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Cosmic rays in cosmological simulations and observations

Review talk at Desy (Hamburg), 18/09/2013, by Franco Vazza
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Franco Vazza

on 9 March 2016

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Transcript of Cosmic rays in cosmological simulations and observations

Thanks!
Questions?

A3376
MACSJ-1752+4440
Simulated
simulated emission for different acceleration efficiencies
Bonafede+2012 with GMRT
dynamical effects?
detectable gamma-emission?
Hadronic gamma emission:
observations vs simulations
Roettgering+97
Vazza+10
Testing the CRs content and acceleration
efficiency in large-scale structures with cosmological simulations












Franco Vazza - Hamburg Observatory
Cosmological runs with CosmicRay feedback
ENZO (FV,Gheller,Bruggen)

2048^3 + 9 x 1024^3
gas: PPM+CRs+AGN
@CURIE on 512 nodes
@DAINT on 1024 nodes
mean emission
+3sigma
-3sigma
-> the statistical comparison with FERMI (+other) limits constrains the acceleration efficiency of DSA at M=2-6 shocks


Curie@Genci
Daint@CSCS
different CRs models
shock dissipation efficiency of
kinetic energy into CR-energy
M=1.5 M=5
CR
Validation,
tests...
different
(re)acceleration efficiency can be tested:


e.g.
Kang+07
Kang&Ryu13
...


Fermi limits
from

to


As=0.001%
CR to gas pressure ratio
this also challenged by
FERMI limits!
Effects of CRs on thermal gas
5-10% modifications of Lx and SZ
signals if CRs are included
Tension with FERMI upper limis for 5-10% of cases
Numerical or physical problem? (see, however, problem with the other codes)
FV, Bruggen, Gheller & Brunetti 2012
density, temperature and pressure are reduced inside 0.5*Rvir
A complementary (semi-analytical) tests:
B fixed, xi_e from matching
-> CRp for Kep=0.01
xi_e from DSA, B from matching
-> CRp for Kep=0.01
30-50% of clusters emitting in gamma close to FERMI limits
energy ratio of
seed CRs
Radio relics:
we can statistically reproduce findings
of other groups:

for B=1-3 muG and
xi_e=0.001%
we reproduce several
observed features of
double relics
do we fullfill gamma constraints for CR-protons?
(some) conclusions:
Radio observations provide evidence for Gev electrons and muG magnetic fields on Mpc in merger clusters
Cosmological matter accretions naturally provide plenty of kinetic energy to dissipate via Fermi I/II mechanisms (+AGN, SNe...)
Cosmological simulations can be powerful tool to constrain parameters/efficiency and "kill" theories
Possible tension between DSA modelling of relics and lack of hadronic gamma-emission
collab.:

M.Brüggen
D.Eckert
C.Gheller
B.Huber
A.Bonafede
Radio Relics
Gamma-rays:
upper limits
The Fermi-LAT coll.+14
Full transcript