The Highest Energy Particles

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The Highest Energy Particles

Angela V. Olinto The University of Chicago
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Nature sends 1020 eV particles
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New Era of Charged Particle Astronomy
Pierre Auger Observatory observed anisotropic sky
at the Highest Energies through correlation
between UHECRs and catalog of nearby Active
Galactic Nuclei (AGN)
Top discovery of 2007 in the Physical
Sciences (by Science Magazine)
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Chargeless vs ChargedCosmic Particles

• Photons
• 1600s Galileo Galilei
• Neutrinos Gravitons
• Solar 2008
• SN87a
• 2008

Cosmic Rays 1912 Victor Hess
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Chargeless vs ChargedCosmic Particles

• Photons
• 1600s Galileo Galilei
• Neutrinos Gravitons
• Solar 2008
• SN87a
• 2008

Cosmic Rays 1912 Victor Hess
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Known unknown
Cosmic Magnetic Fields
RL kpc Z-1 (E / EeV) (B / ?G)-1 EeV1018
eV RL Mpc Z-1 (E / EeV) (B / nG)-1
?
Extra-galactic B? B lt nG
weak deflection
E gt 1019eV
strong deflection
Halo B?
E lt 1018eV
Milky way B ?G
kpc
10 kpc
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Chargeless vs Charged_at_ Highest Energies

• Photons
• 1600s
• G. Galilei

Cosmic Rays 1912 V. Hess
Attenuation Length
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Brief History of UHECRs detection

• 1961 Volcano Ranch - John Linsley - a 1020 eV
  event
• 1 Linsley 1 km2 sr yr L
• 1965 CMB 1966 Greisen, Zatsepin, Kuzmin
• cosmologically meaningful termination
• 1960-1990s Haverah Park, SUGAR, Yakutsk arrays
• 102 L
• 1990- 2006 AGASA array, Flyes Eye, HiRes
  fluorescence
• 103 L
• 2008 Auger South completed
• 104 L to 105L
• 2010 Auger North, JEM-EUSO
• 106L - GOAL

UHECRs Ultra High Energy Cosmic Rays, E gt 1018
eV EeV
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High Energy Cosmic Rays

• OBSERVABLES
• Spectrum
• Composition
• Sky Distribution

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CR arrival directions(E lt 60 EeV)

• Isotropic!

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High Energy Cosmic Rays

• OBSERVABLES
• Spectrum
• Composition
• Sky Distribution

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Cosmic RaySpectrum
Ecm PeV (Euhecr /ZeV)1/2 (2A)1/2

• Non-thermal Phenomena
• Extreme Accelerators
• Emax gt 1020 eV
• Features
• knee, ankle, GZK cutoff
• accelerators
• propagation
• interactions

E-2.7
32 orders of magnitude
E-3.1
Ankle (1 particle /km2 yr)
Tevatron
RHIC
LHC
12 orders of magnitude
Swordy 02
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• knee

ankle
Engel08
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Each Energy range tells its story

• 108 eV lt E lt 1011 eV
• - Solar Modulation
• 1011eV lt E lt 1017.5-18.5? eV
• - Galactic Propagation
• 1017-19eV lt E lt 10 20 - 2? eV
• - Extragalactic Sources

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Galactic Accelerators

• E lt 1017.5-18.5? eV
• Galactic Propagation
• Galactic Sources?

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SNR1006
Tycho SN
CHANDRA NASA/CXC/SAO
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HESS - TeV ?s !
smoking guns of CR acceleration
RX J1713 - 20 ?
Gamma-rays
X-rays
CHANDRA
Hinton, WatsonFest, Leeds
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Galactic Accelerators
Ecm PeV (Euhecr /ZeV)1/2 (2A)1/2

• E lt 1017.5-18.5? eV
• - Galactic Propagation

Ankle (1 particle /km2 yr)
SNR shock acceleration in the Galaxy?
?
HESS SNe
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Extragalactic Accelerators

• 1017-18eV lt E lt 10 20 - 2? eV
• Extragalactic Sources

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Extragalactic Accelerators
Ecm PeV (Euhecr /ZeV)1/2 (2A)1/2

• Extreme Accelerators
• Emax gt 1020 eV

E-2.7
E-3.1
Ankle (1 particle /km2 yr)
Extragalactic Accelerators?
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Challenging Accelerators
to reach 1020 eV LHC magnetic field,radius
107 km (Sun - Mercury)
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E Ze B L

• 10 efficiency
• 1020eV Protons
• 1020eV Iron

B(G)
L(cm)
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E Ze B L

• 10 efficiency
• 1020eV Protons
• 1020eV Iron

Sources?
B(G)
Sources?
L(cm)
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E Ze B L

• 10 efficiency
• 1020eV Protons
• 1020eV Iron

GRBs
B(G)
others
L(cm)
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Ultra High Energy Cosmic Ray Accelerators?

