1. 「すざく」 による超新星残骸 RCW86 の観測 Suzaku Observations of Supernova Remnant RCW86 山口 弘悦 （理研） Hiroya Yamaguchi (RIKEN) ← Preliminary image of the Suzaku mapping observation

2. 1. Introduction RCW86 (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-Newton Chandra Red ： 0.5-1 keV (thermal plasma) Blue ： 2-6 keV (synchrotron X-ray) Vink+2006

3. 1. Introduction Another 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 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.

4. No spatial correlation between the Fe-K  and the hard X-ray 2. Suzaku Image Red : 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

5. East NE 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

6. 3.2 Full-Band Spectrum East NE East Non equilibrium ionization (NEI) plasma× ２ + power-law Low temperature component kT e ~ 0.3 keV, subsolar elemental abundances High temperature component kT e ~ 1.8 keV, Fe-rich ( >> solar abundance) plasma age (ionization timescale) < 380 yr ( << the SNR age of 1800 yr) NE Low temperature component + power-law (power-law dominant) thermal （ low-kT e ） : East >> NE non-thermal (power-law): NE >> East

7. 4.1 Origin of the Components East East : high ISM density NE : high shock velocity v s = 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 NE ~ 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 M Fe = 0.07 (0.06 – 0.6) M ◎ ⇒ A portion of the Fe Ejecta?

8. 4.2 Unified Picture Dense medium Fe-rich ejecta Forward shock Reverse shock East NE 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. > - 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. > - 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.

9. 4.2 Unified Picture Molecular cloud : NANTEN (Matsunaga+2001) -40 km/s < V LSR < -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?

10. 4.3 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

11. 4.4 TeV  -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), F TeV = 9×10 -12 erg cm -2 s -1, cf. F x ~ 2×10 -10 erg cm -2 s -1 Suzaku HESS spectrum - Assuming that the  -ray flux is fully due to IC process… ⇒ B ~ 30  G - Hadronic scenario requires a density of n H > 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!

12. Summary We observed NE rim of RCW86 with Suzaku. 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. 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. 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). Suzaku AO-3 observations detect Fe-K emission from the other regions (Preliminary). TeV  -ray has been detected by HESS. Density determination by MC observation is necessary. TeV  -ray has been detected by HESS. Density determination by MC observation is necessary.