Transcript HIGH RESOLTION SPH SIMULATIONS OF GALAXY CLUSTERS

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 / 0501394
Void dwarf dark halos.
Gottlöber et al 03
Halo Mass function in Voids
The missing dwarf galaxy problem
in 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
Simulations done with GADGET2
Primordial Cooling
Photoionization
Multiphase medium
Star formation
Feedback
Thermal
Kinetic (Winds)
10/h Mpc
10243 effective particle in void region
Mgas = 5.5106 M
Mdark = 3.4107 M
Smoothing= 2-0.8 kpc
(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
The missing dwarf galaxy problem
in 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 fraction
Halos below
few times
109 Msun
are
baryon-poor
Characteristic
mass scale
depends on
redshift
Characteristic mass Mc
Mc rises
significantly
with z
baryon-rich
Halo may start
baryon-rich
and become
later
baryon-poor
baryon-poor
Density temperature phase space
Cold mode
of galactic gas
accretion:
gas creeps along
the equilibrium
line between
heating and
cooling
(Keres et al. 04)
Tentry
How to suppress gas condensation?
Max gas temperature
Relate radius to mass
Condition for suppression
Prediction for Mc
Measurement Mc
Entry temperature versus characteristic mass
General scaling:
factor 1.3
High redshift:
empty halos
has to
develop
Mass accretion history
Baryon poor small halos
total mass
baryonic (condensed) mass
Age of stars
In small halos
stars can only
be formed
at high
redshift
Luminosity function
Thermal feedback
Strong wind model
z=0
Color evolution
z=1
z=0
SOME CLUES ABOUT DWARF
GALAXIES IN VOIDS
Halos below Mlim~ 7x109 M (vc ~27 km/s) are photoevaporated 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:
Baryonfraction again
Metallicity enrichment:
Remove baryons by feedback?
Dekel+Woo
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

LCDM CLUSTER SIMULATIONS

Wm=0.3; WL=0.7, h=0.7; s8=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; a=3 A=1
z=0
LARGE-SCALE SPH SIMULATIONS

Wm=0.3; WL=0.7, h=0.7; s8=0.9, Wb=0.045

500/h Mpc box size. (Initial P(k) for 20483)

Runs with up to 5123 particles.



# Halos=4x105 (M>1012 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
Z=1; a=3 A=1
z=0
Lx-Tx
Clusters at
500 Mpc/h
Tx1.9
. Mvir > 1015 M
. 1014 < Mvir < 1015
.2x1013 < Mvir < 1014
Lx-Tx
Clusters at
500 Mpc/h
Tx1.9
. Mvir > 1015 M
. 1014 < Mvir < 1015
Observations
.2x1013 < Mvir < 1014
Lx-Tx
Clusters at
500 Mpc/h
Resimulated
clusters at
80 Mpc/h
Tx1.9
. Mvir > 1015 M
. 1014 < Mvir < 1015
Observations
.2x1013 < Mvir < 1014
X-ray Temperature Function
LARGE-SCALE SPH
SIMULATIONS
The MareNostrum
Universe Simulation:
500/h Mpc box size.
(Initial P(k) for 20483)
2x10243 particles.
# Halos=106 (M>1012 M)
 Mdark= 1010 M
 Resolution 15 kpc.
500 h-1 Mpc