Astroparticle Physics. Michael Kachelrieß NTNU, Trondheim

Astroparticle Physics Michael Kachelrieß NTNU, Trondheim []

Plan of the lectures: Today: High energy astrophysics Cosmic rays Observations Acceleration, possible sources High energy photons and neutrinos TeV Blazars Elmag. cascades, EBL and primordial B fields diffuse neutrino flux limits, point sources Wednesday: Dark matter particle candidates detection: direct and indirect

1910: Father Wulf measures ionizing radiation in Paris 80m: flux/2

1910: Father Wulf measures ionizing radiation in Paris 300m: flux/2 80m: flux/2

1912: Victor Hess discovers cosmic rays The results are most easily explained by the assumption that radiation with very high penetrating power enters the atmosphere from above; the Sun can hardly be considered as the source. Hess and Kolhoerster s results: 80 excess ionization 60 40 20 0-10 1 2 3 4 5 6 7 8 9 altitude/1000m

What do we know 98 years later? solar modulation LHC

What do we know 98 years later? solar modulation only three bits of information? exponent α of dn/de 1/E α chemical composition for E < 10 17 ev isotropic flux for E < 10 19 ev LHC

What do we know 98 years later? solar modulation only three bits of information? exponent α of dn/de 1/E α chemical composition for E < 10 17 ev isotropic flux for E < few 10 19 ev anything more? LHC

Observing gamma-rays or cosmic rays: GeV-TeV

Observing gamma-rays or cosmic rays: around TeV

Pierre Auger Observatory:

Three options for HE astronomy: High-energy photons: IACT s (HESS, MAGIC, Veritas) extremely successful new sources, extragal. backgrounds, evidence for hadronic accelerators, M87,... synergy with Fermi-LAT next generation experiment CTA on the way

HESS observations of M87: A Declination (deg) M 87 (H.E.S.S.) 12.6 12.4 200 100 0 TeV γ-ray excess events B Declination (deg) 12.5 12.4 12.2 PSF 12.3 h m 12 32 h m 12 31 h m 12 30 h m s 12 31 00 h m s 12 30 30 Right Ascension (hours) Right Ascension (hours)

HESS observations of M87: A ) -1 s -12 10 6 Feb. 2005 March 2005 April 2005 May 2005-2 Φ(E>730GeV) (cm 4 2 B ) -1 s -2 Φ(E>730GeV) (cm 0 1.5 1.0 0.5 0.0 09/Feb -12 ) 10 16/Feb 09/Mar H.E.S.S. average HEGRA 16/Mar Chandra (HST-1) Chandra (nucleus) 30/Mar 2003 06/Apr 2004 2005 04/May 2006 11/May Date 12/1998 12/2000 12/2002 12/2004 12/2006 Date -12 10 40 20 0-1 s -2 f(0.2-6 kev) (erg cm

HESS observations of M87: A ) -1 s -12 10 6 Feb. 2005 March 2005 April 2005 May 2005-2 Φ(E>730GeV) (cm 4 2 B ) -1 s -2 Φ(E>730GeV) (cm 0 1.5 1.0 0.5 0.0 09/Feb -12 ) 10 16/Feb 09/Mar 16/Mar 30/Mar 06/Apr H.E.S.S. 2005 40 fast variability average excludes acceleration along kpc jet HEGRA acceleration Chandra in (HST-1) hot spots 2003marginally okay Chandra (nucleus) favors acceleration close to SMBH 2004 04/May 2006 11/May Date 12/1998 12/2000 12/2002 12/2004 12/2006 Date -12 10 20 0-1 s -2 f(0.2-6 kev) (erg cm

Three options for HE astronomy: VHE photons: successful, but restricted to few Mpc 22 radio 20 18 log10(e/ev) 16 photon horizon γγ e + e CMB 14 IR 12 10 kpc 10kpc 100kpc Mpc 10Mpc 100Mpc Gpc

