dark matter halos
DESCRIPTION
A.Klypin. Dark Matter Halos. GADET. Springel, SDM White. PKDGRAV - GASOLINE. Quinn, Steidel, Wadsley, Governato, Moore. ART. Kravtsov, Klypin, N.Gnedin, Gottlober. ENZO. Bryan, Norman. Major codes:. N-body Hydro Cooling/Heating/SF Metal enrichment Radiative transfer - PowerPoint PPT PresentationTRANSCRIPT
Dark Matter Halos
A.Klypin
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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
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Non-linear evolution: from Zeldovich approximation to DM halos
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Local Group:z=0
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Local Group:z=1
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Local Group:z=7
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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
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Halo Mass Function depends on environment
• Sheth&Tormen 2002
• GottlÖber etal 2003
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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
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SDSS
DM galaxies
DM
SDSS: z=0SDSS: z=0
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DEEP: z=1DEEP: z=1
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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
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Cusps: simulationsDiemand etal 2004
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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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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
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Average profiles of
Milky Way-size halos
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Infall velocities on halos of
different mass
Prada et al 2005
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RMS velocity of isolated halos
Full: simulationsDash: solution of Jeans equation
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SDSS and LCDM: surface number density
of satellites around isolated
galaxies
LCDM
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Evolution of Halo structure• Most of the
accreted mass stays in the outer region of halo.
Diemand etal 2005
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Evolution of Halo structure
Dwarf Halos at high zcusp evolves very little.
Colin etal 2003
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Halo Concentrations Bullock etal 2003
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VoidsR>10Mpc
Patiri et al 2006: SDSS
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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