Galaxy Jets from Black Holes?
Gamma Ray Bursts?
Neutron Stars? Magnetars?
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Highest Energies
Ecm PeV (Euhecr /ZeV)1/2 (2A)1/2

• Pointing
• Feature

E-2.7
E-3.1
Ankle (1 particle /km2 yr)
Tevatron
RHIC
LHC
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Cosmologically Meaningful Termination
p?cmb? ? ? p ?0 ? n ?
Proton Horizon 1020 eV

• GZK Cutoff
• Greisen, Zatsepin, Kuzmin
• 1966

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Proton Attenuation length
ee
?
Attenuation length
Interaction length
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Energy loss Features for protons
Berezinsky et al. 03
redshift
pair
GZK
modification factor Jobs (E,z) ?(E,z) x
Jinjec(E)
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GZK Feature
E-2.7
E-3.1
Ankle (1 particle /km2 yr)
Cosmologically Meaningful Feature
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AGASA (1984-2003) 100 km2 area, 111
scintillators, 1km spacing
High Resolution Flys Eye (1997-2006) 2
fluorescence telescopes
1998
Consistent w/ GZK cutoff
No GZK cutoff
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GZK Effect

• ? Spectral Feature
• LSS
• ? Anisotropic Sky Distribution

? Particle Astronomy!!!
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Horizon - observed Protons
AO, Armengaud, Allard, Kravtsov 07
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Horizons
1019 eV 1 Gpc
Gpc
100 Mpc
1020 eV lt 100 Mpc
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THE SLOAN GREAT WALL
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Protons with gt 1019.5 eV
AO, Armengaud, Allard, Kravtsov 07
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Protons with gt 1020.5 eV
AO, Armengaud, Allard, Kravtsov 07
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Charged Particle Astronomy

• Window of opportunity
• 1019 to 1021 eV
• Maximize the Statistics in this window

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The Pierre Auger Observatoryof Ultra-High Energy
Cosmic Rays
Northern site
gt 300 PhD scientists from gt 70 Institutions and
17 countries
20 000 km2
Argentina Australia Brasil Bolivia Czech
Republic France Germany Italy Mexico Netherl
ands Poland

• Portugal
• Slovenia
• Spain
• UK
• USA
• Vietnam
• Associate Countries

3 000 km2
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The First Hybrid UHECR Observatory
HIGH QUALITY
LARGE QUANTITY
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Auger South
1660 tanks in a 3,000 km2 Surface Array 4
Fluorescence Detector Sites
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The Surface Detector Array
1662 deployed 1639 filled 1619 taking data
of the 1660 tanks, 3,000km2
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surface detector
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tanks aligned seen from Los Leones
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Auger SD station
Cherenkov water tank
Comms antenna
GPS antenna
Solar panel
PMT
battery
Diffusive white liner
Plastic tank
12 m3 of clean water
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Tank 1660
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Example Event 1 A moderate angle event
762238Zenith angle 48º, Energy 70 EeV
Flash ADC traces
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Example Event 2 A high zenith angle event -
787469Zenith angle 60º, Energy 86 EeV

Lateral density distribution
Flash ADC traces
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photons
electrons/positrons
muons
neutrons
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view of Los Leones Fluorescence
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corrector lens (aperture x2)
segmented spherical mirror
aperture box shutter filter UV pass safety curtain
440 PMT camera 1.5 per pixel
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4 times 6 telescopes overlooking the site
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A Hybrid Event
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Hybrid Era

• HYBRID SD only FD only
• Energy A M indep depend independ
• Aperture E, A, M indep independ depend
• Angular 0.2o 1-2o 3-5o
• Resolution

E energy, A mass, M hadronic model
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1st - 4 Fold Hybrid Event
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Cosmic RaySpectrum
E-2.7
E-3.1
Ankle (1 particle /km2 yr)
Cosmologically Meaningful Feature
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Energy spectrum from SD showers with ? 60
5165 km2 sr yr 0.8 full Auger year
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Energy spectrum from SD showers with ? 60
Slope -2.62 0.03
Exp. Obs. gt1019.6 eV
132 9 51 gt 1020 eV 30 2.5 2
significance 6?
5165 km2 sr yr 0.8 full Auger year
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ankle
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AGASA
High Resolution Flys Eye
AUGER 08
HiRes 2008
Consistent w/ GZK cutoff
No GZK cutoff
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Spectrum facts