Three options for HE astronomy: VHE photons: successful, but restricted to few Mpc hadronic photons vs. synchtrotron/compton photons

Three options for HE astronomy: astronomy with VHE photons restricted to few Mpc astronomy with HE neutrinos: smoking gun for hadrons but challenging

Three options for HE astronomy: astronomy with VHE photons restricted to few Mpc astronomy with HE neutrinos: smoking gun for hadrons but challenging large λ ν, but also large uncertainty δϑ > 1 small event numbers: < few/yr for PAO or ICECUBE identification of steady sources challenging without additional input

Three options for HE astronomy: 22 proton horizon 20 18 log10(e/ev) 16 photon horizon γγ e + e CMB 14 IR 12 10 kpc 10kpc 100kpc Mpc Virgo 10Mpc 100Mpc Gpc

Three options for HE astronomy: 22 proton horizon 20 18 log10(e/ev) 16 if UHECRs 14 are protons: deflections may be small photon horizon γγ e + e use 12 larger statistics of UHECRs well-suited horizon scale 10 kpc 10kpc 100kpc Mpc Virgo 10Mpc 100Mpc CMB IR Gpc

Possible sources and the Hillas plot: 13 pulsars AU pc kpc Mpc 11 9 7 log(b/g) 5 3 1 1 3 5 7 9 AGN cores GRB SNR Galactic halo radio galaxies cluster 0 2 4 6 8 10 12 14 16 18 20 22 log(r/km)

Possible sources and the Hillas plot: log(b/g) 13 11 9 7 5 3 1 1 3 5 7 9 pulsars AU pc AGN cores GRB SNR kpc Galactic halo Mpc radio galaxies cluster 0 2 4 6 8 10 12 14 16 18 20 22 log(r/km) contains only size constraint; additionally age limitation: SNR, galaxy clusters energy losses: pulsars, AGN

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Standard Galactic source: SNRs energetics: sources are SNRs: kinetic energy output of SNe: 10M ejected with v 5 10 8 cm/s every 30 yr L SN,kin 3 10 42 erg/s explains local energy density of CR ǫ CR 1 ev/cm 3 for a escape time from disc τ esc 6 10 6 yr and efficieny 1% 1.order Fermi shock acceleration dn/de E γ with γ = 2.0 2.2 diffusion in GMF with D(E) τ esc (E) E δ and δ 0.5 explains observed spectrum E 2.6

2.nd order Fermi acceleration consider CR with initial energy E 1 scattering at a cloud moving with velocity V : E p 2 2 θ θ 1 2 V E p 1 1

Energy gain ξ (E 2 E 1 )/E 1? Lorentz transformation 1: lab (unprimed) cloud (primed) E 1 = γe 1 (1 β cos ϑ 1 ) where β = V/c and γ = 1/ 1 β 2 Lorentz transformation 2: cloud lab E 2 = γe 2(1 + β cos ϑ 2) scattering off magnetic irregularities is collisionless, the cloud is very massive E 2 = E 1

Energy gain ξ (E 2 E 1 )/E 1? E 2 = E 1 : Lorentz transformation 1: lab cloud E 1 = γe 1 (1 β cos ϑ 1 ) }{{} where β = V/c and γ = 1/ 1 β 2 Lorentz transformation 2: cloud lab E 2 = γe 2(1 + β cos ϑ 2) ξ = E 2 E 1 E 1 = 1 β cos ϑ 1 + β cos ϑ 2 β2 cos ϑ 1 cos ϑ 2 1 β 2 1. we need average values of cos ϑ 1 and cos ϑ 2 :

Assume: CR scatters off magnetic irregularities many times in cloud its direction is randomized, cos ϑ 2 = 0. collision rate CR cloud: proportional to their relative velocity (v V cos ϑ 1 ): for ultrarelativistic particles, v = c, dn dω 1 (1 β cos ϑ 1 ), and we obtain cos ϑ 1 = dn dn cos ϑ 1 dω 1 / dω 1 = β dω 1 dω 1 3

