Pfrommer: Non-thermal emission from galaxy clusters

8/14/2019 Pfrommer: Non-thermal emission from galaxy clusters

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Cosmological structure formation shocks

Diffuse radio emission in clusters

High-energy -ray emission

Deciphering an enigma Non-thermalemission from galaxy clusters

Christoph Pfrommer1

in collaboration with

Torsten Enlin2, Volker Springel2, Anders Pinzke3,Nick Battaglia1, Jon Sievers1, Dick Bond1

1Canadian Institute for Theoretical Astrophysics, Canada2Max-Planck Institute for Astrophysics, Germany

3Stockholm University, Sweden

Nov 21, 2008 / Princeton University Cosmology Lunch

Christoph Pfrommer Non-thermal emission from galaxy clusters
http://find/http://goback/


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Outline

1 Cosmological structure formation shocks

Cosmological galaxy cluster simulations

Mach numbers and shock acceleration

Cosmic ray transport and pressure distribution

2 Diffuse radio emission in clustersGeneral picture of non-thermal processes in clusters

Shock related emission

Hadronically induced emission

3 High-energy -ray emissionMorphology and spectra

Predictions for Fermi

Minimum -ray flux



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Outline

1 Cosmological structure formation shocks









Minimum -ray flux



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Shocks in galaxy clusters

1E 0657-56 (Bullet cluster)

(X-ray: NASA/CXC/CfA/M.Markevitch et al.; Optical:

NASA/STScI; Magellan/U.Arizona/D.Clowe et al.; Lensing:

NASA/STScI; ESO WFI; Magellan/U.Arizona/D.Clowe et al.)

Abell 3667

(radio: Johnston-Hollitt. X-ray: ROSAT/PSPC.)



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Topics of interest

consistent picture of non-thermal processes in galaxyclusters (radio, soft/hard X-ray, -ray emission) illuminating the process of structure formation

history of individual clusters: cluster archeology

understanding the non-thermal pressure distribution toaddress biases of thermal cluster observables

nature of dark matter: annihilation signal vs. cosmic ray

(CR) induced -rays

gold sample of clusters for precision cosmology: using

non-thermal observables to gauge hidden parameters

fundamental plasma physics:

diffusive shock acceleration in high-plasmasorigin and evolution of large scale magnetic fieldsnature of turbulent models


C l i l f i h k C l i l l l i l i


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Radiative simulations flowchart


C l i l t t f ti h k C l i l l l t i l ti


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Radiative simulations with cosmic ray (CR) physics


Cosmological structure formation shocks Cosmological galaxy cluster simulations


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Radiative simulations with extended CR physics




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Previous numerical work on cosmic rays in clusters

COSMOCR: A numerical code for cosmic ray studies in computational

cosmology (Miniati, 2001):

advantages: good resolution in momentum space

drawbacks: CR pressure not accounted for in EoM, insufficient spatial

resolution (grid code), non-radiative gas physics

Figure: Hard X-rays, thermal X-rays, -rays, adopted from Miniati (2003)




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Our philosophy and description

An accurate description of CRs should follow the evolution ofthe spectral energy distribution of CRs as a function of time and

space, and keep track of their dynamical, non-linear coupling

with the hydrodynamics.

We seek a compromise between

capturing as many physical properties as possible

requiring as little computational resources as necessary

Assumptions:protons dominate the CR population

a momentum power-law is a typical spectrum

CR energy & particle number conservation




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g



g g y



CR spectral description

p = Pp/mp c

f(p) =dN

dp dV = C p

(p

q)

q() =

0

13

q0

C() = 0+2

3C0

nCR =

0

dp f(p) = C q1

1

PCR =mpc

2

3

0 dp f(p)(p) p

=C mpc

2

6 B 11+q2

2

2 ,3

2




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g



g g y



Thermal & CR energy spectra

Kinetic energy per logarithmic momentum interval:

10-4

10-3

10-2

10-1

100

101

102

103

0.01

0.10

1.00

0.1MeV

p

dTCR

/dlog

p=

pTp

(p)

f(p)

in

mp

c2

= 2.25

= 2.50

= 2.75

10 eV 1 keV




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Cooling time scales of CR protons

Cooling of primordial gas:

104

105

106

107

108

109

T [ K ]

0.0001

0.0010

0.0100

0.1000

1.0000

10.0000

cool

[Gyr]

n = 0.01 cm-3

Cooling of cosmic rays:

0.01 0.10 1.00 10.00 100.00

q

0.01

0.10

1.00

10.00

cool

[Gyr]

n = 0.01 cm-3




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CR protons in clusters

relativistic proton populations can often be expected, since

acceleration mechanisms work for protons . . .

