Ultra-High Energy Cosmic Rays: Results, and Prospects

Transcription

1 26th Texas Symposium on Relativistic Astrophysics, São Paulo, Brazil, , 2012 Ultra-High Energy Cosmic Rays: Results, and Prospects Karl-Heinz Kampert, University Wuppertal Area Grant

2 Karl-Heinz Kampert 2 Contents 1. 0 years of CRs 50 years of 20 ev physics 5 years of revolutionary development 2. Review of observational data: do we see the long awaited GZK-effect or the exhaustion of sources? 3. Recent developments in phenomenology /theory 4. Future plans

3 Intensity Karl-Heinz Kampert University Wuppertal 3 0 years ago: Discovery of Cosmic Radiadion Apparat 1 Apparat Height (m) 1936 Victor-Franz Hess 1912

4 1962, 50 Years ago: The First 20 ev Event VOLUME, NUMBER 4 PHYSICAL RK VIEW LKTTKRS 15 I'EBRUARY 196) EVIDENCE FOR A PRIMARY COSMIC-HAY PARTICLE WITH ENERGY John Linsley Laboratory for Nuclear Science, Massachusetts Institute of Technology, Cambridge, Massachusetts (Received January 1963) ev~ particle densities 0.6 Volcano Ranch Air Shower Array, New Mexico Karl-Heinz Kampert University Wuppertal 4 KlLOMETERS

5 Karl-Heinz Kampert University Wuppertal : Discovery of CMB 1978 G. Gamow Penzias & Wilson 4.08 GHz (7.35 cm)

6 Karl-Heinz Kampert University Wuppertal : End to the CR Spectrum? Greisen, Zatsepin & Kuz min Linsley s event

7 Problem 1: 20 ev sources need to be nearby p CMB p π photo-pion production A CMB 4 Photopair, p Expansion photo disintegration Greisen-Zatsepin-Kuz min (1966) threshold: E p E γ > (m Δ 2 - m p 2) E GZK 6 19 ev GZK-Horizon ~ 60 Mpc Karl-Heinz Kampert University Wuppertal 7 Energy Loss Pathlength (Mpc) CMBR z = 0 Total, p Photopion, p Energy (ev) Photopion, Fe Photopair, Fe Photodisintegration, Fe

8 Problem 2: Sources of 20 ev particles GRB 12 GRB? Neutron Stars E max ~ β s z B L Active Galactic Nuclei (AGN) LHC SNR Magnetic Fieldstrength (Gauß) LHC white dwarfts Interplanetary Space Hillas Diagramm 1AU Galact. Active Galactic Nuclei? ev proton jets from radio galaxies AGN-Jets Colliding Galaxies Karl-Heinz Kampert University Wuppertal 8 SNR Size 20 disk halo 1km 6 km 1pc 1kpc 1Mpc Realistic constraints more severe small acceleration efficiency synchrotron & adiabatic losses { Fe interactions in source region Galactic Clusters IGM

9 Problem 3: Anisotropies Expect anisotropies for protons at E> 19 ev Karl-Heinz Kampert University Wuppertal

10 UHECR Astronomy Cosmic Magnetic Fields R L = kpc Z -1 (E / EeV) (B / μg) -1 R L = Mpc Z -1 (E / EeV) (B / ng) -1 γ,n weak deflection E > 19 ev Halo B? strong deflection E < 18 ev Milky way B ~ μg (E,Z) 0.8 Extra-galactic B < ng? 20 ev E Karl-Heinz Kampert University Wuppertal L Mpc L coh 1 Mpc B 1 ng Z