• There is an ankle

There is a cut-off
Galactic/Extragalactic transition?
GZK suppression?
or
or
Pair-production of pure-proton source?
Limit of the acceleration process? Emax
analyse composition!
analyse arrival directions!
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Composition Spectrum
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Auger South Low Energy Extension
HEAT High Elevation Angle Telescopes
AMIGA Auger Muon and Infill Ground Array
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Telescope Array
Millard County Utah/USA
Aperture 1.4 103 km2 sr
24 x 24 Scintillators (1.2 km spacing) 900
km2 0.3 Auger South
3 x Fluorescence Stations AGASA x 10 by stereo
Low Energy Hybrid Extension
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• knee

ankle
Engel08
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High Energy Cosmic Rays

• OBSERVABLES
• Spectrum
• Composition
• Sky Distribution

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Composition-sensitive observables

• Depth of shower maximum development Xmax

high E
high E
low E
atmospheric depth (g/cm2)
low A
high A
large fluctuations
small fluctuations
Stochastic process
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Composition observable shower maximum
Expectations from different hadronic models
fluctuations in Xmax smaller for heavier nuclei
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Shower maximum over 2 decades in E
fluctuations in Xmax to be exploited
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Horizons for Etot60 EeV
Allard et al 08
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Ecr 60 EeV, ECMB for photodisintegrating ?
Lorentz ?, hence on A Minimum CMB Photon Energies
for He, CNO, and Fe
frequency (1/cm) 5 10
15 20
He CNO
Fe
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Observed Composition
Allard et al 07
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Shower maximum over 2 decades in E
fluctuations in Xmax to be exploited
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Shower maximum over 2 decades in E
fluctuations in Xmax to be exploited
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Comparison with previous studies
Large number of events allows good control and
understanding of systematics
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Photon limit
Top-down models predict large UHE photon flux
SHDM models decay of super-heavy dark matter
accumulated in Galactic halo
Showers at E 1019 eV, ? 0º
TD models supermassive particle decay from
topological defect interaction or annihilation

• Photon-induced showers
• look very different

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Constraints on Super-Heavy Dark Matter as sources
of UHECRs
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Auger results (photon limit)
Super heavy dark matter (SHDM) models are
excluded as UHECR sources!
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Constraints on topological defects as sources of
UHECRs
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Auger results (photon limit)
Topological defects (TD) are still possible UHECR
sources
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Auger results
TD models closer to be constrained by Auger
neutrino limits
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Cosmologically Meaningful Termination
p?cmb? ? ? p ?0 ? n ?

• ?0 ? ? ?
• n ? p e- ?e
• ? ? ? ??
• ? ? e ?e ??

GZK, Photopion, or Cosmogenic Neutrinos and
Photons
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Neutrino fluxes Proton Mixed
Emax
Allard et al 06
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p?cmb? ? ? p ?0 ? n ? n ?
p e- ?e ? ? ? ?? ? ?
e ?e ??
Cosmogenic Neutrinos
Bigas Cazon 06
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High Energy Cosmic Rays

• OBSERVABLES
• Spectrum
• Composition
• Sky Distribution

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Auger anisotropy results

• Angular resolution of 1 good enough!

No large-scale signal (dipole) at any energy
above 1 EeV
e.g. ? lt 0.7 for 1 EeV E 3 EeV
No significant excess from Galactic Center
(as possibly seen by AGASA)
No signal from BL-Lacs (as possibly seen by HiRes)
none of the previous reports have been confirmed
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Main Auger result

• Highest energy cosmic rays have an anisotropic
  distribution!

First evidence that CR astronomy is possible!
Correlation with z lt 0.018 AGNs in the 12th
Véron-Cetty/Véron catalogue
Opening of a new era
Study of particle acceleration in HE
astrophysical sources Multi-messenger study of
sources HEP interactions at 300 TeV cm!
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Equal Exposure Plot Arrival Directions for Egt3
EeV
25 deg
0 deg
-30 deg
-60 deg
RA 0 deg
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The 27 highest energy events
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Significance of the anisotropy result
Not an AGN correlation result!
1st step search for correlations between arrival
directions of UHECR and various source catalogues

