Space-based detectors

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Space-based detectors and global
anisotropy of ultra-high-energy cosmic rays
Oleg Kalashev, Boris Khrenov, Pavel Klimov,
Sergei Sharakin and Sergey Troitsky
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UHECR studies from space - why? - how? - when?
Global anisotropy patterns - astrophysical
sources - nearby structures seen - distant
sources GZK-suppressed
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MOTIVATIONS FOR UHECR STUDIES FROM SPACE
(MY PERSONAL VIEW)

• HUGE EXPOSURE

- the shape of the GZK feature
(tells us about the sources)
- beyond the GZK cutoff (cutoff?zero flux!)
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MOTIVATIONS FOR UHECR STUDIES FROM SPACE
(MY PERSONAL VIEW)

• HUGE EXPOSURE

- the shape of the GZK feature
(tells us about the sources)
- beyond the GZK cutoff (cutoff?zero flux!)
AGASA, HiRes, Auger spectra scaled to HiRes
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MOTIVATIONS FOR UHECR STUDIES FROM SPACE
(MY PERSONAL VIEW)

• FULL SKY WITH A SINGLE INSTRUMENT

- anisotropy studies
(energy calibration or anisotropy?)
15 energy systematics 30 anisotropy (steeply
falling flux)
Energy calibration or anisotropy? Hard to
distinguish!
energy scale
Glushkov, Pravdin, 2008
latitide
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MOTIVATIONS FOR UHECR STUDIES FROM SPACE
(MY PERSONAL VIEW)

• HUGE EXPOSURE

- the shape of the GZK feature
(tells us about the sources)
- beyond the GZK cutoff (cutoff?zero flux!)

• FULL SKY WITH A SINGLE INSTRUMENT

- anisotropy studies
(energy calibration or anisotropy?)
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MOTIVATIONS FOR UHECR STUDIES FROM SPACE
(MY PERSONAL VIEW)

• HUGE EXPOSURE

- the shape of the GZK feature
(tells us about the sources)
- beyond the GZK cutoff (cutoff?zero flux!)

• FULL SKY WITH A SINGLE INSTRUMENT

- anisotropy studies
(energy calibration or anisotropy?)

• EASIER TO RAISE FUNDS

- new technologies - space research
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FLUORESCENT LIGHT FROM AIR SHOWERS SEEN FROM SPACE
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FLUORESCENT LIGHT FROM AIR SHOWERS SEEN FROM SPACE
One detector covers a large atmosphere area
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FLUORESCENT LIGHT FROM AIR SHOWERS SEEN FROM SPACE
One detector covers a large atmosphere area
Looking downwards better atmospheric
transparence
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FLUORESCENT LIGHT FROM AIR SHOWERS SEEN FROM SPACE
One detector covers a large atmosphere area
Looking downwards better atmospheric
transparence Easier determination of the
arrival direction (mono) distance to the
shower known Cherenkov reflected signal
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FLUORESCENT LIGHT FROM AIR SHOWERS SEEN FROM SPACE
One detector covers a large atmosphere area
Looking downwards better atmospheric
transparence Easier determination of the
arrival direction (mono) distance to the
shower known Cherenkov reflected signal
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FLUORESCENT LIGHT FROM AIR SHOWERS SEEN FROM SPACE
One detector covers a large atmosphere area
Looking downwards better atmospheric
transparence Easier determination of the
arrival direction (mono) distance to the
shower known Cherenkov reflected signal
- Average background UV light is higher than in
the special regions where the ground FDs
are operating
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FLUORESCENT LIGHT FROM AIR SHOWERS SEEN FROM SPACE
One detector covers a large atmosphere area
Looking downwards better atmospheric
transparence Easier determination of the
arrival direction (mono) distance to the
shower known Cherenkov reflected signal
- Average background UV light is higher than in
the special regions where the ground FDs
are operating - UV background is changing
on-route of the orbital detector
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FLUORESCENT LIGHT FROM AIR SHOWERS SEEN FROM SPACE
One detector covers a large atmosphere area
Looking downwards better atmospheric
transparence Easier determination of the
arrival direction (mono) distance to the
shower known Cherenkov reflected signal
- Average background UV light is higher than in
the special regions where the ground FDs
are operating - UV background is changing
on-route of the orbital detector - Signal is
much weaker than in the ground measurements and
the FD design meets new technological
problems. High pixel resolution is needed
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TUS 2010 (Russia) 6 000 km2sr, Egt7?1019 eV
3000 km2sr (10 resolution) 3000 km2sr (30)
prototype 2005-2007 (!)
JEM-EUSO 2013 (Japan) 120 000 km2sr (0.1)
Egt5?1019 eV
?
KLYPVE gt2010 (Russia) 10 000 km2sr (1 - 4)
3000 km2sr, Egt1019 eV 7000 km2sr, Egt5?1019 eV
?
S-EUSO gt2017 (Europe) 400 000 km2sr (1 - 5)
Egt1019 eV
Note instantaneous apertures multiplied by the
duty factor 0.2 For comparison AGASA 160 km2sr,
Auger 7 000 km2sr
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ANISOTROPY STUDIES EXAMPLE
Astrophysical sources of cosmic rays (active
galaxies - gamma-ray bursts - interacting
galaxies - galaxy cluster shocks - ) follow the
distribution of galaxies
The distribution of galaxies at the GZK scale is
not isotropic (clusters, superclusters, voids)
Patterns of nearby large-scale structures should
be seen in the distribution of arrival directions
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EXPECTED COSMIC-RAY FLUX
l,b - Galactic coordinates
1. Construct the source density function
n(l,b,r) - take a complete catalog of galaxies -
count numbers in bins - smooth 2. Construct the
propagation function f(r,Emin) - fraction of
surviving hadrons with energy EgtEmin at
distance r from the source - energy losses (GZK
etc.) 3. Convolve the two functions to get the
expected flux
r - distance
E - energy
F(l,b)??dr n(l,b,r) f(r,Emin)/r2
EXPECTED FLUX of HADRONS with EgtEmin from the
DIRECTION (l,b)
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THE SOURCE DENSITY FUNCTION
requires a complete catalog of galaxies
previous studies PSCz catalog (IRAS)
this study XSC catalog (2MASS) HYPERLEDA
database

