Dark MatterDark Matter andand Clustering Clustering Motivation and Findings on Dark Matter Motivation and Findings on Dark Matter from the Study of Structure Formationfrom the Study of Structure Formation

2005. 2. 16 - 192005. 2. 16 - 19

Changbom Park Changbom Park (Korea Institute for Advanced Study)(Korea Institute for Advanced Study)

Workshop for Workshop for Underground Experiments and Astroparticle PhysicsUnderground Experiments and Astroparticle Physics

Dark MatterDark Matter

Theme:Theme: Constraints on Constraints on DMDM from from Clustering of MatterClustering of Matter

Intimate relation between DM & structure formation bIntimate relation between DM & structure formation because DM has been the gravitationally dominant coecause DM has been the gravitationally dominant component of the material universe after tmponent of the material universe after teqeq, and h, and h

ave been controlling the structure formation.ave been controlling the structure formation.

DMDM

What did we learn about DM frWhat did we learn about DM from om δδρρ & & CMB CMB ΔΔTT??

Matter compositionMatter composition ‘What’ and how much are there in our universe?‘What’ and how much are there in our universe?

Properties of each matter componentProperties of each matter component SpSpatial distribution (uniform, clustered)atial distribution (uniform, clustered)

Equ. of stateEqu. of state

Evolution of Modern CosmologyEvolution of Modern Cosmology

1917Einstein’s static model

50s Gravitational Instability(GI)

Theory

29Expansion of space

22-24Friedmann’s models

29Big Bang model

1922External galaxies

70s BB+(γ,ν; baryon)+GI

65 Discovery of CMBR

LSSLSS CMBCMBRR

92 LSS P(k)

Late70s Discovery of

LSS

70s BB+(γ,ν; baryon)+GI

92 COBE dT/T~10-5

mid80 SCDM Model BB+Inflation+(γ,ν; baryon, CDM)+GI

LSSLSS CMBCMBRR

80s CMBR dT/T < 10

-4

Dark matter 82Inflation

98 Accelerating expansion

00-03 WMAP Cℓ

2005 Concordance LCDM Model BB+Inflation+(γ,ν;

baryon, CDM; Dark E)+GI

Standard Model ruled out

SDSS JWST

Planck

?

Energy Contents of the UniverseEnergy Contents of the Universe

Dark EnergyDark Energy (~73%; CC or dynamical?)(~73%; CC or dynamical?) + +

Non-baryonic Dark MatterNon-baryonic Dark Matter (~23%; cold)(~23%; cold) + +

Baryon invisibleBaryon invisible(~4%; MACHOs, ionized gas-IG-intr(~4%; MACHOs, ionized gas-IG-intr

acluster)acluster) + + visiblevisible (~0.3%; *s)(~0.3%; *s)

RadiationRadiation + +

NeutrinoNeutrino

Dark EnergyDark Energy

Dark MatterDark Matter

If primordial gaussian adiabatiIf primordial gaussian adiabatic, scale-invariant density fluctc, scale-invariant density fluct

uationsuations

Motivation for Dark MatterMotivation for Dark Matter Existence through gravitational effects onlyExistence through gravitational effects only

Missing mass(baryon) Missing mass(baryon) non-baryonic non-baryonic DE DE

1. DM associated with galaxies & clusters 1. DM associated with galaxies & clusters [Ostriker..74; Einasto..74; Zwicky33][Ostriker..74; Einasto..74; Zwicky33]

[Dark halos] stability of galaxies, clusters of galaxies[Dark halos] stability of galaxies, clusters of galaxies

2. Baryonic DM2. Baryonic DM [brown dwarfs] *s with m<0.08Mo? [brown dwarfs] *s with m<0.08Mo?

[Why mass & L should be correlated?] *s with m>Mo 95% light but m<Mo >75% mass[Why mass & L should be correlated?] *s with m>Mo 95% light but m<Mo >75% mass

