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Andrey Kravtsov Kavli Institute for Cosmological Physics (KICP) The University of Chicago Simulating galaxy formation at high redshifts Slide 2 The sexiest simulation? http://www.this-wonderful-life.com Slide 3 SDSS survey By Mark SubbaRao (Adler/U.Chicago) Dinoj Surendran, and Randy Landsberg (U.Chicago) http://astro.uchicago.edu/cosmus/ The ultimate simulation should be able to simulate this Slide 4 While resolving this SDSS survey By David Hogg and Michael Blanton (NYU) Slide 5 Simulations are remarkably successful in reproducing the observed LSS ART code: LCDM 60 h -1 Mpc 8 =0.9; m p =10 9 h -1 Msun; = 0.5h -1 kpc Slide 6 n(>V max,acc )=n(>L) Conroy, Wechsler & Kravtsov (astro-ph/0512234) Conroy, Wechsler & Kravtsov (astro-ph/0512234) projected 2-point correlation function projected separation (chimps) Galaxy clustering in SDSS at z~0 Is well reproduced by simulations Slide 7 n(>V max,acc )=n(>L) Conroy, Wechsler & Kravtsov (astro-ph/0512234) Conroy, Wechsler & Kravtsov (astro-ph/0512234) projected 2-point correlation function projected separation (chimps) and at z~1 (DEEP2) Slide 8 n(>V max,acc )=n(>L) Conroy, Wechsler & Kravtsov (astro-ph/0512234) Conroy, Wechsler & Kravtsov (astro-ph/0512234) angular 2-point correlation function projected separation (arcsec/chimps) and at z~4-5 (LBGs, Subaru) Slide 9 CDM paradigm must also be tested on smaller, galactic scales Slide 10 Its a very difficult problem Slide 11 (some of) the reasons: resolution and dynamic range required to simulate internal structure of galaxies, star formation, and feedback properly is enormous: I would argue, we wont get very far until resolution element in star formation regions is ~10 pc (i.e., ~10 6 dynamic range in a box of 10 Mpc). The scale-height of star forming gas disk in the MW is ~100 pc. Bar formation and dynamics requires ~10 pc resolution and millions of stellar particles to resolve the relevant orbital resonances properly. currently, such dynamic range is achievable only at high redshifts high-zs also are less complicated in certain physical aspects (e.g., low dust content) Slide 12 Gasdynamics+DM simulations of a MW-size system Adaptive Refinement Tree (ART) code Eulerian Adaptive Mesh Refinement hydrodynamics N-body dynamics of DM and stellar particles radiative cooling and heating: Compton, UV background heating, density and metallicity dependent net cooling/heating equilibrium rates taking into account line and molecular processes Star formation using a phenomenological recipe Thermal stellar feedback and metal enrichment by SNII/Ia, stellar mass loss Simulation followed formation of a MW-size galaxy at z > 3. A Lagrangian region corresponding to 5 Rvir of the object at z=0 was followed. Peak resolution in this region was ~50 pc particle mass ~10 6 Msun Slide 13 Milky Way progenitor at z=4 Kravtsov 2003; Kravtsov & Gnedin 2005 Kravtsov 2003; Kravtsov & Gnedin 2005 Slide 14 Density PDF and SF Kravtsov 2003 Kravtsov 2003 Slide 15 Stellar cluster mass function Kravtsov & Gnedin 2005 Kravtsov & Gnedin 2005 Slide 16 Stellar cluster mass function in Antennae Slide 17 Exploring dependence on physics: non-equilibrium cooling and radiative transfer visualization with IFRIT (http://home.fnal.gov/~gnedin/IFRIT/) visualization with IFRIT (http://home.fnal.gov/~gnedin/IFRIT/) Slide 18 Dwarf galaxies at z~8 Ricotti & Gnedin 2005 Ricotti & Gnedin 2005 Slide 19 Dwarf galaxies at high z Show correlations observed locally M/L metallicity correlation M/L metallicity correlation Slide 20 Dwarf galaxies at high z Show correlations observed locally metallicity-stellar mass correlation metallicity-stellar mass correlation Slide 21 Dwarf galaxies at high z Show correlations observed locally surface brightness-stellar mass correlation surface brightness-stellar mass correlation Slide 22 Formation of a Milky Way-sized halo ART code simulation (by Anatoly Klypin): standard LCDM, 8=0.9; mp=6x10 5 h -1 Msun; = 0.1h -1 kpc Mvir=3x10 12 h -1 Msun; Rvir=293h -1 kpc; ~5x10 6 particles within Rvir time z = 10z = 7z = 5z = 3 z = 2z = 1z = 0.5z = 0 Slide 23 Survival probability for objects at z~8 Slide 24 Luminosity function of dwarfs in the Local Group Slide 25 Conclusions simulations of galaxy formation at high z have a number of advantages we can learn more about galaxy formation physics, with (arguably) fewer uncertainties in the modeling results are relevant for local observations of galaxies: star formation law, stellar clusters, dwarf galaxies