11 Situation ~5 years ago Experiments: AGASA, HiRes, Haverah Park, Yakutsk, SUGAR does the GZK-suppression exist? - Flux data contradictory AGASA no suppression HiRes possibly a suppression Composition mostly protons Apparent isotropy Apparent continuation of spectrum gave birth to exotic source and propagation scenarios Top Down Models - Topological Defects, Super-Heavy Dark Matter Particles, WIMPzillas, Cryptons,... Z-Burst Model massive neutrinos Energy (ev/particle) expect EHE γ s and ν s Karl-Heinz Kampert University Wuppertal 11 ) 1.5 sec -1 sr -1 ev -2 J(E) (m 2.5 Scaled flux E ATIC HERA ( -p) RHIC (p-p) PROTON RUNJOB 14 Equivalent c.m. energy 3 Tevatron (p-p) s pp KASCADE (QGSJET 01) KASCADE (SIBYLL 2.1) KASCADE-Grande (prel.) Akeno LHC (p-p) 18 (GeV) 5 19 HiRes-MIA HiRes I HiRes II AGASA HIRES 20 6 AGASA

12 A New Generation: Hybrid Observation of EAS Pioneered by the Pierre Auger Collaboration (physics data taking started 01/2004) Telescope Array follows same concept (data taking since 12/2007) light trace at night-sky (calorimetric) Fluorescence light Also: Detection of Radio- & Microwave-Signals Particle-density and -composition at ground Karl-Heinz Kampert University Wuppertal 12

13 Pierre Auger Observatory ~65 km Loma Amarilla HEAT Coihueco 3000 km 2 BLS XLF CLF ~65 km 1660 detector stations on 1.5 km grid Los Morados 27 fluores. telescopes at periphery Los Leones Southern hemisphere: Argentina 160 radio antennas... Karl-Heinz Kampert University Wuppertal 13

14 Telescope Array (TA) Middle Drum: based on HiRes II 507 surface detectors: double-layer scintillators (grid of 1.2 km, 680 km 2 ) LIDAR Laser facility Infill array and high elevation telescopes under construction ~30 km Test setup for radar reflection Electron light source (ELS): ~40 MeV 3 fluorescence detectors (2 new, one station HiRes II) Northern hemisphere: Utah, USA Karl-Heinz Kampert University Wuppertal 14

15 Karl-Heinz Kampert University Wuppertal 15 The UHECR Hybrid Generation Pierre Auger Observatory Telescope Array same scale 700 km km 2

16 Karl-Heinz Kampert University Wuppertal 16 Event Example in Auger Observatory OBSERVATORY 12 km ~ 20 km

17 Event Example in Auger Observatory Cross Correlation OBSERVATORY most energetic event at 75 EeV de/dx (PeV/g cm 2 ) Longitudinal Profile E = 68 EeV X max =770 g/cm Slant Depth (g cm 2 ) ~ 20 km 12 km Signal (VEM) 00 0 S(00) 839 events Lateral Profile S(00)=222 VEM θ = 54 S38=343 VEM E = 71 EeV Distance to Shower Core (m) Karl-Heinz Kampert University Wuppertal 17 1

18 Karl-Heinz Kampert University Wuppertal : Unambigiuous Detection of Flux Suppression ) Equivalent c.m. energy 3 4 s pp (GeV) 5 6 s -1 sr -1 ev -2 J(E) (m RHIC (p-p) HERA ( -p) Tevatron (p-p) 7 TeV 14 TeV LHC (p-p) HiRes-MIA HiRes I HiRes II Auger 2011 TA 2011 (prelim.) 2.5 Scaled flux E ATIC PROTON RUNJOB KASCADE (QGSJET 01) KASCADE (SIBYLL 2.1) KASCADE-Grande 2009 Tibet ASg (SIBYLL 2.1) Abbasi (HiRes), PRL 0 (2008) Abraham (Auger), PRL 1(2008) Energy 20 (ev/particle)

