The structure of the ICM incosmological simulations

Klaus Dolag(∗)

Max-Planck-Institut f̈ur Astrophysik

(∗)

28/10/2005 – p.1

Hutt (High resolution Cluster set)48 Haloes (> 0.7 × 10

14Msol), up to4 × 106 Particles inRvir !

• DM-only (dm)• none radiative gas (gas)• cooling+starformation+winds (csf)• no/week/strong winds (csfnw,csf,csfsw)• thermal conduction (csfc)• new scheme to avoid damping of turbulence (gas nv)• Metals and chemical enrichment

⇒ talk of Luca Tornatore on ”chemical enrichment”

ICM, *

28/10/2005 – p.2

The revenge of the ICM�

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1.5

2.0

2.5

3.0

3.5

4.0

4.5

2.5 2.6 2.7 2.8 2.9 3.0 3.1 3.2 3.3 3.4 3.5

h−1

Mpc

−

subhalo position (DM sim.)subhalo position (GAS sim.)

main halo position

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0

0.002

0.004

0.006

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0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8

sigm

a 7.5

[(M

pc/h

)2 ]

redshift z

DM simulationGAS simulation

CSFC simulation

The presence of gas changes dynamics and profiles !• Strong lensing cross section decreases for none radiative

gas with strong turbulence (e.g. none thermal pressure)• Increases strongly for cooling and starformation.

Puchwein, Bartelmann, Dolag & Meneghetti 2005, A&A 422, 405-412 28/10/2005 – p.3

Structure of the ICM

Mass weighted temperature vs. emission weighted temperature !⇒ Predicted calibration depends on physics included !

28/10/2005 – p.4

Structure of the ICM

Emission is complex, mixture of dynamic & physical processes !

Shape crucial for interpretation of global quantities !Dolag et al. (in prep.) 28/10/2005 – p.4

Structure of the ICM

Mass weighted temperature vs. with of the gaussian fit !⇒ Correlated, but physics, e.g. thermal conduction !

28/10/2005 – p.4

Diagnostic of a Merger

Deviation from gaussianity contain information about dynamics !28/10/2005 – p.5

Diagnostic of a Merger

Gauss fit2−Gauss fit

Single and double gaussian fit to the emission distribution.⇒ with of gaussian not necessarily related to with ofdistribution! 28/10/2005 – p.5

Diagnostic of a Merger

M

T

g72 / gas

M(>3)

M(>1.5)

(Mach number by Pfrommer et al, in prep.)

Time evolution of Mass, Temperature and Mach-number.⇒ High Mach number related to outgoing shock ! 28/10/2005 – p.5

Diagnostic of a Merger

gasGauss2−Gauss

Evolution of single and double Gaussian fit during merger.⇒ no clear signal for high temperature tail ingas ! 28/10/2005 – p.5

Diagnostic of a Merger

csfGauss2−Gauss

Evolution of single and double Gaussian fit during merger.

⇒ double gaussian fit reveals substructure activity ! 28/10/2005 – p.5

Turbulence in the ICMOld viscosity scheme New viscosity scheme

Artificial viscosity completely switched of outside of shocks !• Instabilities less damped (e.g. Kelvin-Helmholtz).

⇒ Inset of turbulence

⇒ Enlarged energy-fraction in gas velocity

Dolag, Vazza, Brunetti, Tormen & Springel 2005, MNRAS in press (astro-ph/0507480)28/10/2005 – p.6

Turbulence in the ICM

lviscsviscovisc

Turbulence can leave to significant pressure support !⇒ Can change Lx up to a factor of 2 !

28/10/2005 – p.6

Turbulence in the ICM

Unsharpened masked: image - smoothed(image,200kpc)2Mpc x 2Mpc x-ray emission ofg1 comparing the two viscosityschemes.

28/10/2005 – p.6

Turbulence in the ICM

Unsharpened masked: image - smoothed(image,200kpc)2Mpc x 2Mpc pressure map (e.g. SZ) ofg1 comparing the twoviscosity schemes.

28/10/2005 – p.6

Turbulence in the ICM

Due to large contribution of bulk motions and beam smearing,

the imprint of “true“ turbulence will be hard to detect, even

resolution like Astro-E2 ! 28/10/2005 – p.6

Leia (Large filament Simulation)27 Haloes (> 0.7 × 10

14Msol), same resolution thanHutt• DM-only (dm)• none radiative gas (svisc)

log(T) [K]log(rho) [g/cm²]

D

a−c

d−b

c−d

a−d

B

A

C

Dolag et al. 2005, submitted28/10/2005 – p.7

The Filament

1 100 100010

1 100 100010

Density dominates over sheets till≈5 Mpc.

Higher temperature in the outskirts / towards voids. 28/10/2005 – p.8

The Filament

28/10/2005 – p.8

The Filament

r−3

r−2

13

40

22

31

ADistance from

Radial density profile along the filament.

Filament∝ r−2, Cluster∝ r−3, Outskirts steeper (∝ r−4?)28/10/2005 – p.8

The Filament

Radii for different density thresholds along the filament.⇒ Cluster felt at≈ 15 Mpc, region of influence 3-5Rvir !?

28/10/2005 – p.8

ConclusionsEmission distribution

• ICM in Complex state, depend on dynamics and physics• Diagnostic by modelling reveals interesting details

Turbulence

• Modelling needs sub grid physics• Potentially very interesting (Lx,κ,~B,CR,...)

Filaments

• Direct detection only by over-density of haloes (4-6)• Total contribution can change Lx (≈10%) and SZ (≈30%)• Cluster environment starts at 3-5Rvir

• Density within filament∝ r−2

28/10/2005 – p.9

S.O.S

S.O.S

B

S.O.S

S.O.S

Stars

Radio Emission

hard/soft X−RayRadio Ghosts

Sharp Edges (cold fronts !)

Cooling

Some Baryonic Matter

Lots of Dark Matter

Turbulence

Thermal Conduction

Lots of Dark Energy ?

EUV excess ?

Do

we u

nd

ersta

nd

ou

r "

wo

rld

" !?

Galaxy clusters as physics laboratory:

Thermal Emission

WHIM

28/10/2005 – p.10

Dark Energy, observedc

Pratt & Arnaud 2004

28/10/2005 – p.11

Dark Energy, observedc

Comparison with results obtained from numerical simulationswithin different cosmologies(from Dolag et al. 2004).

28/10/2005 – p.11