cosmological n-body simulation - topology of large scale structure
DESCRIPTION
Cosmological N-Body Simulation - Topology of Large scale Structure. CCP 2006. 8. 29. Changbom Park with Juhan Kim (Korea Institute for Advanced Study) & J. R. Gott (Princeton) , J. Dubinski (CITA). History of Universe. Theme: Origin & Formation Mechanism of Cosmic Structures. - PowerPoint PPT PresentationTRANSCRIPT
Cosmological N-Body Simulation - Topology of Large scale Structure
Changbom Parkwith Juhan Kim
(Korea Institute for Advanced Study)amp J R Gott (Princeton) J Dubinski (CITA)
CCP 2006 8 29
History of Universe
Theme Theme Origin amp Formation Mechanism Origin amp Formation Mechanism of Cosmic Structuresof Cosmic Structures
1 Want to know1 Want to knowOriginOrigin ndash primordial density fluctuations from inflation ndash primordial density fluctuations from inflation
Formation MechanismFormation Mechanism ndash galaxies form at peaks in density field smoot ndash galaxies form at peaks in density field smoothed over galactic scalehed over galactic scale
2 Time is ripe2 Time is ripeLarge redshift surveys of galaxies Large redshift surveys of galaxies
High precision measurements ofHigh precision measurements of
1 Relations among 1 Relations among internal physical propertiesinternal physical properties
2 Relations between 2 Relations between internal properties and internal properties and
spatial amp temporal environmentsspatial amp temporal environments
SDSS2006
CfA1986
SDSS galaxies
h-1Mpc
(Park et al 2005 ApJ 633 11)
Effects of NL Gravitational Evolution Biasing amp Redshift Space Distortion on galaxy clustering amp properties
For PRECISION COMPARISONFor PRECISION COMPARISON between cosmological models with observationsbetween cosmological models with observations
Cosmological N-Body Simulation
Cosmological N-Body Simulation
Requirement for galaxy formation studyRequirement for galaxy formation study
1 Several times larger than largest survey gtgt 1000 h1 Several times larger than largest survey gtgt 1000 h-1-1MpcMpc
for LSS formation + galaxy formation velocity field for LSS formation + galaxy formation velocity field
SDSS[2006] ~ 500 h SDSS[2006] ~ 500 h-1-1Mpc Hubble Depth S[2015] ~ 2000 hMpc Hubble Depth S[2015] ~ 2000 h-1-1MpcMpc
2 Should resolve objects with ltlt102 Should resolve objects with ltlt101111 h h-1-1MMsunsun (~ M (~ M+2)+2)
mean separation lt 02 h mean separation lt 02 h-1-1MpcMpc
currently 02~2000Mpccurrently 02~2000Mpc
Number of particles gt 5000Number of particles gt 500033 ~ 10000 ~ 1000033 will do will do
(100~1000 billion =10~100 current maximum)(100~1000 billion =10~100 current maximum)
Cosmological N-Body Simulation
ProgressesProgresses
~ 104 CPUs
gt 1010 particles
Log N=02(Y-1970)+2
TreePM CodeTreePM Code11
About CodeAbout Code
1 Long range (rgt4 pixels 1 Long range (rgt4 pixels PMPM) + Short range() + Short range(PMPM++TreeTree) G-forces) G-forces
2 Tree generation in each slab amp in each cube of 42 Tree generation in each slab amp in each cube of 433 pixels pixels
3 Min of particles for tree generation ndash Direct P3 Min of particles for tree generation ndash Direct P22 if (cube) lt N if (cube) lt Ntreetree
4 Memory ~3 4 Memory ~3 xx [16] [16] xx words per particle words per particle
16 per particle index 16 per particle index22 position position33 velocity velocity33 acceleration acceleration33 mass mass11
softening length computational work measurement pointersoftening length computational work measurement pointer
factor ~3 for memory imbalance factor ~3 for memory imbalance
Buffer zone particles Buffer zone particles
TreePM Gravitational Force
PMPM
Tree + PMTree + PM
PMPM
ForceForce
GaussianSmoothed RG=09 pixels
TreePM CodeTreePM Code22
AdvantagesAdvantages
1 O(N log N) Tree operations for short range force ndash unlike P1 O(N log N) Tree operations for short range force ndash unlike P33MM
2 Periodic boundary condition solved by PM ndash unlike Tree2 Periodic boundary condition solved by PM ndash unlike Tree
3 No need to build a global tree ndash force correction only out to 4 pixels3 No need to build a global tree ndash force correction only out to 4 pixels
4 Local Trees 4 Local Trees
Parallelizable by domain decomposition (time)Parallelizable by domain decomposition (time)
amp disposable local trees keeping trees in 8amp disposable local trees keeping trees in 8xx88xxnnzz pixels (memory) pixels (memory)
Parallelization
1 PM part 2 Tree part1 PM part 2 Tree part
Domain slabs of equal thickness Domain slabs of equal of Domain slabs of equal thickness Domain slabs of equal of
tree force interactions amptree force interactions amp Buffer zone particlesBuffer zone particles
TreePM CodeTreePM Code33
5 Accuracy ~ 05 5 Accuracy ~ 05 RMSRMS error in acceleration for error in acceleration for θθ=1=1
6 Performance6 Performance
CPU time per step
1024102433 particles particles
Regular backup amp Regular backup amp
Pre-halo finding Pre-halo finding
calculationcalculation
Load balance
1024102433 particles particles
of particles of particles
in domain slabsin domain slabs
homogeneous homogeneous
distributiondistribution
ΛΛCDM SimulationsCDM Simulations (Ki
m amp Park 2004 7)
TreePM codeTreePM code GOTPM (Dubinski Kim Park 2003)
2048204833 mesh mesh (initial condition)
2048204833 CDM particles CDM particles
1024 amp 5632 h1024 amp 5632 h-1-1MpcMpc size boxes
50 amp 275 h50 amp 275 h-1-1kpckpc force resolutions
FOR PRECISION COMPARISON between cosmological models amp real universe
Using IBM SP3 at KISTI 128 CPUs 900 Gbytes
Growth of Structures from initial Density Fluctuations
137b
118b
77b t=0
Dark Halo Identification(Kimamp Park 2006
ΛΛCDMCDM 1024 h1024 h-1-1MpcMpc)
Physically Self-Bound Halos
Halo centers - local density peaks
Binding E wrt local halo centers
Tidal radii of subhalos wrt bigger halos
Halos with gt=53 particles (5x1011 M⊙)
PSB HalosVS
Others
Topology studyTopology study
1 Gaussianity of the 1 Gaussianity of the linear (primordial) density fieldlinear (primordial) density field pr predicted by simple inflationary scenariosedicted by simple inflationary scenarios
2 Topology of galaxy distribution at NL scales sensitive 2 Topology of galaxy distribution at NL scales sensitive to to cosmological parameterscosmological parameters amp to amp to galaxy formation mechanismgalaxy formation mechanism
3 Direct Intuitive meaning3 Direct Intuitive meaning
Large ScalesLarge Scales Small ScalesSmall Scales
Primordial Gaussianity Galaxy FormationPrimordial Gaussianity Galaxy Formation
Cosmological ParametersCosmological Parameters
GenusGenus ndash A Measure of Topologyndash A Measure of Topology
DefinitionDefinition
G = of holes - of isolated regionsG = of holes - of isolated regions in iso-density contour surfacesin iso-density contour surfaces
= 14= 14ππ intintSS κ dA (Gauss-Bonnet Theorem) κ dA (Gauss-Bonnet Theorem)
[ex G(sphere)=-1 G(torus)=0 ][ex G(sphere)=-1 G(torus)=0 ]
2 holes ndash 1 body = +1
Gaussian FieldGaussian Field Genusunit volume g(ν) = A (1-νGenusunit volume g(ν) = A (1-ν22) exp(- ν) exp(- ν222)2) where ν=(ρ- ρwhere ν=(ρ- ρbb) ρ) ρbbσ amp σ amp
A=1(2π)A=1(2π)22 ltk ltk223gt3gt32 32
if P(k)~kif P(k)~knn A R A RGG33 =[8radic2π =[8radic2π22]]-1 -1 [(n+3)3][(n+3)3]32 32
Non-Gaussian FieldNon-Gaussian Field (Toy models) (Toy models)
Clusters Bubbles HDM
(Weinberg Gott amp Melott 1987)(Weinberg Gott amp Melott 1987)
Non-Gaussianity Genus-related statisticsNon-Gaussianity Genus-related statistics
1 Shift parameter 1 Shift parameter 2 Asymmetry parameters A2 Asymmetry parameters AC C AAVV
3 Amplitude drop R3 Amplitude drop RAAAAobsobsAAPSPS
ACAv
RA
Biased Biased Formation Formation of Galaxiesof Galaxies
L-dependence L-dependence of 1 amp 2 point of 1 amp 2 point distribution distribution
but also but also topology topology
(Park et al 2005)
Topology of LSS can be explained by Topology of LSS can be explained by GF modelsGF models
(Park Kim et al 2005)
Merger Merger Halo formation Halo formationvoid percolationvoid percolation
void splittingvoid splitting
LCDM1024LCDM1024
Matter field canrsquot
Topology of LSS can be explained by Topology of LSS can be explained by GF modelsGF models
Direction of Direction of evolution evolution
~1 amp Little evoluti~1 amp Little evolution at low zon at low z
Mergers of hMergers of halosalos
AV lt 1
ltNltNsatsatgt = (MMgt = (MM11))αα for MgtM for MgtMminmin whe whe
re logMre logMminmin=1176 log M=1176 log M11=1=1
315 315 αα=113=113
HOD model for VL sHOD model for VL sample Mample Mrrlt-195lt-195
(Park et al 2005)Probably yes
Comparison of topology SDSS vs Comparison of topology SDSS vs CDM CDM
SDSS amp 6 h-1Mpc scale Kim+Park(o) amp Springel(x)
Future ofCosmological N-Body
Simulation1 Useful for cosmology amp galaxy formation study1 Useful for cosmology amp galaxy formation study
(until star formation can be properly simulated by radiati(until star formation can be properly simulated by radiative hydro-codes)ve hydro-codes)
2 Need to reach of particles gtgt 50002 Need to reach of particles gtgt 500033 ~ 10000 ~ 1000033
(10~100 current maximum)(10~100 current maximum)
Dynamic range for other studiesDynamic range for other studies Internal properties amp environment 1kpc ~ 100 Mpc Internal properties amp environment 1kpc ~ 100 Mpc
Galactic structure amp star formation 01pc ~ 100kpc Galactic structure amp star formation 01pc ~ 100kpc
History of Universe
Theme Theme Origin amp Formation Mechanism Origin amp Formation Mechanism of Cosmic Structuresof Cosmic Structures
1 Want to know1 Want to knowOriginOrigin ndash primordial density fluctuations from inflation ndash primordial density fluctuations from inflation
Formation MechanismFormation Mechanism ndash galaxies form at peaks in density field smoot ndash galaxies form at peaks in density field smoothed over galactic scalehed over galactic scale
2 Time is ripe2 Time is ripeLarge redshift surveys of galaxies Large redshift surveys of galaxies
High precision measurements ofHigh precision measurements of
1 Relations among 1 Relations among internal physical propertiesinternal physical properties
2 Relations between 2 Relations between internal properties and internal properties and
spatial amp temporal environmentsspatial amp temporal environments
SDSS2006
CfA1986
SDSS galaxies
h-1Mpc
(Park et al 2005 ApJ 633 11)
Effects of NL Gravitational Evolution Biasing amp Redshift Space Distortion on galaxy clustering amp properties
For PRECISION COMPARISONFor PRECISION COMPARISON between cosmological models with observationsbetween cosmological models with observations
Cosmological N-Body Simulation
Cosmological N-Body Simulation
Requirement for galaxy formation studyRequirement for galaxy formation study
1 Several times larger than largest survey gtgt 1000 h1 Several times larger than largest survey gtgt 1000 h-1-1MpcMpc
for LSS formation + galaxy formation velocity field for LSS formation + galaxy formation velocity field
SDSS[2006] ~ 500 h SDSS[2006] ~ 500 h-1-1Mpc Hubble Depth S[2015] ~ 2000 hMpc Hubble Depth S[2015] ~ 2000 h-1-1MpcMpc
2 Should resolve objects with ltlt102 Should resolve objects with ltlt101111 h h-1-1MMsunsun (~ M (~ M+2)+2)
mean separation lt 02 h mean separation lt 02 h-1-1MpcMpc
currently 02~2000Mpccurrently 02~2000Mpc
Number of particles gt 5000Number of particles gt 500033 ~ 10000 ~ 1000033 will do will do
(100~1000 billion =10~100 current maximum)(100~1000 billion =10~100 current maximum)
Cosmological N-Body Simulation
ProgressesProgresses
~ 104 CPUs
gt 1010 particles
Log N=02(Y-1970)+2
TreePM CodeTreePM Code11
About CodeAbout Code
1 Long range (rgt4 pixels 1 Long range (rgt4 pixels PMPM) + Short range() + Short range(PMPM++TreeTree) G-forces) G-forces
2 Tree generation in each slab amp in each cube of 42 Tree generation in each slab amp in each cube of 433 pixels pixels
3 Min of particles for tree generation ndash Direct P3 Min of particles for tree generation ndash Direct P22 if (cube) lt N if (cube) lt Ntreetree
4 Memory ~3 4 Memory ~3 xx [16] [16] xx words per particle words per particle
16 per particle index 16 per particle index22 position position33 velocity velocity33 acceleration acceleration33 mass mass11
softening length computational work measurement pointersoftening length computational work measurement pointer
factor ~3 for memory imbalance factor ~3 for memory imbalance
Buffer zone particles Buffer zone particles
TreePM Gravitational Force
PMPM
Tree + PMTree + PM
PMPM
ForceForce
GaussianSmoothed RG=09 pixels
TreePM CodeTreePM Code22
AdvantagesAdvantages
1 O(N log N) Tree operations for short range force ndash unlike P1 O(N log N) Tree operations for short range force ndash unlike P33MM
2 Periodic boundary condition solved by PM ndash unlike Tree2 Periodic boundary condition solved by PM ndash unlike Tree
3 No need to build a global tree ndash force correction only out to 4 pixels3 No need to build a global tree ndash force correction only out to 4 pixels
4 Local Trees 4 Local Trees
Parallelizable by domain decomposition (time)Parallelizable by domain decomposition (time)
amp disposable local trees keeping trees in 8amp disposable local trees keeping trees in 8xx88xxnnzz pixels (memory) pixels (memory)
Parallelization
1 PM part 2 Tree part1 PM part 2 Tree part
Domain slabs of equal thickness Domain slabs of equal of Domain slabs of equal thickness Domain slabs of equal of
tree force interactions amptree force interactions amp Buffer zone particlesBuffer zone particles
TreePM CodeTreePM Code33
5 Accuracy ~ 05 5 Accuracy ~ 05 RMSRMS error in acceleration for error in acceleration for θθ=1=1
6 Performance6 Performance
CPU time per step
1024102433 particles particles
Regular backup amp Regular backup amp
Pre-halo finding Pre-halo finding
calculationcalculation
Load balance
1024102433 particles particles
of particles of particles
in domain slabsin domain slabs
homogeneous homogeneous
distributiondistribution
ΛΛCDM SimulationsCDM Simulations (Ki
m amp Park 2004 7)
TreePM codeTreePM code GOTPM (Dubinski Kim Park 2003)
2048204833 mesh mesh (initial condition)
2048204833 CDM particles CDM particles
1024 amp 5632 h1024 amp 5632 h-1-1MpcMpc size boxes
50 amp 275 h50 amp 275 h-1-1kpckpc force resolutions
FOR PRECISION COMPARISON between cosmological models amp real universe
Using IBM SP3 at KISTI 128 CPUs 900 Gbytes
Growth of Structures from initial Density Fluctuations
137b
118b
77b t=0
Dark Halo Identification(Kimamp Park 2006
ΛΛCDMCDM 1024 h1024 h-1-1MpcMpc)
Physically Self-Bound Halos
Halo centers - local density peaks
Binding E wrt local halo centers
Tidal radii of subhalos wrt bigger halos
Halos with gt=53 particles (5x1011 M⊙)
PSB HalosVS
Others
Topology studyTopology study
1 Gaussianity of the 1 Gaussianity of the linear (primordial) density fieldlinear (primordial) density field pr predicted by simple inflationary scenariosedicted by simple inflationary scenarios
2 Topology of galaxy distribution at NL scales sensitive 2 Topology of galaxy distribution at NL scales sensitive to to cosmological parameterscosmological parameters amp to amp to galaxy formation mechanismgalaxy formation mechanism
3 Direct Intuitive meaning3 Direct Intuitive meaning
Large ScalesLarge Scales Small ScalesSmall Scales
Primordial Gaussianity Galaxy FormationPrimordial Gaussianity Galaxy Formation
Cosmological ParametersCosmological Parameters
GenusGenus ndash A Measure of Topologyndash A Measure of Topology
DefinitionDefinition
G = of holes - of isolated regionsG = of holes - of isolated regions in iso-density contour surfacesin iso-density contour surfaces
= 14= 14ππ intintSS κ dA (Gauss-Bonnet Theorem) κ dA (Gauss-Bonnet Theorem)
[ex G(sphere)=-1 G(torus)=0 ][ex G(sphere)=-1 G(torus)=0 ]
2 holes ndash 1 body = +1
Gaussian FieldGaussian Field Genusunit volume g(ν) = A (1-νGenusunit volume g(ν) = A (1-ν22) exp(- ν) exp(- ν222)2) where ν=(ρ- ρwhere ν=(ρ- ρbb) ρ) ρbbσ amp σ amp
A=1(2π)A=1(2π)22 ltk ltk223gt3gt32 32
if P(k)~kif P(k)~knn A R A RGG33 =[8radic2π =[8radic2π22]]-1 -1 [(n+3)3][(n+3)3]32 32
Non-Gaussian FieldNon-Gaussian Field (Toy models) (Toy models)
Clusters Bubbles HDM
(Weinberg Gott amp Melott 1987)(Weinberg Gott amp Melott 1987)
Non-Gaussianity Genus-related statisticsNon-Gaussianity Genus-related statistics
1 Shift parameter 1 Shift parameter 2 Asymmetry parameters A2 Asymmetry parameters AC C AAVV
3 Amplitude drop R3 Amplitude drop RAAAAobsobsAAPSPS
ACAv
RA
Biased Biased Formation Formation of Galaxiesof Galaxies
L-dependence L-dependence of 1 amp 2 point of 1 amp 2 point distribution distribution
but also but also topology topology
(Park et al 2005)
Topology of LSS can be explained by Topology of LSS can be explained by GF modelsGF models
