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).