. . . as efficient as for electrons (adiabatic compression) or

. . . more efficient than for electrons (DSA, stochastic acc.)galactic CR protons are observed to have 100 times higherenergy density than electrons

CR protons are very inert against radiative losses and thereforelong-lived ( Hubble time in galaxy clusters, longer outside)

an energetic CR proton population should exist in clusters



Diff di i i i l


M h b d h k l i


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Radiative cool core cluster simulation: gas density

10-1

100

101

102

-15 -10 -5 0 5 1 0 15-15

-10

-5

0

5

10

15

-15 -10 -5 0 5 10 15

x [ h-1 Mpc ]

-15

-10

-5

0

5

10

15

y

[h-1Mpc]

-15 -10 -5 0 5 1 0 15-15

-10

-5

0

5

10

15

1+

gas



Diff di i i i l t


M h b d h k l ti


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Mass weighted temperature

105

106

107

108

-15 -10 -5 0 5 1 0 15-15

-10

-5

0

5

10

15

-15 -10 -5 0 5 10 15

x [ h-1 Mpc ]

-15

-10

-5

0

5

10

15

y[h-1Mpc]

-15 -10 -5 0 5 1 0 15-15

-10

-5

0

5

10

15

T

gas

/gas

[K]







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Mach number distribution weighted by diss

1

10

-15 -10 -5 0 5 1 0 15-15

-10

-5

0

5

10

15

-15 -10 -5 0 5 10 15

x [ h-1 Mpc ]

-15

-10

-5

0

5

10

15

y

[h-1Mpc]

-15 -10 -5 0 5 1 0 15-15

-10

-5

0

5

10

15

M

diss/

dis

s







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Diffusive shock acceleration Fermi 1 mechanism (1)

conditions:

a collisionless shock wave

magnetic fields to confine energetic particles

plasma waves to scatter energetic particles particle diffusion

supra-thermal particles

mechanism:

supra-thermal particles diffuse upstream across shock wave

each shock crossing energizes particles through momentum transfer

from recoil-free scattering off macroscopic scattering agents

momentum increases exponentially with number of shock crossings

particle number decreases exponentially with number of crossings

power-law CR distribution


Cosmological structure formation shocksDiffuse radio emission in clusters

Cosmological galaxy cluster simulationsMach numbers and shock acceleration


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conditions:

a collisionless shock wave

magnetic fields to confine energetic particles

plasma waves to scatter energetic particles particle diffusion

supra-thermal particles

mechanism:

supra-thermal particles diffuse upstream across shock wave

each shock crossing energizes particles through momentum transfer

from recoil-free scattering off macroscopic scattering agents

momentum increases exponentially with number of shock crossings

particle number decreases exponentially with number of crossings

power-law CR distribution





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Spectral index depends on the Mach number of the shock,M = shock/cs:

log p

strong shock

10 GeV

weak shock

keV

log f





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Diffusive shock acceleration efficiency (3)

CR proton energy injection efficiency, inj

= CR

/diss

:

2.0 2.5 3.0 3.5 4.0

0.001

0.010

0.100

1.000

CR

energ

yinjectionefficien

cyinj

inj

Mach number M

kT2 = 10 keVkT2 = 0.3 keVkT2 = 0.01 keV

3 5 11/3 3





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High-energy -ray emission Cosmic ray transport and pressure distribution

Mach number distribution weighted by diss

1

10

-15 -10 -5 0 5 1 0 15-15

-10

-5

0

5

10

15

-15 -10 -5 0 5 10 15

x [ h-1 Mpc ]

-15

-10

-5

0

5

10

15

y

[h-1Mpc]

