Dark Matter Halos

A.Klypin

2

Major codes:

GADET Springel, SDM White

PKDGRAV - GASOLINE

Quinn, Steidel, Wadsley, Governato, Moore

ART Kravtsov, Klypin, N.Gnedin, Gottlober

ENZO Bryan, Norman

•N-body•Hydro•Cooling/Heating/SF•Metal enrichment•Radiative transfer•Multistepping/Multiple masses

3

QuickTime™ and aYUV420 codec decompressor

are needed to see this picture.

QuickTime™ and aYUV420 codec decompressor

are needed to see this picture.

Non-linear evolution: from Zeldovich approximation to DM halos

4

QuickTime™ and aYUV420 codec decompressor

are needed to see this picture.

5

6

7

Local Group:z=0

7

8

Local Group:z=1

8

9

Local Group:z=7

9

10

Mass function of distinct halos

• It started long ago: 32 years to be precise

• Now we live through 5th generation of this.

Warren etal 2005: 13 sims each with 1G particles

11

Halo Mass Function depends on environment

• Sheth&Tormen 2002

• GottlÖber etal 2003

12

Clustering: DM halos and L

Conroy, Wechsler, Kravtsov (2005): N-body onlyGet all halos from high-res simulation

Use maximum circular velocity (NOT mass)

For subhalos use Vmax before they became subhalos

Every halo (or subhalo) is a galaxy

»Every halo has luminosity: LF is as in SDSS

No cooling or major mergers and such. Only DM halos

Reproduces most of the observed clustering of galaxies

12

13

SDSS

DM galaxies

DM

SDSS: z=0SDSS: z=0

14

DEEP: z=1DEEP: z=1

15

Dark Matter and Galaxies- Central DM closely correlates with L: Tully-Fisher, Faber-Jackson

- Morphology-density relation: morphology is mostly defined by halo mass.

- Environment (how many neighbors) is just an indicator of halo mass

Young etal(2003-5), Berrier etal(2005) : Halo occupation distribution→the same conclutions

16

Cusps: simulationsDiemand etal 2004

17

Tasitsiomi etal 2004

Slope gets shallower with decreasing radius, but it does not go below -1

Consistent with what other groups found

Navarro etal 2004

18

19

Profiles are NOT

NFW

Navarro etal 2004Merritt, Navarro 2004Prada etal 2005

ρ(r)=ρo exp(-2nr1/n)+<ρ>

n=6-8 3D Sersic

NFW

NFW

20

Average profiles of

Milky Way-size halos

21

Infall velocities on halos of

different mass

Prada et al 2005

22

RMS velocity of isolated halos

Full: simulationsDash: solution of Jeans equation

23

SDSS and LCDM: surface number density

of satellites around isolated

galaxies

LCDM

24

Evolution of Halo structure• Most of the

accreted mass stays in the outer region of halo.

Diemand etal 2005

25

Evolution of Halo structure

Dwarf Halos at high zcusp evolves very little.

Colin etal 2003

26

Halo Concentrations Bullock etal 2003

27

VoidsR>10Mpc

Patiri et al 2006: SDSS

28

Number-density Profiles of Voids:

n(R)/<n>

SDSS

LCDM

Patiri et al 2006

DM in central parts of galaxies•Adiabatic compression: old approximation

•Adiabatic compression: Gnedin etal 2004

How it

works

Structure of our Galaxy

Prada etal 2004