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CANGAROO-III

Masaki Mori*for the CANGAROO team

*ICRR, The University of Tokyo

ICRR internal talk, October 19, 2005

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CANGAROO team University of Adelaide Australian National University Ibaraki University Ibaraki Prefectural University Konan University Kyoto University STE Lab, Nagoya University National Astronomical Observ

atory of Japan

Kitasato University Shinshu University Institute of Space and Astro

nautical Science Tokai University ICRR, University of Tokyo Yamagata University Yamanashi Gakuin Universit

y

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T2 T4 T3 T1

Woomera: 2004 March

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Basic specifications of telescopes

T2 Location: 3106’S, 13647’E 160m a.s.l.

Telescope: 114 80cm FRP mirrors (57m2, Al surface) 8m focal length Alt-azimuth mount

Camera: T1: 552ch (2.7 FOV) T2,T3,T4: 427ch (4 FOV)

Electronics: TDC+ADC

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History of CANGAROO-III

: Construction

: Observation start

: Expansion to 10m

: Observation: Tuning

T1

T2

T3

T4

20001999 2001 2002 2003 2004

3 311 12 731 6

Ste

reo o

bse

rvati

on

2005

Glo

bal tr

igger

syst

em

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Main

tenance

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6

Global trigger systemd

100m

t=d/c < 500nsvariable

Coincidence

Opt.fiber

650ns

Event number

Trigger

Tele

scop

es

Turnaround~2.5s

Wait time~5s

Tele

scop

es

Opt.fiber

Trigger

Before: “software trigger” Each telescopes triggered

independently Now: “hardware stereo”

Requires at least 2 telescopes If no coincidence Reset

Dead time 1/100

150m

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ICRC2005 contributed papers K. Nishijima: Status of the CANGAROO-III Project (OG27, oral) T. Tanimori: Recent status of the analyses for stereoscopic observations wit

h the CANGAROO-III telescopes (OG22, oral) Y. Sakamoto: Search for Very High Energy Gamma-Rays from Active Galactic

Nuclei with CANGAROO-III Telescope (OG23, poster) S. Kabuki: Observation of TeV Gamma-ray from the Active Radio Galaxy Cent

aurus A with CANGAROO-III (OG23, poster) T. Yoshikoshi: Performance of the Imaging Atmospheric Cherenkov Telescop

e System of CANGAROO-III (OG27, poster) M. Ohishi: Very high energy gamma-ray observations of the Galactic plane wi

th the CANGAROO-III telescopes (OG21, oral) R. Kiuchi: Optical measurements by cooled CCD cameras for CANGAROO-III

(OG27, oral) T. Nakamori: Stereoscopic observations with the CANGAROO-III telescopes a

t the large zenith angles (OG22, oral)

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Stereo observation

TargetIntersection

Angular resolution

0.25deg 0.1 deg

Energy resolution

30% 15%

Better S/N (no local muons)

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Large zenith angle observation of the Crab

NARROWER

Higher energy threshold ~1TeV

Bad intersection accuracy

Far coresmall angle bad accuracy

Even

ts

ONLY

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Unfortunate situation for the Crab

Showers from the Crab

The oldest T1 has higher energy threshold and bad efficiency for stereo observation

Only T2/T3/T4 are used for stereo analysis

Stereo baseline becomes short for the Crab observation at large zenith angles

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IP constraint fit

Blank : After IP fitHatched : Before IP fit

Telescopes

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2 Armlength)Armlength()Width(

ARMw

x,yx,y

Search intersection point (IP) by minimizing 2 so that width along shower axis to be minimum and armlength to be near the expected value (<Armlength>=0.75, Mesh size 0.025o)

Monte Carlo

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/h separation by Fisher discriminant

Linear combination of image parameters (xi)

Difference between signal () and background (h)

Determine i which maximize separation (solvable using correlation matrix)

With calculated i for a known source, the (appropriately normalized) combination F could be the “Fisher discriminant” for other sources.

We use widths and lengths of multiple telescopes for image parameters.

i iixF

hFFD

22)(/ DDDS

R.A. Fisher, Annals of Eugenics, 7 (1936) 179

F

D

h

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Crab signal (3)

•T2 & T3

•890 min (Dec.2003)

Points: On-source

Hatched: Off-source

Plot : observationSolid : MC gammaDashed : background

IP fit +F > 0

203 excess events5.8 sigma

R.Enomoto et al., ApJ in press (2005)

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Crab spectrum

Preliminary10-12

10-13

Flux (

cm-2s-

1)

1 2 5 10 20Energy (TeV)

HEGRA

Excess event map

Angular resolution ~ 0.23 deg

R.Enomoto et al., ApJ in press (2005)