-15 -10 -5 0 5 1 0 15-15

-10

-5

0

5

10

15

M

diss/

diss





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Mach number distribution weighted by CR,inj

1

10

-15 -10 -5 0 5 1 0 15-15

-10

-5

0

5

10

15

-15 -10 -5 0 5 10 15

x [ h-1 Mpc ]

-15

-10

-5

0

5

10

15

y

[h-1Mpc]

-15 -10 -5 0 5 1 0 15-15

-10

-5

0

5

10

15

M

CR,

inj

/CR,

inj





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Mach number distribution weighted by CR,inj(q> 30)

1

10

-15 -10 -5 0 5 1 0 15-15

-10

-5

0

5

10

15

-15 -10 -5 0 5 10 15

x [ h-1 Mpc ]

-15

-10

-5

0

5

10

15

y

[h-1Mpc]

-15 -10 -5 0 5 1 0 15-15

-10

-5

0

5

10

15

M

CR,inj/CR,inj

(q>

30)





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CR pressure PCR

10-17

10-16

10-15

10-14

10-13

10-12

-15 -10 -5 0 5 1 0 15-15

-10

-5

0

5

10

15

-15 -10 -5 0 5 10 15

x [ h-1 Mpc ]

-15

-10

-5

0

5

10

15

y[h-1Mpc]

-15 -10 -5 0 5 1 0 15-15

-10

-5

0

5

10

15

PCRgas

/gas

[erg

cm3h2

]



Hi h i i


C i d di ib i


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Relative CR pressure PCR/Ptotal

10-2

10-1

100

-15 -10 -5 0 5 1 0 15-15

-10

-5

0

5

10

15

-15 -10 -5 0 5 10 15

x [ h-1 Mpc ]

-15

-10

-5

0

5

10

15

y[h-1Mpc]

-15 -10 -5 0 5 1 0 15-15

-10

-5

0

5

10

15

PCR

/Ptotgas

/

gas



Hi h i i


C i t t d di t ib ti


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Relative CR pressure PCR/Ptotal

10-2

10-1

100

-4 -2 0 2 4-4

-2

0

2

4

-4 -2 0 2 4

x [ h-1 Mpc ]

-4

-2

0

2

4

y[h-1Mpc]

-4 -2 0 2 4-4

-2

0

2

4

PCR

/Ptotgas

/

gas



High energy ray emission




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CR phase-space diagram: final distribution @ z= 0

0

0

0

0

1

10-4

10

-3

10-2

10-1

100

phasespacedensity[arbitraryunits]

-2 0 2 4 6 8-4

-3

-2

-1

0

1

2

-2 0 2 4 6 8log[ 1 +

gas]

-4

-3

-2

-1

0

1

2

log[PCR/

Pth

]

-2 0 2 4 6 8-4

-3

-2

-1

0

1

2 -2 0 2 4 6 8

-4

-3

-2

-1

0

1

2



High energy ray emission




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CR impact on SZ effect: Compton y parameter

10-6

10-5

C

omptony

-2 -1 0 1 2-2

-1

0

1

2

-2 -1 0 1 2x [ h-1Mpc ]

-2

-1

0

1

2

y

[h-1Mpc]

-2 -1 0 1 2-2

-1

0

1

2

large merging cluster, Mvir 1015M/h

10-7

10-6

Comptony

-1.0 -0.5 0.0 0.5 1.0-1.0

-0.5

0.0

0.5

1.0

-1.0 -0.5 0.0 0.5 1.0x [ h

-1Mpc ]

-1.0

-0.5

0.0

0.5

1.0

y[

h-1Mpc]

-1.0 -0.5 0.0 0.5 1.0-1.0

-0.5

0.0

0.5

1.0

small cool core cluster, Mvir 1014M/h







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Compton y difference map: yCR yth

-10-4

-10-5

-10-6

-10-7

0

10-7

10-6

10-5

10-4

Compton-ydi

fferencemap:yCR-yth

Y / Y= - 1.6%

-1 0 1

-1

0

1

-1 0 1x [ h-1Mpc ]

-1

0

1

y

[h-1Mpc]