(Park Kim et al 2005)
Merger Merger Halo formation Halo formationvoid percolationvoid percolation
void splittingvoid splitting
LCDM1024LCDM1024
Matter field canrsquot
Topology of LSS can be explained by Topology of LSS can be explained by GF modelsGF models
Direction of Direction of evolution evolution
~1 amp Little evoluti~1 amp Little evolution at low zon at low z
Mergers of hMergers of halosalos
AV lt 1
ltNltNsatsatgt = (MMgt = (MM11))αα for MgtM for MgtMminmin whe whe
re logMre logMminmin=1176 log M=1176 log M11=1=1
315 315 αα=113=113
HOD model for VL sHOD model for VL sample Mample Mrrlt-195lt-195
(Park et al 2005)Probably yes
Comparison of topology SDSS vs Comparison of topology SDSS vs CDM CDM
SDSS amp 6 h-1Mpc scale Kim+Park(o) amp Springel(x)
Future ofCosmological N-Body
Simulation1 Useful for cosmology amp galaxy formation study1 Useful for cosmology amp galaxy formation study
(until star formation can be properly simulated by radiati(until star formation can be properly simulated by radiative hydro-codes)ve hydro-codes)
2 Need to reach of particles gtgt 50002 Need to reach of particles gtgt 500033 ~ 10000 ~ 1000033
(10~100 current maximum)(10~100 current maximum)
Dynamic range for other studiesDynamic range for other studies Internal properties amp environment 1kpc ~ 100 Mpc Internal properties amp environment 1kpc ~ 100 Mpc
Galactic structure amp star formation 01pc ~ 100kpc Galactic structure amp star formation 01pc ~ 100kpc
Theme Theme Origin amp Formation Mechanism Origin amp Formation Mechanism of Cosmic Structuresof Cosmic Structures
1 Want to know1 Want to knowOriginOrigin ndash primordial density fluctuations from inflation ndash primordial density fluctuations from inflation
Formation MechanismFormation Mechanism ndash galaxies form at peaks in density field smoot ndash galaxies form at peaks in density field smoothed over galactic scalehed over galactic scale
2 Time is ripe2 Time is ripeLarge redshift surveys of galaxies Large redshift surveys of galaxies
High precision measurements ofHigh precision measurements of
1 Relations among 1 Relations among internal physical propertiesinternal physical properties
2 Relations between 2 Relations between internal properties and internal properties and
spatial amp temporal environmentsspatial amp temporal environments
SDSS2006
CfA1986
SDSS galaxies
h-1Mpc
(Park et al 2005 ApJ 633 11)
Effects of NL Gravitational Evolution Biasing amp Redshift Space Distortion on galaxy clustering amp properties
For PRECISION COMPARISONFor PRECISION COMPARISON between cosmological models with observationsbetween cosmological models with observations
Cosmological N-Body Simulation
Cosmological N-Body Simulation
Requirement for galaxy formation studyRequirement for galaxy formation study
1 Several times larger than largest survey gtgt 1000 h1 Several times larger than largest survey gtgt 1000 h-1-1MpcMpc
for LSS formation + galaxy formation velocity field for LSS formation + galaxy formation velocity field
SDSS[2006] ~ 500 h SDSS[2006] ~ 500 h-1-1Mpc Hubble Depth S[2015] ~ 2000 hMpc Hubble Depth S[2015] ~ 2000 h-1-1MpcMpc
2 Should resolve objects with ltlt102 Should resolve objects with ltlt101111 h h-1-1MMsunsun (~ M (~ M+2)+2)
mean separation lt 02 h mean separation lt 02 h-1-1MpcMpc
currently 02~2000Mpccurrently 02~2000Mpc
Number of particles gt 5000Number of particles gt 500033 ~ 10000 ~ 1000033 will do will do
(100~1000 billion =10~100 current maximum)(100~1000 billion =10~100 current maximum)
Cosmological N-Body Simulation
ProgressesProgresses
~ 104 CPUs
gt 1010 particles
Log N=02(Y-1970)+2
TreePM CodeTreePM Code11
About CodeAbout Code
1 Long range (rgt4 pixels 1 Long range (rgt4 pixels PMPM) + Short range() + Short range(PMPM++TreeTree) G-forces) G-forces
2 Tree generation in each slab amp in each cube of 42 Tree generation in each slab amp in each cube of 433 pixels pixels
3 Min of particles for tree generation ndash Direct P3 Min of particles for tree generation ndash Direct P22 if (cube) lt N if (cube) lt Ntreetree
4 Memory ~3 4 Memory ~3 xx [16] [16] xx words per particle words per particle
16 per particle index 16 per particle index22 position position33 velocity velocity33 acceleration acceleration33 mass mass11
softening length computational work measurement pointersoftening length computational work measurement pointer
factor ~3 for memory imbalance factor ~3 for memory imbalance
Buffer zone particles Buffer zone particles
TreePM Gravitational Force
PMPM
Tree + PMTree + PM
PMPM
ForceForce
GaussianSmoothed RG=09 pixels
TreePM CodeTreePM Code22
AdvantagesAdvantages
1 O(N log N) Tree operations for short range force ndash unlike P1 O(N log N) Tree operations for short range force ndash unlike P33MM
2 Periodic boundary condition solved by PM ndash unlike Tree2 Periodic boundary condition solved by PM ndash unlike Tree
3 No need to build a global tree ndash force correction only out to 4 pixels3 No need to build a global tree ndash force correction only out to 4 pixels
4 Local Trees 4 Local Trees
Parallelizable by domain decomposition (time)Parallelizable by domain decomposition (time)
amp disposable local trees keeping trees in 8amp disposable local trees keeping trees in 8xx88xxnnzz pixels (memory) pixels (memory)
Parallelization
1 PM part 2 Tree part1 PM part 2 Tree part
Domain slabs of equal thickness Domain slabs of equal of Domain slabs of equal thickness Domain slabs of equal of
tree force interactions amptree force interactions amp Buffer zone particlesBuffer zone particles
TreePM CodeTreePM Code33
5 Accuracy ~ 05 5 Accuracy ~ 05 RMSRMS error in acceleration for error in acceleration for θθ=1=1
6 Performance6 Performance
CPU time per step
1024102433 particles particles
Regular backup amp Regular backup amp
Pre-halo finding Pre-halo finding
calculationcalculation
Load balance
1024102433 particles particles
of particles of particles
in domain slabsin domain slabs
homogeneous homogeneous
distributiondistribution
ΛΛCDM SimulationsCDM Simulations (Ki
m amp Park 2004 7)
TreePM codeTreePM code GOTPM (Dubinski Kim Park 2003)
2048204833 mesh mesh (initial condition)
2048204833 CDM particles CDM particles
1024 amp 5632 h1024 amp 5632 h-1-1MpcMpc size boxes
50 amp 275 h50 amp 275 h-1-1kpckpc force resolutions
FOR PRECISION COMPARISON between cosmological models amp real universe
Using IBM SP3 at KISTI 128 CPUs 900 Gbytes
Growth of Structures from initial Density Fluctuations
137b
118b
77b t=0
Dark Halo Identification(Kimamp Park 2006
ΛΛCDMCDM 1024 h1024 h-1-1MpcMpc)
Physically Self-Bound Halos
Halo centers - local density peaks
Binding E wrt local halo centers
Tidal radii of subhalos wrt bigger halos
Halos with gt=53 particles (5x1011 M⊙)
PSB HalosVS
Others
Topology studyTopology study
1 Gaussianity of the 1 Gaussianity of the linear (primordial) density fieldlinear (primordial) density field pr predicted by simple inflationary scenariosedicted by simple inflationary scenarios
2 Topology of galaxy distribution at NL scales sensitive 2 Topology of galaxy distribution at NL scales sensitive to to cosmological parameterscosmological parameters amp to amp to galaxy formation mechanismgalaxy formation mechanism
3 Direct Intuitive meaning3 Direct Intuitive meaning
Large ScalesLarge Scales Small ScalesSmall Scales
Primordial Gaussianity Galaxy FormationPrimordial Gaussianity Galaxy Formation
Cosmological ParametersCosmological Parameters
GenusGenus ndash A Measure of Topologyndash A Measure of Topology
DefinitionDefinition
G = of holes - of isolated regionsG = of holes - of isolated regions in iso-density contour surfacesin iso-density contour surfaces
= 14= 14ππ intintSS κ dA (Gauss-Bonnet Theorem) κ dA (Gauss-Bonnet Theorem)
[ex G(sphere)=-1 G(torus)=0 ][ex G(sphere)=-1 G(torus)=0 ]
2 holes ndash 1 body = +1
Gaussian FieldGaussian Field Genusunit volume g(ν) = A (1-νGenusunit volume g(ν) = A (1-ν22) exp(- ν) exp(- ν222)2) where ν=(ρ- ρwhere ν=(ρ- ρbb) ρ) ρbbσ amp σ amp
A=1(2π)A=1(2π)22 ltk ltk223gt3gt32 32
if P(k)~kif P(k)~knn A R A RGG33 =[8radic2π =[8radic2π22]]-1 -1 [(n+3)3][(n+3)3]32 32
Non-Gaussian FieldNon-Gaussian Field (Toy models) (Toy models)
Clusters Bubbles HDM
(Weinberg Gott amp Melott 1987)(Weinberg Gott amp Melott 1987)
Non-Gaussianity Genus-related statisticsNon-Gaussianity Genus-related statistics
1 Shift parameter 1 Shift parameter 2 Asymmetry parameters A2 Asymmetry parameters AC C AAVV
3 Amplitude drop R3 Amplitude drop RAAAAobsobsAAPSPS
ACAv
RA
Biased Biased Formation Formation of Galaxiesof Galaxies
L-dependence L-dependence of 1 amp 2 point of 1 amp 2 point distribution distribution
but also but also topology topology
(Park et al 2005)
Topology of LSS can be explained by Topology of LSS can be explained by GF modelsGF models
(Park Kim et al 2005)
Merger Merger Halo formation Halo formationvoid percolationvoid percolation
void splittingvoid splitting
LCDM1024LCDM1024
Matter field canrsquot
Topology of LSS can be explained by Topology of LSS can be explained by GF modelsGF models
Direction of Direction of evolution evolution
~1 amp Little evoluti~1 amp Little evolution at low zon at low z
Mergers of hMergers of halosalos
AV lt 1
ltNltNsatsatgt = (MMgt = (MM11))αα for MgtM for MgtMminmin whe whe
re logMre logMminmin=1176 log M=1176 log M11=1=1
315 315 αα=113=113
HOD model for VL sHOD model for VL sample Mample Mrrlt-195lt-195
(Park et al 2005)Probably yes
Comparison of topology SDSS vs Comparison of topology SDSS vs CDM CDM
SDSS amp 6 h-1Mpc scale Kim+Park(o) amp Springel(x)
Future ofCosmological N-Body
Simulation1 Useful for cosmology amp galaxy formation study1 Useful for cosmology amp galaxy formation study
(until star formation can be properly simulated by radiati(until star formation can be properly simulated by radiative hydro-codes)ve hydro-codes)
2 Need to reach of particles gtgt 50002 Need to reach of particles gtgt 500033 ~ 10000 ~ 1000033
(10~100 current maximum)(10~100 current maximum)
Dynamic range for other studiesDynamic range for other studies Internal properties amp environment 1kpc ~ 100 Mpc Internal properties amp environment 1kpc ~ 100 Mpc
Galactic structure amp star formation 01pc ~ 100kpc Galactic structure amp star formation 01pc ~ 100kpc
SDSS2006
CfA1986
SDSS galaxies
h-1Mpc
(Park et al 2005 ApJ 633 11)
Effects of NL Gravitational Evolution Biasing amp Redshift Space Distortion on galaxy clustering amp properties
For PRECISION COMPARISONFor PRECISION COMPARISON between cosmological models with observationsbetween cosmological models with observations
Cosmological N-Body Simulation
Cosmological N-Body Simulation
Requirement for galaxy formation studyRequirement for galaxy formation study
1 Several times larger than largest survey gtgt 1000 h1 Several times larger than largest survey gtgt 1000 h-1-1MpcMpc
for LSS formation + galaxy formation velocity field for LSS formation + galaxy formation velocity field
SDSS[2006] ~ 500 h SDSS[2006] ~ 500 h-1-1Mpc Hubble Depth S[2015] ~ 2000 hMpc Hubble Depth S[2015] ~ 2000 h-1-1MpcMpc
2 Should resolve objects with ltlt102 Should resolve objects with ltlt101111 h h-1-1MMsunsun (~ M (~ M+2)+2)
mean separation lt 02 h mean separation lt 02 h-1-1MpcMpc
currently 02~2000Mpccurrently 02~2000Mpc
Number of particles gt 5000Number of particles gt 500033 ~ 10000 ~ 1000033 will do will do
(100~1000 billion =10~100 current maximum)(100~1000 billion =10~100 current maximum)
Cosmological N-Body Simulation
ProgressesProgresses
~ 104 CPUs
gt 1010 particles
Log N=02(Y-1970)+2
TreePM CodeTreePM Code11
About CodeAbout Code
1 Long range (rgt4 pixels 1 Long range (rgt4 pixels PMPM) + Short range() + Short range(PMPM++TreeTree) G-forces) G-forces
2 Tree generation in each slab amp in each cube of 42 Tree generation in each slab amp in each cube of 433 pixels pixels
3 Min of particles for tree generation ndash Direct P3 Min of particles for tree generation ndash Direct P22 if (cube) lt N if (cube) lt Ntreetree
4 Memory ~3 4 Memory ~3 xx [16] [16] xx words per particle words per particle
16 per particle index 16 per particle index22 position position33 velocity velocity33 acceleration acceleration33 mass mass11
softening length computational work measurement pointersoftening length computational work measurement pointer
factor ~3 for memory imbalance factor ~3 for memory imbalance
Buffer zone particles Buffer zone particles
TreePM Gravitational Force
PMPM
Tree + PMTree + PM
PMPM
ForceForce
GaussianSmoothed RG=09 pixels
TreePM CodeTreePM Code22
AdvantagesAdvantages
1 O(N log N) Tree operations for short range force ndash unlike P1 O(N log N) Tree operations for short range force ndash unlike P33MM
2 Periodic boundary condition solved by PM ndash unlike Tree2 Periodic boundary condition solved by PM ndash unlike Tree
3 No need to build a global tree ndash force correction only out to 4 pixels3 No need to build a global tree ndash force correction only out to 4 pixels
4 Local Trees 4 Local Trees
Parallelizable by domain decomposition (time)Parallelizable by domain decomposition (time)
amp disposable local trees keeping trees in 8amp disposable local trees keeping trees in 8xx88xxnnzz pixels (memory) pixels (memory)
Parallelization
1 PM part 2 Tree part1 PM part 2 Tree part
Domain slabs of equal thickness Domain slabs of equal of Domain slabs of equal thickness Domain slabs of equal of
tree force interactions amptree force interactions amp Buffer zone particlesBuffer zone particles
TreePM CodeTreePM Code33
5 Accuracy ~ 05 5 Accuracy ~ 05 RMSRMS error in acceleration for error in acceleration for θθ=1=1
6 Performance6 Performance
CPU time per step
1024102433 particles particles
Regular backup amp Regular backup amp
Pre-halo finding Pre-halo finding
calculationcalculation
Load balance
1024102433 particles particles
of particles of particles
in domain slabsin domain slabs
homogeneous homogeneous
distributiondistribution
ΛΛCDM SimulationsCDM Simulations (Ki
m amp Park 2004 7)
TreePM codeTreePM code GOTPM (Dubinski Kim Park 2003)
2048204833 mesh mesh (initial condition)
2048204833 CDM particles CDM particles
1024 amp 5632 h1024 amp 5632 h-1-1MpcMpc size boxes
50 amp 275 h50 amp 275 h-1-1kpckpc force resolutions
FOR PRECISION COMPARISON between cosmological models amp real universe
Using IBM SP3 at KISTI 128 CPUs 900 Gbytes
Growth of Structures from initial Density Fluctuations
137b
118b
77b t=0
Dark Halo Identification(Kimamp Park 2006
ΛΛCDMCDM 1024 h1024 h-1-1MpcMpc)
Physically Self-Bound Halos
Halo centers - local density peaks
Binding E wrt local halo centers
Tidal radii of subhalos wrt bigger halos
Halos with gt=53 particles (5x1011 M⊙)
PSB HalosVS
Others
Topology studyTopology study
1 Gaussianity of the 1 Gaussianity of the linear (primordial) density fieldlinear (primordial) density field pr predicted by simple inflationary scenariosedicted by simple inflationary scenarios
2 Topology of galaxy distribution at NL scales sensitive 2 Topology of galaxy distribution at NL scales sensitive to to cosmological parameterscosmological parameters amp to amp to galaxy formation mechanismgalaxy formation mechanism
3 Direct Intuitive meaning3 Direct Intuitive meaning
Large ScalesLarge Scales Small ScalesSmall Scales
Primordial Gaussianity Galaxy FormationPrimordial Gaussianity Galaxy Formation
Cosmological ParametersCosmological Parameters
GenusGenus ndash A Measure of Topologyndash A Measure of Topology
DefinitionDefinition
G = of holes - of isolated regionsG = of holes - of isolated regions in iso-density contour surfacesin iso-density contour surfaces
= 14= 14ππ intintSS κ dA (Gauss-Bonnet Theorem) κ dA (Gauss-Bonnet Theorem)
[ex G(sphere)=-1 G(torus)=0 ][ex G(sphere)=-1 G(torus)=0 ]
2 holes ndash 1 body = +1
Gaussian FieldGaussian Field Genusunit volume g(ν) = A (1-νGenusunit volume g(ν) = A (1-ν22) exp(- ν) exp(- ν222)2) where ν=(ρ- ρwhere ν=(ρ- ρbb) ρ) ρbbσ amp σ amp
A=1(2π)A=1(2π)22 ltk ltk223gt3gt32 32
if P(k)~kif P(k)~knn A R A RGG33 =[8radic2π =[8radic2π22]]-1 -1 [(n+3)3][(n+3)3]32 32
Non-Gaussian FieldNon-Gaussian Field (Toy models) (Toy models)
Clusters Bubbles HDM
(Weinberg Gott amp Melott 1987)(Weinberg Gott amp Melott 1987)
Non-Gaussianity Genus-related statisticsNon-Gaussianity Genus-related statistics
1 Shift parameter 1 Shift parameter 2 Asymmetry parameters A2 Asymmetry parameters AC C AAVV
3 Amplitude drop R3 Amplitude drop RAAAAobsobsAAPSPS
ACAv
RA
Biased Biased Formation Formation of Galaxiesof Galaxies
L-dependence L-dependence of 1 amp 2 point of 1 amp 2 point distribution distribution
but also but also topology topology
(Park et al 2005)
Topology of LSS can be explained by Topology of LSS can be explained by GF modelsGF models