(data from 2004/01/01 to 2006/05/26)
Very large raw significance found w/ 12th VCV
catalogue of AGNs
Even after generous penalty factors for a
posteriori searches and scanning of parameter
space
Did not seem to be fluctuation
Auger collaboration set up a prescription for
future data
Most significant a posteriori correlation
signal
12 out of 15 events E gt 56 EeV closer than 3.1
from an AGN in 12th VCV with z 0.018 (D 75
Mpc)
3.2 expected from isotropic distribution
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Auger main anisotropy result
1st step Scan for best significance 2st step
Prescription for new data
z 0.018
?? 3.1
E 56 EeV
(D 75 Mpc)
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Significance of the anisotropy result
2nd step predefine a region in the sky of excess
CR flux test if next UHECRs come from this
region
21 chance from isotropic distribution
Independent data set, prescribed
parameters unambiguous significance
Result 99 CL that excess in the original data
set is not a random fluctuation from an isotropic
CR distribution
8 correlating events out of 13 (2.7 expected)
CR distribution is anisotropic at the highest
energies!
Corroborated by other analyses, independent of
source catalogue
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Centaurus A, Virgo, Fornax, etc.
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Auger main anisotropy result
- VCV AGN catalogue
- 27 highest energy events UHECRs
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Significance of the anisotropy result
Not an AGN correlation result!

• Véron-Cetty / Véron, 12th Edition, 2006

This catalogue should not be used for any
statistical analysis as it is not complete in any
sense, except that it is, we hope, a complete
survey of the literature.
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Auger main anisotropy result
correlation is most significant above E 56 EeV
where the CR flux drops (GZK interpretation)
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Astrophysical Implications?
Not clear yet! Very low statistics to check
against any specific model
Can UHECRs come from AGNs?
YES
Do UHECRs have to come from AGNs?
NO!
NB no claim from Auger!
See further analysis of the correlation, analyses
with other catalogues, catalogue independent
anisotropy studies
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Astrophysical Accelerators

• NOT Galactic Accelerators
• Neutron Stars
• Magnetars
• Microquasars
• shocks in the Galaxy
• NOT very Distant Accelerators
• Clusters of Galaxies
• (cluster shocks)
• Quasars
• BL Lacs

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E Ze B L

• 10 efficiency
• 1020eV Protons
• 1020eV Iron

GRBs
B(G)
others
L(cm)
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E Ze B L

• 10 efficiency
• 1020eV Protons
• 1020eV Iron

GRBs
X
B(G)
X
others
X
X
L(cm)
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• AGN Acceleration Models

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Shower maximum over 2 decades in E
fluctuations in Xmax to be exploited
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3 sources in the South
Wibig Wofendale 07
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Proton
Carbon
Schussler et al 07
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Horizons for Etot60 EeV
Allard et al 08
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Allard et al 08
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Centaurus A, Virgo, Fornax, etc.
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Centaurus A
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Astro/Phys Implications

• Intergalactic Fields
• Brmslt 10-9 G (Mpc/Lc)1/2
• if Proton Primaries on Earth, then modification
• 100 TeV interactions - Xmax, ?Xmax, N?
• Cosmogenic Neutrinos - low if heavies

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What Next?
Increase Exposure!
Auger SOUTH 2007
Auger NORTH, JEM-EUSO, .
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Source Spectra
Sources!
Armengaud
10-3/Mpc3 ANS 7 105 L
Blasi DeMarco
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Sky Exposure Auger North
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Sky Exposure Auger North South
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Auger South Area
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Auger North Area
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Auger North in SE Colorado
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Auger SOUTH NORTH

• Auger SOUTH
• 3,000 km2 1,157 mile2
• Hexagonal grid -
• 1.5 km separation
• FD sites - 4 (180o)
• Auger NORTH
• 20,000 km2 8,000 mile2
• SQUARE GRID -
• 1.414 mile separation
• (2.26 km)
• 1 large PMT / tank
• 40 FD telescopes

7x Area for 2x the price
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Auger North FD Layout Plans
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Auger NORTH
based on the GREAT SUCESS of Auger South
Design Enlarge Exposure Lower Costs
1 mile
SQUARE GRID - 1.414 mile separation
1609 m
(1 mile 1.609 km)
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Apertures Energy Threshold
Auger North
Anisotropies
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Auger SD NORTH
Need Insulation!!!
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JEM-EUSODesign Study is ongoing in JAXA
Japanese Experiment Module of ISS in 2013 Extreme
Universe Space Observatory
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• Nadir (2 yrs)
• 35o tilt (3 yrs)
• - 3 x area, but
• Eth gt 1020 eV

Fluorescence only 20 duty cycle no muons info
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Next to next generationFree Flyers OWL, Super
EUSO,

• Free Flyer
• Fluorescence
• from ABOVE!

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Lindsleys
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Pierre Auger ProjectSouth North
to discover Ultra-High Energy Cosmic Ray
Sources study Ultra-High Energy interactions
detect Ultra-High Energy Neutrinos
Charged Particle Astronomy
Just beginning!