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Cen A: the nearest AGN

No signal seen

S. Kabuki, Ph.D. thesis

Preliminary

Observation term

Observation time (T2-T3)

Observation time (T2-T4)

Average zenithangle

15 – 28 Mar 2004

603 min 414 min 17 degree

15 – 28 Apr 2004

444 min 468 min 17 degree

Total 1047 min 882 min

•Elliptical •Radio galaxy•Fanaroff-Riley type I•“Misaligned” BL Lac (~ 60o)•Distance 3.5 Mpc (z=0.00183)

Near infrared image2MASS1.2-2.17m

CANGAROO-III Angular resolution

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Cen A: flux limit

Energy bin (GeV) 530 700 1120

2 upper limit flux(10-12cm-2sec-1)

3.2 1.8 0.9

Preliminary

CrabUpper limit:

~7% Crab

Note that this is a highly variable source, and the TeV claim in 70’s was based on observations during its flaring activity.

CANGAROO-III

S. Kabuki, Ph.D. thesis

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Galactic diffuse emission

Milagro4.5 detection

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Observation of the Galactic disk

Obs.term tel.pair b=0 b=-3 b=+3

2004Jun T2-T3 635.3 322.3 292.9

2004Jun T2-T4 380.0 201.9 192.5

Obs.term tel.pair ON OFF

2004Jun T2-T3 289.6 340.0

2004Jun T2-T4 199.5 270.0

2004Aug T2-T3 224.9 183.6

2004Aug T2-T4 280.0 85.7

l=-19.5 2004Jun

l=+13 2004Jun/Aug

(Obs.time in minutes)

T2-T3

T2-T4

EL>45deg

Eth ~600 GeV

M. Ohishi, Ph.D. thesis

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Galactic disk scan result

No excess at the disk!

(expected ~1deg)

Preliminary

l =19.5

M. Ohishi, Ph.D. thesis

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SNR RX J0852.0-4622 [stereo]

Excess event map

•T2 & T3 wobble

•1,204 min. (2004 Jan/Feb)

•Off region: Vela or out of SNR

2 from SNR center

Fisher discriminant

ON OFF

R.Enomoto et al., to be submitted

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SN1006 [stereo]•NE-rim pointing (2004 May)

•T2, T3 & T4 long ON/OFF

•1,625 min. ON, 1,738 min. OFF

•T2 & T3 results on likelihood

•Independent analysis (Fisher disc.)

Gamma-ray energy (TeV)

T.Tanimori et al., ICRC2005

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PSR 1706-44 [stereo]•Pulsar pointing (2004 May)

•T2, T3 & T4 long ON/OFF

•1,625 min. ON, 1,738 min. OFF

•T2 & T3 results on square cut

•Independent analysis (Fisher disc.)

T.Tanimori et al., ICRC2005

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Vela [stereo]•Pulsar pointing (2004 Jan/Feb)

•T2 & T3 wobble, 1,311 min.

•Fisher discriminant

Pulsar position

2 from Vela X center

Vela X nebula

(HESS, ICRC2005)

R.Enomoto et al., ApJ in press (2005)

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Summary We have been carrying out stereo observations of sub-Te

V gamma-rays since 2004 March. Stereo analysis are developed and the flux of the Crab is

consistent with other results. Upper limits were set for gamma-rays from Cen A and the

Galactic disk. The extended profile of SNR RX J0852.0-4622 is observe

d. Preliminary results on SN1006, PSR 1706-44 and Vela p

ulsar show no gamma-ray signal.

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CANGAROO-I results: summary

SNR/Pulsar Crab ApJL’94 SNR SN1006 ApJL’98 SNR RX J1713.7-3946 A&AL’00 SNR W28 A&A’00 Pulsar PSR 1706-44 ApJL’95 Pulsar Vela ApJL’97 Pulsar PSR 1509-58 ApJ’00 Pulsar PSR 1055-52 (Ph.D.’97) AGNs: PKS0521-365, EXO0423.4-0840, PKS0548-322, PKS2316-423

A&A’98 Blazars: PKS2005-489 and PKS2155-304

A&A’99 Radio galaxy Cen A (Proc.’99)

Signal Publish

Signal: detected, upper limit, marginal, v: variable

H.E.S.S.

v

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CANGAROO-II results: summary

SNR RX J1713.7-3946 Nature’02 Blazar Mrk421 ApJL’02 Starburst galaxy NGC253 A&AL’03 SNR SN1987A ApJL’03 Galactic Center ApJL’04 Pulsar binary PSR 1259-63/SS2883 ApJ’04 SNR RX J0852.0-4622 (Vela Jr.) ApJL’05

Signal Publish

Signal: detected, upper limit, v: variable

H.E.S.S.v