The Mira-Titan Universe. III. Emulation of the Halo Mass Function

Journal Article · Tue Sep 01 00:00:00 EDT 2020 · Astrophysical Journal

DOI:https://doi.org/10.3847/1538-4357/abac5c· OSTI ID:1757991

Bocquet, Sebastian; Heitmann, Katrin; Habib, Salman; Lawrence, Earl; Uram, Thomas; Frontiere, Nicholas; Pope, Adrian; Finkel, Hal

We construct an emulator for the halo mass function over group and cluster mass scales for a range of cosmologies, including the effects of dynamical dark energy and massive neutrinos. The emulator is based on the recently completed Mira-Titan Universe suite of cosmological N-body simulations. The main set of simulations spans 111 cosmological models with 2.1 Gpc boxes. We extract halo catalogs in the redshift range z = [0.0, 2.0] and for masses M-200c >= 10(13)M(circle dot)/h. The emulator covers an eight-dimensional hypercube spanned by {Omega(m)h(2), Omega(b)h(2), Omega(nu)h(2), sigma(8), h, n(s), w(0), w(a)}; spatial flatness is assumed. We obtain smooth halo mass functions by fitting piecewise second-order polynomials to the halo catalogs and employ Gaussian process regression to construct the emulator while keeping track of the statistical noise in the input halo catalogs and uncertainties in the regression process. For redshifts z less than or similar to 1, the typical emulator precision is better than 2% for 10(13)-10(14)M(circle dot)/h and <10<^> M similar or equal to 101(circle dot)(54)/h. For comparison, fitting functions using the traditional universal form for the halo mass function can be biased at up to 30% at M similar or equal to 10(144)M(circle dot)/h for z = 0. Our emulator is publicly available at https://github.com/SebastianBocquet/MiraTitanHMFemulator.

• Research Organization: Argonne National Lab. (ANL), Argonne, IL (United States)
• Sponsoring Organization: USDOE Office of Science - Office of Advanced Scientific Computing Research (ASCR) - Scientific Discovery through Advanced Computing (SciDAC); USDOE Office of Science - Office of High Energy Physics; German Research Foundation (DFG); University of Munich (Ludwig Maximilians Universitat Munchen)
• DOE Contract Number: AC02-06CH11357
• OSTI ID: 1757991
• Journal Information: Astrophysical Journal, Vol. 901, Issue 1
• Country of Publication: United States
• Language: English

Related Subjects

cosmology: theory
large-scale structure of the universe
methods: numerical
methods: statistical