[Ly-a clouds at high z] not seen now[Ly-a clouds at high z] not seen now

[Nucleosynthesis] Omega_B=0.02~0.1 vs Omega_Bobs=~0.006 (solar neighborhood)[Nucleosynthesis] Omega_B=0.02~0.1 vs Omega_Bobs=~0.006 (solar neighborhood)

3. Non-baryonic DM3. Non-baryonic DM [Dynamical estimate of Omega] Omega_m=0.2~0.3[Dynamical estimate of Omega] Omega_m=0.2~0.3

[Inflationary scenarios and flat universe] Omega_tot=1[Inflationary scenarios and flat universe] Omega_tot=1

4. Growth of matter fluctuations & epoch of structure formation4. Growth of matter fluctuations & epoch of structure formation

Dark MatterDark Matter

δδnownow ~ 1 and ~ 1 and δδ(t) ~ a(t) (t) ~ a(t)

in Einstein-de Sitter U in Einstein-de Sitter U

δδdecdec(theory) ~ 10(theory) ~ 10-3-3 but but

δδdecdec(obs) ~10(obs) ~10-5-5

Consider DM which is NL at aConsider DM which is NL at aeqeq ! !

Structure formation starts at aStructure formation starts at aeqeq earlier than a earlier than adecdec

Baryon falls into the potential wells developed by DMBaryon falls into the potential wells developed by DM

aaeqeq aadecdec aa00

During RDE : During RDE : δδmm frozen (total grow=2.5) – Meszaros effect frozen (total grow=2.5) – Meszaros effect

(for k ~ 0)(for k ~ 0)

Evolution of large scale density fluctuations in RDE & MDEEvolution of large scale density fluctuations in RDE & MDE

Weighing Dark MatterWeighing Dark Matter

CMBR Power Spectrum CMBR Power Spectrum (z ~ 10(z ~ 1033))

– – Amplitude of Sachs-Wolfe effects: Amplitude of Sachs-Wolfe effects: ΩΩtottot ~1 ~1 – – Amplitude of PS at subhorizon scales : Amplitude of PS at subhorizon scales : ΩΩmm

– – First 3 Doppler peaks First 3 Doppler peaks : shape : shape ΩΩBB = 0.04 (agreement btw z=10 = 0.04 (agreement btw z=1033 & 10 & 1099!)!) location location ΩΩtot tot ~1 ~1 ΩΩmm

Ly-a forest clouds Ly-a forest clouds (z ~ 3)(z ~ 3)

– – abundance vs ionizing photons abundance vs ionizing photons ΩΩBB = 0.04 = 0.04

Galaxy clusters Galaxy clusters (z ~ 0)(z ~ 0)

– – X-ray emission of hot gas X-ray emission of hot gas ΩΩBB = 0.04 = 0.04

Dark MatterDark Matter

Cosmic Microwave Background Cosmic Microwave Background AnisotropyAnisotropyInitial conditions Initial conditions Gravitational forcing, baryon loading Gravitational forcing, baryon loading

Initial phase of osc. the same for all modes Initial phase of osc. the same for all modes peaks & troughs as a function of wavenumber (Doppler peaks) peaks & troughs as a function of wavenumber (Doppler peaks)

Shape of Shape of ΔΔT/T Power SpectrumT/T Power Spectrum

Super-horizon scale fluc.

SW effect

1 0.1r∼ H fluc. with initially coherent pha

ses

Oscillation & Doppler effec

t

Radial averaging &

radiation diffusion

Enhances the compressional phase !

WMAP CMBR PSWMAP CMBR PS - baryon oscillation- baryon oscillation

||2

12

1aC lmll

HotHot like babieslike babies?? ColdCold like old menlike old men??

