE
thermal (low-kTe) East gtgt NE non-thermal
(power-law) NE gtgt East
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4.1 Origin of the Components
East
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4.2 Unified Picture
Possible scenario to explain the present
morphologies and spectra of each component
The East and NE rims were expanding with same
high velocity until a few hundred years
ago. ltltEast rimgtgt - Collided with a dense
medium very recently. ? Forward shock
decelerated rapidly. - At the same time,
reverse shock began to move inward to
the interior of the SNR. ? Fe-rich
ejecta was heated. ltltNE rimgtgt - Forward
shock is still expanding in a tenuous
region, and hence keeps a high shock velocity.
? Efficient acceleration is maintained.
- Reverse shock also expand with high velocity.
Therefore, it has not yet reached to ejecta
layers ? Fe-K emission at NE is
absent.
Forward shock
NE
Dense medium
East
Fe-rich ejecta
Reverse shock
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4.2 Unified Picture
What is the dense medium? RCW86 is an SNR
in the OB association (Westerlund 1969). ?
A candidate of the dense medium is either a
wind-blown wall surrounding the SNR
(suggested by Vink1997) or a
molecular cloud.
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4.3 Fe-K Mapping with Suzaku
Preliminary Results
Entire SNR was observed with Suzaku Southwest
PV phase (Ueno2007) Northeast AO-1
(Yamaguchi2008) Other 4 pointings AO-3 Fe-Ka
( shocked ejecta) morphology has been revealed
for the first time !!
Newly found Fe-K emissions
Red 0.6-1.0 keV (blast-shocked ISM) Blue
3.0-5.5 keV (non-thermal emission) Green
6.3-6.5 keV (reverse-shocked ejecta)
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4.4 TeV g-ray Detection
HESS spectrum
Suzaku
HESS
TeV g-ray was detected with 8.5s confidence
level. (Aharonian2009) - Morphologies of the
X-ray and g-ray emissions are different from each
other. Unlikely to RX J1713 and Vela Jr. -
G 2.5 (2.2-2.9), FTeV 910-12 erg cm-2 s-1,
cf. Fx 210-10 erg cm-2 s-1
- Assuming that the g-ray flux is fully due to IC
process ? B 30mG - Hadronic scenario requires
a density of nH gt 0.1cm-3 The density
determined from the thermal X-ray is not reliable
in this case. ? MC and GeV g-ray observations
are very important!
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Summary

• We observed NE rim of RCW86 with Suzaku.
• Morphology of the Fe-K emission was revealed for
  the first time. It is enhanced at the inner
  region from the soft thermal rim.
• Fe-K line originates from the Fe-rich ejecta
  heated by the reverse shock very recently.
• Suzaku AO-3 observations detect Fe-K emission
  from the other regions (Preliminary).
• TeV g-ray has been detected by HESS. Density
  determination by MC observation is necessary.