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تسجيل مستخدم جديدExtracting Angular Diameter Distance and Expansion Rate of the Universe from Two-dimensional Galaxy Power Spectrum at High Redshifts: Baryon Acoustic Oscillation Fitting versus Full Modeling
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We present a method for extracting the angular diameter distances, $D_A$, and the expansion rates, $H$, of the universe from the {it two-dimensional} Baryon Acoustic Oscillations (BAO) in the galaxy power spectrum. Our method builds upon the existing algorithm called the fit-and-extract (FITEX) method, which allows one to extract only $D_A^2/H$ from a spherically averaged one-dimensional power spectrum. We develop the FITEX-2d method, an extension of the FITEX method, to include the two-dimensional information, which allows us to extract $D_A$ and $H$ simultaneously. We test the FITEX-2d method using the Millennium Simulation as well as simplified Monte Carlo simulations with a bigger volume. The BAOs, however, contain only a limited amount of information. We show that the full modeling, including the overall shape of the power spectrum, yields much better determinations of $D_A$ and $H$, hence the dark energy equation of state parameters such as $w_0$ and $w_a$, than the BAO-only analysis by more than a factor of two, provided that non-linear effects are under control.
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