-1 0 1

-1

0

1

large merging cluster, Mvir 1015M/h

-10-5

-10-6

-10-7

-10-8

0

10-8

10-7

10-6

10-5

Compton-ydifferencemap:yCR-yth

Y / Y= - 0.8%

-0.5 0.0 0.5

-0.5

0.0

0.5

-0.5 0.0 0.5x [ h

-1Mpc ]

-0.5

0.0

0.5

y[

h-1Mpc]

-0.5 0.0 0.5

-0.5

0.0

0.5

small cool core cluster, Mvir 1014M/h




Non-thermal processes in clustersShock related emission



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High energy ray emission Hadronically induced emission

Outline

1 Cosmological structure formation shocksCosmological galaxy cluster simulations






3 High-energy -ray emissionMorphology and spectraPredictions for Fermi

Minimum -ray flux







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High energy ray emission Hadronically induced emission

Multi messenger approach for non-thermal processes







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g gy y y








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g gy y y








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Cosmic web: Mach number

1

10

-15 -10 -5 0 5 1 0 15-15

-10

-5

0

5

10

15

-15 -10 -5 0 5 10 15

x [ h-1 Mpc ]

-15

-10

-5

0

5

10

15

y

[h-1Mpc]

-15 -10 -5 0 5 1 0 15-15

-10

-5

0

5

10

15

M

diss/

diss







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Radio gischt (relics): primary CRe (1.4 GHz)

10-8

10-6

10-4

10-2

100

S,primary

[mJyarcm

in-2h70

2]

-15 -10 -5 0 5 10 15-15

-10

-5

0

5

10

15

-15 -10 -5 0 5 10 15

x [ h-1Mpc ]

-15

-10

-5

0

5

10

15

y

[h-1Mpc]

-15 -10 -5 0 5 10 15-15

-10

-5

0

5

10

15







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Radio gischt: primary CRe (150 MHz)

10-8

10-6

10-4

10-2

100

S,primary

[mJyarcm

in-2h70

2]

-15 -10 -5 0 5 10 15-15

-10

-5

0

5

10

15

-15 -10 -5 0 5 10 15

x [ h-1Mpc ]

-15

-10

-5

0

5

10

15

y

[h-1Mpc]

-15 -10 -5 0 5 10 15-15

-10

-5

0

5

10

15







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10-8

10-6

10-4

10-2

100

S,primary

[mJyarcm

in-2h70

2]

-15 -10 -5 0 5 10 15-15

-10

-5

0

5

10

15

-15 -10 -5 0 5 10 15

x [ h-1Mpc ]

-15

-10

-5

0

5

10

15

y

[h-1Mpc]

-15 -10 -5 0 5 10 15-15

-10

-5

0

5

10

15







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Radio gischt: primary CRe (15 MHz), slower magnetic decline

10-8

10-6

10-4

10-2

100

S,primary

[mJyarcm

in-2h70

2]

-15 -10 -5 0 5 10 15-15

-10

-5

0

5

10

15

-15 -10 -5 0 5 10 15

x [ h-1Mpc ]

-15

-10

-5

0

5

10

15

y

[h-1Mpc]

-15 -10 -5 0 5 10 15-15

-10

-5

0

5

10

15







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Radio gischt illuminates cosmic magnetic fields

1

3

2

-2 -1 0 1 2-2

-1

0

1

2

-2 -1 0 1 2

x [ h-1 Mpc ]

-2

-1

0

1

2

y[

h-1Mpc]

-2 -1 0 1 2-2

-1

0

1

2

Mdiss

/diss

Structure formation shocks triggered

by a recent merger of a large galaxy

cluster.