• IRAS angular resolution ? arcmin
• 2MASS angular resolution lt arcsec
• LEDA angular resolution ? arcsec

poor angular resolution IRAS did not resolve
galaxies in dense clusters systematic undercounts
in density
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THE NEARBY UNIVERSE SEEN BY 2MASS
Jarrett et al. 2004
colour distance
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THE NEARBY UNIVERSE SEEN BY 2MASS
Jarrett et al. 2004
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2MASS photometric redshifts

• complete sample for b gt5?, r lt270 Mpc
• accuracy 20 for average distances
• not suitable at low distances

30lt r lt 270 Mpc 2MASS XSC
30lt r lt 50 Mpc calibration
LEDA spectroscopic redshifts

• complete sample for b gt15?, r lt50 Mpc
• Hubble flow distances
• suitable at low distances

0lt r lt 30 Mpc LEDA
COMPLETE SAMPLE for b gt15?, r lt270 Mpc
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COMPLETE SAMPLE for b gt15?, r lt270 Mpc
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Flux suppression with distance
code by Oleg Kalashev
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EXPECTED FLUX (EUSO)
Egt5.6?1019 eV protons Galactic coordinates 3 deg
smoothing
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EXPECTED FLUX (TUS)
Egt7?1019 eV protons Galactic coordinates 10 deg
smoothing
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SUPERGALACTIC PLANE (TUS)
Egt7?1019 eV protons 30 events in the full-sky
sample for 95 CL evidence/exclusion
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APPLICATION FOR TERRESTRIAL EXPERIMENTS
Yakutsk
AGASA
HiRes
Auger
Egt5.6?1019 eV protons, Supergalactic coordinates
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APPLICATION FOR TERRESTRIAL EXPERIMENTS
Yakutsk
AGASA
HiRes
Auger
Egt5.6?1019 eV protons, Supergalactic coordinates
(data)
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• UHECR studies from space
• - important
• shape of the spectrum at and beyond GZK
• full-sky anisotropy
• new techniques
• - started in 2005 with the TUS prototype (Russia)
• - will continue with TUS (2010), JEM-EUSO (2012),
• KLYPVE (gt2010?), S-EUSO (gt2017?)

Example of an anisotropy task - astrophysical
sources in nearby large-scale structures in
the Universe - can be firmly tested already with
TUS
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THANK YOU!
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Kachelrieß, Parizot, Semikoz 2007
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