(Park Kim et al 2005)
Merger Merger Halo formation Halo formationvoid percolationvoid percolation
void splittingvoid splitting
LCDM1024LCDM1024
Matter field canrsquot
Topology of LSS can be explained by Topology of LSS can be explained by GF modelsGF models
Direction of Direction of evolution evolution
~1 amp Little evoluti~1 amp Little evolution at low zon at low z
Mergers of hMergers of halosalos
AV lt 1
ltNltNsatsatgt = (MMgt = (MM11))αα for MgtM for MgtMminmin whe whe
re logMre logMminmin=1176 log M=1176 log M11=1=1
315 315 αα=113=113
HOD model for VL sHOD model for VL sample Mample Mrrlt-195lt-195
(Park et al 2005)Probably yes
Comparison of topology SDSS vs Comparison of topology SDSS vs CDM CDM
SDSS amp 6 h-1Mpc scale Kim+Park(o) amp Springel(x)
Future ofCosmological N-Body
Simulation1 Useful for cosmology amp galaxy formation study1 Useful for cosmology amp galaxy formation study
(until star formation can be properly simulated by radiati(until star formation can be properly simulated by radiative hydro-codes)ve hydro-codes)
2 Need to reach of particles gtgt 50002 Need to reach of particles gtgt 500033 ~ 10000 ~ 1000033
(10~100 current maximum)(10~100 current maximum)
Dynamic range for other studiesDynamic range for other studies Internal properties amp environment 1kpc ~ 100 Mpc Internal properties amp environment 1kpc ~ 100 Mpc
Galactic structure amp star formation 01pc ~ 100kpc Galactic structure amp star formation 01pc ~ 100kpc
SDSS galaxies
h-1Mpc
(Park et al 2005 ApJ 633 11)
Effects of NL Gravitational Evolution Biasing amp Redshift Space Distortion on galaxy clustering amp properties
For PRECISION COMPARISONFor PRECISION COMPARISON between cosmological models with observationsbetween cosmological models with observations
Cosmological N-Body Simulation
Cosmological N-Body Simulation
Requirement for galaxy formation studyRequirement for galaxy formation study
1 Several times larger than largest survey gtgt 1000 h1 Several times larger than largest survey gtgt 1000 h-1-1MpcMpc
for LSS formation + galaxy formation velocity field for LSS formation + galaxy formation velocity field
SDSS[2006] ~ 500 h SDSS[2006] ~ 500 h-1-1Mpc Hubble Depth S[2015] ~ 2000 hMpc Hubble Depth S[2015] ~ 2000 h-1-1MpcMpc
2 Should resolve objects with ltlt102 Should resolve objects with ltlt101111 h h-1-1MMsunsun (~ M (~ M+2)+2)
mean separation lt 02 h mean separation lt 02 h-1-1MpcMpc
currently 02~2000Mpccurrently 02~2000Mpc
Number of particles gt 5000Number of particles gt 500033 ~ 10000 ~ 1000033 will do will do
(100~1000 billion =10~100 current maximum)(100~1000 billion =10~100 current maximum)
Cosmological N-Body Simulation
ProgressesProgresses
~ 104 CPUs
gt 1010 particles
Log N=02(Y-1970)+2
TreePM CodeTreePM Code11
About CodeAbout Code
1 Long range (rgt4 pixels 1 Long range (rgt4 pixels PMPM) + Short range() + Short range(PMPM++TreeTree) G-forces) G-forces
2 Tree generation in each slab amp in each cube of 42 Tree generation in each slab amp in each cube of 433 pixels pixels
3 Min of particles for tree generation ndash Direct P3 Min of particles for tree generation ndash Direct P22 if (cube) lt N if (cube) lt Ntreetree
4 Memory ~3 4 Memory ~3 xx [16] [16] xx words per particle words per particle
16 per particle index 16 per particle index22 position position33 velocity velocity33 acceleration acceleration33 mass mass11
softening length computational work measurement pointersoftening length computational work measurement pointer
factor ~3 for memory imbalance factor ~3 for memory imbalance
Buffer zone particles Buffer zone particles
TreePM Gravitational Force
PMPM
Tree + PMTree + PM
PMPM
ForceForce
GaussianSmoothed RG=09 pixels
TreePM CodeTreePM Code22
AdvantagesAdvantages
1 O(N log N) Tree operations for short range force ndash unlike P1 O(N log N) Tree operations for short range force ndash unlike P33MM
2 Periodic boundary condition solved by PM ndash unlike Tree2 Periodic boundary condition solved by PM ndash unlike Tree
3 No need to build a global tree ndash force correction only out to 4 pixels3 No need to build a global tree ndash force correction only out to 4 pixels
4 Local Trees 4 Local Trees
Parallelizable by domain decomposition (time)Parallelizable by domain decomposition (time)
amp disposable local trees keeping trees in 8amp disposable local trees keeping trees in 8xx88xxnnzz pixels (memory) pixels (memory)
Parallelization
1 PM part 2 Tree part1 PM part 2 Tree part
Domain slabs of equal thickness Domain slabs of equal of Domain slabs of equal thickness Domain slabs of equal of
tree force interactions amptree force interactions amp Buffer zone particlesBuffer zone particles
TreePM CodeTreePM Code33
5 Accuracy ~ 05 5 Accuracy ~ 05 RMSRMS error in acceleration for error in acceleration for θθ=1=1
6 Performance6 Performance
CPU time per step
1024102433 particles particles
Regular backup amp Regular backup amp
Pre-halo finding Pre-halo finding
calculationcalculation
Load balance
1024102433 particles particles
of particles of particles
in domain slabsin domain slabs
homogeneous homogeneous
distributiondistribution
ΛΛCDM SimulationsCDM Simulations (Ki
m amp Park 2004 7)
TreePM codeTreePM code GOTPM (Dubinski Kim Park 2003)
2048204833 mesh mesh (initial condition)
2048204833 CDM particles CDM particles
1024 amp 5632 h1024 amp 5632 h-1-1MpcMpc size boxes
50 amp 275 h50 amp 275 h-1-1kpckpc force resolutions
FOR PRECISION COMPARISON between cosmological models amp real universe
Using IBM SP3 at KISTI 128 CPUs 900 Gbytes
Growth of Structures from initial Density Fluctuations
137b
118b
77b t=0
Dark Halo Identification(Kimamp Park 2006
ΛΛCDMCDM 1024 h1024 h-1-1MpcMpc)
Physically Self-Bound Halos
Halo centers - local density peaks
Binding E wrt local halo centers
Tidal radii of subhalos wrt bigger halos
Halos with gt=53 particles (5x1011 M⊙)
PSB HalosVS
Others
Topology studyTopology study
1 Gaussianity of the 1 Gaussianity of the linear (primordial) density fieldlinear (primordial) density field pr predicted by simple inflationary scenariosedicted by simple inflationary scenarios
2 Topology of galaxy distribution at NL scales sensitive 2 Topology of galaxy distribution at NL scales sensitive to to cosmological parameterscosmological parameters amp to amp to galaxy formation mechanismgalaxy formation mechanism
3 Direct Intuitive meaning3 Direct Intuitive meaning
Large ScalesLarge Scales Small ScalesSmall Scales
Primordial Gaussianity Galaxy FormationPrimordial Gaussianity Galaxy Formation
Cosmological ParametersCosmological Parameters
GenusGenus ndash A Measure of Topologyndash A Measure of Topology
DefinitionDefinition
G = of holes - of isolated regionsG = of holes - of isolated regions in iso-density contour surfacesin iso-density contour surfaces
= 14= 14ππ intintSS κ dA (Gauss-Bonnet Theorem) κ dA (Gauss-Bonnet Theorem)
[ex G(sphere)=-1 G(torus)=0 ][ex G(sphere)=-1 G(torus)=0 ]
2 holes ndash 1 body = +1
Gaussian FieldGaussian Field Genusunit volume g(ν) = A (1-νGenusunit volume g(ν) = A (1-ν22) exp(- ν) exp(- ν222)2) where ν=(ρ- ρwhere ν=(ρ- ρbb) ρ) ρbbσ amp σ amp
A=1(2π)A=1(2π)22 ltk ltk223gt3gt32 32
if P(k)~kif P(k)~knn A R A RGG33 =[8radic2π =[8radic2π22]]-1 -1 [(n+3)3][(n+3)3]32 32
Non-Gaussian FieldNon-Gaussian Field (Toy models) (Toy models)
Clusters Bubbles HDM
(Weinberg Gott amp Melott 1987)(Weinberg Gott amp Melott 1987)
Non-Gaussianity Genus-related statisticsNon-Gaussianity Genus-related statistics
1 Shift parameter 1 Shift parameter 2 Asymmetry parameters A2 Asymmetry parameters AC C AAVV
3 Amplitude drop R3 Amplitude drop RAAAAobsobsAAPSPS
ACAv
RA
Biased Biased Formation Formation of Galaxiesof Galaxies
L-dependence L-dependence of 1 amp 2 point of 1 amp 2 point distribution distribution
but also but also topology topology
(Park et al 2005)
Topology of LSS can be explained by Topology of LSS can be explained by GF modelsGF models
(Park Kim et al 2005)
Merger Merger Halo formation Halo formationvoid percolationvoid percolation
void splittingvoid splitting
LCDM1024LCDM1024
Matter field canrsquot
Topology of LSS can be explained by Topology of LSS can be explained by GF modelsGF models
Direction of Direction of evolution evolution
~1 amp Little evoluti~1 amp Little evolution at low zon at low z
Mergers of hMergers of halosalos
AV lt 1
ltNltNsatsatgt = (MMgt = (MM11))αα for MgtM for MgtMminmin whe whe
re logMre logMminmin=1176 log M=1176 log M11=1=1
315 315 αα=113=113
HOD model for VL sHOD model for VL sample Mample Mrrlt-195lt-195
(Park et al 2005)Probably yes
Comparison of topology SDSS vs Comparison of topology SDSS vs CDM CDM
SDSS amp 6 h-1Mpc scale Kim+Park(o) amp Springel(x)
Future ofCosmological N-Body
Simulation1 Useful for cosmology amp galaxy formation study1 Useful for cosmology amp galaxy formation study
(until star formation can be properly simulated by radiati(until star formation can be properly simulated by radiative hydro-codes)ve hydro-codes)
2 Need to reach of particles gtgt 50002 Need to reach of particles gtgt 500033 ~ 10000 ~ 1000033
(10~100 current maximum)(10~100 current maximum)
Dynamic range for other studiesDynamic range for other studies Internal properties amp environment 1kpc ~ 100 Mpc Internal properties amp environment 1kpc ~ 100 Mpc
Galactic structure amp star formation 01pc ~ 100kpc Galactic structure amp star formation 01pc ~ 100kpc
Effects of NL Gravitational Evolution Biasing amp Redshift Space Distortion on galaxy clustering amp properties
For PRECISION COMPARISONFor PRECISION COMPARISON between cosmological models with observationsbetween cosmological models with observations
Cosmological N-Body Simulation
Cosmological N-Body Simulation
Requirement for galaxy formation studyRequirement for galaxy formation study
1 Several times larger than largest survey gtgt 1000 h1 Several times larger than largest survey gtgt 1000 h-1-1MpcMpc
for LSS formation + galaxy formation velocity field for LSS formation + galaxy formation velocity field
SDSS[2006] ~ 500 h SDSS[2006] ~ 500 h-1-1Mpc Hubble Depth S[2015] ~ 2000 hMpc Hubble Depth S[2015] ~ 2000 h-1-1MpcMpc
2 Should resolve objects with ltlt102 Should resolve objects with ltlt101111 h h-1-1MMsunsun (~ M (~ M+2)+2)
mean separation lt 02 h mean separation lt 02 h-1-1MpcMpc
currently 02~2000Mpccurrently 02~2000Mpc
Number of particles gt 5000Number of particles gt 500033 ~ 10000 ~ 1000033 will do will do
(100~1000 billion =10~100 current maximum)(100~1000 billion =10~100 current maximum)
Cosmological N-Body Simulation
ProgressesProgresses
~ 104 CPUs
gt 1010 particles
Log N=02(Y-1970)+2
TreePM CodeTreePM Code11
About CodeAbout Code
1 Long range (rgt4 pixels 1 Long range (rgt4 pixels PMPM) + Short range() + Short range(PMPM++TreeTree) G-forces) G-forces
2 Tree generation in each slab amp in each cube of 42 Tree generation in each slab amp in each cube of 433 pixels pixels
3 Min of particles for tree generation ndash Direct P3 Min of particles for tree generation ndash Direct P22 if (cube) lt N if (cube) lt Ntreetree
4 Memory ~3 4 Memory ~3 xx [16] [16] xx words per particle words per particle
16 per particle index 16 per particle index22 position position33 velocity velocity33 acceleration acceleration33 mass mass11
softening length computational work measurement pointersoftening length computational work measurement pointer
factor ~3 for memory imbalance factor ~3 for memory imbalance
Buffer zone particles Buffer zone particles
TreePM Gravitational Force
PMPM
Tree + PMTree + PM
PMPM
ForceForce
GaussianSmoothed RG=09 pixels
TreePM CodeTreePM Code22
AdvantagesAdvantages
1 O(N log N) Tree operations for short range force ndash unlike P1 O(N log N) Tree operations for short range force ndash unlike P33MM
2 Periodic boundary condition solved by PM ndash unlike Tree2 Periodic boundary condition solved by PM ndash unlike Tree
3 No need to build a global tree ndash force correction only out to 4 pixels3 No need to build a global tree ndash force correction only out to 4 pixels
4 Local Trees 4 Local Trees
Parallelizable by domain decomposition (time)Parallelizable by domain decomposition (time)
amp disposable local trees keeping trees in 8amp disposable local trees keeping trees in 8xx88xxnnzz pixels (memory) pixels (memory)
Parallelization
1 PM part 2 Tree part1 PM part 2 Tree part
Domain slabs of equal thickness Domain slabs of equal of Domain slabs of equal thickness Domain slabs of equal of
tree force interactions amptree force interactions amp Buffer zone particlesBuffer zone particles
TreePM CodeTreePM Code33
5 Accuracy ~ 05 5 Accuracy ~ 05 RMSRMS error in acceleration for error in acceleration for θθ=1=1
6 Performance6 Performance
CPU time per step
1024102433 particles particles
Regular backup amp Regular backup amp
Pre-halo finding Pre-halo finding
calculationcalculation
Load balance
1024102433 particles particles
of particles of particles
in domain slabsin domain slabs
homogeneous homogeneous
distributiondistribution
ΛΛCDM SimulationsCDM Simulations (Ki
m amp Park 2004 7)
TreePM codeTreePM code GOTPM (Dubinski Kim Park 2003)
2048204833 mesh mesh (initial condition)
2048204833 CDM particles CDM particles
1024 amp 5632 h1024 amp 5632 h-1-1MpcMpc size boxes
50 amp 275 h50 amp 275 h-1-1kpckpc force resolutions
FOR PRECISION COMPARISON between cosmological models amp real universe
Using IBM SP3 at KISTI 128 CPUs 900 Gbytes
Growth of Structures from initial Density Fluctuations
137b
118b
77b t=0
Dark Halo Identification(Kimamp Park 2006
ΛΛCDMCDM 1024 h1024 h-1-1MpcMpc)
Physically Self-Bound Halos
Halo centers - local density peaks
Binding E wrt local halo centers
Tidal radii of subhalos wrt bigger halos
Halos with gt=53 particles (5x1011 M⊙)
PSB HalosVS
Others
Topology studyTopology study
1 Gaussianity of the 1 Gaussianity of the linear (primordial) density fieldlinear (primordial) density field pr predicted by simple inflationary scenariosedicted by simple inflationary scenarios
2 Topology of galaxy distribution at NL scales sensitive 2 Topology of galaxy distribution at NL scales sensitive to to cosmological parameterscosmological parameters amp to amp to galaxy formation mechanismgalaxy formation mechanism
3 Direct Intuitive meaning3 Direct Intuitive meaning
Large ScalesLarge Scales Small ScalesSmall Scales
Primordial Gaussianity Galaxy FormationPrimordial Gaussianity Galaxy Formation
Cosmological ParametersCosmological Parameters
GenusGenus ndash A Measure of Topologyndash A Measure of Topology
DefinitionDefinition
G = of holes - of isolated regionsG = of holes - of isolated regions in iso-density contour surfacesin iso-density contour surfaces
= 14= 14ππ intintSS κ dA (Gauss-Bonnet Theorem) κ dA (Gauss-Bonnet Theorem)
[ex G(sphere)=-1 G(torus)=0 ][ex G(sphere)=-1 G(torus)=0 ]
2 holes ndash 1 body = +1
Gaussian FieldGaussian Field Genusunit volume g(ν) = A (1-νGenusunit volume g(ν) = A (1-ν22) exp(- ν) exp(- ν222)2) where ν=(ρ- ρwhere ν=(ρ- ρbb) ρ) ρbbσ amp σ amp
A=1(2π)A=1(2π)22 ltk ltk223gt3gt32 32
if P(k)~kif P(k)~knn A R A RGG33 =[8radic2π =[8radic2π22]]-1 -1 [(n+3)3][(n+3)3]32 32
Non-Gaussian FieldNon-Gaussian Field (Toy models) (Toy models)
Clusters Bubbles HDM
(Weinberg Gott amp Melott 1987)(Weinberg Gott amp Melott 1987)
Non-Gaussianity Genus-related statisticsNon-Gaussianity Genus-related statistics
1 Shift parameter 1 Shift parameter 2 Asymmetry parameters A2 Asymmetry parameters AC C AAVV
3 Amplitude drop R3 Amplitude drop RAAAAobsobsAAPSPS
ACAv
RA
Biased Biased Formation Formation of Galaxiesof Galaxies
L-dependence L-dependence of 1 amp 2 point of 1 amp 2 point distribution distribution
but also but also topology topology
(Park et al 2005)
Topology of LSS can be explained by Topology of LSS can be explained by GF modelsGF models
(Park Kim et al 2005)
Merger Merger Halo formation Halo formationvoid percolationvoid percolation
void splittingvoid splitting
LCDM1024LCDM1024
Matter field canrsquot
Topology of LSS can be explained by Topology of LSS can be explained by GF modelsGF models
Direction of Direction of evolution evolution
~1 amp Little evoluti~1 amp Little evolution at low zon at low z
Mergers of hMergers of halosalos
AV lt 1
ltNltNsatsatgt = (MMgt = (MM11))αα for MgtM for MgtMminmin whe whe
re logMre logMminmin=1176 log M=1176 log M11=1=1
315 315 αα=113=113
HOD model for VL sHOD model for VL sample Mample Mrrlt-195lt-195
(Park et al 2005)Probably yes
Comparison of topology SDSS vs Comparison of topology SDSS vs CDM CDM
SDSS amp 6 h-1Mpc scale Kim+Park(o) amp Springel(x)
Future ofCosmological N-Body
Simulation1 Useful for cosmology amp galaxy formation study1 Useful for cosmology amp galaxy formation study
