Bibcode
Vakili, M.; Kitaura, F.-Sh.; Feng, Yu; Yepes, Gustavo; Zhao, Cheng; Chuang, Chia-Hsun; Hahn, ChangHoon
Bibliographical reference
Monthly Notices of the Royal Astronomical Society, Volume 472, Issue 4, p.4144-4154
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12
2017
Citations
16
Refereed citations
13
Description
Reliable extraction of cosmological information from clustering
measurements of galaxy surveys requires estimation of the error
covariance matrices of observables. The accuracy of covariance matrices
is limited by our ability to generate sufficiently large number of
independent mock catalogues that can describe the physics of galaxy
clustering across a wide range of scales. Furthermore, galaxy mock
catalogues are required to study systematics in galaxy surveys and to
test analysis tools. In this investigation, we present a fast and
accurate approach for generation of mock catalogues for the upcoming
galaxy surveys. Our method relies on low-resolution approximate gravity
solvers to simulate the large-scale dark matter field, which we then
populate with haloes according to a flexible non-linear and stochastic
bias model. In particular, we extend the patchy code with an efficient
particle mesh algorithm to simulate the dark matter field (the fastpm
code), and with a robust MCMC method relying on the emcee code for
constraining the parameters of the bias model. Using the haloes in the
BigMultiDark high-resolution N-body simulation as a reference catalogue,
we demonstrate that our technique can model the bivariate probability
distribution function (counts-in-cells), power spectrum and bispectrum
of haloes in the reference catalogue. Specifically, we show that the new
ingredients permit us to reach percentage accuracy in the power spectrum
up to k ˜ 0.4 h Mpc-1 (within 5 per cent up to k
˜ 0.6 h Mpc-1) with accurate bispectra improving
previous results based on Lagrangian perturbation theory.
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The Cosmic Microwave Background (CMB) contains the statistical information about the early seeds of the structure formation in our Universe. Its natural counterpart in the local universe is the distribution of galaxies that arises as a result of gravitational growth of those primordial and small density fluctuations. The characterization of the
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