Fast computation of non-linear power spectrum in cosmologies with massive neutrinos. (arXiv:2208.02791v1 [astro-ph.CO])

<a href="http://arxiv.org/find/astro-ph/1/au:+Noriega_H/0/1/0/all/0/1">Hernán E. Noriega</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Aviles_A/0/1/0/all/0/1">Alejandro Aviles</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Fromenteau_S/0/1/0/all/0/1">Sebastien Fromenteau</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Vargas_Magana_M/0/1/0/all/0/1">Mariana Vargas-Magaña</a>

We compute 1-loop corrections to the redshift space galaxy power spectrum in

cosmologies containing additional scales, and hence kernels different from

Einstein-de Sitter (EdS). Specifically, our method is tailored for cosmologies

in the presence of massive neutrinos and some modified gravity models; in this

article we concentrate on the former case. The perturbative kernels have

contributions that we notice appear either from the logarithmic growth factor

$f(k,t)$, which is scale-dependent because of the neutrino free-streaming, or

from the failure of the commonly used approximation $f^2=Omega_m$. The latter

contributions make the computation of loop corrections quite slow, precluding

full-shape analyses for parameter estimation. However, we identify that the

dominant pieces of the kernels come from the growth factor, allowing us to

simplify the kernels but retaining the characteristic free-streaming scale

introduced by the neutrinos’ mass. Moreover, with this simplification one can

exploit FFTLog methods to speed up the computations even more. We validate our

analytical modeling and numerical method with halo catalogs extracted from the

Quijote simulations finding good agreement with the, a priori, known

cosmological parameters. We make public our Python code FOLPS$nu$ to compute

the redshift space power spectrum in a fraction of second. Code available at

https://github.com/henoriega/FOLPS-nu.

We compute 1-loop corrections to the redshift space galaxy power spectrum in

cosmologies containing additional scales, and hence kernels different from

Einstein-de Sitter (EdS). Specifically, our method is tailored for cosmologies

in the presence of massive neutrinos and some modified gravity models; in this

article we concentrate on the former case. The perturbative kernels have

contributions that we notice appear either from the logarithmic growth factor

$f(k,t)$, which is scale-dependent because of the neutrino free-streaming, or

from the failure of the commonly used approximation $f^2=Omega_m$. The latter

contributions make the computation of loop corrections quite slow, precluding

full-shape analyses for parameter estimation. However, we identify that the

dominant pieces of the kernels come from the growth factor, allowing us to

simplify the kernels but retaining the characteristic free-streaming scale

introduced by the neutrinos’ mass. Moreover, with this simplification one can

exploit FFTLog methods to speed up the computations even more. We validate our

analytical modeling and numerical method with halo catalogs extracted from the

Quijote simulations finding good agreement with the, a priori, known

cosmological parameters. We make public our Python code FOLPS$nu$ to compute

the redshift space power spectrum in a fraction of second. Code available at

https://github.com/henoriega/FOLPS-nu.

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