Status of CANGAROO III Akihiro Asahara ( Kyoto Univ.) CANGAROO expanded meeting 1.Introduction 2.Resent Results 3.Brand-new! CANGAROO T2 4.Stereo Analysis

C ollaboration of A ustralia and N ippon for a GA mma R ay O bservatory in the O utback An array of imaging atmospheric Cherenkov telescopes to detect high- energy gamma-rays from celestial objects in Woomera, Australia

CANGAROO team University of Adelaide Australian National University Ibaraki University Ibaraki Prefectural University Kanagawa University Konan University Kyoto University Nagoya University National Astronomical Observatory of Japan Osaka city University The University of Tokyo (ICRR) Shinshu University Institute for Space and Aeronautical Science Tokai University Tokyo Institute of Technology Yamagata University Yamanashi Gakuin University 17 institutes join this project.

Gamma-ray simulation Proton simulation Observation Method Camera image

Alpha plot Gamma Proton α distribution （ simulation ） Observation Data (Crab Nebula) OFF run ON run Residual

CANGAROO 10m telescope Upgraded to 10m in x 80cm CFRP mirror segments (first plastic-base mirror in the world!) Focal length 8m Alt-azimuth mount 552ch imaging camera Charge and timing electronics (March 2000) 552ch PMTs

TeV gamma-ray sky ~ 2002 Grade A Grade B Grade C CANGAROO FOV (El > 40 degree)

TeV sources 3 Pulsar nebulaeCrab Vela PSR BlazarsMrk 421 Mrk501 1ES PKS C66A BL Lac 1H ES Supernova remnants SN1006 Cas A RX J X-ray BinaryCen X-3 1 Starburst galaxyNGC253 Red: Grade A Blue: Grade B Black: Grade C

SNR RX J : emission from protons? Hard to explain by emission from electrons (Brems, IC)  Emission from protons(  0 )?  Cosmic ray origin? Enomoto et al. Nature 2002

Starburst galaxy NGC 253 New kind of TeV source Similar in size to our own galaxy Nearby spiral galaxy (2.4Mpc) Broad emission region. Itoh et al. A&AL 2002 Radio CANGAROO Non-thermal radiation from Galactic Halo Optical Multi-wave-length spectrum of Galactic Halo Itoh et al. ApJL 2003

Mrk 421: hint for cosmology? Fewer IR backgroun photons? Okumura et al. ApJL 2002 Emission above 20 TeV Cosmology: galaxy formation 5TeV

Peak intensity of detected TeV gamma-ray flux becomes ten times stronger than that of X-ray flux from the nebula. TeV gamma-ray flux is difficult to explain by Sync-IC (2.7k CMB) model in the nebula. ～ 10arcsec Chandra ACIS Image (0.7-9 keV) Nebula PSR Kushida, 2003, Ph. D thesis, Tokyo Inst. of Tech. The magnetic field is too week.

SNR/Pulsar Crab SNR SN 1006 SNR RCW 86 SNR RX J SN 1987A PSR /SS2833 PSR PSR Vela pulsar AGN PKS , PKS AGN PKS EXO Galactic Center/Sgr A* Galactic jet object SS433 Galaxy The Small Magellanic Cloud EGRET un-ID 3EG J Other Targets Detected Upper limit Positive Signal Status On analysis Finished; In prep. On analysis Finished

CANGAROO-III project Caution! This is prospective image.

Time schedule ’04 ’03 10m X 2 10m X 3 10m X 4 Sep 2003 EXO 0556 RX J0852 Stereo Targets RCW86 SN1006 PSR 1706, RXJ 1713 Observation

Stereo observation Better angular resolution  =0.25  (One month observation)  0.15  (event by event) Better energy resolution  E/E=30%  15% And improvement of S/N ratio.

Merit of Stereo (1) 0.25 deg (Single) 0.05 deg (Stereo) SN1006 significance map (CANGAROO 10m single) TeV  -rays from shell-type SNRs Detailed mapping Of the emission region Angular resolution Single Telescope ~0.25deg (one month observation) 10m X 2 Stereo Telescope ~ 0.15deg (event by event) ~ 0.05deg, or better than that!! (one month observation)

Alpha <15 ゜ 952±137events(6.9σ) 0.45<E(TeV)<6.25 Merit of Stereo (2) Stereo observation Effective area → ×0.8 S/N → ×6 ～ 7 (Enomoto et al. 2002) 750±60 (12σ)

Present status: Three 10m telescopes in Woomera T2 T3 T1 Started operation in Dec Assembled in Dec In operation since 2000

10m telescope No.2 (CANGAROO T2) Completed in 2002 Focal length 8m Improved FRP mirror segments 427ch imaging camera Placed Hex; FOV 4.0 HV imposed on each PMTs 4.0°

T2 event samples ADC TDC PMT hit Scaler Star Info.

Stereo Analysis DAQ phase I (current): Both telescopes are operated Independently. Attached information on T2 data: Trigger delay time (1nsec resolution). Current event number of T1. Stereo analysis is conducted on off-line.

Stereo Trigger rate T1: trigger rate ~ 40Hz T2: trigger rate ~ 30Hz Coincidence ~ 2Hz T1 rate after cut ~2Hz The Stereo trigger rate is limited by T1.

Trigger delay time  0.02 ns/min ns/min Measured by TDC Calculated from Telescope movement OFF-line stereo analysis is working well.

ADC spectrum of T2 Red:ADC spectrum of T2 Blue:ADC spectrum of T2 made from the data triggered by T1 Pink:Power law function (index -2.7) Eth(blue) / Eth(red) ~ 4 T2 Energy threshold ~ 200GeV

Stereo Events Distribution of Arrival directions (not ready) TDC (hit timing) ADC (light intensity) T1 T2

Sensitivity of CANGAROO III Typical Observation time (ON-OFF total): 80h/month 0.01Crab

Summary Stereo Observation Started in Dec 2002!! Telescope 3 will be started in Aug Telescope 4 will be started in Dec CANGAROO team published 3 papers in RXJ1713 (Enomoto et al., Nature) NGC253 (Itoh et al., A&A) Mrk 421 (Okumura et al., ApJ) And we have several papers in prep. Telescope 2 is in expected performance. Energy threshold~ 200GeV Sensitivity will become~ 0.01Crab 20 hour).