Status of CANGAROO III 1.Introduction 2.Resent Results 3.Brand-new! CANGAROO T2 Akihiro Asahara ( Kyoto Univ.) 4.Stereo Analysis CANGAROO expanded meeting 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 � The University of Tokyo � Australian National (ICRR) University � Shinshu University � Ibaraki University � Institute for Space and � Ibaraki Prefectural Aeronautical Science University � Tokai University � Kanagawa University � Tokyo Institute of Technology � Konan University � Yamagata University � Kyoto University � Yamanashi Gakuin University � Nagoya University � National Astronomical 17 institutes join this project. Observatory of Japan � Osaka city University Observation Method Gamma-ray Proton simulation simulation Camera image
Observation Data Alpha plot (Crab Nebula) α distribution （ simulation ） ON run OFF run Residual Gamma Proton CANGAROO 10m telescope 552ch PMTs � Upgraded to 10m in 2000 � 114 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)
TeV gamma-ray sources ~ 2002 (l,b) Grade A (>5sigma, multiple) CANGAROO FOV Grade B (>5sigma) (El > 40 degree) Grade C (strong but with some qualifications) Red: Grade A TeV sources Blue: Grade B Black: Grade C 3 Pulsar nebulae Crab Vela PSR 1706-44 8 Blazars Mrk 421 Mrk501 1ES2344+514 PKS2155-304 3C66A BL Lac 1H1426+428 1ES1959+65 3 Supernova SN1006 Cas A remnants RX J1713.7-3946 1 X-ray Binary Cen X-3 1 Starburst galaxy NGC253
SNR RX J1713.7-3946: emission from protons? Hard to explain by emission from electrons (Brems, IC) ⇒ Emission from protons( π 0 )? ⇒ Cosmic ray origin? Enomoto et al. Nature 2002 Starburst galaxy NGC 253 Multi-wave-length spectrum of Galactic Halo Radio Itoh et al. A&AL 2002 Non-thermal radiation Itoh et al. ApJL 2003 from Galactic Halo Optical � New kind of TeV source � Similar in size to our own galaxy � Nearby spiral galaxy (2.4Mpc) � Broad emission region. CANGAROO
Mrk 421: hint for cosmology? 5TeV Okumura et al. ApJL 2002 Gamma-ray Emission above 20 TeV Fewer IR background photons? Cosmology: galaxy formation PSR 1706-44 � 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. The magnetic field is too week. Nebula ～ 10arcsec Chandra ACIS Image (0.7-9 keV) Kushida, 2003, Ph. D thesis, Tokyo Inst. of Tech.
Detected Positive Other Targets Upper limit Signal Status � SNR/Pulsar Crab Finished � SNR SN 1006 On analysis � SNR RCW 86 On analysis � SNR RX J0852-4622 On analysis � SN 1987A Finished; In prep. � PSR 1259-63/SS2833 Finished; In prep. � PSR 1509-58 On analysis � PSR 1420-6048 On analysis � Vela pulsar On analysis � AGN PKS 2155-304, PKS 2005-489 Finished; In prep. � AGN PKS 0548-322 On analysis � EXO 055625-3838.6 On analysis � Galactic Center/Sgr A* On analysis � Galactic jet object SS433 On analysis � Galaxy The Small Magellanic Cloud On analysis � EGRET un-ID 3EG J1234-1318 On analysis CANGAROO-III project Caution! This is prospective image.
Time schedule 10m X 2 10m X 3 10m X 4 Observation Sep 2003 EXO 0556 RX J0852 RCW86 Stereo SN1006 Targets PSR 1706, RXJ 1713 ’04 ’03 Stereo observation � Better angular resolution ∆θ =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) Angular resolution is improved. � Single Telescope ~0.25deg (one month observation) 0.05 deg (Stereo) � 10m X 2 Stereo Telescope ~ 0.15deg ( event by event ) ~ 0.05deg , or better than that!! (one month observation) TeV γ -rays from shell-type SNRs 0.25 deg (Single) Detailed mapping Of the emission region SN1006 significance map (CANGAROO 10m single) Merit of Stereo (2) Alpha <15 ゜ Useful to noise reduction 952 ± 137events(6.9 σ ) Stereo observation Effective area → × 0.8 S/N → × 6 ～ 7 (Enomoto et al. 2002) 750 ± 60 (12 σ ) 0.45<E(TeV)<6.25
Present status: Three 10m telescopes in Woomera Started operation in Assembled in In operation Dec. 2002 since 2000 Dec. 2002 Second Telescope Third Telescope First Telescope (CANGAROO T2) (CANGAROO T3) (CANGAROO T1) Second 10m telescope (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 rate after cut ~2Hz T1: trigger rate ~ 40Hz T2: trigger rate ~ 30Hz Coincidence ~ 2Hz The Stereo trigger rate is limited by T1. Trigger delay time -1.0515 ± 0.02 ns/min Measured by TDC -1.105 ns/min 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 The sample of stereo events TDC ADC (hit timing) (light intensity) T1 T2
Sensitivity of CANGAROO III 0.01Crab (@200GeV) Typical Observation time (ON-OFF total): 8 0 h/ m onth Summary Stereo Observation Started in Dec 2002!! Second Telescope is in expected performance. Energy threshold ~ 200GeV •Telescope 3 will be started in Aug 2003. •Telescope 4 will be started in Dec 2003. Sensitivity will become ~ 0.01Crab (@200GeV, 20 hour). CANGAROO team published 3 papers in 2002. •RXJ1713 (Enomoto et al. , Nature) •NGC253 (Itoh et al. , A&A) •Mrk 421 (Okumura et al. , ApJ) And we have several papers in prep.
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