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Title: THE MIRA–TITAN UNIVERSE: PRECISION PREDICTIONS FOR DARK ENERGY SURVEYS

Large-scale simulations of cosmic structure formation play an important role in interpreting cosmological observations at high precision. The simulations must cover a parameter range beyond the standard six cosmological parameters and need to be run at high mass and force resolution. A key simulation-based task is the generation of accurate theoretical predictions for observables using a finite number of simulation runs, via the method of emulation. Using a new sampling technique, we explore an eight-dimensional parameter space including massive neutrinos and a variable equation of state of dark energy. We construct trial emulators using two surrogate models (the linear power spectrum and an approximate halo mass function). The new sampling method allows us to build precision emulators from just 26 cosmological models and to systematically increase the emulator accuracy by adding new sets of simulations in a prescribed way. Emulator fidelity can now be continuously improved as new observational data sets become available and higher accuracy is required. Finally, using one ΛCDM cosmology as an example, we study the demands imposed on a simulation campaign to achieve the required statistics and accuracy when building emulators for investigations of dark energy.
Authors:
; ; ; ;  [1] ; ;  [2] ;  [3] ;  [4] ; ;  [5]
  1. HEP Division, Argonne National Laboratory, Lemont, IL 60439 (United States)
  2. Department of Statistics and Actuarial Science, Simon Fraser University, Burnaby, BC (Canada)
  3. CCS-6, CCS Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)
  4. Social and Decision Analytics Laboratory, Virginia Bioinformatics Institute, Virginia Tech, Arlington, VA 22203 (United States)
  5. ALCF Division, Argonne National Laboratory, Lemont, IL 60439 (United States)
Publication Date:
OSTI Identifier:
22518547
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 820; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; APPROXIMATIONS; COMPUTERIZED SIMULATION; COSMOLOGICAL MODELS; COSMOLOGY; EQUATIONS OF STATE; MASS; NONLUMINOUS MATTER; RESOLUTION; UNIVERSE