-2 -1 0 1 2-2

-1

0

1

2

-2 -1 0 1 2

x [ h-1Mpc ]

-2

-1

0

1

2

y[

h-1Mpc]

-2 -1 0 1 2-2

-1

0

1

2-2 -1 0 1 2

-2

-1

0

1

2

red/yellow: shock-dissipated energy,

blue/contours: 150 MHz radio gischt

emission from shock-accelerated CRe







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Diffuse cluster radio emission an inverse problemExploring the magnetized cosmic web

Battaglia, Pfrommer, Sievers, Bond, Enlin (2008):

By suitably combining the observables associated with diffusepolarized radio emission at low frequencies ( 150 MHz,GMRT/LOFAR/MWA/LWA), we can probe

the strength and coherence scale of magnetic fields on scales ofgalaxy clusters,

the process of diffusive shock acceleration of electrons,

the existence and properties of the WHIM,

the exploration of observables beyond the thermal clusteremission which are sensitive to the dynamical state of thecluster.







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Population of faint radio relics in merging clustersProbing the large scale magnetic fields

Finding radio relics in 3D cluster simulations using a friends-of-friends finderwith an emission threshold relic luminosity function

10-3

10-2

10-1

1

101

S[

mJyarcmin-2]

-2 -1 0 1 2-2

-1

0

1

2

-2 -1 0 1 2

x [ h-1Mpc ]

-2

-1

0

1

2

y

[h-1Mpc]

-2 -1 0 1 2-2

-1

0

1

2

radio map with GMRT emissivity threshold

10-3

10-2

10-1

1

101

S[

mJyarcmin-2]

-2 -1 0 1 2-2

-1

0

1

2

-2 -1 0 1 2

x [ h-1Mpc ]

-2

-1

0

1

2

y

[h-1Mpc]

-2 -1 0 1 2-2

-1

0

1

2

theoretical threshold (towards SKA)






R li l i i f i h


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Relic luminosity function theory

Relic luminosity function is very sensitive to large scale behavior of the

magnetic field and dynamical state of cluster:

1

10

Numberofrelics

25 26 27 28 29 30 31 32

10-2 10-1 100 101 102 103 104F [mJy] for a cluster @ z ~ 0.05

B = 0.3

= 150MHz, B0 = 5 G

B = 0.5B = 0.7

B = 0.9

log(J/J0), J0 = 1 erg/Hz/s/ster

varying magnetic decline with radius

1

10

Numberofrelics

25 26 27 28 29 30 31 32

10-2 10-1 100 101 102 103 104F [mJy] for a cluster @ z ~ 0.05

B0 = 10 G

= 150MHz, B = 0.5

B0 = 5 GB0 = 2.5 G

log(J/J0), J0 = 1 erg/Hz/s/ster

varying overall normalization of the mag-

netic field






R t ti (RM)


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Rotation measure (RM)

RM maps and power spectra have the potential to infer the magnetic

pressure support and discriminate the nature of MHD turbulence in clusters:

-150

-75

0

75

150

RM[radm-2]

-0.4 -0.2 0.0 0.2 0.4x [ Mpc]

-0.4

-0.2

0.0

0.2

0.4

y[Mpc]

-5 0 5arcmin

-5

0

5

arcmin

1

10

P

[RM](k)k2[

rad2m

-4]

10-7

10-6

P

[Bz]

(k)k2[

G2M

pc]

P[RM] (k)P[Bz]

(k)

1 10 100k[h Mpc-1]

1

10

P

[RM](k)k2[

rad2m

-4]

MFR1

MFR2

MFR3

Left: RM map of the largest relic, right: Magnetic and RM power spectrum comparing

Kolmogorow and Burgers turbulence models.






H d i i t i t ti


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Hadronic cosmic ray proton interaction






Cl t di i i b h d i ll d d CR


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Cluster radio emission by hadronically produced CRe

10-8

10-6

10-4

10-2

100

S,secondary

[mJyarc

min-2h70

3]

-15 -10 -5 0 5 10 15-15

-10

-5

0

5

10

15

-15 -10 -5 0 5 10 15

x [ h-1Mpc ]

-15

-10

-5

0

5

10

15

y

[h-1Mp

c]

-15 -10 -5 0 5 10 15-15

-10

-5

0

5

10

15






Thermal X ray emission


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Thermal X-ray emission

10-9

10-8

10-7

10-6

10-5

10-4

SX

[ergcm-2s

-1h

3]

-15 -10 -5 0 5 10 15-15

-10

-5

0

5

10

15

-15 -10 -5 0 5 10 15x [ h-1Mpc ]