Energy gain ξ for 2.nd order Fermi: Plugging cos ϑ 2 = 0 and cos ϑ 1 = β 3 since β 1. ξ β 2 > 0 energy gain ξ = 1 + β2 /3 1 β 2 1 4 3 β2 into formula for ξ gives O(ξ) = β 2, because β 1: average energy gain is very small ξ depends on drift velocity of clouds

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Diffusive shock acceleration consider CR with initial energy E 1 scattering at a shock moving with velocity V s : E 1 V p θ 1 E 1 V s E 1 E 1 V p E 2 shock E 2 θ 2 E 2 E 2

same discussion, but now different angular averages: projection of istropic flux on planar shock: dn d cos ϑ 1 = { 2 cos ϑ1 cos ϑ 1 < 0 0 cos ϑ 1 > 0 thus cos ϑ 1 = 2 3 and cos ϑ 2 = 2 3 ξ 4 3 β = 4 3 (u 1 u 2 ) + ξ β: efficient + test particle approximation: universal spectrum

Energy spectrum energy after n acceleration cycles E n = E 0 (1 + ξ) n

Energy spectrum energy after n acceleration cycles E n = E 0 (1 + ξ) n if escape probability per encounter is p esc, then probability to stay in acceleration region after n encounters is (1 p esc ) n number of encounters needed to reach E n is ( ) En n = ln / ln(1 + ξ) E 0

Energy spectrum number of encounters needed to reach E is ( ) E n = ln / ln(1 + ξ) E 0 }{{} fraction with energy > E is f(> E) = (1 p esc) n p esc 1 p esc ( γ = ln 1 1 p esc ( ) E γ where E 0 ) / ln(1 + ξ) p esc /ξ shock: p esc u 2 γ p esc /ξ 3 u 1 /u 2 1 strong shock: R u 1 /u 2 = 4 and dn/de E 2

Maximal energy of SNR: Lagage-Cesarsky limit acceleration rate β acc = de dt = 3Ev2 sh acc ζd(e), ζ 8 20

Maximal energy of SNR: Lagage-Cesarsky limit acceleration rate β acc = de dt = 3Ev2 sh acc ζd(e), ζ 8 20 assume Bohm diffusion D(E) = cr L /3 E and B µg

Maximal energy of SNR: Lagage-Cesarsky limit acceleration rate β acc = de dt = 3Ev2 sh acc ζd(e), ζ 8 20 assume Bohm diffusion D(E) = cr L /3 E and B µg E max 10 13 10 14 ev

Maximal energy of SNR: [Bell, Luzcek 02, Bell 04 ] (resonant) coupling CR Alfven waves

Maximal energy of SNR: [Bell, Luzcek 02, Bell 04 ] (resonant) coupling CR Alfven waves non-linear non-resonant magnetic field amplification

Maximal energy of SNR: [Bell, Luzcek 02, Bell 04 ] (resonant) coupling CR Alfven waves non-linear non-resonant magnetic field amplification requires also D(E) E 0.5 E

Maximal energy of SNR: [Bell, Luzcek 02, Bell 04 ] (resonant) coupling CR Alfven waves non-linear non-resonant magnetic field amplification requires also D(E) E 0.5 E observational evidence for B 100µG in young SNR rims

SNR RX J1713.7-3946 changes on δt 1 yr imply B 1mG

Knee: J(E)E 2.5, m -2 s -1 sr -1 GeV 1.5 p p Fe 10 3 He He C C Fe 10 2 KASCADE AKENO 10 6 10 7 10 8 E, GeV

Energy losses, the dip and the GZK cutoff 1e-07 1e-08 (1/E)*dE/dt [1/yr] 1e-09 pion production pair production 1e-10 redshift 1e-11 18 18.5 19 19.5 20 20.5 21 21.5 log10(e/ev) at E 4 10 19 ev: N + γ 3K N + π starts and reduces free mean path to 20 Mpc pair production leeds to a dip at 10 19 ev