19 Comparison of Experiments ev 2 )) sr -1 s -1-2 J /(m 3 ( E log Auger (ICRC 2011) (E 1.2 ) Telescope Array (E ) Yakutsk (E ) HiRes I (E ) HiRes II (E ) Syst. uncertainty on E-scale HiRes Auger TA Photometric calibration % 9.5% % Fluorescence Yield 6% 14% 11% Atmosphere 5% 8% 11% Reconstruction 15% % % Invisible Energy 5% 4% incl. above TOTAL 17% 22% 21% E[eV] 20 2 log (E/eV) Karl-Heinz Kampert University Wuppertal global shifts to energy scale by ±% perfect agreement (except for Yakutsk) well allowed for by error budgets Auger-TA-HiRes-Yakutsk Working UHECR2012 to appear in EPJ (web of conf)

20 Karl-Heinz Kampert University Wuppertal 20 New Measurement of Fluorescence Yield Kakimoto et al. [5] Nagano et al. [6] used by TA and HiRes used by Auger FLASH Coll. [7] AIRFLY Coll. this measurement MACFLY Coll. [8] AirFly 2012 final (Ave et al., arxiv: ) Lefeuvre et al. [9] Waldenmaier et al. [] Y 337 [photons/mev] Y337 = 5.61 ± 0.06stat ± 0.21syst (now with only 4% uncertainty!) This will almost eliminate the difference between Auger and TA/HiRes!

21 Flux Suppression in Detail ) Equivalent c.m. energy 3 4 s pp (GeV) 5 6 s -1 sr -1 ev -2 J(E) (m RHIC (p-p) HERA ( -p) Tevatron (p-p) 7 TeV 14 TeV LHC (p-p) HiRes-MIA HiRes I HiRes II Auger 2011 TA 2011 (prelim.) Is this the GZK-effect...? 2.5 Scaled flux E ATIC PROTON RUNJOB KASCADE (QGSJET 01) KASCADE (SIBYLL 2.1) KASCADE-Grande 2009 Tibet ASg (SIBYLL 2.1) Energy 20 (ev/particle) E 3 J(E) (km 2 yr 1 sr 1 ev 2 ) also: absence of HE ν s and γ s (would be expected if spectrum showed no cut-off) 18 γ 1 =3.27± log(e/ev) γ 1 =2.63±0.02 log(e ankle )=18.62±0.01 log(e cut-off )= 19.63± /ndf=33.7/16= Energy (ev) Karl-Heinz Kampert University Wuppertal 21 OBSERVATORY

22 Flux Suppression in Detail ) Equivalent c.m. energy 3 4 s pp (GeV) 5 6 s -1 sr -1 ev -2 J(E) (m 2.5 Scaled flux E RHIC (p-p) HERA ( -p) ATIC PROTON RUNJOB Tevatron (p-p) 7 TeV 14 TeV LHC (p-p) KASCADE (QGSJET 01) KASCADE (SIBYLL 2.1) KASCADE-Grande 2009 Tibet ASg (SIBYLL 2.1) HiRes-MIA HiRes I HiRes II Auger 2011 TA 2011 (prelim.)... or the limiting energy of sources? Energy 20 (ev/particle) (Allard, APP 39-40, 2012) Expect to see heavier composition at high energy! However, astrophysically very exotic result!! (dn/desource ~ E -1.6 ) Protons Emax,p = 18.4 ev Iron Emax, Fe = 26 Emax,p = 20 ev Karl-Heinz Kampert University Wuppertal 22

23 Karl-Heinz Kampert University Wuppertal 23 Rigidity Effect established at Knee di/de x E 2.7 (m -2 sr -1 s -1 ev 1.7 ) KASCADE-Grande = = = ev all-particle (4489 events) electron-poor sample electron-rich sample Fe-Knee = ev = ) -2 s -1 sr -1 ev -2 x dn/de (m 3 E 24 Biermann & de Souza, ApJ 746 (2012) Cen A as extragalactic source above the knee Sum He H CNO Ne-S Fe KASCADE-Grande, PRL 7 (2011) Cl-Mn KASCADE QGSJet KASCADE Sibyll KASCADE Grande Auger log (E/eV) E (ev/nucleus) Limiting energy of galactic sources Limiting energy of extragalactic sources?

