Year: 2018
Type: article
Abstract: Perturbation theory calculation of large-scale structures has been used to interpret the observed nonlinear statistics of large-scale structures at the quasilinear regime. In particular, the so-called standard perturbation theory (SPT) provides a basis for the analytical computation of the higher-order quantities of large-scale structures. Here, we present a novel grid-based algorithm for the SPT calculation, hence named GridSPT, to generate the higher-order density and velocity fields from a given linear power spectrum. Taking advantage of the fast Fourier transform, the GridSPT quickly generates the nonlinear density fields at each order, from which we calculate the statistical quantities such as nonlinear power spectrum and bispectrum. Comparing the density fields (to fifth order) from GridSPT with those from the full $N$-body simulations in the configuration space, we find that GridSPT accurately reproduces the $N$-body result on large scales. The agreement worsens with smaller smoothing radius, particularly for the underdense regions where we find that the second-order Lagrangian perturbation theory algorithm performs well.
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
Awards: G112659553, G3243641794, Development and application of data analysis method for precision cosmology based on two- and three-point statistics of large-scale structure of the Universe, Theoretical foundation of large-scale structure formation for numerical statistical cosmology, G5741291435, Cosmology with the galaxy bispectrum: galaxy bias, redshift-space distortion, and primordial non-Gaussianity, WE PROPOSE A RESEARCH PROGRAM THE AIMING AT EXPLOITING THE DATASET FROM THE UPCOMING SPACE MISSIONS: SPHEREX WFIRST AND EUCLID. IN PARTICULAR WE WILL STUDY THE TWO OBSERVABLES THAT ARE NOT PARTS OF THE CURRENT COSMOLOGICAL ANALYSIS: 1) THE GALAXY THREEPOINT CORRELATION FUNCTION AND 2) CLUSTERING FOSSILS. EXPLOITING THE GALAXY THREE-POINT CORRELATION FUNCTION (3PCF) WILL IMPROVE THE DARK ENERGY CONSTRAINT (BOTH GEOMETRICAL AND DYNAMICAL) BY A FACTOR OF TWO COMPARED TO THE CONVENTIONAL ANALYSIS USING ONLY THE TWO-POINT CORRELATION FUNCTION. THE CLUSTERING FOSSILS MEASUREMENT CAN POTENTIALLY BE A POWERFUL TEST OF INFLATIONARY THEORY BY SEARCHING FOR SIGNATURES OF SPECTATOR FIELDS WITH GENERAL-SPIN (THIS INCLUDES THE PRIMORDIAL GRAVITATIONAL WAVES) THAT MIGHT HAVE EXISTED IN THE EARLY UNIVERSE. BY USING THE ANALYTICAL THEORY BASED ON THE GENERAL THEORY OF RELATIVITY AS WELL AS RECENTLY DEVELOPED TOTAL ANGULAR MOMENTUM WAVE METHOD WE PLAN TO INCORPORATE THE RELATIVISTIC PROJECTION EFFECT AS WELL AS WIDE-ANGLE EFFECT. FOR BOTH OBSERVABLES THE KEY THEORETICAL CHALLENGE IS TO MODEL THE COUPLING BETWEEN LONG-WAVELENGTH MODES AND SHORT-WAVELENGTH MODES. WE PLAN TO DEVELOP A THEORETICAL MODEL BY USING THE PERTURBATION THEORY TECHNIQUES AND COMPARE THE VALIDITY OF THE MODELS AGAINST COSMOLOGICAL N-BODY SIMULATIONS. PARALLEL TO THE THEORETICAL STUDIES WE ALSO PLAN TO STUDY THE METHOD TO IDENTIFYING AND MODELING THE SURVEY SYSTEMATICS INDUCED BY DUST CONTAMINATION BRIGHT STARS AS WELL AS OVERLAPPING SPECTRA. FOR THIS STUDY WE SHALL GENERATE THE LOG-NORMAL MOCK CATALOGUES FOR WHICH WE KNOW COMPLETE UNDERLYING STATISTICS. AS AN END PRODUCT OF THE RESEARCH PROGRAM WE WILL HAVE AN END-TO-END DATA ANALYSIS TOOLKIT FOR THE GALAXY 3PCF AND CLUSTERING FOSSILS. THE TOOLKITS INCLUDE FROM THE OPTIMAL ESTIMATOR OF THE SIGNATURE TO ACCURATE THEORETICAL TEMPLATE FOR THE COSMOLOGICAL INTERPRETATION.
OpenAlex ID: W2877790239