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Andrey Kravtsov Kavli Institute for Cosmological Physics (KICP) The University of Chicago Simulating galaxy formation at high redshifts.

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Presentation on theme: "Andrey Kravtsov Kavli Institute for Cosmological Physics (KICP) The University of Chicago Simulating galaxy formation at high redshifts."— Presentation transcript:

1 Andrey Kravtsov Kavli Institute for Cosmological Physics (KICP) The University of Chicago Simulating galaxy formation at high redshifts

2 The sexiest simulation?

3 SDSS survey By Mark SubbaRao (Adler/U.Chicago) Dinoj Surendran, and Randy Landsberg (U.Chicago) The ultimate simulation should be able to simulate this…

4 While resolving this SDSS survey By David Hogg and Michael Blanton (NYU)

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

6 n(>V max,acc )=n(>L) Conroy, Wechsler & Kravtsov (astro-ph/ ) Conroy, Wechsler & Kravtsov (astro-ph/ ) projected 2-point correlation function projected separation (chimps) Galaxy clustering in SDSS at z~0 Is well reproduced by simulations

7 n(>V max,acc )=n(>L) Conroy, Wechsler & Kravtsov (astro-ph/ ) Conroy, Wechsler & Kravtsov (astro-ph/ ) projected 2-point correlation function projected separation (chimps) and at z~1 (DEEP2)

8 n(>V max,acc )=n(>L) Conroy, Wechsler & Kravtsov (astro-ph/ ) Conroy, Wechsler & Kravtsov (astro-ph/ ) angular 2-point correlation function projected separation (arcsec/chimps) and at z~4-5 (LBGs, Subaru)

9 CDM paradigm must also be tested on smaller, galactic scales

10 It’s a very difficult problem

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 won’t 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-z’s also are less complicated in certain physical aspects (e.g., low dust content)

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

13 Milky Way progenitor at z=4 Kravtsov 2003; Kravtsov & Gnedin 2005 Kravtsov 2003; Kravtsov & Gnedin 2005

14 Density PDF and SF Kravtsov 2003 Kravtsov 2003

15 Stellar cluster mass function Kravtsov & Gnedin 2005 Kravtsov & Gnedin 2005

16 Stellar cluster mass function in Antennae

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/)

18 Dwarf galaxies at z~8 Ricotti & Gnedin 2005 Ricotti & Gnedin 2005

19 Dwarf galaxies at high z Show correlations observed locally M/L – metallicity correlation M/L – metallicity correlation

20 Dwarf galaxies at high z Show correlations observed locally metallicity-stellar mass correlation metallicity-stellar mass correlation

21 Dwarf galaxies at high z Show correlations observed locally surface brightness-stellar mass correlation surface brightness-stellar mass correlation

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

23 Survival probability for objects at z~8

24 Luminosity function of dwarfs in the Local Group

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


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