TeV gamma-ray observation of RCW86 with the CANGAROO-II telescope WATANABE Shio (Kyoto university) for the CANGAROO Collaboration Contents The CANGAROO telescope Motivation Observation Analysis Result Summary 28 th ICRC Tsukuba, 3 August 2003

Site: Woomera, South Australia C ollaboration of A ustralia and N ippon for a GA mma R ay O bservatory in the O utback University of Adelaide Australian National University Ibaraki University Ibaraki Prefectural University of Health Science Institute for Cosmic Ray Research, U. Tokyo Institute of Space and Astronautical Science Kitasato University Konan University Kyoto University National Astronomical Observatory of Japan Osaka City University Shinshu University STE Laboratory, Nagoya University Tokai University Tokyo Institute of Technology Yamagata University Yamanashi Gakuin University Australian Institutes : 2 & Japanese Institutes : 15 31°06’ S 136°47’ E 160m a.s.l.

—— = —   C  max U photon dE 4 2 dt I.C. 3 —— = —   C  max — dE 4 2 B 2 dt Synch. 3 2 TeV gamma-ray from SNRs  0 decay スペクトルの形に 違い Synchrotron SN1006 NE rim RX J Inverse Compton scattering p vs. matter   0  =5e13 Naito Enomoto et al. 2002

Type-II SNR Diameter  0.8 deg. Distance  2.5 kpc Age ~2000 yr Supernova Remnant RCW86 Observed Low temperature High temperature Non-thermal Bamba et al [keV] RCW86 SW shell Image by ASCA SW shell Red: keV Blue: keV Bamba et al. 2000

Multi wavelength spectrum B < 15 µG Detectable for CANGAROO-II Radio RCW86 SW-shell SN1006 NE-rim X-ray (ASCA) SN1006 CANGAROO-II 10m Hara et al Synchrotron Inverse Compton scattering (estimated) Synchrotron emission  SN1006  10

Observation with CANGAROO observationselected ON26h 23m20h 29m OFF27h 46m18h 05m Strongest emission (E>2.0 keV) R.A. = Dec.= ( ~ 32deg.) 2001 (March, April, May) observationselected ON41h 11m30h 08m OFF38h 37m33h 49m 2002 (March, April)  Suffering from light pollution

Estimation of Threshold Energy Energy threshold [events] [TeV] Generated all Detected E th  900GeV 32 – 40 degree (relatively large) High energy threshold Monte Carlo simulation Gamma-ray photon index= GeV – 15 TeV Observation zenith angle

Imaging method SumADC-5000ch ( -1 TeV) ch (1-2 TeV) 14000ch- (2 TeV- ) Distance Length Width ADC>500(  5.4 p.e) & T4a  shower event  calculate Image Parameter

Energy > 1 TeV (ADC>5000ch) Excess events 577±125(4.6  ) Excess events -72±12 (0.6  ) Preliminary Result No excess below 1 TeV  inverse Compton scattering ? Signal  <15 deg. Normalize  >30 deg. Energy < 1 TeV (ADC<5000ch) Cosmic ray Index=2.7

Summary Supernova remnant RCW86 (emitting synchrotron X-ray) was observed with the CANGAROO-II telescope. Preliminarily, we found gamma-ray like events ~4 sigma level > 1 TeV). –We need more data to confirm this result. In this year, we took additional data. –More data (~65 hours) –High quality (Stereo observation; Enomoto OG2.5-6) High Signal/Noise ratio Lower energy region

Observation in 2003 MarchTelescope 1Telescope 2 ON 27h 29m26h 53m OFF 23h 47m20h 16m AprilTelescope 1Telescope 2 ON 42h 20m37h 41m OFF39h 36m35h 19m TotalTelescope 1Telescope 2 ON 69h 49m64h 37m OFF63h 23m55h 35m

X-ray Observation by Chandra High resolution imaging detector Soft band(<2 keV): Diffusive Hard band(>2 keV): Filament RCW86 SW shell by Chandra keV 1-2 keV 2-8 keV Soft and hard regions are completely resolved. Non-thermal Thermal Rho et al., 2002 Soft Hard filament

Nearby Molecular Cloud Red: thermal X-ray (ROSAT) Contour: molecular cloud

Multi wavelength spectrum Radio RCW86 SW-shell SN1006 NE-rim X-ray (ASCA) SN1006 CANGAROO-II 10m Hara et al Synchrotron Inverse Compton scattering (estimated) Cosmic ray Index=2.7

Energy dependence of Alpha distribution Signal  <15 Normalize  >30 Energy < 1 TeV TeV 2 TeV ±98 events 4.3  117±73 events 1.6  -72±12 events 0.6 