-15

-10

-5

0

5

10

15

y[h-1Mp

c]

-15 -10 -5 0 5 10 15-15

-10

-5

0

5

10

15








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10-8

10-6

10-4

10-2

100

S,primary

[mJyarcmin-2h70

2]

-15 -10 -5 0 5 10 15-15

-10

-5

0

5

10

15

-15 -10 -5 0 5 10 15

x [ h-1Mpc ]

-15

-10

-5

0

5

10

15

y

[h-1Mp

c]

-15 -10 -5 0 5 10 15-15

-10

-5

0

5

10

15






Radio gischt + central hadronic halo giant radio halo


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Radio gischt + central hadronic halo = giant radio halo

10-8

10-6

10-4

10-2

100

S,total

[mJyarcm

in-2h70

3]

-15 -10 -5 0 5 10 15-15

-10

-5

0

5

10

15

-15 -10 -5 0 5 10 15

x [ h-1Mpc ]

-15

-10

-5

0

5

10

15

y

[h-1Mp

c]

-15 -10 -5 0 5 10 15-15

-10

-5

0

5

10

15






Which one is the simulation/observation of A2256?


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Which one is the simulation/observation of A2256?

red/yellow: thermal X-ray emission,

blue/contours: 1.4 GHz radio emission with giant radio halo and relic





Non-thermal processes in clusters



Observation simulation of A2256


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Observation simulation of A2256

Clarke & Enlin (2006) Pfrommer et al. (2008 in prep.)

red/yellow: thermal X-ray emission,

blue/contours: 1.4 GHz radio emission with giant radio halo and relic








Unified model of radio halos and relics


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Unified model of radio halos and relics

Cluster radio emission varies with dynamical stage of a cluster:

Cluster relaxes and develops cool core: radio mini-halo develops due to

hadronically produced CR electrons, magnetic fields are adiabatically

compressed (cooling gas triggers radio mode feedback of AGN that

outshines mini-halo selection effect).

Cluster experiences major merger: two leading shock waves are

produced that become stronger as they break at the shallow peripheralcluster potential shock-acceleration of primary electrons and

development of radio relics.

Generation of morphologically complex network of virializing shock

waves. Lower sound speed in the cluster outskirts lead to strong shocks

irregular distribution of primary electrons, MHD turbulence amplifiesmagnetic fields.

Giant radio halo develops due to (1) boost of the hadronically generated

radio emission in the center (2) irregular radio gischt emission in the

cluster outskirts.








Non-thermal emission from clusters


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Non thermal emission from clustersExploring the memory of structure formation

primary, shock-accelerated CR electrons resemble currentaccretion and merging shock waves

CR protons/hadronically produced CR electrons trace the timeintegrated non-equilibrium activities of clusters that is modulatedby the recent dynamical activities

How can we read out this information about non-thermal populations? new era of multi-frequency experiments, e.g.:

GMRT, LOFAR, MWA, LWA, SKA: interferometric array of radio

telescopes at low frequencies (

(15

240) MHz)Simbol-X/NuSTAR: future hard X-ray satellites (E (1100) keV)

Fermi -ray space telescope (E (0.1 300) GeV)

Imaging air Cerenkov telescopes (E (0.1 100) TeV)








Non-thermal emission from clusters


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Non thermal emission from clustersExploring the memory of structure formation

primary, shock-accelerated CR electrons resemble currentaccretion and merging shock waves

CR protons/hadronically produced CR electrons trace the timeintegrated non-equilibrium activities of clusters that is modulatedby the recent dynamical activities

How can we read out this information about non-thermal populations? new era of multi-frequency experiments, e.g.:

GMRT, LOFAR, MWA, LWA, SKA: interferometric array of radio

telescopes at low frequencies (

(15

240) MHz)Simbol-X/NuSTAR: future hard X-ray satellites (E (1100) keV)

Fermi -ray space telescope (E (0.1 300) GeV)

Imaging air Cerenkov telescopes (E (0.1 100) TeV)





Morphology and spectra


Minimum -ray flux

Outline


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Outline

1 Cosmological structure formation shocksCosmological galaxy cluster simulations



2

Diffuse radio emission in clustersGeneral picture of non-thermal processes in clusters