(until star formation can be properly simulated by radiati(until star formation can be properly simulated by radiative hydro-codes)ve hydro-codes)
2 Need to reach of particles gtgt 50002 Need to reach of particles gtgt 500033 ~ 10000 ~ 1000033
(10~100 current maximum)(10~100 current maximum)
Dynamic range for other studiesDynamic range for other studies Internal properties amp environment 1kpc ~ 100 Mpc Internal properties amp environment 1kpc ~ 100 Mpc
Galactic structure amp star formation 01pc ~ 100kpc Galactic structure amp star formation 01pc ~ 100kpc
Cosmological N-Body Simulation
Requirement for galaxy formation studyRequirement for galaxy formation study
1 Several times larger than largest survey gtgt 1000 h1 Several times larger than largest survey gtgt 1000 h-1-1MpcMpc
for LSS formation + galaxy formation velocity field for LSS formation + galaxy formation velocity field
SDSS[2006] ~ 500 h SDSS[2006] ~ 500 h-1-1Mpc Hubble Depth S[2015] ~ 2000 hMpc Hubble Depth S[2015] ~ 2000 h-1-1MpcMpc
2 Should resolve objects with ltlt102 Should resolve objects with ltlt101111 h h-1-1MMsunsun (~ M (~ M+2)+2)
mean separation lt 02 h mean separation lt 02 h-1-1MpcMpc
currently 02~2000Mpccurrently 02~2000Mpc
Number of particles gt 5000Number of particles gt 500033 ~ 10000 ~ 1000033 will do will do
(100~1000 billion =10~100 current maximum)(100~1000 billion =10~100 current maximum)
Cosmological N-Body Simulation
ProgressesProgresses
~ 104 CPUs
gt 1010 particles
Log N=02(Y-1970)+2
TreePM CodeTreePM Code11
About CodeAbout Code
1 Long range (rgt4 pixels 1 Long range (rgt4 pixels PMPM) + Short range() + Short range(PMPM++TreeTree) G-forces) G-forces
2 Tree generation in each slab amp in each cube of 42 Tree generation in each slab amp in each cube of 433 pixels pixels
3 Min of particles for tree generation ndash Direct P3 Min of particles for tree generation ndash Direct P22 if (cube) lt N if (cube) lt Ntreetree
4 Memory ~3 4 Memory ~3 xx [16] [16] xx words per particle words per particle
16 per particle index 16 per particle index22 position position33 velocity velocity33 acceleration acceleration33 mass mass11
softening length computational work measurement pointersoftening length computational work measurement pointer
factor ~3 for memory imbalance factor ~3 for memory imbalance
Buffer zone particles Buffer zone particles
TreePM Gravitational Force
PMPM
Tree + PMTree + PM
PMPM
ForceForce
GaussianSmoothed RG=09 pixels
TreePM CodeTreePM Code22
AdvantagesAdvantages
1 O(N log N) Tree operations for short range force ndash unlike P1 O(N log N) Tree operations for short range force ndash unlike P33MM
2 Periodic boundary condition solved by PM ndash unlike Tree2 Periodic boundary condition solved by PM ndash unlike Tree
3 No need to build a global tree ndash force correction only out to 4 pixels3 No need to build a global tree ndash force correction only out to 4 pixels
4 Local Trees 4 Local Trees
Parallelizable by domain decomposition (time)Parallelizable by domain decomposition (time)
amp disposable local trees keeping trees in 8amp disposable local trees keeping trees in 8xx88xxnnzz pixels (memory) pixels (memory)
Parallelization
1 PM part 2 Tree part1 PM part 2 Tree part
Domain slabs of equal thickness Domain slabs of equal of Domain slabs of equal thickness Domain slabs of equal of
tree force interactions amptree force interactions amp Buffer zone particlesBuffer zone particles
TreePM CodeTreePM Code33
5 Accuracy ~ 05 5 Accuracy ~ 05 RMSRMS error in acceleration for error in acceleration for θθ=1=1
6 Performance6 Performance
CPU time per step
1024102433 particles particles
Regular backup amp Regular backup amp
Pre-halo finding Pre-halo finding
calculationcalculation
Load balance
1024102433 particles particles
of particles of particles
in domain slabsin domain slabs
homogeneous homogeneous
distributiondistribution
ΛΛCDM SimulationsCDM Simulations (Ki
m amp Park 2004 7)
TreePM codeTreePM code GOTPM (Dubinski Kim Park 2003)
2048204833 mesh mesh (initial condition)
2048204833 CDM particles CDM particles
1024 amp 5632 h1024 amp 5632 h-1-1MpcMpc size boxes
50 amp 275 h50 amp 275 h-1-1kpckpc force resolutions
FOR PRECISION COMPARISON between cosmological models amp real universe
Using IBM SP3 at KISTI 128 CPUs 900 Gbytes
Growth of Structures from initial Density Fluctuations
137b
118b
77b t=0
Dark Halo Identification(Kimamp Park 2006
ΛΛCDMCDM 1024 h1024 h-1-1MpcMpc)
Physically Self-Bound Halos
Halo centers - local density peaks
Binding E wrt local halo centers
Tidal radii of subhalos wrt bigger halos
Halos with gt=53 particles (5x1011 M⊙)
PSB HalosVS
Others
Topology studyTopology study
1 Gaussianity of the 1 Gaussianity of the linear (primordial) density fieldlinear (primordial) density field pr predicted by simple inflationary scenariosedicted by simple inflationary scenarios
2 Topology of galaxy distribution at NL scales sensitive 2 Topology of galaxy distribution at NL scales sensitive to to cosmological parameterscosmological parameters amp to amp to galaxy formation mechanismgalaxy formation mechanism
3 Direct Intuitive meaning3 Direct Intuitive meaning
Large ScalesLarge Scales Small ScalesSmall Scales
Primordial Gaussianity Galaxy FormationPrimordial Gaussianity Galaxy Formation
Cosmological ParametersCosmological Parameters
GenusGenus ndash A Measure of Topologyndash A Measure of Topology
DefinitionDefinition
G = of holes - of isolated regionsG = of holes - of isolated regions in iso-density contour surfacesin iso-density contour surfaces
= 14= 14ππ intintSS κ dA (Gauss-Bonnet Theorem) κ dA (Gauss-Bonnet Theorem)
[ex G(sphere)=-1 G(torus)=0 ][ex G(sphere)=-1 G(torus)=0 ]
2 holes ndash 1 body = +1
Gaussian FieldGaussian Field Genusunit volume g(ν) = A (1-νGenusunit volume g(ν) = A (1-ν22) exp(- ν) exp(- ν222)2) where ν=(ρ- ρwhere ν=(ρ- ρbb) ρ) ρbbσ amp σ amp
A=1(2π)A=1(2π)22 ltk ltk223gt3gt32 32
if P(k)~kif P(k)~knn A R A RGG33 =[8radic2π =[8radic2π22]]-1 -1 [(n+3)3][(n+3)3]32 32
Non-Gaussian FieldNon-Gaussian Field (Toy models) (Toy models)
Clusters Bubbles HDM
(Weinberg Gott amp Melott 1987)(Weinberg Gott amp Melott 1987)
Non-Gaussianity Genus-related statisticsNon-Gaussianity Genus-related statistics
1 Shift parameter 1 Shift parameter 2 Asymmetry parameters A2 Asymmetry parameters AC C AAVV
3 Amplitude drop R3 Amplitude drop RAAAAobsobsAAPSPS
ACAv
RA
Biased Biased Formation Formation of Galaxiesof Galaxies
L-dependence L-dependence of 1 amp 2 point of 1 amp 2 point distribution distribution
but also but also topology topology
(Park et al 2005)
Topology of LSS can be explained by Topology of LSS can be explained by GF modelsGF models
(Park Kim et al 2005)
Merger Merger Halo formation Halo formationvoid percolationvoid percolation
void splittingvoid splitting
LCDM1024LCDM1024
Matter field canrsquot
Topology of LSS can be explained by Topology of LSS can be explained by GF modelsGF models
Direction of Direction of evolution evolution
~1 amp Little evoluti~1 amp Little evolution at low zon at low z
Mergers of hMergers of halosalos
AV lt 1
ltNltNsatsatgt = (MMgt = (MM11))αα for MgtM for MgtMminmin whe whe
re logMre logMminmin=1176 log M=1176 log M11=1=1
315 315 αα=113=113
HOD model for VL sHOD model for VL sample Mample Mrrlt-195lt-195
(Park et al 2005)Probably yes
Comparison of topology SDSS vs Comparison of topology SDSS vs CDM CDM
SDSS amp 6 h-1Mpc scale Kim+Park(o) amp Springel(x)
Future ofCosmological N-Body
Simulation1 Useful for cosmology amp galaxy formation study1 Useful for cosmology amp galaxy formation study
(until star formation can be properly simulated by radiati(until star formation can be properly simulated by radiative hydro-codes)ve hydro-codes)
2 Need to reach of particles gtgt 50002 Need to reach of particles gtgt 500033 ~ 10000 ~ 1000033
(10~100 current maximum)(10~100 current maximum)
Dynamic range for other studiesDynamic range for other studies Internal properties amp environment 1kpc ~ 100 Mpc Internal properties amp environment 1kpc ~ 100 Mpc
Galactic structure amp star formation 01pc ~ 100kpc Galactic structure amp star formation 01pc ~ 100kpc
Cosmological N-Body Simulation
ProgressesProgresses
~ 104 CPUs
gt 1010 particles
Log N=02(Y-1970)+2
TreePM CodeTreePM Code11
About CodeAbout Code
1 Long range (rgt4 pixels 1 Long range (rgt4 pixels PMPM) + Short range() + Short range(PMPM++TreeTree) G-forces) G-forces
2 Tree generation in each slab amp in each cube of 42 Tree generation in each slab amp in each cube of 433 pixels pixels
3 Min of particles for tree generation ndash Direct P3 Min of particles for tree generation ndash Direct P22 if (cube) lt N if (cube) lt Ntreetree
4 Memory ~3 4 Memory ~3 xx [16] [16] xx words per particle words per particle
16 per particle index 16 per particle index22 position position33 velocity velocity33 acceleration acceleration33 mass mass11
softening length computational work measurement pointersoftening length computational work measurement pointer
factor ~3 for memory imbalance factor ~3 for memory imbalance
Buffer zone particles Buffer zone particles
TreePM Gravitational Force
PMPM
Tree + PMTree + PM
PMPM
ForceForce
GaussianSmoothed RG=09 pixels
TreePM CodeTreePM Code22
AdvantagesAdvantages
1 O(N log N) Tree operations for short range force ndash unlike P1 O(N log N) Tree operations for short range force ndash unlike P33MM
2 Periodic boundary condition solved by PM ndash unlike Tree2 Periodic boundary condition solved by PM ndash unlike Tree
3 No need to build a global tree ndash force correction only out to 4 pixels3 No need to build a global tree ndash force correction only out to 4 pixels
4 Local Trees 4 Local Trees
Parallelizable by domain decomposition (time)Parallelizable by domain decomposition (time)
amp disposable local trees keeping trees in 8amp disposable local trees keeping trees in 8xx88xxnnzz pixels (memory) pixels (memory)
Parallelization
1 PM part 2 Tree part1 PM part 2 Tree part
Domain slabs of equal thickness Domain slabs of equal of Domain slabs of equal thickness Domain slabs of equal of
tree force interactions amptree force interactions amp Buffer zone particlesBuffer zone particles
TreePM CodeTreePM Code33
5 Accuracy ~ 05 5 Accuracy ~ 05 RMSRMS error in acceleration for error in acceleration for θθ=1=1
6 Performance6 Performance
CPU time per step
1024102433 particles particles
Regular backup amp Regular backup amp
Pre-halo finding Pre-halo finding
calculationcalculation
Load balance
1024102433 particles particles
of particles of particles
in domain slabsin domain slabs
homogeneous homogeneous
distributiondistribution
ΛΛCDM SimulationsCDM Simulations (Ki
m amp Park 2004 7)
TreePM codeTreePM code GOTPM (Dubinski Kim Park 2003)
2048204833 mesh mesh (initial condition)
2048204833 CDM particles CDM particles
1024 amp 5632 h1024 amp 5632 h-1-1MpcMpc size boxes
50 amp 275 h50 amp 275 h-1-1kpckpc force resolutions
FOR PRECISION COMPARISON between cosmological models amp real universe
Using IBM SP3 at KISTI 128 CPUs 900 Gbytes
Growth of Structures from initial Density Fluctuations
137b
118b
77b t=0
Dark Halo Identification(Kimamp Park 2006
ΛΛCDMCDM 1024 h1024 h-1-1MpcMpc)
Physically Self-Bound Halos
Halo centers - local density peaks
Binding E wrt local halo centers
Tidal radii of subhalos wrt bigger halos
Halos with gt=53 particles (5x1011 M⊙)
PSB HalosVS
Others
Topology studyTopology study
1 Gaussianity of the 1 Gaussianity of the linear (primordial) density fieldlinear (primordial) density field pr predicted by simple inflationary scenariosedicted by simple inflationary scenarios
2 Topology of galaxy distribution at NL scales sensitive 2 Topology of galaxy distribution at NL scales sensitive to to cosmological parameterscosmological parameters amp to amp to galaxy formation mechanismgalaxy formation mechanism
3 Direct Intuitive meaning3 Direct Intuitive meaning
Large ScalesLarge Scales Small ScalesSmall Scales
Primordial Gaussianity Galaxy FormationPrimordial Gaussianity Galaxy Formation
Cosmological ParametersCosmological Parameters
GenusGenus ndash A Measure of Topologyndash A Measure of Topology
DefinitionDefinition
G = of holes - of isolated regionsG = of holes - of isolated regions in iso-density contour surfacesin iso-density contour surfaces
= 14= 14ππ intintSS κ dA (Gauss-Bonnet Theorem) κ dA (Gauss-Bonnet Theorem)
[ex G(sphere)=-1 G(torus)=0 ][ex G(sphere)=-1 G(torus)=0 ]
2 holes ndash 1 body = +1
Gaussian FieldGaussian Field Genusunit volume g(ν) = A (1-νGenusunit volume g(ν) = A (1-ν22) exp(- ν) exp(- ν222)2) where ν=(ρ- ρwhere ν=(ρ- ρbb) ρ) ρbbσ amp σ amp
A=1(2π)A=1(2π)22 ltk ltk223gt3gt32 32
if P(k)~kif P(k)~knn A R A RGG33 =[8radic2π =[8radic2π22]]-1 -1 [(n+3)3][(n+3)3]32 32
Non-Gaussian FieldNon-Gaussian Field (Toy models) (Toy models)
Clusters Bubbles HDM
(Weinberg Gott amp Melott 1987)(Weinberg Gott amp Melott 1987)
Non-Gaussianity Genus-related statisticsNon-Gaussianity Genus-related statistics
1 Shift parameter 1 Shift parameter 2 Asymmetry parameters A2 Asymmetry parameters AC C AAVV
3 Amplitude drop R3 Amplitude drop RAAAAobsobsAAPSPS
ACAv
RA
Biased Biased Formation Formation of Galaxiesof Galaxies
L-dependence L-dependence of 1 amp 2 point of 1 amp 2 point distribution distribution
but also but also topology topology
(Park et al 2005)
Topology of LSS can be explained by Topology of LSS can be explained by GF modelsGF models
(Park Kim et al 2005)
Merger Merger Halo formation Halo formationvoid percolationvoid percolation
void splittingvoid splitting
LCDM1024LCDM1024
Matter field canrsquot
Topology of LSS can be explained by Topology of LSS can be explained by GF modelsGF models
Direction of Direction of evolution evolution
~1 amp Little evoluti~1 amp Little evolution at low zon at low z
Mergers of hMergers of halosalos
AV lt 1
ltNltNsatsatgt = (MMgt = (MM11))αα for MgtM for MgtMminmin whe whe
re logMre logMminmin=1176 log M=1176 log M11=1=1
315 315 αα=113=113
HOD model for VL sHOD model for VL sample Mample Mrrlt-195lt-195
(Park et al 2005)Probably yes
Comparison of topology SDSS vs Comparison of topology SDSS vs CDM CDM
SDSS amp 6 h-1Mpc scale Kim+Park(o) amp Springel(x)
Future ofCosmological N-Body
Simulation1 Useful for cosmology amp galaxy formation study1 Useful for cosmology amp galaxy formation study
(until star formation can be properly simulated by radiati(until star formation can be properly simulated by radiative hydro-codes)ve hydro-codes)
2 Need to reach of particles gtgt 50002 Need to reach of particles gtgt 500033 ~ 10000 ~ 1000033
(10~100 current maximum)(10~100 current maximum)
Dynamic range for other studiesDynamic range for other studies Internal properties amp environment 1kpc ~ 100 Mpc Internal properties amp environment 1kpc ~ 100 Mpc
Galactic structure amp star formation 01pc ~ 100kpc Galactic structure amp star formation 01pc ~ 100kpc
TreePM CodeTreePM Code11
About CodeAbout Code
1 Long range (rgt4 pixels 1 Long range (rgt4 pixels PMPM) + Short range() + Short range(PMPM++TreeTree) G-forces) G-forces
2 Tree generation in each slab amp in each cube of 42 Tree generation in each slab amp in each cube of 433 pixels pixels
3 Min of particles for tree generation ndash Direct P3 Min of particles for tree generation ndash Direct P22 if (cube) lt N if (cube) lt Ntreetree
4 Memory ~3 4 Memory ~3 xx [16] [16] xx words per particle words per particle
16 per particle index 16 per particle index22 position position33 velocity velocity33 acceleration acceleration33 mass mass11
softening length computational work measurement pointersoftening length computational work measurement pointer
factor ~3 for memory imbalance factor ~3 for memory imbalance
Buffer zone particles Buffer zone particles
TreePM Gravitational Force
PMPM
Tree + PMTree + PM
PMPM
ForceForce
GaussianSmoothed RG=09 pixels
TreePM CodeTreePM Code22
AdvantagesAdvantages
1 O(N log N) Tree operations for short range force ndash unlike P1 O(N log N) Tree operations for short range force ndash unlike P33MM
2 Periodic boundary condition solved by PM ndash unlike Tree2 Periodic boundary condition solved by PM ndash unlike Tree
3 No need to build a global tree ndash force correction only out to 4 pixels3 No need to build a global tree ndash force correction only out to 4 pixels
4 Local Trees 4 Local Trees
Parallelizable by domain decomposition (time)Parallelizable by domain decomposition (time)
amp disposable local trees keeping trees in 8amp disposable local trees keeping trees in 8xx88xxnnzz pixels (memory) pixels (memory)
Parallelization
1 PM part 2 Tree part1 PM part 2 Tree part
Domain slabs of equal thickness Domain slabs of equal of Domain slabs of equal thickness Domain slabs of equal of
