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1
CANGAROO-III
Masaki Mori*for the CANGAROO team
*ICRR, The University of Tokyo
ICRR internal talk, October 19, 2005
2
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
3
T2 T4 T3 T1
Woomera: 2004 March
4
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
5
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
12
Main
tenance
8
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
7
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)
8
Stereo observation
TargetIntersection
Angular resolution
0.25deg 0.1 deg
Energy resolution
30% 15%
Better S/N (no local muons)
9
Large zenith angle observation of the Crab
NARROWER
Higher energy threshold ~1TeV
Bad intersection accuracy
Far coresmall angle bad accuracy
Even
ts
ONLY
10
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
11
IP constraint fit
Blank : After IP fitHatched : Before IP fit
Telescopes
22
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
12
/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
13
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)
14
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)
15
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
16
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
17
Galactic diffuse emission
Milagro4.5 detection
18
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
19
Galactic disk scan result
No excess at the disk!
(expected ~1deg)
Preliminary
l =19.5
M. Ohishi, Ph.D. thesis
20
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
21
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
22
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
23
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)
24
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.
27
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
28
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