AGASA update

M. TeshimaICRR, U of Tokyo

@ CfCP mini workshopOct 4 2002

AGASAAkeno Giant Air Shower

Array

111 Electron Det.27 Muon Det.

0 4km

Exposures in various experiments

AGASA: Ground Array

HiRes: Air Fluorescence

Energy　 DeterminationLocal density at 600mGood energy estimator by M.Hillas

E=2x1020eV, Emin = 1.6x1020eV

Attenuation curve S(600) vs Nch

1018eV Proton

Atmospheric depth

S600 Intrinsic fluctuation for

proton and iron

Proton

Iron

Energy Determination in AGASA

Please read astro-ph/0209422

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)

Detector Simulation (GEANT)

Detector Housing (Fe 0.4mm)Detector Box (Fe 1.6mm)Scintillator (50mm)Earth (Backscattering)

vertical θ = 60deg

Detector Response

Energy spectra of shower particles

Energy Resolution Angular Resolution

AGASA

Energy Resolution

The Conversion from S600 to Energy

Time profile of shower particles

Over estimation factorDue to the shower frontthickness

Delayed particles and Over estimation factor

Major Systematics in AGASAastro-ph/0209422

Detector Detector Absolute gain ± 0.7% Detector Linearity ± 7% Detector response(box, housing) ± 5%

Energy Estimator S(600) Interaction model, P/Fe, Height -10% ±15%

Air shower phenomenology Lateral distribution function ± 7% S(600) attenuation ± 5% Shower front structure +5% ± 5% Delayed particle(neutron) +5% ± 5%

Total ±0% ± 18%

Energy Spectrum by AGASA (θ<45)

10 obs. / 1.6 exp. 4.0σ

Red -Inside ArrayGreen –Well Inside

4.6 x 1016 m2 s sr

Energy determined by Ne andEnergy determined by S600

Ne 8.5x1018eV

S600 9.3x1018eV

Akeno 1km2 and AGASA

AGASA vs HiRes (astro-ph)See new paper: Energy determination in AGASA (astro-ph/0209422)See new paper: Energy determination in AGASA (astro-ph/0209422)

AGASA & HiRes

2001 ICRC 1999 ICRC 2002 Astro-ph

Possible Systematics in HiResMost of them are energy dependent

Air Fluorescence yield Total yield is known with 10% accuracy Yields of individual lines are not known well

Rayleigh Scattering effect ( 1/λ∝ 4)

Light transmission in air Mie Scattering

Horizontal attenuation, Scale Height, Wind velocity, Temperature single model represents whole data

Horizontal 12km (1999) 25km (2001)

Cherenkov light subtractionErrors in Mono analysis

Aperture estimation (Narrow F.O.V.) Chemical composition / Interaction dependent

Arrival Direction Distribution

Arrival directions of 59events > 4 x1019eV observed by AGASA

No Large Scale Anisotropy. Event Clusters: 1Triplet and 6 doublets P(chance) ~ 0.07%.Interacting Galaxy VV141 in the direction of triplet at 100Mpc.

Arrival Direction Distribution of EHE cosmic rays

>4x1019eV

>1019eV

The distribution of Space angle between events

Suggest compact sources!!5 sigma effect

>4x1019eV >1019eV

3 sigma effect

V1-V2 plot in Galactic coordinate

Outer Galaxy region|bII|<60, 90<lII<180

Log(E)>19.00 19.15 19.70

1. From 1019eV2. Extended linearlyΔｂ

II

ΔｌII

20ox20o

The polarization angle

40 degrees

1.8 degree x 10 degree box

1019eV

Cosmic Ray propagation in Galactic Magnetic Field

By Stanev

ΔｂII

ΔｌII

Aperture

Energy spectrum of Cluster events∝E -1.8+-0.3

Cluster Component

Gamma Rays in EHECR

With 95% C.L.γ/all　 < 28% at >1019eVγ/all < 67% at >1019.5eV

Summary

Super GZK particles exist AGASA HiRes inconsistency???

Statistically consistent, but we need cross-calibration Origin of EHECR (Possible scenario)

Decay of Heavy Relics in our Halo Z-burst by EHE neutrino Violation of Special Relativity AGN’s, GRB’s or other astronomical objects

Clear evidence for point sources of EHECR

Elongated shaped excess of ~10°in 2-D correlation map Consistent with the charged particle deflection by G.M.F.The beginning of the EHECR astronomy