Cosmological Shock Waves and Inverse Compton Emission from Large Scale Structures

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Cosmological Shock Waves and Inverse Compton
Emission from Large Scale Structures by FRANCO
VAZZA G.Brunetti Radio Astronomy Institute
Bologna University C.Gheller High Performance
System Division, Bologna Rhodes,
03-07-07
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Outline

• Observational and numerical background
• Our simulations with ENZO and our shock
  detecting scheme
• Results on LLS
• CR diffusive acceleration and IC emissions
• (Vazza, Brunetti Gheller to be submitted)

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OBSERVATIONAL BG Observed shocks in GC are a few
and weak, M lt 3 (e.g. Markevitch Vikhlinin 2007)
Abell 520

• Non-thermal emissions in Radio and HXR bands
  require
• 0.1-1?G B field and
• ? 104 Cosmic Rays
• (e.g. Review by Sarazin 2002 Brunetti 2004
  Feretti 2005
• Blasi 2007)

Feretti 1998
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OBSERVATIONAL BG Observed shocks in GC are a few
and weak, M lt 3 (e.g. Markevitch Vikhlinin 2007)
Abell 520

• Non-thermal emissions in Radio and HXR bands
  require
• 0.1-1?G B field and
• ? 104 Cosmic Rays
• (e.g. Review by Sarazin 2002 Brunetti 2004
  Feretti 2005
• Blasi 2007)

Fusco-Femiano et al. 2004
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OBSERVATIONAL BG Observed shocks in GC are a few
and weak, M lt 3 (e.g. Markevitch Vikhlinin 2007)
Turbulence acceleration (Brunetti et al.01,04
Petrosian 01)
Abell 520

• Non-thermal emissions in Radio and HXR bands
  require
• 0.1-1?G B field and
• ? 104 Cosmic Rays

Shock acceleration (Roettiger et al.1997 Ensslin
et al. 1999)
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Cosmological Shocks

• Heating of the ICM
• Dominant(?) source of CR in LSS
• Continuous injection of fast electrons in the
  cluster outskirts

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NUMERICAL BG Ryu et al.2003
Pfrommer et al.2006
Eulerian TVD, fixed mesh res140 kpc Temperature
Jumps

Lagrangian Gadget2 Entropy Jumps
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NUMERICAL BG Ryu et al.2003
Pfrommer et al.2006
Eulerian TVD, fixed mesh res140 kpc Temperature
Jumps

Lagrangian Gadget2 Entropy Jumps
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SIMULATIONS
ENZO CODE O'Shea et al.2004 Norman et
al.2007 PPM code so far no Adaptive Mesh Ref.

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parameters
?CDM cosmology Vol 1503 Mpc3 Res 125
kpc zinitial50 Adiabatic / Radiative Reionizatio
n 113 GCs in the range 10 13ltMlt10 15Mo/h

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Our novel method of recovering shocks from
velocity jumps
Shocks from temperature jumps
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Baryon density
Detected Shocks
80 Mpc
1 3 10 30
100 300
Mach
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Mean shock strength
matter overdensity
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Distribution of shocks strengths in various
environments
whole box
outskirts
clusters
filaments
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Cosmic Rays via Diffusive Shock
Acceleration (e.g. Eichler Blandford 1987...)
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Inverse Compton from electrons accelerated in
shocks We assume that a F ratio of the energy of
the accelerated CR goes into fast
electrons/positrons with an energy
distribution For ? gtgt 103 electrons we
assume a stationary solution for electron
spectrum
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Maps large scale structures
80 Mpc l.o.s depth10Mpc
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Maps a relaxed cluster of M 1015MO
hard X soft X
6 Mpc
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Profiles IC dominates from 0.5Rv
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Summary

• We have developed an efficient shock-detecting
  scheme and performed large simulations with ENZO.
• Influence of radiative processes, resolutions
  and cosmic parameters, except in Galaxy Clusters,
  are well-converged
• Energy distribution of shocks are steeper than
  other simulations, the mean acceleration
  efficency of Cosmic Rays is lower eCR lt 0.1
  eTH
• We estimate IC emission from LSS the IC signal
  may be detected by future X-Ray experiments with
  low background (e.g. EDGE)