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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. UHECR studies from space: - why? - how? - when?. Global anisotropy patterns: - astrophysical sources
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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
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! energy scale Glushkov, Pravdin, 2008 latitide
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
TUS 2010 (Russia) 6 000 km2sr, E>71019 eV 3000 km2sr (10° resolution) +3000 km2sr (30°) prototype: 2005-2007 (!) 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 ? S-EUSO >2017 (Europe) 400 000 km2sr (1° - 5°) E>1019eV Note: instantaneous apertures multiplied by the duty factor 0.2 For comparison: AGASA 160km2sr, Auger 7 000km2sr
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
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 E>Emin 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 E>Eminfrom the DIRECTION(l,b)
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 < arcsec • LEDA angular resolution arcsec • poor angular resolution • IRAS did not resolve galaxies in dense clusters • systematic undercounts in density
THE NEARBY UNIVERSE SEEN BY 2MASS Jarrett et al. 2004 colour = distance
THE NEARBY UNIVERSE SEEN BY 2MASS Jarrett et al. 2004
2MASS: photometric redshifts • complete sample for |b| >5, r <270Mpc • accuracy 20% for average distances • not suitable at low distances 30< r < 270 Mpc 2MASS XSC 30< r < 50 Mpc “calibration” LEDA: spectroscopic redshifts • complete sample for |b| >15, r <50Mpc • Hubble flow distances • suitable at low distances 0< r < 30 Mpc LEDA COMPLETE SAMPLE for |b| >15, r <270 Mpc
Flux suppression with distance code by Oleg Kalashev
EXPECTED FLUX (EUSO) E>5.61019 eV protons Galactic coordinates 3 deg smoothing
EXPECTED FLUX (TUS) E>71019 eV protons Galactic coordinates 10 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 Yakutsk AGASA HiRes Auger E>5.61019 eV protons, Supergalactic coordinates
APPLICATION FOR TERRESTRIAL EXPERIMENTS Yakutsk AGASA HiRes Auger E>5.61019 eV protons, Supergalactic coordinates (+data)
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