Space-based detectorsand

global anisotropyof

ultra-high-energycosmic rays

Oleg Kalashev, Boris Khrenov,Pavel Klimov, Sergei Sharakin

andSergey Troitsky

UHECR studies from space:- why?- how?- when?

Global anisotropy patterns:- astrophysical sources- nearby structures seen- distant sources GZK-suppressed

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 (cutoffzero flux!)

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 (cutoffzero flux!)

AGASA, HiRes, Auger spectra scaled to HiRes

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!

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Glushkov,Pravdin, 2008

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 (cutoffzero flux!)

• FULL SKY WITH A SINGLE INSTRUMENT:- anisotropy studies

(energy calibration or anisotropy?)

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 (cutoffzero flux!)

• FULL SKY WITH A SINGLE INSTRUMENT:- anisotropy studies

(energy calibration or anisotropy?)

• EASIER TO RAISE FUNDS:- new technologies- space research

FLUORESCENT LIGHT FROM AIR SHOWERS SEEN FROM SPACE

+ One detector covers a large atmosphere area

FLUORESCENT LIGHT FROM AIR SHOWERS SEEN FROM SPACE

+ One detector covers a large atmosphere area

+ Looking downwards = better atmospheric transparence

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

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

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 FD’s are operating

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 FD’s are operating

- UV background is changing on-route of the orbital detector

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 FD’s 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

FLUORESCENT LIGHT FROM AIR SHOWERS SEEN FROM SPACE

TUS 2010 (Russia) 6 000 km2sr, E>71019 eV

JEM-EUSO 2013 (Japan) 120 000 km2sr (0.1°) E>51019 eV

KLYPVE >2010 (Russia) 10 000 km2sr (1° - 4°) 3000 km2sr, E>1019 eV +7000 km2sr, E>51019 eV

3000 km2sr (10° resolution) +3000 km2sr (30°)prototype: 2005-2007 (!)

Note: instantaneous apertures multiplied by the duty factor 0.2For comparison: AGASA 160 km2sr, Auger 7 000 km2sr

S-EUSO >2017 (Europe) 400 000 km2sr (1° - 5°) E>1019 eV

?

?

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 structuresshould be seen in the distribution of arrival directions

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 E>Emin

at distance r from the source- energy losses (GZK etc.)

3. Convolve the two functions to get the expected flux:

F(l,b)dr n(l,b,r) f(r,Emin)/r2

EXPECTED COSMIC-RAY FLUX:l,b - Galacticcoordinates

r - distance

E - energy

EXPECTED FLUX of HADRONS with E>Emin from the DIRECTION (l,b)

requires a complete catalog of galaxies

THE SOURCE DENSITY FUNCTION:

previous studies: PSCz catalog (IRAS)

this study: XSC catalog (2MASS) + HYPERLEDA database

• IRAS angular resolution arcmin• 2MASS angular resolution < arcsec• LEDA angular resolution arcsec

poor angular resolutionIRAS did not resolve galaxies in dense clusterssystematic undercounts in density

THE NEARBY UNIVERSE SEEN BY 2MASS

Jarrett et al. 2004colour = distance

THE NEARBY UNIVERSE SEEN BY 2MASS

Jarrett et al. 2004

2MASS: photometric redshifts

• complete sample for |b| >5, r <270 Mpc• accuracy 20% for average distances• not suitable at low distances

LEDA: spectroscopic redshifts

• complete sample for |b| >15, r <50 Mpc• Hubble flow distances• suitable at low distances

30< r < 270 Mpc2MASS XSC

0< r < 30 MpcLEDA

30< r < 50 Mpc“calibration”

COMPLETE SAMPLE for |b| >15, r <270 Mpc

COMPLETE SAMPLE for |b| >15, r <270 Mpc

Flux suppression with distance

code by Oleg Kalashev

EXPECTED FLUX (EUSO)

E>5.61019 eV protonsGalactic coordinates3 deg smoothing

EXPECTED FLUX (TUS)

E>71019 eV protonsGalactic coordinates10 deg smoothing

SUPERGALACTIC PLANE (TUS)

E>71019 eV protons:30 events in the full-sky sample for 95% CL evidence/exclusion

APPLICATION FOR TERRESTRIAL EXPERIMENTS

E>5.61019 eV protons, Supergalactic coordinates

Yakutsk AGASA

HiRes Auger

APPLICATION FOR TERRESTRIAL EXPERIMENTS

E>5.61019 eV protons, Supergalactic coordinates (+data)

Yakutsk AGASA

HiRes Auger

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 (>2010?), S-EUSO (>2017?)

Example of an anisotropy task:- astrophysical sources in nearby large-scale structures in the Universe- can be firmly tested already with TUS

THANK YOU!

Kachelrieß, Parizot, Semikoz 2007