GALAXIES IN DIFFERENT GALAXIES IN DIFFERENT ENVIRONMENTS: ENVIRONMENTS: VOIDS TO CLUSTERS: 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 DIFFERENT ENVIRONMENTS: VOIDS TO CLUSTERS: Simulations will require to model full physics: Cooling, heating, star formation feedbacks…
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GALAXIES IN DIFFERENT GALAXIES IN DIFFERENT ENVIRONMENTS: ENVIRONMENTS:
VOIDS TO CLUSTERS: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
GALAXIES IN VOIDSGALAXIES IN VOIDS
M. Hoeft, G. Yepes, S. Gottlober and V. SpringelM. Hoeft, G. Yepes, S. Gottlober and V. Springelastro-ph / 0501394astro-ph / 0501394
Void dwarf dark halos.Void dwarf dark halos.
Gottlöber et al 03Void dwarf galax
Halo Mass function in VoidsHalo Mass function in Voids
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?
VOIDS FROM A 80/h Mpc Box
1024102433 effective particle in void region effective particle in void region MMgas gas = = 5.5106 M MMdark dark = = 3.4107 M Smoothing= 2-0.8 kpcSmoothing= 2-0.8 kpc
10/h Mpc10/h Mpc Simulations done with GADGET2Simulations done with GADGET2Primordial CoolingPrimordial CoolingPhotoionization Photoionization Multiphase mediumMultiphase mediumStar formationStar formationFeedback Feedback
ThermalThermalKinetic (Winds)Kinetic (Winds)
• 20483 effective particles
• RUN with 10243
– Mgas = 1.5106 M
– Mdark= 8.2106 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
(ULTRA)HIGH-RESOLUTION SIMULATIONS OF A VOID IN THE 50/h Mpc Box
10/h Mpc10/h Mpc
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?
Baryon fractionBaryon fraction
Halos belowfew times109 Msun
arebaryon-poor
Characteristicmass scaledepends onredshift
Baryon fract
Characteristic massCharacteristic mass Mc
baryon-rich
baryon-poor
Mc risessignificantlywith z
Halo may startbaryon-richand becomelaterbaryon-poor
Char mass
Tentry
Density temperature phase spaceDensity temperature phase space
Cold modeof galactic gasaccretion:gas creeps alongthe equilibriumline betweenheating and cooling(Keres et al. 04)
Rho T
Max gas temperature
Relate radius to mass
Prediction for Mc
Measurement Mc
Condition for suppression
How to suppress gas condensation?How to suppress gas condensation?How to
Entry temperature versus characteristic massEntry temperature versus characteristic mass
General scaling:factor 1.3
High redshift:empty halos has todevelop
T entry
Mass accretion historyMass accretion historyMass accr hist
Baryon poor small halosBaryon poor small halosMAH, several
total mass baryonic (condensed) mass
Age of starsAge of stars
In small halosstars can onlybe formed at highredshift
Age
Thermal feedbackThermal feedback
Strong wind modelStrong wind model
z=0z=0
Luminosity functionLuminosity function
Color evolutionColor evolution
z=0z=0
z=1z=1
SOME CLUES ABOUT DWARF SOME CLUES ABOUT DWARF GALAXIES IN VOIDSGALAXIES 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,
WORK IN PROGRESS...
DWARF GALAXIES IN GROUPS:
Group five
Baryonfraction againBaryonfraction again
Baryonfraction again
Metallicity enrichment:Metallicity enrichment:Remove baryons by feedback?Remove baryons by feedback?
Dekel+Woo
Feedback
GALAXIES IN CLUSTERSGALAXIES 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.
STAR FORMATION IN STAR FORMATION IN CLUSTERS CLUSTERS
PhotonisationPhotonisationCoolingCoolingMultiphase mediumMultiphase mediumMetallicity Metallicity Wind modelWind model
Springel & Herquist 2003Springel & Herquist 2003
Obtain observational Obtain observational properties of dark halos from properties of dark halos from stars using BC2003 SSP stars using BC2003 SSP models models
Study Study
CDM CLUSTER SIMULATIONSCDM CLUSTER SIMULATIONS
m=0.3; =0.7, h=0.7;
8=0.9
● 80/h Mpc box size. (Initial P(k) for 10243)
● Resample to 1283 particles.
● Identify clusters for
resimulation
GADGET (2-5 kpc)
Z=1; =3 A=1
z=0
LARGE-SCALE SPH SIMULATIONS
m=0.3; =0.7, h=0.7;
8=0.9, b=0.045
500/h Mpc box size. (Initial P(k) for 20483) Runs with up to 5123 particles.