The dip model 10 0 2 modification factor 10-1 10-2 1: γ g =2.7 2: γ g =2.0 η total η ee 10 17 10 18 10 19 10 20 10 21 2 1 1

The dip model 10 0 modification factor 10-1 HiRes I - HiRes II η ee 10-2 γ g =2.7 η total 10 17 10 18 10 19 10 20 10 21

The dip model modification factor 10 0 10-1 p He Al Fe red shift η ee γ g =2.7 10-2 η total 10 17 10 18 10 19 10 20 10 21 Nordic Winterschool, Gausdal 2011 Michael Kachelrieß E, ev High Energy Astrophysics

The dip model 10 0 modification factor 10-1 HiRes I - HiRes II η ee 10-2 η total good fitγ g w. =2.7 1 parameter: evidence for protons transition below E 10 18 ev 10 17 10 18 10 19 10 20 10 21

Deflection of protons in Galactic B-field:

Unified AGN picture

Correlations with AGNs: PAO analysis 27 CRs ( ) and 472 AGN ( ):

Correlations with AGNs: PAO analysis adding more date: data p 1 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0 p = 0.21 iso Data 68% CL 95% CL 99.7% CL 10 20 30 40 50 Total number of events (excluding exploratory scan)

Chemical composition via X max : ] 2 <X max > [g/cm 850 800 750 QGSJET01 QGSJETII Sibyll2.1 EPOSv1.99 proton 700 650 iron Auger 2009 HiRes ApJ 2005

Chemical composition via RMS(X max ) from Auger: ] 2 ) [g/cm max RMS(X 70 60 50 40 30 18 10 proton 19 10 E [ev] 20 10 18 10 iron 19 10 E [ev]

Mixed composition: 0.12 Mean 744.8 RMS 62.02 0.1 0.08 0.06 70% proton 30% iron sum 0.04 0.02 0 600 650 700 750 800 850 900 950 2 X max [g/cm ] σ 2 = f i σi 2 + f i f j (X max,i X max,j ) 2 i i<j

Restricting QCD: Color Glass Condensates,... X max [g/cm 2 ] 850 800 750 700 650 600 Sibyll (p,fe) BBL r.c. (p) BBL f.c. (p) Hires Stereo Seneca 1.2 550 10 8 10 9 10 10 10 11 energy [GeV] [Drescher, Dumitru, Strikman 04 ]

Violation of Lorentz invariance (LI) quantum gravity ( space-time foam ) or dim. reduction d = n > 4 4 could induce tiny departures from LI

Violation of Lorentz invariance (LI) quantum gravity ( space-time foam ) or dim. reduction d = n > 4 4 could induce tiny departures from LI non-universal maximal velocities changed dispersion relations may allow p p + γ or γ e + e example: modify by L QED = 1 4 η νρη µσ F νµ F ρσ η νρ η µσ η νρ η µσ + κ νρµσ observation of TeV photons and UHECRs gives κ νρµσ < 10 18

Violation of Lorentz invariance (LI) quantum gravity ( space-time foam ) or dim. reduction d = n > 4 4 could induce tiny departures from LI non-universal maximal velocities changed dispersion relations may allow p p + γ or γ e + e generically: linear terms excluded, but allowed ( ω 0 = ω 2 k 2 2 k 2 ) + M 2 P

suppose, c γ c π 0 = c γ c e = 10 22 then π 0 is stable above E 10 19 ev and photon unstable! similar in the GZK cutoff reaction p + γ 3K (1232) threshold condition for head-on collision changed to 2ω + m2 p 2E (c c p )E + M2 2E if c c p 2 10 25, reaction forbidden

Summary qualitative agreement of standard DSA in SNRs picture with data requires non-linear field amplification quantitative description from first principles in reach? main experimental question: fixing discrepancies in exp. results for chemical composition progress in multi-messenger astronomy requires: go beyond IceCube better astrophysical understanding of sources