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Status of CANGAROO III
Akihiro Asahara ( Kyoto Univ.)CANGAROO expanded meeting
1.Introduction2.Resent Results3.Brand-new! CANGAROO T24.Stereo Analysis
Collaboration of Australia and Nippon for a GAmma Ray Observatory in the Outback
An array of imaging atmospheric Cherenkov telescopes to detect high-energy gamma-rays from celestial objects in Woo
mera, Australia
CANGAROO team
University of Adelaide Australian National Univer
sity Ibaraki University Ibaraki Prefectural Univers
ity Kanagawa University Konan University Kyoto University Nagoya University National Astronomical Ob
servatory of Japan Osaka city University
The University of Tokyo
(ICRR) Shinshu University Institute for Space and Aerona
utical Science Tokai University Tokyo Institute of Technology Yamagata University Yamanashi Gakuin University
17 institutes join this project.
Gamma-raysimulation
Protonsimulation
Observation Method
Camera image
Alpha plot
GammaProton
α distribution( simulation)
Observation Data(Crab Nebula)
OFF run
ON run
Residual
CANGAROO 10m telescope
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)
552ch PMTs
TeV gamma-ray sky ~ 2002
Grade A
Grade B
Grade C
CANGAROO FOV(El > 40 degree)
TeV sources
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 remnants
SN1006 Cas A
RX J1713.7-3946
1 X-ray Binary Cen X-3
1 Starburst galaxy NGC253
Red: Grade A
Blue: Grade B
Black: Grade C
SNR RX J1713.7-3946: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-thermalradiationfrom 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 1706-44
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 J0852-4622 SN 1987A PSR 1259-63/SS2833 PSR 1509-58 PSR 1420-6048 Vela pulsar AGN PKS 2155-304, PKS 2005-489 AGN PKS 0548-322 EXO 055625-3838.6 Galactic Center/Sgr A* Galactic jet object SS433 Galaxy The Small Magellanic Cloud EGRET un-ID 3EG J1234-1318
Other TargetsDetected
Upper limit
Positive
Signal Status
On analysis
On analysis
On analysis
On analysis
On analysis
Finished; In prep.
Finished; In prep.
Finished; In prep.
On analysis
On analysis
On analysis
On analysis
On analysis
On analysis
On analysis
Finished
CANGAROO-III project
Caution! This is prospective image.
Time schedule
’04’03
10m X 210m X 3
10m X 4
Sep 2003
EXO 0556RX J0852
StereoTargets
RCW86
SN1006PSR 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 mappingOf 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 observationEffective area → ×0.8S/N → ×6 ~ 7(Enomoto et al. 2002)
750±60 (12σ)
Present status: Three 10m telescopes in Woomera
T2 T3 T1
Started operation in Dec. 2002
Assembled in Dec. 2002
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
ADCTDC
PMT hit Scaler Star Info.
Stereo Analysis
DAQ phase I (current):Both telescopes are operatedIndependently.
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 ~ 40HzT2: trigger rate ~ 30Hz
Coincidence ~ 2Hz
T1 rate after cut ~2Hz
The Stereo trigger rate is limited by T1.
Trigger delay time
-1.0515 0.02 ns/min
-1.105 ns/min
Measured by TDC
Calculated from Telescope movement
OFF-line stereo analysis is working well.
ADC spectrum of T2
Red: ADC spectrum of T2Blue: ADC spectrum of T2
made from the data triggered by T1Pink: 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(@200GeV)
Summary
Stereo Observation Started in Dec 2002!!
•Telescope 3 will be started in Aug 2003.•Telescope 4 will be started in Dec 2003.
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.
Telescope 2 is in expected performance.
Energy threshold ~ 200GeV
Sensitivity will become ~ 0.01Crab (@200GeV, 20 hour).