24 Karl-Heinz Kampert University Wuppertal 24 Longitudinal Shower Development Primary Mass KHK, Unger, APP 35 (2012) EPOS 1.99 Simulations Example of a 3 19 ev EAS event )] 2 energy deposit [PeV/(g/cm 50 Auger event OBSERVATORY slant depth [g/cm ]

25 Longitudinal Shower Development Primary Mass Number of charged particles ( 9 ) a Iron proton Proton γ-ray Auger event shower Xmax ,000 Slant depth (g cm 2 ) Position of Xmax can be measured using fluorescence telescopes; Xmax and RMS(Xmax) primary mass OBSERVATORY Karl-Heinz Kampert University Wuppertal 25

26 ] 2 <X max > [g/cm Much debated: Auger vs HiRes 47 The same holds true for the measurements 6 of 750 the shower-to-shower fluctuations, wher both experiments corrected the measurements for the detector resolution. The lines indicat ] 2 Auger Collab. PRL 4, 20, updated: Facal, ICRC 2011 ) [g/cm max RMS(X OBSERVATORY 18 EPOSv1.99 QGSJET01 SIBYLL2.1 QGSJETII light light OBSERVATORY Sys. uncertainty: 6 g/cm heavy 6 47 p Sys. uncertainty: 13 g/cm 2 heavy E [ev] p Fe E [ev] max i (left) and RMS(X max ) E (right) [ev] as measured by the HiRes experiment. The lines ar Karl-Heinz Kampert University Wuppertal 26 ] 2 [g/cm meas X max 700 Fe different line types corresponding to different 650 high energy hadronic interaction model 850 EPJ Web of Conferences h QGSJet01 QGSJetII SIBYLL2.1 the predictions from air shower simulations for proton and iron compositions. There ar QGSJet-01, QGSJet-II, SIBYLL2.1 and EPOSv1.99. ] 2 [g/cm meas X max 18 QGSJet01 QGSJetII SIBYLL Fig. 4. The hx meas the corresponding hx meas i and s proton iron E [ev] ] 2 [g/cm σ X HiRes Collab., Nucl. Phys. Proc. Suppl (2011) 74 i 70 QGSJetII QGSJet01 QGSJetII SIBYLL proton iron Sys. uncertainty: 30 g/cm 2 proton iron proton E [ev] expectations for proton and iron compositions. The different lin

27 Karl-Heinz Kampert University Wuppertal 27 lna as a fct of Energy Auger-TA-HiRes-Yakutsk Working UHECR2012 to appear in EPJ (web of conf) fit to constant compos. allowing a break lna lna lna lna Auger HiRes TA Yakutsk χ 2 /dof = 133/ 0 Auger χ 2 /dof = 7.4/9 lg(e/ev) = 4.4/7 = 1.2/6 0 HiRes 2 = 9.8/7 = 3.4/ TA = 7.7/7 = 4.2/8 Yakutsk lg(e/ev) 1. All experiments prefer an increasing mass 2. Due to statistics, all but Auger are consistent with a constant composition 3. Absolute scale differs, needs further study

28 Karl-Heinz Kampert University Wuppertal 28 A more global view on composition lna 4 EPOS 1.99 Kampert, Unger APP 35:660 (2012) TA, preliminary HiRes HiRes/MIA CASA-BLANCA Yakutsk Fe Tunka Auger 3 N 2 1 He 2nd knee 0 p knee ankle E [ev] E p max,g ~3 15 ev E p max,eg ~4 18 ev?

