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Astroparticle Physics
Key Issues
Jan Kuijpers
Dep. of Astrophysics/ HEFIN
University of Nijmegen
260404
Astroparticle Physics
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Cosmic Ray Energy Spectrum
_10-1 __(1 per m2-sec)
E-2.7
Flux
(m2 sr s GeV)-1
E-3
Knee
__(1 per m2-year)
Flux x E2.75
e- up to 1 TeV, only 1 %
Ankle (1 per km2-year)__
_10-25
LHC
Swordy
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|
109
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Energy (eV)
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1020
Astroparticle Physics
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1 Energy (GeV/n)
|
107
2
Cosmic Rays
Direct detection:
• Nuclei, power-law
• Gamma-rays up to TeV (AGN, pulsars)
• Neutrinos (solar, SN1987a)
Indirect detection from radiation: optically thin
synchrotron, inverse Compton, bremsstrahlung:
• Electrons: power-law –2/–2.7/-3 over many decades
in extragalactic radio galaxies. Also in extragal.
GRBs, galactic SNRs, X-ray binaries, jets.
• Protons (X-ray and MeV galactic)
Main question:
1: UNIVERSAL ACCELERATION PROCESS?
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Particle acceleration processes
• Shock waves
(Bell,..1977;
Fermi
1954):

De HoffmannTeller frame

2
u2
1
u1

v v c v c2 

 "    1  2 2  2 
c
c 

NR shock  st
 1 order Fermi
v c

N( E )  E
2
c

2v
 c

c
SNRs: vs~few 104 km/s
Jets: Radio galaxies
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Astroparticle Physics
E
 2u2 u1 


u

u
 1 2 
 

  1 acc 
  esc 
E
2
GRBs: ~300
X-ray binaries
4

Magnetars
Pulsars
Stellar mass black holes
109 G_
Emax=
Flare stars
Massive black holes
ZeBL
B
10-9 G_
1 AU
|
Size (km) 10
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1 pc 1 kpc 1 Mpc
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10
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More questions:
2: TeV gamma rays from electrons or protons?
sync
e  B   radio optical  X ray (  fL )

2
IC
  e   2

 0  ...  ...    

p/ nN  
()
()






 / K  ...       ...  e         e
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Case study: L3+Cosmics: search for TeV photons
from GRBs
Significance
of muon
excess
GRB 990903
# muons per square degree per sec
from 64 EGRET
unidentified
30 MeV/30 GeV
galactic
coordin.
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Astroparticle Physics
not corrected for detector
accept.
GRSs
Van den Akker
2004 PhD Thesis
7
KUN
3: Origin e plasma?
Rotation
axis
Linear acceleration of primary electrons in
unipolar inductor (neutron stars,
C
accretion discs, black hole collapse +
torus) and subsequent pair creation in
strong B or photon background.
V 
 v  B  d
Pair plasma production
in circuit C
C
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Case study: Coherent emission from particle beams
1000
varying
magnetic
wiggler
E (V/m)

950
t (10-5 sec)
f (10-10 Hz)
P (1013 W)
Radio pulsars as
Free Electron
Lasers
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t (10-5 sec)
Astroparticle Physics
Fung & Kuijpers,
2004, A&A subm.
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4: Origin of magnetic field?
Dynamo
Poynting flux dominated
Magnetized wind
Jets
accretion disk
compact object
5: Origin energy fireball?
- Magnetic reconnection
- Plasma turbulence
- Stochastic acceleration
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Astroparticle Physics
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v
v


v
 "   c2  1  2 2 c  c2 
c
c 

2nd order Fermi

4v c2
 2
 10 c
Case study: Coupling gravitational waves – mhd waves
GWx
GW+
z
z
x
y
Magnetosonic wave
Alfven
S
F
G
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wave
A
G
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Moortgat & Kuijpers 2003 A&A 402, 905 ; 2004 Phys Rev D, subm.
6. Is there a high energy CR cut-off?
Photopair production
Photopion production
|
GZK cutoff
Cronin 2004
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7. Origin of highest energy CRs?
Conflicting observ.
Inconclusive statistics
Cronin 2004
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Case study: L3+Cosmics: composition – forward cross-section
muons
Comparison to Monte Carlo CORSIKA muon mul;tiplicity
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Wilkens, 2003,
PhD Thesis KUN
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Case study: L3+Cosmics: muon spectrum at sea level
Accurate absolute
spectrum
Charge ratio
Petersen, 2002
PhD Thesis, KUN
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Air showers
Gamma ray: ----Fe: _______
Protons: ______
LOFAR cornerstone:
study of CRs and their sources
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Astroparticle Physics
Cronin 2004
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Outreach opportunities: NAHSA – HiSPARC
- LOFAR
High schools &
cosmic rays:
detector construction,
observations,
analysis
Timmermans et al,
2004, KUN
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Astroparticle Physics
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Key questions in astroparticle physics:
• ORIGINS CRs (HADRONS+LEPTONS):
SNRs, BHs, NSs, DARK MATTER, DARK ENERGY
• UNIVERSAL ACCELERATION PROCESS?
• TeV GAMMA RAYS FROM ELECTRONS OR PROTONS?
• ORIGIN e PLASMA?
• ORIGIN OF MAGNETIC FIELD?
• ENERGY PARTITIONING
• IS THERE A HIGH ENERGY CR CUT-OFF?
• QUEST FOR HIGHEST ENERGY CRs AND SOURCES
2 communities astroparticle detectors
LOFAR + ANTARES
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