「すざく」「すざく」による超新星残による超新星残骸骸 RCW86RCW86 の観測の観測

Suzaku Observations of Suzaku Observations of Supernova Remnant RCW86Supernova Remnant RCW86

　山口 弘悦 （理研）Hiroya Yamaguchi (RIKEN)

　← Preliminary image of the Suzaku mapping observation

1. Introduction1. IntroductionRCW86 (G315.4 -2.3)SN185 Age ~ 1800 yr⇒D = 2.8 kpc (Rosado+1996)

ASCA : Discovered synchrotron X-rays (Bamba+2000; Borkowski+2001)

Chandra, XMM-Newton : Revealed the detailed structure

Northeast rim : soft-thermal and non-thermal emission filament join smoothly along the outer shell

XMM-NewtonChandra

Red ： 0.5-1 keV (thermal plasma)Blue ： 2-6 keV (synchrotron X-ray)

Vink+2006

1. Introduction1. IntroductionAnother remarkable results of ASCA : Detection of Fe-K line at 6.4keV （ = corresponds to neutral Fe)　→ Fluorescent by supra-thermal electrons ?? (Vink+1997)　→ Fluorescent by synchrotron X-rays ?? (Tomida+1999)

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 ofFe-K emission is necessary

The merit of Suzaku : high sensitivity and good spectral resolutionin the energy range above 5keV where Fe-K is included.

No spatial correlation betweenthe Fe-K and the hard X-ray

2. Suzaku Image2. Suzaku ImageRed : 0.5-1 keV (thermal) Blue : 3-6 keV (non-thermal) Green : 6.3-6.5 keV (Fe-K)

soft-thermal

Fe-K

2’

Peak of the Fe-K is shifted to the inner region from the soft emission.

Projection

EastEast

NENE

3.1 Hard Band Spectrum 3.1 Hard Band Spectrum Fe-K energy : 6424 (6404-6444) eV 　→ ionization state = +8 ~ +16

(cf. neutral Fe = 6400eV) NOT fluorescence origin

Fe-K flux : (NE) < 1/3 × (East)

NE

East

3.2 Full-Band Spectrum3.2 Full-Band SpectrumEast

NE

EastNon equilibrium ionization (NEI) plasma× ２ + power-law

Low temperature componentkTe ~ 0.3 keV, subsolar elemental abundances

High temperature componentkTe ~ 1.8 keV, Fe-rich ( >> solar abundance)plasma age (ionization timescale) < 380 yr

( << the SNR age of 1800 yr)

NELow temperature component + power-law

(power-law dominant)

thermal （ low-kTe ） : East >> NEnon-thermal (power-law) : 　 NE >> East

4.1 Origin of the 4.1 Origin of the ComponentsComponents

EastEastEast : high ISM density

NE : high shock velocity　 vs = 2700 km/s (Vink+2006)

~ 0.3 keV plasma - Sub-solar abundance - Coincident with H filament

(Smith 1997) ⇒ ISM heated by

the forward shock

Power-law （ ~ 2.8 ） - Spatially connected from East

⇒ Synchrotron emission from TeV electrons accelerated at the forward shock front

NENE

~ 1.8 keV plasma (Fe-K) - Fe abundance : over-solar - Enhanced at inward region - Plasma age < 380 yr

⇒ Fe-rich ejecta heated by reverse shock very recently

MFe = 0.07 (0.06 – 0.6) M◎

⇒ A portion of the Fe Ejecta?

4.2 Unified Picture4.2 Unified Picture

Dense medium

Fe-rich ejecta

Forward shock

Reverse shock

EastEast

NENE

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. <<East rim>> - 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. <<NE rim>> - 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.

4.2 Unified Picture4.2 Unified Picture

Molecular cloud : NANTEN (Matsunaga+2001) -40 km/s < VLSR < -30 km/s, d ~ 2.4 kpc (consistent with RCW86)

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 Vink+1997) or a molecular cloud.

East

NE

Color image Suzaku (0.5-1keV) Is it really interacting

with the SNR?

4.3 Fe-K Mapping with Suzaku4.3 Fe-K Mapping with Suzaku

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)

Preliminary Results

Entire SNR was observed with Suzaku

Southwest : PV phase (Ueno+2007)Northeast : AO-1 (Yamaguchi+2008)Other 4 pointings : AO-3

Fe-K (= shocked ejecta) morphology has been revealed for the first time !!

Newly found Fe-K emissions

4.4 TeV 4.4 TeV -ray Detection-ray Detection

TeV -ray was detected with 8.5 confidence level. (Aharonian+2009) - Morphologies of the X-ray and g-ray emissions are different from each other.

… Unlikely to RX J1713 and Vela Jr.

- = 2.5 (2.2-2.9), FTeV = 9×10-12 erg cm-2 s-1, cf. Fx ~ 2×10-10 erg cm-2 s-1

SuzakuHESS

HESS spectrum

- Assuming that the -ray flux is fully due to IC process… B ~ 30⇒ G- Hadronic scenario requires a density of nH > 0.1cm-3

The density determined from the thermal X-ray is not reliable in this case. ⇒ MC and GeV -ray observations are very important!

SummarySummary We observed NE rim of RCW86 with Suzaku.We observed NE rim of RCW86 with Suzaku. Morphology of the Fe-K emission was revealed fMorphology of the Fe-K emission was revealed f

or the first time. It is enhanced at the inner regioor the first time. It is enhanced at the inner region from the soft thermal rim.n from the soft thermal rim.

Fe-K line originates from the Fe-rich ejecta heatFe-K line originates from the Fe-rich ejecta heated by the reverse shock very recently.ed by the reverse shock very recently.

Suzaku AO-3 observations detect Fe-K emission Suzaku AO-3 observations detect Fe-K emission from the other regions (Preliminary).from the other regions (Preliminary).

TeV TeV -ray has been detected by HESS. Density -ray has been detected by HESS. Density determination by MC observation is necessary.determination by MC observation is necessary.