Year: 2020
Type: article
Abstract: Future high spectroscopic resolution galaxy surveys will observe galaxies with nearly full-sky footprints. Modeling the galaxy clustering for these surveys, therefore, must include the wide-angle effect with narrow redshift binning. In particular, when the redshift-bin size is comparable to the typical peculiar velocity field, the nonlinear redshift-space distortion (RSD) effect becomes important. A naive projection of the Fourier-space RSD model to spherical harmonic space leads to diverging expressions. In this paper we present a general formalism of projecting the higher-order RSD terms into spherical harmonic space. We show that the nonlinear RSD effect, including the fingers-of-God, can be entirely attributed to a modification of the radial window function. We find that while linear RSD enhances the harmonic-space power spectrum, unlike the three-dimensional case, the enhancement decreases on small angular scales. The fingers-of-God suppress the angular power spectrum on all transverse scales if the bin size is smaller than $\mathrm{\ensuremath{\Delta}}r\ensuremath{\lesssim}\ensuremath{\pi}{\ensuremath{\sigma}}_{u}$; for example, the radial bin sizes corresponding to a spectral resolution $R=\ensuremath{\lambda}/\mathrm{\ensuremath{\Delta}}\ensuremath{\lambda}$ of a few hundred satisfy the condition. We also provide the flat-sky approximation which reproduces the full calculation to subpercent accuracy.
Institution: Pennsylvania State University
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
Awards: 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: W3054159643