29 Karl-Heinz Kampert University Wuppertal 29 (Auger) Data suggest that we may see the exhaustion of sources

30 Karl-Heinz Kampert University Wuppertal 30 Large Scale Anisotropies Auger Collaboration: ApJL, 762, L13 (2012), ApJS 203,34 (2012) Upper Limit - Dipole Amplitude Z=1 Dipole Amplitudes data 1 Z=1 Z=26 E [EeV] Upper Limit - Amplitude λ Z=1 Quadrupole Amplitudes Z=26 Z=26 1 expectations from stationary galactic sources distributed in the disk data Z=1 Z=26 E [EeV] light CR component cannot originate from stationary sources in the galactic disk

31 Karl-Heinz Kampert University Wuppertal 31 Neutron Astronomy ddecay = 9.2 kpc E (EeV) above 2 EeV see most of galactic disk produced more efficiently than γ s from π 0 : puhecr+penv nuhecr + penv + π + (n takes most of energy) " puhecr+penv puhecr + penv + π 0 (π 0 takes small energy only) log (F) 1 ev/cm 2 /s E -2 <0.1 ev/cm 2 /s TeV PeV EeV log (E) galactic TeV sources should plausibly produce neutrons energy flux of some γ sources exceeds 1 ev/cm 2 /s at Earth assuming E -2 spectrum expect also 1 ev/cm 2 EeV energy upper limits of neutrons further down by more than a factor of!

32 Karl-Heinz Kampert University Wuppertal 32 Neutrons Upper Limit Sky-Maps Auger Collaboration, ApJ, 760, 148 (2012) 1-2 EeV 2-3 EeV >1 EeV >3 EeV if hadronic galactic sources with E -2 spectrum up to EeV, we would have seen them

33 Karl-Heinz Kampert University Wuppertal 33 UHECR Astronomy: Correlation with AGN Astropart. Phys. 34 (20) 314 OBSERVATORY AGN position (3.1 circle) event direction Auger Observatory: 28/84 = 33% with iso-bkg = 21% <1 % chance probability Centaurus A Combined chance probability < Telescope Array: 11/25 = 44% with iso-bkg = 24% 2% chance probability agree with Auger ApJ 757 (2012) 26 when correcting for accidentals, ~ 15 % of events with E > 56 EeV point to nearby AGN

34 21 Karl-Heinz Kampert 34 Closest Active Galactic Nucleus: Centaurus A 3.7 Mpc Distance Moon for comparison of apparent size

35 Karl-Heinz Kampert University Wuppertal 35 Cen A a dominant UHECR Source? 5 radius around Cen A G. Farrar et al., JCAP 2012 Galactic magnetic field model of Jansson-Farrar EeV protons off by ~ 3 R.-Y. Liu, et al, ApJ 755, 139 (2012), Hardcastle, et al.,... Particles with Z< may remain within opening of 20 H. B. Kim, arxiv: ,...: Further support for source in direction of Cen A H. Yüksel et al, ApJ 758, 16 (2012): If UHECRs were protons EGMF would be > 20 ng N. Fraija et al, ApJ 753, 40 (2012) & S. Sahu et al. PRD 85, (2012): Assuming pp-interactions at source MeV-TeV γ s agree with Auger flux

36 Volume limited all-sky catalog of RG NGC 1275 M87 Cen A Sjoert van Velzen, KHK, et al., ApJ 544 (2012) constructed from NVSS and SUMSS radio surveys + 2MASS Redshift Survey (2MRS) NGC Fornax A Galactic coordinates z < 0.03 K > & ( F1400 > 213 mjy or F843 > 289 mjy) total of 575 sources area of circles ~ radio flux of the source Karl-Heinz Kampert University Wuppertal 36