Minimum -ray flux







Minimum -ray flux

The quest for high-energy -ray emission from clusters


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The quest for high energy ray emission from clustersMulti-messenger approach towards fundamental astrophysics

1 complements current non-thermal observations of galaxyclusters in radio and hard X-rays:

identifying the nature of emission processes

unveiling the contribution of cosmic ray protons2 elucidates the nature of dark matter:

disentangling annihilation signal vs. CR induced -raysspectral and morphological -ray signatures DMproperties

3 probes plasma astrophysics such as macroscopic parametersfor diffusive shock acceleration







Minimum -ray flux

Hadronic -ray emission, E > 100 GeV


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Hadronic ray emission, E > 100 GeV

10-12

10-11

10

-10

10-9

10-8

S

(100GeV,

100TeV)[

cm-2s

-1h70

3]

-3 -2 -1 0 1 2 3-3

-2

-1

0

1

2

3

-3 -2 -1 0 1 2 3

x [ h-1Mpc ]

-3

-2

-1

0

1

2

3

y

[h-1Mpc]

-3 -2 -1 0 1 2 3-3

-2

-1

0

1

2

3







Minimum -ray flux

Inverse Compton emission, EIC > 100 GeV


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e se Co pto e ss o , IC > 00 Ge

10-12

10-11

10-10

10-9

10-8

S

(100GeV,

100TeV)[

cm-2s

-1h70

3]

-3 -2 -1 0 1 2 3-3

-2

-1

0

1

2

3

-3 -2 -1 0 1 2 3

x [ h-1Mpc ]

-3

-2

-1

0

1

2

3

y

[h-1Mpc]

-3 -2 -1 0 1 2 3-3

-2

-1

0

1

2

3







Minimum -ray flux

Total -ray emission, E > 100 GeV


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y ,

10-12

10-11

10-10

10-9

10-8

S

(100GeV,

100TeV

)[

cm-2s

-1h70

3]

-3 -2 -1 0 1 2 3-3

-2

-1

0

1

2

3

-3 -2 -1 0 1 2 3

x [ h-1Mpc ]

-3

-2

-1

0

1

2

3

y

[h-1Mpc]

-3 -2 -1 0 1 2 3-3

-2

-1

0

1

2

3







Minimum -ray flux

Universal CR spectrum in clusters


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p

GLAST: ~ 2.4

IACT: ~ 2.2p

p

10-4

10-2

100

102

104

106

108

1010

p

0.001

0.01

0.1

1

10

Normalized CR spectrum shows universal concave shape governed

mainly by hierarchical structure formation and adiabatic CR transport

processes. (Pinzke & Pfrommer, in prep.)







Minimum -ray flux

Gamma-ray scaling relations


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y g

1014

1015

1044

1045

1046

L

(E

>100Me

V)[

s-1h70

]

S1, B0 = 10G, B = 0.5

S2, B0 = 10G, B = 0.5

Scaling relation + complete sample of the brightest X-ray clusters (extended

HIFLUCGS) predictions for Fermi







Minimum -ray flux

Predicted cluster sample for Fermi
http://goback/http://find/http://goback/


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p

10-9

10-8

0

2

4

6

8

10

12

14model S3

Ophiu

chus,

Forna

x

Coma

A3627Pe

rseus,

Centau

rus,A1060

M49

AWM7

,3C129

NGC4

636

A075

4

Trian

gulum

Nclusters

F [cm2 s1]







Minimum -ray flux

Minimum -ray flux in the hadronic model (1)


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0.1 1.0 10.0

10-3

10-2

10-1

100

101

B[G]

j,IC(B)/j

,IC(BCMB)

j(B)/j(BCMB)

jIC(B)/jIC(BCMB)

For j(B) :

= 1 = 1.15

= 1.30

= 1.45

Synchrotron emissivity of high-

energy, steady state electrondistribution is independent of the

magnetic field for B BCMB!