tree force interactions amptree force interactions amp Buffer zone particlesBuffer zone particles
TreePM CodeTreePM Code33
5 Accuracy ~ 05 5 Accuracy ~ 05 RMSRMS error in acceleration for error in acceleration for θθ=1=1
6 Performance6 Performance
CPU time per step
1024102433 particles particles
Regular backup amp Regular backup amp
Pre-halo finding Pre-halo finding
calculationcalculation
Load balance
1024102433 particles particles
of particles of particles
in domain slabsin domain slabs
homogeneous homogeneous
distributiondistribution
ΛΛCDM SimulationsCDM Simulations (Ki
m amp Park 2004 7)
TreePM codeTreePM code GOTPM (Dubinski Kim Park 2003)
2048204833 mesh mesh (initial condition)
2048204833 CDM particles CDM particles
1024 amp 5632 h1024 amp 5632 h-1-1MpcMpc size boxes
50 amp 275 h50 amp 275 h-1-1kpckpc force resolutions
FOR PRECISION COMPARISON between cosmological models amp real universe
Using IBM SP3 at KISTI 128 CPUs 900 Gbytes
Growth of Structures from initial Density Fluctuations
137b
118b
77b t=0
Dark Halo Identification(Kimamp Park 2006
ΛΛCDMCDM 1024 h1024 h-1-1MpcMpc)
Physically Self-Bound Halos
Halo centers - local density peaks
Binding E wrt local halo centers
Tidal radii of subhalos wrt bigger halos
Halos with gt=53 particles (5x1011 M⊙)
PSB HalosVS
Others
Topology studyTopology study
1 Gaussianity of the 1 Gaussianity of the linear (primordial) density fieldlinear (primordial) density field pr predicted by simple inflationary scenariosedicted by simple inflationary scenarios
2 Topology of galaxy distribution at NL scales sensitive 2 Topology of galaxy distribution at NL scales sensitive to to cosmological parameterscosmological parameters amp to amp to galaxy formation mechanismgalaxy formation mechanism
3 Direct Intuitive meaning3 Direct Intuitive meaning
Large ScalesLarge Scales Small ScalesSmall Scales
Primordial Gaussianity Galaxy FormationPrimordial Gaussianity Galaxy Formation
Cosmological ParametersCosmological Parameters
GenusGenus ndash A Measure of Topologyndash A Measure of Topology
DefinitionDefinition
G = of holes - of isolated regionsG = of holes - of isolated regions in iso-density contour surfacesin iso-density contour surfaces
= 14= 14ππ intintSS κ dA (Gauss-Bonnet Theorem) κ dA (Gauss-Bonnet Theorem)
[ex G(sphere)=-1 G(torus)=0 ][ex G(sphere)=-1 G(torus)=0 ]
2 holes ndash 1 body = +1
Gaussian FieldGaussian Field Genusunit volume g(ν) = A (1-νGenusunit volume g(ν) = A (1-ν22) exp(- ν) exp(- ν222)2) where ν=(ρ- ρwhere ν=(ρ- ρbb) ρ) ρbbσ amp σ amp
A=1(2π)A=1(2π)22 ltk ltk223gt3gt32 32
if P(k)~kif P(k)~knn A R A RGG33 =[8radic2π =[8radic2π22]]-1 -1 [(n+3)3][(n+3)3]32 32
Non-Gaussian FieldNon-Gaussian Field (Toy models) (Toy models)
Clusters Bubbles HDM
(Weinberg Gott amp Melott 1987)(Weinberg Gott amp Melott 1987)
Non-Gaussianity Genus-related statisticsNon-Gaussianity Genus-related statistics
1 Shift parameter 1 Shift parameter 2 Asymmetry parameters A2 Asymmetry parameters AC C AAVV
3 Amplitude drop R3 Amplitude drop RAAAAobsobsAAPSPS
ACAv
RA
Biased Biased Formation Formation of Galaxiesof Galaxies
L-dependence L-dependence of 1 amp 2 point of 1 amp 2 point distribution distribution
but also but also topology topology
(Park et al 2005)
Topology of LSS can be explained by Topology of LSS can be explained by GF modelsGF models
(Park Kim et al 2005)
Merger Merger Halo formation Halo formationvoid percolationvoid percolation
void splittingvoid splitting
LCDM1024LCDM1024
Matter field canrsquot
Topology of LSS can be explained by Topology of LSS can be explained by GF modelsGF models
Direction of Direction of evolution evolution
~1 amp Little evoluti~1 amp Little evolution at low zon at low z
Mergers of hMergers of halosalos
AV lt 1
ltNltNsatsatgt = (MMgt = (MM11))αα for MgtM for MgtMminmin whe whe
re logMre logMminmin=1176 log M=1176 log M11=1=1
315 315 αα=113=113
HOD model for VL sHOD model for VL sample Mample Mrrlt-195lt-195
(Park et al 2005)Probably yes
Comparison of topology SDSS vs Comparison of topology SDSS vs CDM CDM
SDSS amp 6 h-1Mpc scale Kim+Park(o) amp Springel(x)
Future ofCosmological N-Body
Simulation1 Useful for cosmology amp galaxy formation study1 Useful for cosmology amp galaxy formation study
(until star formation can be properly simulated by radiati(until star formation can be properly simulated by radiative hydro-codes)ve hydro-codes)
2 Need to reach of particles gtgt 50002 Need to reach of particles gtgt 500033 ~ 10000 ~ 1000033
(10~100 current maximum)(10~100 current maximum)
Dynamic range for other studiesDynamic range for other studies Internal properties amp environment 1kpc ~ 100 Mpc Internal properties amp environment 1kpc ~ 100 Mpc
Galactic structure amp star formation 01pc ~ 100kpc Galactic structure amp star formation 01pc ~ 100kpc
TreePM Gravitational Force
PMPM
Tree + PMTree + PM
PMPM
ForceForce
GaussianSmoothed RG=09 pixels
TreePM CodeTreePM Code22
AdvantagesAdvantages
1 O(N log N) Tree operations for short range force ndash unlike P1 O(N log N) Tree operations for short range force ndash unlike P33MM
2 Periodic boundary condition solved by PM ndash unlike Tree2 Periodic boundary condition solved by PM ndash unlike Tree
3 No need to build a global tree ndash force correction only out to 4 pixels3 No need to build a global tree ndash force correction only out to 4 pixels
4 Local Trees 4 Local Trees
Parallelizable by domain decomposition (time)Parallelizable by domain decomposition (time)
amp disposable local trees keeping trees in 8amp disposable local trees keeping trees in 8xx88xxnnzz pixels (memory) pixels (memory)
Parallelization
1 PM part 2 Tree part1 PM part 2 Tree part
Domain slabs of equal thickness Domain slabs of equal of Domain slabs of equal thickness Domain slabs of equal of
tree force interactions amptree force interactions amp Buffer zone particlesBuffer zone particles
TreePM CodeTreePM Code33
5 Accuracy ~ 05 5 Accuracy ~ 05 RMSRMS error in acceleration for error in acceleration for θθ=1=1
6 Performance6 Performance
CPU time per step
1024102433 particles particles
Regular backup amp Regular backup amp
Pre-halo finding Pre-halo finding
calculationcalculation
Load balance
1024102433 particles particles
of particles of particles
in domain slabsin domain slabs
homogeneous homogeneous
distributiondistribution
ΛΛCDM SimulationsCDM Simulations (Ki
m amp Park 2004 7)
TreePM codeTreePM code GOTPM (Dubinski Kim Park 2003)
2048204833 mesh mesh (initial condition)
2048204833 CDM particles CDM particles
1024 amp 5632 h1024 amp 5632 h-1-1MpcMpc size boxes
50 amp 275 h50 amp 275 h-1-1kpckpc force resolutions
FOR PRECISION COMPARISON between cosmological models amp real universe
Using IBM SP3 at KISTI 128 CPUs 900 Gbytes
Growth of Structures from initial Density Fluctuations
137b
118b
77b t=0
Dark Halo Identification(Kimamp Park 2006
ΛΛCDMCDM 1024 h1024 h-1-1MpcMpc)
Physically Self-Bound Halos
Halo centers - local density peaks
Binding E wrt local halo centers
Tidal radii of subhalos wrt bigger halos
Halos with gt=53 particles (5x1011 M⊙)
PSB HalosVS
Others
Topology studyTopology study
1 Gaussianity of the 1 Gaussianity of the linear (primordial) density fieldlinear (primordial) density field pr predicted by simple inflationary scenariosedicted by simple inflationary scenarios
2 Topology of galaxy distribution at NL scales sensitive 2 Topology of galaxy distribution at NL scales sensitive to to cosmological parameterscosmological parameters amp to amp to galaxy formation mechanismgalaxy formation mechanism
3 Direct Intuitive meaning3 Direct Intuitive meaning
Large ScalesLarge Scales Small ScalesSmall Scales
Primordial Gaussianity Galaxy FormationPrimordial Gaussianity Galaxy Formation
Cosmological ParametersCosmological Parameters
GenusGenus ndash A Measure of Topologyndash A Measure of Topology
DefinitionDefinition
G = of holes - of isolated regionsG = of holes - of isolated regions in iso-density contour surfacesin iso-density contour surfaces
= 14= 14ππ intintSS κ dA (Gauss-Bonnet Theorem) κ dA (Gauss-Bonnet Theorem)
[ex G(sphere)=-1 G(torus)=0 ][ex G(sphere)=-1 G(torus)=0 ]
2 holes ndash 1 body = +1
Gaussian FieldGaussian Field Genusunit volume g(ν) = A (1-νGenusunit volume g(ν) = A (1-ν22) exp(- ν) exp(- ν222)2) where ν=(ρ- ρwhere ν=(ρ- ρbb) ρ) ρbbσ amp σ amp
A=1(2π)A=1(2π)22 ltk ltk223gt3gt32 32
if P(k)~kif P(k)~knn A R A RGG33 =[8radic2π =[8radic2π22]]-1 -1 [(n+3)3][(n+3)3]32 32
Non-Gaussian FieldNon-Gaussian Field (Toy models) (Toy models)
Clusters Bubbles HDM
(Weinberg Gott amp Melott 1987)(Weinberg Gott amp Melott 1987)
Non-Gaussianity Genus-related statisticsNon-Gaussianity Genus-related statistics
1 Shift parameter 1 Shift parameter 2 Asymmetry parameters A2 Asymmetry parameters AC C AAVV
3 Amplitude drop R3 Amplitude drop RAAAAobsobsAAPSPS
ACAv
RA
Biased Biased Formation Formation of Galaxiesof Galaxies
L-dependence L-dependence of 1 amp 2 point of 1 amp 2 point distribution distribution
but also but also topology topology
(Park et al 2005)
Topology of LSS can be explained by Topology of LSS can be explained by GF modelsGF models
(Park Kim et al 2005)
Merger Merger Halo formation Halo formationvoid percolationvoid percolation
void splittingvoid splitting
LCDM1024LCDM1024
Matter field canrsquot
Topology of LSS can be explained by Topology of LSS can be explained by GF modelsGF models
Direction of Direction of evolution evolution
~1 amp Little evoluti~1 amp Little evolution at low zon at low z
Mergers of hMergers of halosalos
AV lt 1
ltNltNsatsatgt = (MMgt = (MM11))αα for MgtM for MgtMminmin whe whe
re logMre logMminmin=1176 log M=1176 log M11=1=1
315 315 αα=113=113
HOD model for VL sHOD model for VL sample Mample Mrrlt-195lt-195
(Park et al 2005)Probably yes
Comparison of topology SDSS vs Comparison of topology SDSS vs CDM CDM
SDSS amp 6 h-1Mpc scale Kim+Park(o) amp Springel(x)
Future ofCosmological N-Body
Simulation1 Useful for cosmology amp galaxy formation study1 Useful for cosmology amp galaxy formation study
(until star formation can be properly simulated by radiati(until star formation can be properly simulated by radiative hydro-codes)ve hydro-codes)
2 Need to reach of particles gtgt 50002 Need to reach of particles gtgt 500033 ~ 10000 ~ 1000033
(10~100 current maximum)(10~100 current maximum)
Dynamic range for other studiesDynamic range for other studies Internal properties amp environment 1kpc ~ 100 Mpc Internal properties amp environment 1kpc ~ 100 Mpc
Galactic structure amp star formation 01pc ~ 100kpc Galactic structure amp star formation 01pc ~ 100kpc
TreePM CodeTreePM Code22
AdvantagesAdvantages
1 O(N log N) Tree operations for short range force ndash unlike P1 O(N log N) Tree operations for short range force ndash unlike P33MM
2 Periodic boundary condition solved by PM ndash unlike Tree2 Periodic boundary condition solved by PM ndash unlike Tree
3 No need to build a global tree ndash force correction only out to 4 pixels3 No need to build a global tree ndash force correction only out to 4 pixels
4 Local Trees 4 Local Trees
Parallelizable by domain decomposition (time)Parallelizable by domain decomposition (time)
amp disposable local trees keeping trees in 8amp disposable local trees keeping trees in 8xx88xxnnzz pixels (memory) pixels (memory)
Parallelization
1 PM part 2 Tree part1 PM part 2 Tree part
Domain slabs of equal thickness Domain slabs of equal of Domain slabs of equal thickness Domain slabs of equal of
tree force interactions amptree force interactions amp Buffer zone particlesBuffer zone particles
TreePM CodeTreePM Code33
5 Accuracy ~ 05 5 Accuracy ~ 05 RMSRMS error in acceleration for error in acceleration for θθ=1=1
6 Performance6 Performance
CPU time per step
1024102433 particles particles
Regular backup amp Regular backup amp
Pre-halo finding Pre-halo finding
calculationcalculation
Load balance
1024102433 particles particles
of particles of particles
in domain slabsin domain slabs
homogeneous homogeneous
distributiondistribution
ΛΛCDM SimulationsCDM Simulations (Ki
m amp Park 2004 7)
TreePM codeTreePM code GOTPM (Dubinski Kim Park 2003)
2048204833 mesh mesh (initial condition)
2048204833 CDM particles CDM particles
1024 amp 5632 h1024 amp 5632 h-1-1MpcMpc size boxes
50 amp 275 h50 amp 275 h-1-1kpckpc force resolutions
FOR PRECISION COMPARISON between cosmological models amp real universe
Using IBM SP3 at KISTI 128 CPUs 900 Gbytes
Growth of Structures from initial Density Fluctuations
137b
118b
77b t=0
Dark Halo Identification(Kimamp Park 2006
ΛΛCDMCDM 1024 h1024 h-1-1MpcMpc)
Physically Self-Bound Halos
Halo centers - local density peaks
Binding E wrt local halo centers
Tidal radii of subhalos wrt bigger halos
Halos with gt=53 particles (5x1011 M⊙)
PSB HalosVS
Others
Topology studyTopology study
1 Gaussianity of the 1 Gaussianity of the linear (primordial) density fieldlinear (primordial) density field pr predicted by simple inflationary scenariosedicted by simple inflationary scenarios
2 Topology of galaxy distribution at NL scales sensitive 2 Topology of galaxy distribution at NL scales sensitive to to cosmological parameterscosmological parameters amp to amp to galaxy formation mechanismgalaxy formation mechanism
3 Direct Intuitive meaning3 Direct Intuitive meaning
Large ScalesLarge Scales Small ScalesSmall Scales
Primordial Gaussianity Galaxy FormationPrimordial Gaussianity Galaxy Formation
Cosmological ParametersCosmological Parameters
GenusGenus ndash A Measure of Topologyndash A Measure of Topology
DefinitionDefinition
G = of holes - of isolated regionsG = of holes - of isolated regions in iso-density contour surfacesin iso-density contour surfaces
= 14= 14ππ intintSS κ dA (Gauss-Bonnet Theorem) κ dA (Gauss-Bonnet Theorem)
[ex G(sphere)=-1 G(torus)=0 ][ex G(sphere)=-1 G(torus)=0 ]
2 holes ndash 1 body = +1
Gaussian FieldGaussian Field Genusunit volume g(ν) = A (1-νGenusunit volume g(ν) = A (1-ν22) exp(- ν) exp(- ν222)2) where ν=(ρ- ρwhere ν=(ρ- ρbb) ρ) ρbbσ amp σ amp
A=1(2π)A=1(2π)22 ltk ltk223gt3gt32 32
if P(k)~kif P(k)~knn A R A RGG33 =[8radic2π =[8radic2π22]]-1 -1 [(n+3)3][(n+3)3]32 32
Non-Gaussian FieldNon-Gaussian Field (Toy models) (Toy models)
Clusters Bubbles HDM
(Weinberg Gott amp Melott 1987)(Weinberg Gott amp Melott 1987)
Non-Gaussianity Genus-related statisticsNon-Gaussianity Genus-related statistics
1 Shift parameter 1 Shift parameter 2 Asymmetry parameters A2 Asymmetry parameters AC C AAVV
3 Amplitude drop R3 Amplitude drop RAAAAobsobsAAPSPS
ACAv
RA
Biased Biased Formation Formation of Galaxiesof Galaxies
L-dependence L-dependence of 1 amp 2 point of 1 amp 2 point distribution distribution
but also but also topology topology
(Park et al 2005)
Topology of LSS can be explained by Topology of LSS can be explained by GF modelsGF models
(Park Kim et al 2005)
Merger Merger Halo formation Halo formationvoid percolationvoid percolation
void splittingvoid splitting
LCDM1024LCDM1024
Matter field canrsquot
Topology of LSS can be explained by Topology of LSS can be explained by GF modelsGF models
Direction of Direction of evolution evolution
~1 amp Little evoluti~1 amp Little evolution at low zon at low z
Mergers of hMergers of halosalos
AV lt 1
ltNltNsatsatgt = (MMgt = (MM11))αα for MgtM for MgtMminmin whe whe
re logMre logMminmin=1176 log M=1176 log M11=1=1
315 315 αα=113=113
HOD model for VL sHOD model for VL sample Mample Mrrlt-195lt-195
(Park et al 2005)Probably yes
Comparison of topology SDSS vs Comparison of topology SDSS vs CDM CDM
SDSS amp 6 h-1Mpc scale Kim+Park(o) amp Springel(x)
Future ofCosmological N-Body
Simulation1 Useful for cosmology amp galaxy formation study1 Useful for cosmology amp galaxy formation study
(until star formation can be properly simulated by radiati(until star formation can be properly simulated by radiative hydro-codes)ve hydro-codes)
2 Need to reach of particles gtgt 50002 Need to reach of particles gtgt 500033 ~ 10000 ~ 1000033
(10~100 current maximum)(10~100 current maximum)
Dynamic range for other studiesDynamic range for other studies Internal properties amp environment 1kpc ~ 100 Mpc Internal properties amp environment 1kpc ~ 100 Mpc
Galactic structure amp star formation 01pc ~ 100kpc Galactic structure amp star formation 01pc ~ 100kpc
Parallelization
1 PM part 2 Tree part1 PM part 2 Tree part
Domain slabs of equal thickness Domain slabs of equal of Domain slabs of equal thickness Domain slabs of equal of
tree force interactions amptree force interactions amp Buffer zone particlesBuffer zone particles
TreePM CodeTreePM Code33
5 Accuracy ~ 05 5 Accuracy ~ 05 RMSRMS error in acceleration for error in acceleration for θθ=1=1
6 Performance6 Performance
CPU time per step
1024102433 particles particles
