agasa masahiro teshima max-planck-institut für physik, münchen, germany for agasa collaboration
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AGASAAGASA
Masahiro TeshimaMasahiro TeshimaMax-Planck-Institut fMax-Planck-Institut füür Physik, Mr Physik, Müünchen, nchen,
GermanyGermany
for AGASA collaborationfor AGASA collaboration
AGASA
Cosmic Ray Energy SpectrumCosmic Ray Energy Spectrum
P
γ3K
ΔN
π
GZK mechanism
AGASA Energy Spectrum
Super GZK part.~1/km2 century
AGASA AAkeno keno GGiant iant AAir ir SShower hower AArrayrrayoperated in 1991~2004operated in 1991~2004
111 Electron Det.27 Muon Det.
0 4km
Closed in Jan 2004
AGASA Linearity check after dismantling detectors in 2004 Feb
At Akeno Observatory Central building in 2004 Jan
AGASA Detector Calibration in AGASA experiment
Detector Gain by muons in each run
Cable delay (optic fiber cable)
Gain as a function of time(11years data)
Accuracy of 100ps by measuring the round trip time in each run
Detector Position
Survey from AirplaneΔX, ΔY= 0.1m, ΔZ= 0.3m
Linearity as a function of time(11years data)
AGASAD
ete
ctor
Sim
ula
tion
(GEA
NT-3
)Detector Housing (Fe 0.4mm)Detector Box (Fe 1.6mm)Scintillator (50mm)Earth (Backscattering)
vertical θ = 60deg
Detector Response
Energy spectra of shower particles
AGASA
EnergyEnergy DeterminationDeterminationLocal density at 600mLocal density at 600m Good energy estimator by M.HillasGood energy estimator by M.Hillas
E=2.1x1020eV
AGASA
The Highest Energy Event The Highest Energy Event 2.5 x102.5 x102020eV on 10 May 2001eV on 10 May 2001
AGASA
Attenuation curveAttenuation curveS(600) vs Nch
1018eV Proton
Atmospheric depth
AGASA
S6
00
Intr
insi
c fluct
uati
on
Proton
Iron
AGASA
Energy ResolutionEnergy Resolution
30% 25%
mainly due to measurement errors (particle density measurement and core location determination)not due to shower fluctuation
AGASA The Conversion from S600 to Energy
Muon/Neutrino
Ele. Mag
AGASA Major Systematics in AGASAMajor Systematics in AGASAastro-ph/0209422astro-ph/0209422
DetectorDetector Detector Absolute gainDetector Absolute gain ±± 0.7% 0.7% Detector LinearityDetector Linearity ±± 7% 7% Detector response(box, housing)Detector response(box, housing) ±± 5% 5%
Energy Estimator S(600)Energy Estimator S(600) Interaction model, P/Fe, HeightInteraction model, P/Fe, Height ±±15%15%
Air shower phenomenologyAir shower phenomenology Lateral distribution functionLateral distribution function ±± 7% 7% S(600) attenuationS(600) attenuation ±± 5% 5% Shower front structureShower front structure ±± 5% 5% Delayed particle(neutron)Delayed particle(neutron) ±± 5% 5%
TotalTotal ±± 20% 20%
AGASA
Energy Spectrum by AGASA (θ<45)
11 obs. / 1.3~2.6 exp.
5.1 x 1016 m2 s sr
AGASA Critical review of energy Critical review of energy estimation and spectrumestimation and spectrum
Acceptance of ArrayAcceptance of Array AGASA fast simulation (based on empirical formula and toy simuAGASA fast simulation (based on empirical formula and toy simu
lation)lation) Based on CORSIKA M.C.Based on CORSIKA M.C. Essentially acceptance is saturated Essentially acceptance is saturated No difference No difference
Lateral distribution of showersLateral distribution of showers Lateral distribution determined by experimentLateral distribution determined by experiment Lateral distribution estimated by Corsika M.C.Lateral distribution estimated by Corsika M.C. No differenceNo difference
Attenuation of S(600)Attenuation of S(600) Attenuation curve determined by experimentAttenuation curve determined by experiment Attenuation curve estimated by Corsika M.C.Attenuation curve estimated by Corsika M.C. There is systematic difference of 10-20%There is systematic difference of 10-20%
AGASA S600 attenuation with recent CorS600 attenuation with recent Corsikasika
Overestimation factorcompared with Corsika
We are very close to S600 maximum at 1020eV
AGASA Preliminary spectra with recent CoPreliminary spectra with recent Corsikarsika
No difference in Models and Compositions
Energy shift to lower direction~10% at 1019eV~15% at 1020eV
Above 1020eV11events 5~6 events
Featureless spectrumvery close to E-3
P-SIBYLL (above 1019eV)γ = 2.95 ±0.08 (χ2 / NDF = 8.5/11)
Fe-QGSJET (above 1019eV)γ = 2.90 ± 0.08(χ2 /NDF = 8.5/11)
~10%
~15%
AGASAArrival Direction Distribution >4x10Arrival Direction Distribution >4x101919eVeV
zenith angle <50deg.zenith angle <50deg.
Isotropic in the large scale Isotropic in the large scale Extra-Galactic origin Extra-Galactic originBut, Clusters in small scale (But, Clusters in small scale (ΔθΔθ<<2.5deg)2.5deg)
1triplet and 6 doublets (2.0 doublets are expected from random)1triplet and 6 doublets (2.0 doublets are expected from random)
AGASA Space Angle Distribution of Arbitrary Space Angle Distribution of Arbitrary two events >4x10two events >4x101919eVeV
Normalized sigma
3.2 sigma excess
AGASA
Arrival Direction Distribution >10Arrival Direction Distribution >101919eVeV
AGASAS
pace
An
gle
S
pace
An
gle
D
istr
ibu
tion
Dis
trib
uti
on
Log E>19.6 Log E>19.4
Log E>19.2 Log E>19.0
AGASA
AGASA Triplet + HiResAGASA Triplet + HiRes
These events are on the supergalactic plane
Arp299: 40MpcColliding galaxy
NGC3610: 33MpcMerger Remnant
NGC3613: 36MpcAGN Remnant
MAGIC made the observationof these objects,Results will come in ICRC07
AGASA
ρρμμ(1000) distribution(1000) distribution
AGASA
SummarySummary
Super GZK particlesSuper GZK particles Preliminary study with recent CORSIKAPreliminary study with recent CORSIKA
If we evaluate energies with the recent CORSIKAIf we evaluate energies with the recent CORSIKA Energy scale shift down by ~10% at 10Energy scale shift down by ~10% at 101919eV and by ~15% at 10eV and by ~15% at 102020
eVeV 11 events above 1011 events above 102020eV / 1.3~2.6 expected eV / 1.3~2.6 expected
5~6 events / 1.0~1.9 expected 5~6 events / 1.0~1.9 expected
Small scale anisotropy of UHECRSmall scale anisotropy of UHECR The arrival direction of UHECRs is uniform in large scaThe arrival direction of UHECRs is uniform in large sca
lele But AGASA data shows clusters, 1 triplets and 6 doublBut AGASA data shows clusters, 1 triplets and 6 doubl
ets ets granularity granularity Source density ~10Source density ~10-5-5/Mpc/Mpc3 3 ~ density of AGNs ~ density of AGNs