Synchrotron luminosity:

L = A

dV nCRngas

(+1)/2B

CMB + B

A

dV nCRngas (B CMB)

-ray luminosity:

L = A

dV nCRngas

minimum -ray flux:

F,min =AA

L4D2







Minimum -ray flux



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0.1 1.0 10.0

10-3

10-2

10-1

100

101

B[G]

j,IC(B)/j

,IC(BCMB)

j(B)/j(BCMB)

jIC(B)/jIC(BCMB)

For j(B) :

= 1 = 1.15

= 1.30

= 1.45

Synchrotron emissivity of high-

energy, steady state electrondistribution is independent of the

magnetic field for B BCMB!

Synchrotron luminosity:

L = A

dV nCRngas

(+1)/2B

CMB + B

A

dV nCRngas (B CMB)

-ray luminosity:

L = A

dV nCRngas

minimum -ray flux:

F,min =AA

L4D2



Diffuse radio emission in clustersHigh-energy -ray emission


Predictions for FermiMinimum -ray flux



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Minimum -ray flux (E > 100 MeV) for the Coma cluster:

CR spectral index 2.0 2.3 2.6 2.9

F [1010cm2s1] 0.8 1.6 3.4 7.1

These limits can be made even tighter when consideringenergy constraints, PB < Pgas/20 and B-fields derivedfrom Faraday rotation studies, B0 = 3 G:F,COMA 2 10

9cm2s1 = FFermi, 2yr

Non-detection by Fermiseriously challenges the hadronicmodel.

Potential of measuring the CR acceleration efficiency for

diffusive shock acceleration.






Conclusions


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In contrast to the thermal plasma, the non-equilibrium distributions ofCRs preserve the information about their injection and transportprocesses and provide thus a unique window of current and paststructure formation processes and fundamental plasma astrophysics!

1 Cosmological hydrodynamical simulations are indispensable for

understanding non-thermal processes in galaxy clusters illuminating the process of structure formation

2 Unified model for the generation of giant radio halos, radiomini-halos, and relics: interplay of primary and secondarysynchrotron emission.

3 We predict Fermito detect ten -ray clusters: test of thepresented scenario






Literature for the talk


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Battaglia, Pfrommer, Sievers, Bond, Enlin, 2008, MNRAS, in print,

arXiv:0806.3272, Exploring the magnetized cosmic web through low frequencyradio emission

Pfrommer, 2008, MNRAS, 385, 1242 Simulating cosmic rays in clusters ofgalaxies III. Non-thermal scaling relations and comparison to observations

Pfrommer, Enlin, Springel, 2008, MNRAS, 385, 1211, Simulating cosmic rays inclusters of galaxies II. A unified scheme for radio halos and relics with

predictions of the-ray emissionPfrommer, Enlin, Springel, Jubelgas, Dolag, 2007, MNRAS, 378, 385,Simulating cosmic rays in clusters of galaxies I. Effects on theSunyaev-Zeldovich effect and the X-ray emission

Pfrommer, Springel, Enlin, Jubelgas, 2006, MNRAS, 367, 113,Detecting shock waves in cosmological smoothed particle hydrodynamics

simulationsEnlin, Pfrommer, Springel, Jubelgas, 2007, A&A, 473, 41,Cosmic ray physics in calculations of cosmological structure formation

Jubelgas, Springel, Enlin, Pfrommer, A&A, , 481, 33,Cosmic ray feedback in hydrodynamical simulations of galaxy formation






Diffuse low-frequency radio emission in Abell 521


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Brunetti et al. 2008, Nature, 455, 944:

colors: thermal X-ray emission, contours: diffuse radio emission, presence of radio structure at 610 MHz and their absence at three

times higher/lower frequency is incompatible with synchrotron theory!






Radio spectrum of radio halo in Abell 521


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Brunetti et al. 2008, Nature, 455, 944:

asterisks denote spectrum ofthe radio relic with 1.5

filled circles that of radio

halo with 2.1

radio halo interpretation:

re-acceleration of relativisticelectrons (Brunetti et al.)

hadronic model inconsistent

with spectra and morphologyradio relic interpretations:

aged population ofshock-accelerated electrons

populations of severalshock-compressed radioghosts (aged radio lobes)

polarization is key to differentiate


Pfrommer: Non-thermal emission from galaxy clusters

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