Regular backup amp Regular backup amp
Pre-halo finding Pre-halo finding
calculationcalculation
Load balance
1024102433 particles particles
of particles of particles
in domain slabsin domain slabs
homogeneous homogeneous
distributiondistribution
ΛΛCDM SimulationsCDM Simulations (Ki
m amp Park 2004 7)
TreePM codeTreePM code GOTPM (Dubinski Kim Park 2003)
2048204833 mesh mesh (initial condition)
2048204833 CDM particles CDM particles
1024 amp 5632 h1024 amp 5632 h-1-1MpcMpc size boxes
50 amp 275 h50 amp 275 h-1-1kpckpc force resolutions
FOR PRECISION COMPARISON between cosmological models amp real universe
Using IBM SP3 at KISTI 128 CPUs 900 Gbytes
Growth of Structures from initial Density Fluctuations
137b
118b
77b t=0
Dark Halo Identification(Kimamp Park 2006
ΛΛCDMCDM 1024 h1024 h-1-1MpcMpc)
Physically Self-Bound Halos
Halo centers - local density peaks
Binding E wrt local halo centers
Tidal radii of subhalos wrt bigger halos
Halos with gt=53 particles (5x1011 M⊙)
PSB HalosVS
Others
Topology studyTopology study
1 Gaussianity of the 1 Gaussianity of the linear (primordial) density fieldlinear (primordial) density field pr predicted by simple inflationary scenariosedicted by simple inflationary scenarios
2 Topology of galaxy distribution at NL scales sensitive 2 Topology of galaxy distribution at NL scales sensitive to to cosmological parameterscosmological parameters amp to amp to galaxy formation mechanismgalaxy formation mechanism
3 Direct Intuitive meaning3 Direct Intuitive meaning
Large ScalesLarge Scales Small ScalesSmall Scales
Primordial Gaussianity Galaxy FormationPrimordial Gaussianity Galaxy Formation
Cosmological ParametersCosmological Parameters
GenusGenus ndash A Measure of Topologyndash A Measure of Topology
DefinitionDefinition
G = of holes - of isolated regionsG = of holes - of isolated regions in iso-density contour surfacesin iso-density contour surfaces
= 14= 14ππ intintSS κ dA (Gauss-Bonnet Theorem) κ dA (Gauss-Bonnet Theorem)
[ex G(sphere)=-1 G(torus)=0 ][ex G(sphere)=-1 G(torus)=0 ]
2 holes ndash 1 body = +1
Gaussian FieldGaussian Field Genusunit volume g(ν) = A (1-νGenusunit volume g(ν) = A (1-ν22) exp(- ν) exp(- ν222)2) where ν=(ρ- ρwhere ν=(ρ- ρbb) ρ) ρbbσ amp σ amp
A=1(2π)A=1(2π)22 ltk ltk223gt3gt32 32
if P(k)~kif P(k)~knn A R A RGG33 =[8radic2π =[8radic2π22]]-1 -1 [(n+3)3][(n+3)3]32 32
Non-Gaussian FieldNon-Gaussian Field (Toy models) (Toy models)
Clusters Bubbles HDM
(Weinberg Gott amp Melott 1987)(Weinberg Gott amp Melott 1987)
Non-Gaussianity Genus-related statisticsNon-Gaussianity Genus-related statistics
1 Shift parameter 1 Shift parameter 2 Asymmetry parameters A2 Asymmetry parameters AC C AAVV
3 Amplitude drop R3 Amplitude drop RAAAAobsobsAAPSPS
ACAv
RA
Biased Biased Formation Formation of Galaxiesof Galaxies
L-dependence L-dependence of 1 amp 2 point of 1 amp 2 point distribution distribution
but also but also topology topology
(Park et al 2005)
Topology of LSS can be explained by Topology of LSS can be explained by GF modelsGF models
(Park Kim et al 2005)
Merger Merger Halo formation Halo formationvoid percolationvoid percolation
void splittingvoid splitting
LCDM1024LCDM1024
Matter field canrsquot
Topology of LSS can be explained by Topology of LSS can be explained by GF modelsGF models
Direction of Direction of evolution evolution
~1 amp Little evoluti~1 amp Little evolution at low zon at low z
Mergers of hMergers of halosalos
AV lt 1
ltNltNsatsatgt = (MMgt = (MM11))αα for MgtM for MgtMminmin whe whe
re logMre logMminmin=1176 log M=1176 log M11=1=1
315 315 αα=113=113
HOD model for VL sHOD model for VL sample Mample Mrrlt-195lt-195
(Park et al 2005)Probably yes
Comparison of topology SDSS vs Comparison of topology SDSS vs CDM CDM
SDSS amp 6 h-1Mpc scale Kim+Park(o) amp Springel(x)
Future ofCosmological N-Body
Simulation1 Useful for cosmology amp galaxy formation study1 Useful for cosmology amp galaxy formation study
(until star formation can be properly simulated by radiati(until star formation can be properly simulated by radiative hydro-codes)ve hydro-codes)
2 Need to reach of particles gtgt 50002 Need to reach of particles gtgt 500033 ~ 10000 ~ 1000033
(10~100 current maximum)(10~100 current maximum)
Dynamic range for other studiesDynamic range for other studies Internal properties amp environment 1kpc ~ 100 Mpc Internal properties amp environment 1kpc ~ 100 Mpc
Galactic structure amp star formation 01pc ~ 100kpc Galactic structure amp star formation 01pc ~ 100kpc
TreePM CodeTreePM Code33
5 Accuracy ~ 05 5 Accuracy ~ 05 RMSRMS error in acceleration for error in acceleration for θθ=1=1
6 Performance6 Performance
CPU time per step
1024102433 particles particles
Regular backup amp Regular backup amp
Pre-halo finding Pre-halo finding
calculationcalculation
Load balance
1024102433 particles particles
of particles of particles
in domain slabsin domain slabs
homogeneous homogeneous
distributiondistribution
ΛΛCDM SimulationsCDM Simulations (Ki
m amp Park 2004 7)
TreePM codeTreePM code GOTPM (Dubinski Kim Park 2003)
2048204833 mesh mesh (initial condition)
2048204833 CDM particles CDM particles
1024 amp 5632 h1024 amp 5632 h-1-1MpcMpc size boxes
50 amp 275 h50 amp 275 h-1-1kpckpc force resolutions
FOR PRECISION COMPARISON between cosmological models amp real universe
Using IBM SP3 at KISTI 128 CPUs 900 Gbytes
Growth of Structures from initial Density Fluctuations
137b
118b
77b t=0
Dark Halo Identification(Kimamp Park 2006
ΛΛCDMCDM 1024 h1024 h-1-1MpcMpc)
Physically Self-Bound Halos
Halo centers - local density peaks
Binding E wrt local halo centers
Tidal radii of subhalos wrt bigger halos
Halos with gt=53 particles (5x1011 M⊙)
PSB HalosVS
Others
Topology studyTopology study
1 Gaussianity of the 1 Gaussianity of the linear (primordial) density fieldlinear (primordial) density field pr predicted by simple inflationary scenariosedicted by simple inflationary scenarios
2 Topology of galaxy distribution at NL scales sensitive 2 Topology of galaxy distribution at NL scales sensitive to to cosmological parameterscosmological parameters amp to amp to galaxy formation mechanismgalaxy formation mechanism
3 Direct Intuitive meaning3 Direct Intuitive meaning
Large ScalesLarge Scales Small ScalesSmall Scales
Primordial Gaussianity Galaxy FormationPrimordial Gaussianity Galaxy Formation
Cosmological ParametersCosmological Parameters
GenusGenus ndash A Measure of Topologyndash A Measure of Topology
DefinitionDefinition
G = of holes - of isolated regionsG = of holes - of isolated regions in iso-density contour surfacesin iso-density contour surfaces
= 14= 14ππ intintSS κ dA (Gauss-Bonnet Theorem) κ dA (Gauss-Bonnet Theorem)
[ex G(sphere)=-1 G(torus)=0 ][ex G(sphere)=-1 G(torus)=0 ]
2 holes ndash 1 body = +1
Gaussian FieldGaussian Field Genusunit volume g(ν) = A (1-νGenusunit volume g(ν) = A (1-ν22) exp(- ν) exp(- ν222)2) where ν=(ρ- ρwhere ν=(ρ- ρbb) ρ) ρbbσ amp σ amp
A=1(2π)A=1(2π)22 ltk ltk223gt3gt32 32
if P(k)~kif P(k)~knn A R A RGG33 =[8radic2π =[8radic2π22]]-1 -1 [(n+3)3][(n+3)3]32 32
Non-Gaussian FieldNon-Gaussian Field (Toy models) (Toy models)
Clusters Bubbles HDM
(Weinberg Gott amp Melott 1987)(Weinberg Gott amp Melott 1987)
Non-Gaussianity Genus-related statisticsNon-Gaussianity Genus-related statistics
1 Shift parameter 1 Shift parameter 2 Asymmetry parameters A2 Asymmetry parameters AC C AAVV
3 Amplitude drop R3 Amplitude drop RAAAAobsobsAAPSPS
ACAv
RA
Biased Biased Formation Formation of Galaxiesof Galaxies
L-dependence L-dependence of 1 amp 2 point of 1 amp 2 point distribution distribution
but also but also topology topology
(Park et al 2005)
Topology of LSS can be explained by Topology of LSS can be explained by GF modelsGF models
(Park Kim et al 2005)
Merger Merger Halo formation Halo formationvoid percolationvoid percolation
void splittingvoid splitting
LCDM1024LCDM1024
Matter field canrsquot
Topology of LSS can be explained by Topology of LSS can be explained by GF modelsGF models
Direction of Direction of evolution evolution
~1 amp Little evoluti~1 amp Little evolution at low zon at low z
Mergers of hMergers of halosalos
AV lt 1
ltNltNsatsatgt = (MMgt = (MM11))αα for MgtM for MgtMminmin whe whe
re logMre logMminmin=1176 log M=1176 log M11=1=1
315 315 αα=113=113
HOD model for VL sHOD model for VL sample Mample Mrrlt-195lt-195
(Park et al 2005)Probably yes
Comparison of topology SDSS vs Comparison of topology SDSS vs CDM CDM
SDSS amp 6 h-1Mpc scale Kim+Park(o) amp Springel(x)
Future ofCosmological N-Body
Simulation1 Useful for cosmology amp galaxy formation study1 Useful for cosmology amp galaxy formation study
(until star formation can be properly simulated by radiati(until star formation can be properly simulated by radiative hydro-codes)ve hydro-codes)
2 Need to reach of particles gtgt 50002 Need to reach of particles gtgt 500033 ~ 10000 ~ 1000033
(10~100 current maximum)(10~100 current maximum)
Dynamic range for other studiesDynamic range for other studies Internal properties amp environment 1kpc ~ 100 Mpc Internal properties amp environment 1kpc ~ 100 Mpc
Galactic structure amp star formation 01pc ~ 100kpc Galactic structure amp star formation 01pc ~ 100kpc
CPU time per step
1024102433 particles particles
Regular backup amp Regular backup amp
Pre-halo finding Pre-halo finding
calculationcalculation
Load balance
1024102433 particles particles
of particles of particles
in domain slabsin domain slabs
homogeneous homogeneous
distributiondistribution
ΛΛCDM SimulationsCDM Simulations (Ki
m amp Park 2004 7)
TreePM codeTreePM code GOTPM (Dubinski Kim Park 2003)
2048204833 mesh mesh (initial condition)
2048204833 CDM particles CDM particles
1024 amp 5632 h1024 amp 5632 h-1-1MpcMpc size boxes
50 amp 275 h50 amp 275 h-1-1kpckpc force resolutions
FOR PRECISION COMPARISON between cosmological models amp real universe
Using IBM SP3 at KISTI 128 CPUs 900 Gbytes
Growth of Structures from initial Density Fluctuations
137b
118b
77b t=0
Dark Halo Identification(Kimamp Park 2006
ΛΛCDMCDM 1024 h1024 h-1-1MpcMpc)
Physically Self-Bound Halos
Halo centers - local density peaks
Binding E wrt local halo centers
Tidal radii of subhalos wrt bigger halos
Halos with gt=53 particles (5x1011 M⊙)
PSB HalosVS
Others
Topology studyTopology study
1 Gaussianity of the 1 Gaussianity of the linear (primordial) density fieldlinear (primordial) density field pr predicted by simple inflationary scenariosedicted by simple inflationary scenarios
2 Topology of galaxy distribution at NL scales sensitive 2 Topology of galaxy distribution at NL scales sensitive to to cosmological parameterscosmological parameters amp to amp to galaxy formation mechanismgalaxy formation mechanism
3 Direct Intuitive meaning3 Direct Intuitive meaning
Large ScalesLarge Scales Small ScalesSmall Scales
Primordial Gaussianity Galaxy FormationPrimordial Gaussianity Galaxy Formation
Cosmological ParametersCosmological Parameters
GenusGenus ndash A Measure of Topologyndash A Measure of Topology
DefinitionDefinition
G = of holes - of isolated regionsG = of holes - of isolated regions in iso-density contour surfacesin iso-density contour surfaces
= 14= 14ππ intintSS κ dA (Gauss-Bonnet Theorem) κ dA (Gauss-Bonnet Theorem)
[ex G(sphere)=-1 G(torus)=0 ][ex G(sphere)=-1 G(torus)=0 ]
2 holes ndash 1 body = +1
Gaussian FieldGaussian Field Genusunit volume g(ν) = A (1-νGenusunit volume g(ν) = A (1-ν22) exp(- ν) exp(- ν222)2) where ν=(ρ- ρwhere ν=(ρ- ρbb) ρ) ρbbσ amp σ amp
A=1(2π)A=1(2π)22 ltk ltk223gt3gt32 32
if P(k)~kif P(k)~knn A R A RGG33 =[8radic2π =[8radic2π22]]-1 -1 [(n+3)3][(n+3)3]32 32
Non-Gaussian FieldNon-Gaussian Field (Toy models) (Toy models)
Clusters Bubbles HDM
(Weinberg Gott amp Melott 1987)(Weinberg Gott amp Melott 1987)
Non-Gaussianity Genus-related statisticsNon-Gaussianity Genus-related statistics
1 Shift parameter 1 Shift parameter 2 Asymmetry parameters A2 Asymmetry parameters AC C AAVV
3 Amplitude drop R3 Amplitude drop RAAAAobsobsAAPSPS
ACAv
RA
Biased Biased Formation Formation of Galaxiesof Galaxies
L-dependence L-dependence of 1 amp 2 point of 1 amp 2 point distribution distribution
but also but also topology topology
(Park et al 2005)
Topology of LSS can be explained by Topology of LSS can be explained by GF modelsGF models
(Park Kim et al 2005)
Merger Merger Halo formation Halo formationvoid percolationvoid percolation
void splittingvoid splitting
LCDM1024LCDM1024
Matter field canrsquot
Topology of LSS can be explained by Topology of LSS can be explained by GF modelsGF models
Direction of Direction of evolution evolution
~1 amp Little evoluti~1 amp Little evolution at low zon at low z
Mergers of hMergers of halosalos
AV lt 1
ltNltNsatsatgt = (MMgt = (MM11))αα for MgtM for MgtMminmin whe whe
re logMre logMminmin=1176 log M=1176 log M11=1=1
315 315 αα=113=113
HOD model for VL sHOD model for VL sample Mample Mrrlt-195lt-195
(Park et al 2005)Probably yes
Comparison of topology SDSS vs Comparison of topology SDSS vs CDM CDM
SDSS amp 6 h-1Mpc scale Kim+Park(o) amp Springel(x)
Future ofCosmological N-Body
Simulation1 Useful for cosmology amp galaxy formation study1 Useful for cosmology amp galaxy formation study
(until star formation can be properly simulated by radiati(until star formation can be properly simulated by radiative hydro-codes)ve hydro-codes)
2 Need to reach of particles gtgt 50002 Need to reach of particles gtgt 500033 ~ 10000 ~ 1000033
(10~100 current maximum)(10~100 current maximum)
Dynamic range for other studiesDynamic range for other studies Internal properties amp environment 1kpc ~ 100 Mpc Internal properties amp environment 1kpc ~ 100 Mpc
Galactic structure amp star formation 01pc ~ 100kpc Galactic structure amp star formation 01pc ~ 100kpc
Load balance
1024102433 particles particles
of particles of particles
in domain slabsin domain slabs
homogeneous homogeneous
distributiondistribution
ΛΛCDM SimulationsCDM Simulations (Ki
m amp Park 2004 7)
TreePM codeTreePM code GOTPM (Dubinski Kim Park 2003)
2048204833 mesh mesh (initial condition)
2048204833 CDM particles CDM particles
1024 amp 5632 h1024 amp 5632 h-1-1MpcMpc size boxes
50 amp 275 h50 amp 275 h-1-1kpckpc force resolutions
FOR PRECISION COMPARISON between cosmological models amp real universe
Using IBM SP3 at KISTI 128 CPUs 900 Gbytes
Growth of Structures from initial Density Fluctuations
137b
118b
77b t=0
Dark Halo Identification(Kimamp Park 2006
ΛΛCDMCDM 1024 h1024 h-1-1MpcMpc)
Physically Self-Bound Halos
Halo centers - local density peaks
Binding E wrt local halo centers
Tidal radii of subhalos wrt bigger halos
Halos with gt=53 particles (5x1011 M⊙)
PSB HalosVS
Others
Topology studyTopology study
1 Gaussianity of the 1 Gaussianity of the linear (primordial) density fieldlinear (primordial) density field pr predicted by simple inflationary scenariosedicted by simple inflationary scenarios
2 Topology of galaxy distribution at NL scales sensitive 2 Topology of galaxy distribution at NL scales sensitive to to cosmological parameterscosmological parameters amp to amp to galaxy formation mechanismgalaxy formation mechanism
3 Direct Intuitive meaning3 Direct Intuitive meaning
Large ScalesLarge Scales Small ScalesSmall Scales
Primordial Gaussianity Galaxy FormationPrimordial Gaussianity Galaxy Formation
Cosmological ParametersCosmological Parameters
GenusGenus ndash A Measure of Topologyndash A Measure of Topology
DefinitionDefinition
G = of holes - of isolated regionsG = of holes - of isolated regions in iso-density contour surfacesin iso-density contour surfaces
= 14= 14ππ intintSS κ dA (Gauss-Bonnet Theorem) κ dA (Gauss-Bonnet Theorem)
[ex G(sphere)=-1 G(torus)=0 ][ex G(sphere)=-1 G(torus)=0 ]
2 holes ndash 1 body = +1
Gaussian FieldGaussian Field Genusunit volume g(ν) = A (1-νGenusunit volume g(ν) = A (1-ν22) exp(- ν) exp(- ν222)2) where ν=(ρ- ρwhere ν=(ρ- ρbb) ρ) ρbbσ amp σ amp
A=1(2π)A=1(2π)22 ltk ltk223gt3gt32 32
if P(k)~kif P(k)~knn A R A RGG33 =[8radic2π =[8radic2π22]]-1 -1 [(n+3)3][(n+3)3]32 32
Non-Gaussian FieldNon-Gaussian Field (Toy models) (Toy models)
Clusters Bubbles HDM
(Weinberg Gott amp Melott 1987)(Weinberg Gott amp Melott 1987)
Non-Gaussianity Genus-related statisticsNon-Gaussianity Genus-related statistics
1 Shift parameter 1 Shift parameter 2 Asymmetry parameters A2 Asymmetry parameters AC C AAVV
3 Amplitude drop R3 Amplitude drop RAAAAobsobsAAPSPS
ACAv
RA
Biased Biased Formation Formation of Galaxiesof Galaxies
L-dependence L-dependence of 1 amp 2 point of 1 amp 2 point distribution distribution
but also but also topology topology
(Park et al 2005)
Topology of LSS can be explained by Topology of LSS can be explained by GF modelsGF models
(Park Kim et al 2005)
