High-precision spectra for dynamical Dark Energy cosmologies from constant-w models - Astrophysics > Cosmology and Nongalactic AstrophysicsReport as inadecuate




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Abstract: Spanning the whole functional space of cosmologies with any admissible DEstate equations wa seems a need, in view of forthcoming observations, namelythose aiming to provide a tomography of cosmic shear. In this paper I show thatthis duty can be eased and that a suitable use of results for constant-wcosmologies can be sufficient. More in detail, I ``assign- here sixcosmologies, aiming to span the space of state equations wa = w o + w a1-a,for w o and w a values consistent with WMAP5 and WMAP7 releases and run N-bodysimulations to work out their non-linear fluctuation spectra at variousredshifts z. Such spectra are then compared with those of suitable auxiliarymodels, characterized by constant w. For each z a different auxiliary model isneeded. Spectral discrepancies between the assigned and the auxiliary models,up to k ~ 2-3 h Mpc^{-1}, are shown to keep within 1%. Quite in general,discrepancies are smaller at greater z and exhibit a specific trend across thew o and w a plane. Besides of aiming at simplifying the evaluation of spectrafor a wide range of models, this paper also outlines a specific danger forfuture studies of the DE state equation, as models fairly distant on the w 0 -w a plane can be easily confused.



Author: Luciano Casarini

Source: https://arxiv.org/







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