Horizon of human knowledge is expandingHorizon of human knowledge is expandingSDSS V ~ 10SDSS V ~ 1022 CfA V ~ 10 CfA V ~ 10-4-4 Horizon V Horizon VSKorea ~ 10SKorea ~ 1022 Seoul MPA ~ 10 Seoul MPA ~ 10-4-4 Earth Surface Earth Surface

1986 CfA1986 CfA

2004 SDSS2004 SDSS

HDMHDM?? CDMCDM??

Clustering differences Clustering differences * observed LSS* observed LSS * fingers-of-god* fingers-of-godEpoch of formation of Epoch of formation of

massive structures massive structures * 1* 1stst NL structures NL structures

CDMCDM : NR much before a : NR much before aeqeq

HDMHDM

Real Real SpaceSpace

MatterMatter

HDMHDM

Z SpaceZ Space

MatterMatter

CDMCDM

Z SpaceZ Space

GalaxiesGalaxies

CDMCDM

Real Real SpaceSpace

GalaxiesGalaxies

HDM?HDM? CDM? CDM?

Clusters of galaxiesClusters of galaxies mass functionmass function

High-z quasarsHigh-z quasarsGalaxy formation scenarioGalaxy formation scenario top-downtop-down (pancake) vs (pancake) vs bottom-upbottom-up (hierarchical) (hierarchical)

Dark Dark EnergyEnergy

Dynamics at horizon scaleDynamics at horizon scaleAffected by matter compositionAffected by matter composition

Riess..04Riess..04

ΛΛCDM SimulationCDM Simulation (Kim & Park 2004)

PMTree codePMTree code (Dubinski, Kim, Park 2003)

2048204833 mesh mesh (initial condition)

2048204833 (8.6G) (8.6G) CDM particles

1024 & 5632 h1024 & 5632 h-1-1MpcMpc size boxes

50 & 275 h50 & 275 h-1-1kpckpc force resolutions

PRECISION COMPARISON between PRECISION COMPARISON between cosmological models with the real universecosmological models with the real universe

(Park et al. 1994)(Tegmark et al.

2004)

Validity of CDMValidity of CDM Initial conditionsInitial conditions

Growth by gravitational instabilityGrowth by gravitational instability

weakly interacting & cold matterweakly interacting & cold matter

LCDM1024LCDM1024

Sloan Digital Sky Survey Sloan Digital Sky Survey

1. Imaging of North Galactic Cap1. Imaging of North Galactic Cap2.5m APO telescope with a mosaic CCD camera 2.5m APO telescope with a mosaic CCD camera u, g, r, i, z photometric bandpasses u, g, r, i, z photometric bandpasses selected for spectroscopy selected for spectroscopy

2. Spectroscopy2. Spectroscopy~~ 10 1066 galaxies & 10 galaxies & 1055 quasars with rms z-error quasars with rms z-error ~ 30 km/s~ 30 km/s

3. Samples3. SamplesMain Galaxies: Main Galaxies: rrPetPet < 17.77 ; Quasars < 17.77 ; Quasars

Luminous Red Galaxies (LRG): z<0.4 & >0.4 samplesLuminous Red Galaxies (LRG): z<0.4 & >0.4 samples

3D 3D View View

of of SDSS SDSS

HOD galaxy HOD galaxy formation formation

prescriptionprescription

3D 3D View View of a of a

mock mock SDSSSDSS

Way to the FutureWay to the Future

Measure Measure ΩΩmm , , ΩΩBB & & ΩΩΛΛ ( ( ΩΩtottot ) more accurately ) more accurately Measure eq. of state of DE componentMeasure eq. of state of DE component Find the clustering of DM at small scalesFind the clustering of DM at small scales through CMB anisotropy, LSS clustering, LS peculiar velocity field, through CMB anisotropy, LSS clustering, LS peculiar velocity field, high-z distance indicator, gravitational lensinghigh-z distance indicator, gravitational lensing

New generation telescopesNew generation telescopes dedicated 8m, 30~100m optical, multi-dedicated 8m, 30~100m optical, multi-λλ New generation simulationsNew generation simulations matching the entire history of the universematching the entire history of the universe