Merger Merger Halo formation Halo formationvoid percolationvoid percolation
void splittingvoid splitting
LCDM1024LCDM1024
Matter field canrsquot
Topology of LSS can be explained by Topology of LSS can be explained by GF modelsGF models
Direction of Direction of evolution evolution
~1 amp Little evoluti~1 amp Little evolution at low zon at low z
Mergers of hMergers of halosalos
AV lt 1
ltNltNsatsatgt = (MMgt = (MM11))αα for MgtM for MgtMminmin whe whe
re logMre logMminmin=1176 log M=1176 log M11=1=1
315 315 αα=113=113
HOD model for VL sHOD model for VL sample Mample Mrrlt-195lt-195
(Park et al 2005)Probably yes
Comparison of topology SDSS vs Comparison of topology SDSS vs CDM CDM
SDSS amp 6 h-1Mpc scale Kim+Park(o) amp Springel(x)
Future ofCosmological N-Body
Simulation1 Useful for cosmology amp galaxy formation study1 Useful for cosmology amp galaxy formation study
(until star formation can be properly simulated by radiati(until star formation can be properly simulated by radiative hydro-codes)ve hydro-codes)
2 Need to reach of particles gtgt 50002 Need to reach of particles gtgt 500033 ~ 10000 ~ 1000033
(10~100 current maximum)(10~100 current maximum)
Dynamic range for other studiesDynamic range for other studies Internal properties amp environment 1kpc ~ 100 Mpc Internal properties amp environment 1kpc ~ 100 Mpc
Galactic structure amp star formation 01pc ~ 100kpc Galactic structure amp star formation 01pc ~ 100kpc
ΛΛCDM SimulationsCDM Simulations (Ki
m amp Park 2004 7)
TreePM codeTreePM code GOTPM (Dubinski Kim Park 2003)
2048204833 mesh mesh (initial condition)
2048204833 CDM particles CDM particles
1024 amp 5632 h1024 amp 5632 h-1-1MpcMpc size boxes
50 amp 275 h50 amp 275 h-1-1kpckpc force resolutions
FOR PRECISION COMPARISON between cosmological models amp real universe
Using IBM SP3 at KISTI 128 CPUs 900 Gbytes
Growth of Structures from initial Density Fluctuations
137b
118b
77b t=0
Dark Halo Identification(Kimamp Park 2006
ΛΛCDMCDM 1024 h1024 h-1-1MpcMpc)
Physically Self-Bound Halos
Halo centers - local density peaks
Binding E wrt local halo centers
Tidal radii of subhalos wrt bigger halos
Halos with gt=53 particles (5x1011 M⊙)
PSB HalosVS
Others
Topology studyTopology study
1 Gaussianity of the 1 Gaussianity of the linear (primordial) density fieldlinear (primordial) density field pr predicted by simple inflationary scenariosedicted by simple inflationary scenarios
2 Topology of galaxy distribution at NL scales sensitive 2 Topology of galaxy distribution at NL scales sensitive to to cosmological parameterscosmological parameters amp to amp to galaxy formation mechanismgalaxy formation mechanism
3 Direct Intuitive meaning3 Direct Intuitive meaning
Large ScalesLarge Scales Small ScalesSmall Scales
Primordial Gaussianity Galaxy FormationPrimordial Gaussianity Galaxy Formation
Cosmological ParametersCosmological Parameters
GenusGenus ndash A Measure of Topologyndash A Measure of Topology
DefinitionDefinition
G = of holes - of isolated regionsG = of holes - of isolated regions in iso-density contour surfacesin iso-density contour surfaces
= 14= 14ππ intintSS κ dA (Gauss-Bonnet Theorem) κ dA (Gauss-Bonnet Theorem)
[ex G(sphere)=-1 G(torus)=0 ][ex G(sphere)=-1 G(torus)=0 ]
2 holes ndash 1 body = +1
Gaussian FieldGaussian Field Genusunit volume g(ν) = A (1-νGenusunit volume g(ν) = A (1-ν22) exp(- ν) exp(- ν222)2) where ν=(ρ- ρwhere ν=(ρ- ρbb) ρ) ρbbσ amp σ amp
A=1(2π)A=1(2π)22 ltk ltk223gt3gt32 32
if P(k)~kif P(k)~knn A R A RGG33 =[8radic2π =[8radic2π22]]-1 -1 [(n+3)3][(n+3)3]32 32
Non-Gaussian FieldNon-Gaussian Field (Toy models) (Toy models)
Clusters Bubbles HDM
(Weinberg Gott amp Melott 1987)(Weinberg Gott amp Melott 1987)
Non-Gaussianity Genus-related statisticsNon-Gaussianity Genus-related statistics
1 Shift parameter 1 Shift parameter 2 Asymmetry parameters A2 Asymmetry parameters AC C AAVV
3 Amplitude drop R3 Amplitude drop RAAAAobsobsAAPSPS
ACAv
RA
Biased Biased Formation Formation of Galaxiesof Galaxies
L-dependence L-dependence of 1 amp 2 point of 1 amp 2 point distribution distribution
but also but also topology topology
(Park et al 2005)
Topology of LSS can be explained by Topology of LSS can be explained by GF modelsGF models
(Park Kim et al 2005)
Merger Merger Halo formation Halo formationvoid percolationvoid percolation
void splittingvoid splitting
LCDM1024LCDM1024
Matter field canrsquot
Topology of LSS can be explained by Topology of LSS can be explained by GF modelsGF models
Direction of Direction of evolution evolution
~1 amp Little evoluti~1 amp Little evolution at low zon at low z
Mergers of hMergers of halosalos
AV lt 1
ltNltNsatsatgt = (MMgt = (MM11))αα for MgtM for MgtMminmin whe whe
re logMre logMminmin=1176 log M=1176 log M11=1=1
315 315 αα=113=113
HOD model for VL sHOD model for VL sample Mample Mrrlt-195lt-195
(Park et al 2005)Probably yes
Comparison of topology SDSS vs Comparison of topology SDSS vs CDM CDM
SDSS amp 6 h-1Mpc scale Kim+Park(o) amp Springel(x)
Future ofCosmological N-Body
Simulation1 Useful for cosmology amp galaxy formation study1 Useful for cosmology amp galaxy formation study
(until star formation can be properly simulated by radiati(until star formation can be properly simulated by radiative hydro-codes)ve hydro-codes)
2 Need to reach of particles gtgt 50002 Need to reach of particles gtgt 500033 ~ 10000 ~ 1000033
(10~100 current maximum)(10~100 current maximum)
Dynamic range for other studiesDynamic range for other studies Internal properties amp environment 1kpc ~ 100 Mpc Internal properties amp environment 1kpc ~ 100 Mpc
Galactic structure amp star formation 01pc ~ 100kpc Galactic structure amp star formation 01pc ~ 100kpc
Growth of Structures from initial Density Fluctuations
137b
118b
77b t=0
Dark Halo Identification(Kimamp Park 2006
ΛΛCDMCDM 1024 h1024 h-1-1MpcMpc)
Physically Self-Bound Halos
Halo centers - local density peaks
Binding E wrt local halo centers
Tidal radii of subhalos wrt bigger halos
Halos with gt=53 particles (5x1011 M⊙)
PSB HalosVS
Others
Topology studyTopology study
1 Gaussianity of the 1 Gaussianity of the linear (primordial) density fieldlinear (primordial) density field pr predicted by simple inflationary scenariosedicted by simple inflationary scenarios
2 Topology of galaxy distribution at NL scales sensitive 2 Topology of galaxy distribution at NL scales sensitive to to cosmological parameterscosmological parameters amp to amp to galaxy formation mechanismgalaxy formation mechanism
3 Direct Intuitive meaning3 Direct Intuitive meaning
Large ScalesLarge Scales Small ScalesSmall Scales
Primordial Gaussianity Galaxy FormationPrimordial Gaussianity Galaxy Formation
Cosmological ParametersCosmological Parameters
GenusGenus ndash A Measure of Topologyndash A Measure of Topology
DefinitionDefinition
G = of holes - of isolated regionsG = of holes - of isolated regions in iso-density contour surfacesin iso-density contour surfaces
= 14= 14ππ intintSS κ dA (Gauss-Bonnet Theorem) κ dA (Gauss-Bonnet Theorem)
[ex G(sphere)=-1 G(torus)=0 ][ex G(sphere)=-1 G(torus)=0 ]
2 holes ndash 1 body = +1
Gaussian FieldGaussian Field Genusunit volume g(ν) = A (1-νGenusunit volume g(ν) = A (1-ν22) exp(- ν) exp(- ν222)2) where ν=(ρ- ρwhere ν=(ρ- ρbb) ρ) ρbbσ amp σ amp
A=1(2π)A=1(2π)22 ltk ltk223gt3gt32 32
if P(k)~kif P(k)~knn A R A RGG33 =[8radic2π =[8radic2π22]]-1 -1 [(n+3)3][(n+3)3]32 32
Non-Gaussian FieldNon-Gaussian Field (Toy models) (Toy models)
Clusters Bubbles HDM
(Weinberg Gott amp Melott 1987)(Weinberg Gott amp Melott 1987)
Non-Gaussianity Genus-related statisticsNon-Gaussianity Genus-related statistics
1 Shift parameter 1 Shift parameter 2 Asymmetry parameters A2 Asymmetry parameters AC C AAVV
3 Amplitude drop R3 Amplitude drop RAAAAobsobsAAPSPS
ACAv
RA
Biased Biased Formation Formation of Galaxiesof Galaxies
L-dependence L-dependence of 1 amp 2 point of 1 amp 2 point distribution distribution
but also but also topology topology
(Park et al 2005)
Topology of LSS can be explained by Topology of LSS can be explained by GF modelsGF models
(Park Kim et al 2005)
Merger Merger Halo formation Halo formationvoid percolationvoid percolation
void splittingvoid splitting
LCDM1024LCDM1024
Matter field canrsquot
Topology of LSS can be explained by Topology of LSS can be explained by GF modelsGF models
Direction of Direction of evolution evolution
~1 amp Little evoluti~1 amp Little evolution at low zon at low z
Mergers of hMergers of halosalos
AV lt 1
ltNltNsatsatgt = (MMgt = (MM11))αα for MgtM for MgtMminmin whe whe
re logMre logMminmin=1176 log M=1176 log M11=1=1
315 315 αα=113=113
HOD model for VL sHOD model for VL sample Mample Mrrlt-195lt-195
(Park et al 2005)Probably yes
Comparison of topology SDSS vs Comparison of topology SDSS vs CDM CDM
SDSS amp 6 h-1Mpc scale Kim+Park(o) amp Springel(x)
Future ofCosmological N-Body
Simulation1 Useful for cosmology amp galaxy formation study1 Useful for cosmology amp galaxy formation study
(until star formation can be properly simulated by radiati(until star formation can be properly simulated by radiative hydro-codes)ve hydro-codes)
2 Need to reach of particles gtgt 50002 Need to reach of particles gtgt 500033 ~ 10000 ~ 1000033
(10~100 current maximum)(10~100 current maximum)
Dynamic range for other studiesDynamic range for other studies Internal properties amp environment 1kpc ~ 100 Mpc Internal properties amp environment 1kpc ~ 100 Mpc
Galactic structure amp star formation 01pc ~ 100kpc Galactic structure amp star formation 01pc ~ 100kpc
Dark Halo Identification(Kimamp Park 2006
ΛΛCDMCDM 1024 h1024 h-1-1MpcMpc)
Physically Self-Bound Halos
Halo centers - local density peaks
Binding E wrt local halo centers
Tidal radii of subhalos wrt bigger halos
Halos with gt=53 particles (5x1011 M⊙)
PSB HalosVS
Others
Topology studyTopology study
1 Gaussianity of the 1 Gaussianity of the linear (primordial) density fieldlinear (primordial) density field pr predicted by simple inflationary scenariosedicted by simple inflationary scenarios
2 Topology of galaxy distribution at NL scales sensitive 2 Topology of galaxy distribution at NL scales sensitive to to cosmological parameterscosmological parameters amp to amp to galaxy formation mechanismgalaxy formation mechanism
3 Direct Intuitive meaning3 Direct Intuitive meaning
Large ScalesLarge Scales Small ScalesSmall Scales
Primordial Gaussianity Galaxy FormationPrimordial Gaussianity Galaxy Formation
Cosmological ParametersCosmological Parameters
GenusGenus ndash A Measure of Topologyndash A Measure of Topology
DefinitionDefinition
G = of holes - of isolated regionsG = of holes - of isolated regions in iso-density contour surfacesin iso-density contour surfaces
= 14= 14ππ intintSS κ dA (Gauss-Bonnet Theorem) κ dA (Gauss-Bonnet Theorem)
[ex G(sphere)=-1 G(torus)=0 ][ex G(sphere)=-1 G(torus)=0 ]
2 holes ndash 1 body = +1
Gaussian FieldGaussian Field Genusunit volume g(ν) = A (1-νGenusunit volume g(ν) = A (1-ν22) exp(- ν) exp(- ν222)2) where ν=(ρ- ρwhere ν=(ρ- ρbb) ρ) ρbbσ amp σ amp
A=1(2π)A=1(2π)22 ltk ltk223gt3gt32 32
if P(k)~kif P(k)~knn A R A RGG33 =[8radic2π =[8radic2π22]]-1 -1 [(n+3)3][(n+3)3]32 32
Non-Gaussian FieldNon-Gaussian Field (Toy models) (Toy models)
Clusters Bubbles HDM
(Weinberg Gott amp Melott 1987)(Weinberg Gott amp Melott 1987)
Non-Gaussianity Genus-related statisticsNon-Gaussianity Genus-related statistics
1 Shift parameter 1 Shift parameter 2 Asymmetry parameters A2 Asymmetry parameters AC C AAVV
3 Amplitude drop R3 Amplitude drop RAAAAobsobsAAPSPS
ACAv
RA
Biased Biased Formation Formation of Galaxiesof Galaxies
L-dependence L-dependence of 1 amp 2 point of 1 amp 2 point distribution distribution
but also but also topology topology
(Park et al 2005)
Topology of LSS can be explained by Topology of LSS can be explained by GF modelsGF models
(Park Kim et al 2005)
Merger Merger Halo formation Halo formationvoid percolationvoid percolation
void splittingvoid splitting
LCDM1024LCDM1024
Matter field canrsquot
Topology of LSS can be explained by Topology of LSS can be explained by GF modelsGF models
Direction of Direction of evolution evolution
~1 amp Little evoluti~1 amp Little evolution at low zon at low z
Mergers of hMergers of halosalos
AV lt 1
ltNltNsatsatgt = (MMgt = (MM11))αα for MgtM for MgtMminmin whe whe
re logMre logMminmin=1176 log M=1176 log M11=1=1
315 315 αα=113=113
HOD model for VL sHOD model for VL sample Mample Mrrlt-195lt-195
(Park et al 2005)Probably yes
Comparison of topology SDSS vs Comparison of topology SDSS vs CDM CDM
SDSS amp 6 h-1Mpc scale Kim+Park(o) amp Springel(x)
Future ofCosmological N-Body
Simulation1 Useful for cosmology amp galaxy formation study1 Useful for cosmology amp galaxy formation study
(until star formation can be properly simulated by radiati(until star formation can be properly simulated by radiative hydro-codes)ve hydro-codes)
2 Need to reach of particles gtgt 50002 Need to reach of particles gtgt 500033 ~ 10000 ~ 1000033
(10~100 current maximum)(10~100 current maximum)
Dynamic range for other studiesDynamic range for other studies Internal properties amp environment 1kpc ~ 100 Mpc Internal properties amp environment 1kpc ~ 100 Mpc
Galactic structure amp star formation 01pc ~ 100kpc Galactic structure amp star formation 01pc ~ 100kpc
PSB HalosVS
Others
Topology studyTopology study
1 Gaussianity of the 1 Gaussianity of the linear (primordial) density fieldlinear (primordial) density field pr predicted by simple inflationary scenariosedicted by simple inflationary scenarios
2 Topology of galaxy distribution at NL scales sensitive 2 Topology of galaxy distribution at NL scales sensitive to to cosmological parameterscosmological parameters amp to amp to galaxy formation mechanismgalaxy formation mechanism
3 Direct Intuitive meaning3 Direct Intuitive meaning
Large ScalesLarge Scales Small ScalesSmall Scales
Primordial Gaussianity Galaxy FormationPrimordial Gaussianity Galaxy Formation
Cosmological ParametersCosmological Parameters
GenusGenus ndash A Measure of Topologyndash A Measure of Topology
DefinitionDefinition
G = of holes - of isolated regionsG = of holes - of isolated regions in iso-density contour surfacesin iso-density contour surfaces
= 14= 14ππ intintSS κ dA (Gauss-Bonnet Theorem) κ dA (Gauss-Bonnet Theorem)
[ex G(sphere)=-1 G(torus)=0 ][ex G(sphere)=-1 G(torus)=0 ]
2 holes ndash 1 body = +1
Gaussian FieldGaussian Field Genusunit volume g(ν) = A (1-νGenusunit volume g(ν) = A (1-ν22) exp(- ν) exp(- ν222)2) where ν=(ρ- ρwhere ν=(ρ- ρbb) ρ) ρbbσ amp σ amp
A=1(2π)A=1(2π)22 ltk ltk223gt3gt32 32
if P(k)~kif P(k)~knn A R A RGG33 =[8radic2π =[8radic2π22]]-1 -1 [(n+3)3][(n+3)3]32 32
Non-Gaussian FieldNon-Gaussian Field (Toy models) (Toy models)
Clusters Bubbles HDM
(Weinberg Gott amp Melott 1987)(Weinberg Gott amp Melott 1987)
Non-Gaussianity Genus-related statisticsNon-Gaussianity Genus-related statistics
1 Shift parameter 1 Shift parameter 2 Asymmetry parameters A2 Asymmetry parameters AC C AAVV
3 Amplitude drop R3 Amplitude drop RAAAAobsobsAAPSPS
ACAv
RA
Biased Biased Formation Formation of Galaxiesof Galaxies
L-dependence L-dependence of 1 amp 2 point of 1 amp 2 point distribution distribution
but also but also topology topology
(Park et al 2005)
Topology of LSS can be explained by Topology of LSS can be explained by GF modelsGF models
(Park Kim et al 2005)
Merger Merger Halo formation Halo formationvoid percolationvoid percolation
void splittingvoid splitting
LCDM1024LCDM1024
Matter field canrsquot
Topology of LSS can be explained by Topology of LSS can be explained by GF modelsGF models
Direction of Direction of evolution evolution
~1 amp Little evoluti~1 amp Little evolution at low zon at low z
Mergers of hMergers of halosalos
AV lt 1
ltNltNsatsatgt = (MMgt = (MM11))αα for MgtM for MgtMminmin whe whe
re logMre logMminmin=1176 log M=1176 log M11=1=1
315 315 αα=113=113
HOD model for VL sHOD model for VL sample Mample Mrrlt-195lt-195
(Park et al 2005)Probably yes
Comparison of topology SDSS vs Comparison of topology SDSS vs CDM CDM
SDSS amp 6 h-1Mpc scale Kim+Park(o) amp Springel(x)
Future ofCosmological N-Body
Simulation1 Useful for cosmology amp galaxy formation study1 Useful for cosmology amp galaxy formation study
(until star formation can be properly simulated by radiati(until star formation can be properly simulated by radiative hydro-codes)ve hydro-codes)
2 Need to reach of particles gtgt 50002 Need to reach of particles gtgt 500033 ~ 10000 ~ 1000033
(10~100 current maximum)(10~100 current maximum)
Dynamic range for other studiesDynamic range for other studies Internal properties amp environment 1kpc ~ 100 Mpc Internal properties amp environment 1kpc ~ 100 Mpc