37 observed UHECR flux. However, we also find that the cross-correlation of radio galaxieshillas with UHECRs Diagram is not significantlyof stronger Radio than the cross-correlation Galaxies with the local matter distribution. We conclude by discussing how our catalog can, in principle, Sjoert van bevelzen used to et rule al. (work out the in progress) hypothesis that radio galaxies are the source of all ultra-high energy protons Luminosity (erg s 1 Hz 1 ) ntroduction 31 NGC 1275 M87 Radio-emitting galaxies within z < J y radio galaxies have been considered a potential source of ultra-high energ Fornax A it synchrotron 28 radiation. The magnitude of the magnetic field (B) in these lobe E Fe ~ 20 ev Karl-Heinz Kampert University Wuppertal 37 Cen A Protons, E 20 = 1 Protons, E 20 = 0.5 Iron, E 20 = 1 Galaxy Within 0 Mpc re 2: The radio luminosity and size of radio-emitting galaxies within z = 0.04 (or -moving distance of 170 Mpc), for the region! 2/7 with the largest! 6/7 value of B R. For ponents that are not resolved, L / we use the upper limit R on R given by B = the resolution e radio survey (at 50 Mpc 31 erg thiss corresponds 1 Hz 1 to 0 kpc). kpcthe minimum GHzluminosity size that are needed to contain cosmic rays (Eq. 3) are shown. Only a handfull of E p ~ 20 ev ~5 19 ev c rays (UHECRs) since the 1960s [1]. The jets of radio galaxies carry energy o cretion disk 29 away from the black hole, creating lobes filled relativistic electron estimated 27 from their observed radio luminosity (L ) and radius (R). For an otron-emitting 0 source, the 1 total energyis 2 minimum when 3 the energy densit magnetic fields (U B ) is in equipartition Size (kpc) with the relativistic particles that ar g the radiation Magnetic (U e ). field Using inferred this minimum from radio energy luminosity argument, and we find size 1/7 µg (1

38 A quite natural scenario... The most nearby source most Emax,2 likely will have a low E max dn de max / E Emax,1<EGZK R2 DGZK for ρs -5 Mpc -3 lg(emax) F cr / 1 R 2 We may see a nearby low-emax source on a background of protons from distant sources R1 < DGZK Karl-Heinz Kampert University Wuppertal 38

39 How to Uncover the Origin of the Flux Suppression? Composition on event-by-event basis up to the highest energies Expect a different sky and E-spectrum for light vs heavy primaries: p-like primaries (~15% of flux?): point back to sources, strong AGN correlation GZK-like E-spectrum intermediate-heavy primaries much more isotropic, no AGN correlation Karl-Heinz Kampert University Wuppertal 39

40 Karl-Heinz Kampert University Wuppertal 40 GZK-Photons and Neutrinos sr -1 y -1 ] -2 integral flux [km Present Upper limits on photon fluxes SHDM GZK p AGASA TD GZK Fe Yakutsk 1 Z-burst Auger SD Auger Hybrid GZK p TA SD γ-showers penetrate deeper into atmosphere and contain almost no µ s Presence of GZKeffect could independently be verified by EHE photons and neutrinos -4 GZK Fe KHK, Unger APP 35:660 (2012) E [ev]

41 Karl-Heinz Kampert University Wuppertal 41 Next Steps... where to we need to go?

42 UHECR Mission I: Ground Based Understand Nature of End of Cosmic Ray Spectrum Particle Physics at Ecm ~ 0 ELHC Pierre Auger Observatory: Upgrades to improve a) shower-based primary mass measurement at highest energies b) particle physics capabilities (true high energy frontier!) Telescope Array Upgrades to improve statistics with surface array World-Wide Consortium: NGGO Study UHECR Sources Prepare for a Next Generation Ground-based Observatory (NGGO) with much larger aperture and with particle physics capabilities (to be operated in 2022 ff) Karl-Heinz Kampert University Wuppertal 42

43 Karl-Heinz Kampert University Wuppertal 43 UHECR Mission II: Space Based UHECR Astronomy and Source Hunting Effective aperture 5- times larger than Auger (but little particle physics capabilities) full-sky by construction hope for launch 2017/18

44 Thanks for your Attention! Sorry, Prof. Hess, we are almost there but still need a bit more time Karl-Heinz Kampert 44