Numerical Cosmology

1
Numerical Cosmology

• Argonne-Fermilab-University of Chicago
  Collaboration Meeting

2
Need Simulations to Extract Science from Surveys

• Dark Matter
• Dark Energy
• Neutrino Mass
• Inflation

• Gravitational Instability is nonlinear
• Baryons governed by hydrodynamics
• Radiation Field affects and is affected by
  structure
• Stars form, Supernovae explode,

3
Progress
1000 Core Cluster at New Muon Lab
ANL LDRD
KICP, TAG Investments
DOE Dark Energy Grant
FRA Grant
Spring 07 Summer 07 Fall 07 Winter 08 Spring 08 Summer 08
Task Force Report
560 Core Cluster at New Muon Lab
DOE Lab Meeting
Presentation to PAC
4
Projects Using the Cluster

1. Tinker, Kravtsov et al. 2008, ApJ in press
   http//arxiv.org/abs/0803.2706 "Toward a halo
   mass function for precision cosmology the limits
   of universality" The project has used the
   KICP/FNAL cluster for analyses of billion
   particle cosmological simulations aimed at
   calibrating predictions for halo mass function
   and its evolution to an accuracy of a few per
   cent. Figures 6 and/or 7 from the above paper can
   be used to illustrate results of the project.
2. Brant Robertson, Andrey Kravtsov have used the
   cluster to perform simulationsof dwarf galaxy
   mergers with dark halos. The project is aimed
   at exploring possible morphological signatures of
   such "phantom mergers" to constrain incidence
   of pure dark halos using available data. The
   draft of a paper is being prepared for
   submission (planned submission in the next
   several months).
3. Konstantinos Tassis, Nick Gnedin, Andrey
   Kravtsov are using the cluster to run the first
   cosmological simulations of galaxy formation
   with 3D radiative transfer, molecular hydrogen
   formation on dust and its self-shielding from
   dissociating radiation. The simulations are
   using a model for star formation that is based on
   molecular hydrogen. Gnedin, N. Y., Tassis,
   K., Kravtsov, A. V., in preparation
   "Molecular-Hydrogen-Based Star Formation
   Prescription for Cosmological Simulations"
4. Brant Robertson, Andrey Kravtsov, Jeremy Tinker
   are using the cluster to run Monte Carlo
   calculations of mass functions and bias of dark
   matter halos in different models for halo
   collapse (using different collapse barriers to
   reproduce simulation results). The aim of the
   project is to understand the barrier required to
   reproduce the simulation results and
   implications for halo formation.
5. Robyn Levine, Nick Gnedin, Andrey Kravtsov,
   Andrew Hamilton (Univ. of Colorado) are running
   simulations of the circumnuclear region of a
   supermassive black hole within a cosmological
   volume. The goal of this project is to understand
   the formation and evolution of supermassive
   black holes and their feedback on large-scale
   distribution of mass in the universe. Levine,
   R, Gnedin, N. Y., Hamilton, A. J. S., Kravtsov,
   A. V., ApJ in press http//arxiv.org/abs/0711.
   3478 "Resolving Gas Dynamics in the
   Circumnuclear Region of a Disk Galaxy in a
   Cosmological Simulation" Levine, R, Gnedin, N.
   Y., Hamilton, A. J. S., Kravtsov, A. V., in
   preparation "Matter Transport in the Host
   Galaxy of a Supermassive Black Hole
6. Maria Beltran, Wayne Hu have used the cluster for
   calculating some MCMC chains for a work in
   progress about the impact of future BAO surveys
   on the determination of the isocurvature
   amplitude of the curvaton and the degeneracies
   in two other cosmological parameters the
   equation of state of the DE and the spatial
   curvature.
7. Marcos Lima, Hiroaki Oyaizu, Wayne Hu run N-body
   simulations of f(R) modified gravity to study
   the impact on nonlinear growth of structure and
   help distinguish modified gravity from dark
   energy models. The interesting results is that
   such models have a unique signature in P(k) at
   k0.1h/Mpc because gravity is stronger outside
   halos (so there is more power on those scales
   compared to LCDM). The effect is shown in Fig.
   11 of the paper (http//yummy.uchicago.edu/misc/
   methodpaper.pdf) H. Oyaizu, "Nonlinear
   evolution in f(R) cosmologies I Methodology",
   in prep. H. Oyaizu, M. Lima, W. Hu, "Nonlinear
   evolution in f(R) cosmologies II Power
   Spectrum", in prep. M. Lima, H. Oyaizu, W. Hu,
   "Nonlinear evolution in f(R) cosmologies III
   Halo abundance and bias", in prep.
8. Qizhi Zhang, Steve Kulhmann, Peter van Gemmeren
   (ANL) use the cluster to manage the SQL
   database for the DES-related simulation work.
9. Douglas Rudd, Andrey Kravtsov have been running
   cluster simulations for convergence studies
   within the framework of an international Galaxy
   Cluster Comparison Project.
10. Ben Dilday is working on the measurements of the
    type-Ia SN rate from the SDSS-II SN Survey.
    Dilday, B, et al, "Rate of type-Ia SNe at zlt0.25
    from the SDSS-II SN Survey" Dilday, B, et
    al, "Rate of type-Ia SNe in galaxy clusters from
    the SDSS-II SN Survey" both in prep.
11. Sheng Wang is modeling CMB anisotropies in
    modified gravity models. Fang et
    al.,"Challenges for the Self-accelerating
    Braneworld Model on the Horizon from the CMB",
    in prep.
12. The VERITAS group at U of Chicago is using the
    cluster to run simulations of very-high-energy
    gamma rays hitting the atmosphere and being
    reconstructed by our detector. These
    simulations will have an important impact in all
    the VERITAS papers under preparation.  

5
E.g. Was Einstein Right?

• Marcos Lima, Hiroaki Oyaizu, Wayne Hu run N-body
  simulations of f(R) modified gravity to study
  the impact on nonlinear growth of structure and
  help distinguish modified gravity from dark
  energy models.
• H. Oyaizu, "Nonlinear evolution in f(R)
  cosmologies I Methodology", in prep.
• H. Oyaizu, M. Lima, W. Hu, "Nonlinear evolution
  in f(R) cosmologies II Power Spectrum", in
  prep.
• M. Lima, H. Oyaizu, W. Hu, "Nonlinear evolution
  in f(R) cosmologies III Halo abundance and
  bias", in prep.

6
Particle Astro Physics and the Brain
Symmetry
Litke
Ermentrout
7
Exploratory Meeting (June 2007)

• Dodelson (FNAL) with Murray Sherman (Chair, Dept.
  of Neurobiology, UC) Sam Sisodia (Director,
  Center for Neurobiology, UC) . Suggested two step
  process
• Invite Visiting Committee (e.g. Abbott, Koch,
  Woody, Litke) to FNAL/UC to scout out areas of
  overlap 5-10k
• Highlight these areas in joint workshop 20k