Galactic structure amp star formation 01pc ~ 100kpc Galactic structure amp star formation 01pc ~ 100kpc
Topology studyTopology study
1 Gaussianity of the 1 Gaussianity of the linear (primordial) density fieldlinear (primordial) density field pr predicted by simple inflationary scenariosedicted by simple inflationary scenarios
2 Topology of galaxy distribution at NL scales sensitive 2 Topology of galaxy distribution at NL scales sensitive to to cosmological parameterscosmological parameters amp to amp to galaxy formation mechanismgalaxy formation mechanism
3 Direct Intuitive meaning3 Direct Intuitive meaning
Large ScalesLarge Scales Small ScalesSmall Scales
Primordial Gaussianity Galaxy FormationPrimordial Gaussianity Galaxy Formation
Cosmological ParametersCosmological Parameters
GenusGenus ndash A Measure of Topologyndash A Measure of Topology
DefinitionDefinition
G = of holes - of isolated regionsG = of holes - of isolated regions in iso-density contour surfacesin iso-density contour surfaces
= 14= 14ππ intintSS κ dA (Gauss-Bonnet Theorem) κ dA (Gauss-Bonnet Theorem)
[ex G(sphere)=-1 G(torus)=0 ][ex G(sphere)=-1 G(torus)=0 ]
2 holes ndash 1 body = +1
Gaussian FieldGaussian Field Genusunit volume g(ν) = A (1-νGenusunit volume g(ν) = A (1-ν22) exp(- ν) exp(- ν222)2) where ν=(ρ- ρwhere ν=(ρ- ρbb) ρ) ρbbσ amp σ amp
A=1(2π)A=1(2π)22 ltk ltk223gt3gt32 32
if P(k)~kif P(k)~knn A R A RGG33 =[8radic2π =[8radic2π22]]-1 -1 [(n+3)3][(n+3)3]32 32
Non-Gaussian FieldNon-Gaussian Field (Toy models) (Toy models)
Clusters Bubbles HDM
(Weinberg Gott amp Melott 1987)(Weinberg Gott amp Melott 1987)
Non-Gaussianity Genus-related statisticsNon-Gaussianity Genus-related statistics
1 Shift parameter 1 Shift parameter 2 Asymmetry parameters A2 Asymmetry parameters AC C AAVV
3 Amplitude drop R3 Amplitude drop RAAAAobsobsAAPSPS
ACAv
RA
Biased Biased Formation Formation of Galaxiesof Galaxies
L-dependence L-dependence of 1 amp 2 point of 1 amp 2 point distribution distribution
but also but also topology topology
(Park et al 2005)
Topology of LSS can be explained by Topology of LSS can be explained by GF modelsGF models
(Park Kim et al 2005)
Merger Merger Halo formation Halo formationvoid percolationvoid percolation
void splittingvoid splitting
LCDM1024LCDM1024
Matter field canrsquot
Topology of LSS can be explained by Topology of LSS can be explained by GF modelsGF models
Direction of Direction of evolution evolution
~1 amp Little evoluti~1 amp Little evolution at low zon at low z
Mergers of hMergers of halosalos
AV lt 1
ltNltNsatsatgt = (MMgt = (MM11))αα for MgtM for MgtMminmin whe whe
re logMre logMminmin=1176 log M=1176 log M11=1=1
315 315 αα=113=113
HOD model for VL sHOD model for VL sample Mample Mrrlt-195lt-195
(Park et al 2005)Probably yes
Comparison of topology SDSS vs Comparison of topology SDSS vs CDM CDM
SDSS amp 6 h-1Mpc scale Kim+Park(o) amp Springel(x)
Future ofCosmological N-Body
Simulation1 Useful for cosmology amp galaxy formation study1 Useful for cosmology amp galaxy formation study
(until star formation can be properly simulated by radiati(until star formation can be properly simulated by radiative hydro-codes)ve hydro-codes)
2 Need to reach of particles gtgt 50002 Need to reach of particles gtgt 500033 ~ 10000 ~ 1000033
(10~100 current maximum)(10~100 current maximum)
Dynamic range for other studiesDynamic range for other studies Internal properties amp environment 1kpc ~ 100 Mpc Internal properties amp environment 1kpc ~ 100 Mpc
Galactic structure amp star formation 01pc ~ 100kpc Galactic structure amp star formation 01pc ~ 100kpc
GenusGenus ndash A Measure of Topologyndash A Measure of Topology
DefinitionDefinition
G = of holes - of isolated regionsG = of holes - of isolated regions in iso-density contour surfacesin iso-density contour surfaces
= 14= 14ππ intintSS κ dA (Gauss-Bonnet Theorem) κ dA (Gauss-Bonnet Theorem)
[ex G(sphere)=-1 G(torus)=0 ][ex G(sphere)=-1 G(torus)=0 ]
2 holes ndash 1 body = +1
Gaussian FieldGaussian Field Genusunit volume g(ν) = A (1-νGenusunit volume g(ν) = A (1-ν22) exp(- ν) exp(- ν222)2) where ν=(ρ- ρwhere ν=(ρ- ρbb) ρ) ρbbσ amp σ amp
A=1(2π)A=1(2π)22 ltk ltk223gt3gt32 32
if P(k)~kif P(k)~knn A R A RGG33 =[8radic2π =[8radic2π22]]-1 -1 [(n+3)3][(n+3)3]32 32
Non-Gaussian FieldNon-Gaussian Field (Toy models) (Toy models)
Clusters Bubbles HDM
(Weinberg Gott amp Melott 1987)(Weinberg Gott amp Melott 1987)
Non-Gaussianity Genus-related statisticsNon-Gaussianity Genus-related statistics
1 Shift parameter 1 Shift parameter 2 Asymmetry parameters A2 Asymmetry parameters AC C AAVV
3 Amplitude drop R3 Amplitude drop RAAAAobsobsAAPSPS
ACAv
RA
Biased Biased Formation Formation of Galaxiesof Galaxies
L-dependence L-dependence of 1 amp 2 point of 1 amp 2 point distribution distribution
but also but also topology topology
(Park et al 2005)
Topology of LSS can be explained by Topology of LSS can be explained by GF modelsGF models
(Park Kim et al 2005)
Merger Merger Halo formation Halo formationvoid percolationvoid percolation
void splittingvoid splitting
LCDM1024LCDM1024
Matter field canrsquot
Topology of LSS can be explained by Topology of LSS can be explained by GF modelsGF models
Direction of Direction of evolution evolution
~1 amp Little evoluti~1 amp Little evolution at low zon at low z
Mergers of hMergers of halosalos
AV lt 1
ltNltNsatsatgt = (MMgt = (MM11))αα for MgtM for MgtMminmin whe whe
re logMre logMminmin=1176 log M=1176 log M11=1=1
315 315 αα=113=113
HOD model for VL sHOD model for VL sample Mample Mrrlt-195lt-195
(Park et al 2005)Probably yes
Comparison of topology SDSS vs Comparison of topology SDSS vs CDM CDM
SDSS amp 6 h-1Mpc scale Kim+Park(o) amp Springel(x)
Future ofCosmological N-Body
Simulation1 Useful for cosmology amp galaxy formation study1 Useful for cosmology amp galaxy formation study
(until star formation can be properly simulated by radiati(until star formation can be properly simulated by radiative hydro-codes)ve hydro-codes)
2 Need to reach of particles gtgt 50002 Need to reach of particles gtgt 500033 ~ 10000 ~ 1000033
(10~100 current maximum)(10~100 current maximum)
Dynamic range for other studiesDynamic range for other studies Internal properties amp environment 1kpc ~ 100 Mpc Internal properties amp environment 1kpc ~ 100 Mpc
Galactic structure amp star formation 01pc ~ 100kpc Galactic structure amp star formation 01pc ~ 100kpc
Non-Gaussian FieldNon-Gaussian Field (Toy models) (Toy models)
Clusters Bubbles HDM
(Weinberg Gott amp Melott 1987)(Weinberg Gott amp Melott 1987)
Non-Gaussianity Genus-related statisticsNon-Gaussianity Genus-related statistics
1 Shift parameter 1 Shift parameter 2 Asymmetry parameters A2 Asymmetry parameters AC C AAVV
3 Amplitude drop R3 Amplitude drop RAAAAobsobsAAPSPS
ACAv
RA
Biased Biased Formation Formation of Galaxiesof Galaxies
L-dependence L-dependence of 1 amp 2 point of 1 amp 2 point distribution distribution
but also but also topology topology
(Park et al 2005)
Topology of LSS can be explained by Topology of LSS can be explained by GF modelsGF models
(Park Kim et al 2005)
Merger Merger Halo formation Halo formationvoid percolationvoid percolation
void splittingvoid splitting
LCDM1024LCDM1024
Matter field canrsquot
Topology of LSS can be explained by Topology of LSS can be explained by GF modelsGF models
Direction of Direction of evolution evolution
~1 amp Little evoluti~1 amp Little evolution at low zon at low z
Mergers of hMergers of halosalos
AV lt 1
ltNltNsatsatgt = (MMgt = (MM11))αα for MgtM for MgtMminmin whe whe
re logMre logMminmin=1176 log M=1176 log M11=1=1
315 315 αα=113=113
HOD model for VL sHOD model for VL sample Mample Mrrlt-195lt-195
(Park et al 2005)Probably yes
Comparison of topology SDSS vs Comparison of topology SDSS vs CDM CDM
SDSS amp 6 h-1Mpc scale Kim+Park(o) amp Springel(x)
Future ofCosmological N-Body
Simulation1 Useful for cosmology amp galaxy formation study1 Useful for cosmology amp galaxy formation study
(until star formation can be properly simulated by radiati(until star formation can be properly simulated by radiative hydro-codes)ve hydro-codes)
2 Need to reach of particles gtgt 50002 Need to reach of particles gtgt 500033 ~ 10000 ~ 1000033
(10~100 current maximum)(10~100 current maximum)
Dynamic range for other studiesDynamic range for other studies Internal properties amp environment 1kpc ~ 100 Mpc Internal properties amp environment 1kpc ~ 100 Mpc
Galactic structure amp star formation 01pc ~ 100kpc Galactic structure amp star formation 01pc ~ 100kpc
Non-Gaussianity Genus-related statisticsNon-Gaussianity Genus-related statistics
1 Shift parameter 1 Shift parameter 2 Asymmetry parameters A2 Asymmetry parameters AC C AAVV
3 Amplitude drop R3 Amplitude drop RAAAAobsobsAAPSPS
ACAv
RA
Biased Biased Formation Formation of Galaxiesof Galaxies
L-dependence L-dependence of 1 amp 2 point of 1 amp 2 point distribution distribution
but also but also topology topology
(Park et al 2005)
Topology of LSS can be explained by Topology of LSS can be explained by GF modelsGF models
(Park Kim et al 2005)
Merger Merger Halo formation Halo formationvoid percolationvoid percolation
void splittingvoid splitting
LCDM1024LCDM1024
Matter field canrsquot
Topology of LSS can be explained by Topology of LSS can be explained by GF modelsGF models
Direction of Direction of evolution evolution
~1 amp Little evoluti~1 amp Little evolution at low zon at low z
Mergers of hMergers of halosalos
AV lt 1
ltNltNsatsatgt = (MMgt = (MM11))αα for MgtM for MgtMminmin whe whe
re logMre logMminmin=1176 log M=1176 log M11=1=1
315 315 αα=113=113
HOD model for VL sHOD model for VL sample Mample Mrrlt-195lt-195
(Park et al 2005)Probably yes
Comparison of topology SDSS vs Comparison of topology SDSS vs CDM CDM
SDSS amp 6 h-1Mpc scale Kim+Park(o) amp Springel(x)
Future ofCosmological N-Body
Simulation1 Useful for cosmology amp galaxy formation study1 Useful for cosmology amp galaxy formation study
(until star formation can be properly simulated by radiati(until star formation can be properly simulated by radiative hydro-codes)ve hydro-codes)
2 Need to reach of particles gtgt 50002 Need to reach of particles gtgt 500033 ~ 10000 ~ 1000033
(10~100 current maximum)(10~100 current maximum)
Dynamic range for other studiesDynamic range for other studies Internal properties amp environment 1kpc ~ 100 Mpc Internal properties amp environment 1kpc ~ 100 Mpc
Galactic structure amp star formation 01pc ~ 100kpc Galactic structure amp star formation 01pc ~ 100kpc
Biased Biased Formation Formation of Galaxiesof Galaxies
L-dependence L-dependence of 1 amp 2 point of 1 amp 2 point distribution distribution
but also but also topology topology
(Park et al 2005)
Topology of LSS can be explained by Topology of LSS can be explained by GF modelsGF models
(Park Kim et al 2005)
Merger Merger Halo formation Halo formationvoid percolationvoid percolation
void splittingvoid splitting
LCDM1024LCDM1024
Matter field canrsquot
Topology of LSS can be explained by Topology of LSS can be explained by GF modelsGF models
Direction of Direction of evolution evolution
~1 amp Little evoluti~1 amp Little evolution at low zon at low z
Mergers of hMergers of halosalos
AV lt 1
ltNltNsatsatgt = (MMgt = (MM11))αα for MgtM for MgtMminmin whe whe
re logMre logMminmin=1176 log M=1176 log M11=1=1
315 315 αα=113=113
HOD model for VL sHOD model for VL sample Mample Mrrlt-195lt-195
(Park et al 2005)Probably yes
Comparison of topology SDSS vs Comparison of topology SDSS vs CDM CDM
SDSS amp 6 h-1Mpc scale Kim+Park(o) amp Springel(x)
Future ofCosmological N-Body
Simulation1 Useful for cosmology amp galaxy formation study1 Useful for cosmology amp galaxy formation study
(until star formation can be properly simulated by radiati(until star formation can be properly simulated by radiative hydro-codes)ve hydro-codes)
2 Need to reach of particles gtgt 50002 Need to reach of particles gtgt 500033 ~ 10000 ~ 1000033
(10~100 current maximum)(10~100 current maximum)
Dynamic range for other studiesDynamic range for other studies Internal properties amp environment 1kpc ~ 100 Mpc Internal properties amp environment 1kpc ~ 100 Mpc
Galactic structure amp star formation 01pc ~ 100kpc Galactic structure amp star formation 01pc ~ 100kpc
Topology of LSS can be explained by Topology of LSS can be explained by GF modelsGF models
(Park Kim et al 2005)
Merger Merger Halo formation Halo formationvoid percolationvoid percolation
void splittingvoid splitting
LCDM1024LCDM1024
Matter field canrsquot
Topology of LSS can be explained by Topology of LSS can be explained by GF modelsGF models
Direction of Direction of evolution evolution
~1 amp Little evoluti~1 amp Little evolution at low zon at low z
Mergers of hMergers of halosalos
AV lt 1
ltNltNsatsatgt = (MMgt = (MM11))αα for MgtM for MgtMminmin whe whe
re logMre logMminmin=1176 log M=1176 log M11=1=1
315 315 αα=113=113
HOD model for VL sHOD model for VL sample Mample Mrrlt-195lt-195
(Park et al 2005)Probably yes
Comparison of topology SDSS vs Comparison of topology SDSS vs CDM CDM
SDSS amp 6 h-1Mpc scale Kim+Park(o) amp Springel(x)
Future ofCosmological N-Body
Simulation1 Useful for cosmology amp galaxy formation study1 Useful for cosmology amp galaxy formation study
(until star formation can be properly simulated by radiati(until star formation can be properly simulated by radiative hydro-codes)ve hydro-codes)
2 Need to reach of particles gtgt 50002 Need to reach of particles gtgt 500033 ~ 10000 ~ 1000033
(10~100 current maximum)(10~100 current maximum)
Dynamic range for other studiesDynamic range for other studies Internal properties amp environment 1kpc ~ 100 Mpc Internal properties amp environment 1kpc ~ 100 Mpc
Galactic structure amp star formation 01pc ~ 100kpc Galactic structure amp star formation 01pc ~ 100kpc
Topology of LSS can be explained by Topology of LSS can be explained by GF modelsGF models
Direction of Direction of evolution evolution
~1 amp Little evoluti~1 amp Little evolution at low zon at low z
Mergers of hMergers of halosalos
AV lt 1
ltNltNsatsatgt = (MMgt = (MM11))αα for MgtM for MgtMminmin whe whe
re logMre logMminmin=1176 log M=1176 log M11=1=1
315 315 αα=113=113
HOD model for VL sHOD model for VL sample Mample Mrrlt-195lt-195
(Park et al 2005)Probably yes
Comparison of topology SDSS vs Comparison of topology SDSS vs CDM CDM
SDSS amp 6 h-1Mpc scale Kim+Park(o) amp Springel(x)
Future ofCosmological N-Body
Simulation1 Useful for cosmology amp galaxy formation study1 Useful for cosmology amp galaxy formation study
(until star formation can be properly simulated by radiati(until star formation can be properly simulated by radiative hydro-codes)ve hydro-codes)
2 Need to reach of particles gtgt 50002 Need to reach of particles gtgt 500033 ~ 10000 ~ 1000033
(10~100 current maximum)(10~100 current maximum)
Dynamic range for other studiesDynamic range for other studies Internal properties amp environment 1kpc ~ 100 Mpc Internal properties amp environment 1kpc ~ 100 Mpc
Galactic structure amp star formation 01pc ~ 100kpc Galactic structure amp star formation 01pc ~ 100kpc
Comparison of topology SDSS vs Comparison of topology SDSS vs CDM CDM
SDSS amp 6 h-1Mpc scale Kim+Park(o) amp Springel(x)
Future ofCosmological N-Body
Simulation1 Useful for cosmology amp galaxy formation study1 Useful for cosmology amp galaxy formation study
(until star formation can be properly simulated by radiati(until star formation can be properly simulated by radiative hydro-codes)ve hydro-codes)
2 Need to reach of particles gtgt 50002 Need to reach of particles gtgt 500033 ~ 10000 ~ 1000033
(10~100 current maximum)(10~100 current maximum)
Dynamic range for other studiesDynamic range for other studies Internal properties amp environment 1kpc ~ 100 Mpc Internal properties amp environment 1kpc ~ 100 Mpc
Galactic structure amp star formation 01pc ~ 100kpc Galactic structure amp star formation 01pc ~ 100kpc
Future ofCosmological N-Body
Simulation1 Useful for cosmology amp galaxy formation study1 Useful for cosmology amp galaxy formation study
(until star formation can be properly simulated by radiati(until star formation can be properly simulated by radiative hydro-codes)ve hydro-codes)
2 Need to reach of particles gtgt 50002 Need to reach of particles gtgt 500033 ~ 10000 ~ 1000033
(10~100 current maximum)(10~100 current maximum)
Dynamic range for other studiesDynamic range for other studies Internal properties amp environment 1kpc ~ 100 Mpc Internal properties amp environment 1kpc ~ 100 Mpc
Galactic structure amp star formation 01pc ~ 100kpc Galactic structure amp star formation 01pc ~ 100kpc