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COSMIC RAYS IN GALAXY CLUSTERS

First prezi trial for a talk at the Hamburg Observatory, by Franco Vazza, 08-02-2013
by

Franco Vazza

on 30 August 2013

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Transcript of COSMIC RAYS IN GALAXY CLUSTERS

Cosmic Rays and Large Scale Structures















Franco Vazza - Hamburger Sternwarte
MERGERS AND STRUCTURE FORMATION
temperature evolution
TURBULENCE AND MAGNETIC FIELD AMPLIFICATION
SHOCKS
"Microscopic" structure
of a shock wave
Radio at 600MHz
X-ray
A3667
shock-heating,
thermalization fof kinetic energy
virialization
acceleration of particles
at low redshift, most of shocks M<<10
Curl of
velocity
Mach number
of shocks
Outline
Large-scale structures and non-thermal mechanisms

Radio emissions from galaxy clusters

numerical modeling of Cosmic Rays feedback
Thanks to:
M.Brueggen, A.Bonafede
C.Gheller
G.Brunetti
5 Mpc
turbulent velocities of ~10^2 km/s (M~0.1)
on ~ 10^2 kpc
diffusion of metals, CR, entropy...
small-scale dynamo, B~muG
1 Mpc
"cold" (T=10^4K) gas infalling
hot (T=10^7K) post-shock ICM
COSMIC RAYS
The acceleration efficiency increases with Mach
MACSJ-1752+4440
Simulated
simulated emission for different acceleration efficiencies
TEMPERATURE CUT (12kpc)
COSMIC RAYS IN THE ICM
- how many CR protons?
- how many CR electrons?

--> observations necessary
synchrotron emission on ~ Mpc
electrons ~1-10 GeV
B~muG
Bonafede+2012
Electron efficiency:
~ 1e-5
electron energy
("visible")
proton energy
("hidden")
gamma-ray
synchrotron
PROTONS
E(cr-p)<0.1Eth

ELECTRONS:
they probe <10^9 Gyr acceleration events
degeneracy with B field
E(cr-e)<10^-5 Eth
pressure support ?
gamma flux ?
E(CR) is 1-10% of E(gas)
would this produce detectable gamma-emission?
100 Mpc
Cosmic rays protons energy gas energy
"standard" DSA
modified DSA (lower efficiency for M<6)
The combination of radio obs (->electrons) and deeper gamma upper limits (->protons) will help us constraining the acceleration of particles at SHOCK
hadronic gamma emission:
observations vs simulations
End, questions?
Full transcript