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

GALAXIES IN VOIDS M. Hoeft, G. Yepes, S. Gottlober and V. Springel astro-ph /

Void dwarf dark halos. Gottlöber et al 03 Void dwarf galax

Halo Mass function in Voids

The missing dwarf galaxy problem in VOIDS ● No galaxies brighter than M b =-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 effective particle in void region M gas = M gas = 5.5  10 6 M  M dark = M dark = 3.4  10 7 M  Smoothing= kpc Smoothing= kpc 10/h Mpc Simulations done with GADGET2 Primordial Cooling Photoionization Multiphase medium Star formation FeedbackThermal Kinetic (Winds)

effective particles RUN with –M gas = 1.5  10 6 M  –M dark = 8.2  10 6 M  Spatial smoothing= 0.5 kpc Different feedback params. Same void was resimulated with full resolution –M gas  2  10 5 M  –M dark  10 6 M  –Spatial smoothing= 0.5 kpc (ULTRA)HIGH-RESOLUTION SIMULATIONS OF A VOID IN THE 50/h Mpc Box 10/h Mpc

The missing dwarf galaxy problem in VOIDS ● No galaxies brighter than M b =-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 fraction Halos below few times 10 9 M sun are baryon-poor Characteristic mass scale depends on redshift Baryon fract

Characteristic mass Characteristic mass M c baryon-rich baryon-poor M c rises significantly with z Halo may start baryon-rich and become later baryon-poor Char mass

T entry Density temperature phase space Cold mode of galactic gas accretion: gas creeps along the equilibrium line between heating and cooling (Keres et al. 04) Rho T

Max gas temperature Relate radius to mass Prediction for M c Measurement M c Condition for suppression How to suppress gas condensation? How to

Entry temperature versus characteristic mass General scaling: factor 1.3 High redshift: empty halos has to develop T entry

Mass accretion history Mass accr hist

Baryon poor small halos MAH, several total massbaryonic (condensed) mass

Age of stars In small halos stars can only be formed at high redshift Age

Thermal feedback Strong wind model z=0 Luminosity function

Color evolution z=0 z=1

SOME CLUES ABOUT DWARF GALAXIES IN VOIDS Halos below M lim ~ 7x10 9 M  (v c ~ 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 again

Metallicity enrichment: Remove baryons by feedback? Dekel+Woo Feedback

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.

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

 CDM CLUSTER SIMULATIONS   m =0.3;   =0.7, h=0.7;  8 =0.9 ● 80/h Mpc box size. (Initial P(k) for ) ● Resample to 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 )  Runs with up to particles.  # Halos=4x10 5 (M>10 12 M  )  M dark = 7x10 10 M   Identify clusters for resimulation with  Mass of clusters  M cluster  2.5  M   Same resolution than previous simulations 500 h -1 Mpc

Z=1;  =3 A=1 z=0

Lx-Tx T x 1.9. M vir > M  < M vir < x10 13 < M vir < Clusters at 500 Mpc/h

Lx-Tx. M vir > M  < M vir < x10 13 < M vir < T x 1.9 Observations Clusters at 500 Mpc/h

Lx-Tx. M vir > M  < M vir < x10 13 < M vir < T x 1.9 Observations Clusters at 500 Mpc/h Resimulated clusters at 80 Mpc/h

X-ray Temperature Function

LARGE-SCALE SPH SIMULATIONS  The MareNostrum Universe Simulation:  500/h Mpc box size. (Initial P(k) for )  2x particles.  # Halos=10 6 (M>10 12 M  )  M dark = M   Resolution 15 kpc. 500 h -1 Mpc