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 Non-linear evolution: from Zeldovich approximation to DM halos

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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 Gottl Ö ber etal 2003

12 Clustering: DM halos and L Conroy, Wechsler, Kravtsov (2005): N-body only Get all halos from high-res simulation Use maximum circular velocity (NOT mass) For subhalos use V max 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=0

14 DEEP: 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: simulations Diemand 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

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19 Profiles are NOT NFW Navarro etal 2004 Merritt, Navarro 2004 Prada etal 2005 ρ(r)=ρ o exp(-2nr 1/n )+ n=6-8 3D Sersic 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: simulations Dash: 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 z cusp evolves very little. Colin etal 2003

26 Halo Concentrations Bullock etal 2003

27 Voids R>10Mpc Patiri et al 2006: SDSS

28 Number-density Profiles of Voids: n(R)/ 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