Non-linear power spectrum and forecasts for Generalized Cubic Covariant Galileon

Luís Atayde; Noemi Frusciante; Benjamin Bose; Santiago Casas; Baojiu Li

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arXiv · 2404.11471

Non-linear power spectrum and forecasts for Generalized Cubic Covariant Galileon

Luís Atayde·Noemi Frusciante·Benjamin Bose·Santiago Casas·Baojiu Li

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Abstract

To fully exploit the data from next generation surveys, we need an accurate modelling of the matter power spectrum up to non-linear scales. Therefore in this work we present the halo model reaction framework for the Generalized Cubic Covariant Galileon (GCCG) model, a modified gravity model within the Horndeski class of theories which extends the cubic covariant Galileon (G3) by including power laws of the derivatives of the scalar field in the K-essence and cubic terms. We modify the publicly available software ReACT for the GCCG in order to obtain an accurate prediction of the non-linear power spectrum. In the limit of the G3 model we compare the modified ReACT code to $N$-body simulations and we find agreement within 5\% for a wide range of scales and redshifts. We then study the relevant effects of the modifications introduced by the GCCG on the non-linear matter power spectrum. Finally, we provide forecasts from spectroscopic and photometric primary probes by next generation surveys using a Fisher matrix method. We show that future data will be able to constrain at 1$σ$ the two additional parameters of the model at the percent level and that considering non-linear corrections to the matter power spectrum beyond the linear regime is crucial to obtain this result.

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Luís Atayde, Noemi Frusciante, Benjamin Bose, Santiago Casas, Baojiu Li. 2024-04-17. Non-linear power spectrum and forecasts for Generalized Cubic Covariant Galileon. https://arxiv.org/abs/2404.11471

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