GALAXIES IN DIFFERENT ENVIRONMENTS: VOIDS TO CLUSTERS:

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GALAXIES IN DIFFERENT ENVIRONMENTS VOIDS TO
CLUSTERS

• Simulations will require to model full physics
• Cooling, heating, star formation feedbacks
• Large dynamical range resolving galaxies in
  different density environments.
• Important problems to address
• Excess of small scale structure in CDM models
  making small halos invisible?.
• Hubble sequence (formation of disks)
• Interactions galaxy -ICM

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GALAXIES IN VOIDS
M. Hoeft, G. Yepes, S. Gottlober and V.
Springel astro-ph / 0501394
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Void dwarf galax
Void dwarf dark halos.
Gottlöber et al 03
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Halo Mass function in Voids
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The missing dwarf galaxy problemin VOIDS

• No galaxies brighter than Mb-15 found.
• What happens with baryons of small halos in
  voids?
• Are they visible but faint?. Magnitude, colors.
  (Red Dwarfs)
• Are they just baryonless dark halos?
• What are the physical mechanism
• Gas evaporation by UV photoionization
• Supernova feedback (e.g Dekel Silk)
• What is the typical halo mass for this to happen?

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VOIDS FROM A 80/h Mpc Box
10/h Mpc
Simulations done with GADGET2 Primordial
Cooling Photoionization Multiphase
medium Star formation Feedback
Thermal Kinetic (Winds)
10243 effective particle in void region Mgas
5.5?106 M? Mdark 3.4?107 M?
Smoothing 2-0.8 kpc
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(ULTRA)HIGH-RESOLUTION SIMULATIONS OF A VOID IN
THE 50/h Mpc Box

• 20483 effective particles
• RUN with 10243
• Mgas 1.5?106 M?
• Mdark 8.2?106 M?
• Spatial smoothing 0.5 kpc
• Different feedback params.
• Same void was resimulated
• with full resolution 20483
• Mgas ? 2 ?105 M?
• Mdark? 106 M?
• Spatial smoothing 0.5 kpc

10/h Mpc
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The missing dwarf galaxy problemin VOIDS

• No galaxies brighter than Mb-15 found.
• What happens with baryons of small halos in
  voids?
• Are they visible but faint?. Magnitude, colors.
  (Red Dwarfs)
• Are they just baryonless dark halos?
• What are the physical mechanism
• Gas evaporation by UV photoionization
• Supernova feedback (e.g Dekel Silk)
• What is the typical halo mass for this to happen?

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Baryon fract
Baryon fraction
Halos below few times 109 Msun are baryon-poor Ch
aracteristic mass scale depends on redshift
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Char mass
Characteristic mass Mc
Mc rises significantly with z Halo may
start baryon-rich and become later baryon-poor
baryon-rich
baryon-poor
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Rho T
Density temperature phase space
Cold mode of galactic gas accretion gas creeps
along the equilibrium line between heating and
cooling (Keres et al. 04)
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How to
How to suppress gas condensation?
Max gas temperature
Relate radius to mass
Prediction for Mc
Measurement Mc
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T entry
Entry temperature versus characteristic mass
General scaling factor 1.3 High redshift empty
halos has to develop
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Mass accr hist
Mass accretion history
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MAH, several
Baryon poor small halos
total mass
baryonic (condensed) mass
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Age
Age of stars
In small halos stars can only be formed at
high redshift
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Luminosity function
Thermal feedback
Strong wind model
z0
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Color evolution
z1
z0
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SOME CLUES ABOUT DWARF GALAXIES IN VOIDS

• Halos below Mlim 7x109 M? (vc 27 km/s) are
  photo-evaporated and have almost no baryon
  content, either cold gas or stars. This mass
  scale decreases with redshift. Very small
  dependence of UV flux.
• UV-heating not able to suppress small galaxies
  Problem for semianalitical models to explain
  substructure in the Local Group.
• Thermal feedback does not play a significant role
  in keeping gas out of halos.
• Kinetic feedback (winds) can be very efficient
  in inhibitting star-formation Z agreement,
  redder colors,

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WORK IN PROGRESS...
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DWARF GALAXIES IN GROUPS
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Group five
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Baryonfraction again
Baryonfraction again
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Feedback
Metallicity enrichment Remove baryons by
feedback?
DekelWoo
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GALAXIES IN CLUSTERS

• Entropy generation from galactic feedback.
• Scaling relations and non-adiabatic physics.
• Understanding Intracluster light.
• Effect of central Cd-galaxy on ICM radial
  profiles.
• Cold fronts and cold flows.
• How many galaxies survive in the cluster
  environment?
• Very demanding simulations
• E.g. Cluster 6 simulated with 4.5 million
  particles within 3 virial radius took more than
  680,000 timesteps to finished.

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STAR FORMATION IN CLUSTERS

• Photonisation
• Cooling
• Multiphase medium
• Metallicity
• Wind model
• Springel Herquist 2003
• Obtain observational properties of dark halos
  from stars using BC2003 SSP models
• Study

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LCDM CLUSTER SIMULATIONS

• Wm0.3 WL0.7, h0.7 s80.9
• 80/h Mpc box size. (Initial P(k) for 10243)
• Resample to 1283 particles.
• Identify clusters for
• resimulation
• GADGET (2-5 kpc)

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Z1 a3 A1
z0
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LARGE-SCALE SPH SIMULATIONS

• Wm0.3 WL0.7, h0.7 s80.9, Wb0.045
• 500/h Mpc box size. (Initial P(k) for 20483)
• Runs with up to 5123 particles.
• Halos4x105 (Mgt1012 M?)
• Mdark 7x1010 M?
• Identify clusters for
• resimulation with 1283
• Mass of clusters
• Mcluster ? 2.5?1015 M?
• Same resolution than
• previous simulations

500 h-1 Mpc
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Z1 a3 A1
z0
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Lx-Tx
Clusters at 500 Mpc/h
Tx1.9
. Mvir gt 1015 M? . 1014 lt Mvir lt 1015 .2x1013 lt
Mvir lt 1014
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Lx-Tx
Clusters at 500 Mpc/h
Tx1.9
. Mvir gt 1015 M? . 1014 lt Mvir lt 1015 .2x1013 lt
Mvir lt 1014
Observations
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Lx-Tx
Clusters at 500 Mpc/h
Tx1.9
Resimulated clusters at 80 Mpc/h
. Mvir gt 1015 M? . 1014 lt Mvir lt 1015 .2x1013 lt
Mvir lt 1014
Observations
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X-ray Temperature Function
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LARGE-SCALE SPH SIMULATIONS

• The MareNostrum Universe Simulation
• 500/h Mpc box size. (Initial P(k) for 20483)
• 2x10243 particles.
• Halos106 (Mgt1012 M?)
• Mdark 1010 M?
• Resolution 15 kpc.

500 h-1 Mpc