DEMNUni: comparing nonlinear power spectra prescriptions in the presence of massive neutrinos and dynamical dark energy
Year: 2022
Type: article
Abstract: We provide an accurate comparison, against large cosmologicalN-body simulations, of different prescriptions for modelling nonlinear matter power spectra in the presence of massive neutrinos and dynamical dark energy. We test the current most widely used approaches: fitting functions (HALOFIT and HMcode), the halo-model reaction (ReACT) and emulators (baccoemuand EuclidEmulator2). Focussing on redshiftsz≤ 2 and scalesk≲ 1h/Mpc (where the simulation mass resolution provides ∼ 1% accuracy), we find that HMcode andReACTconsiderably improve over the HALOFIT prescriptions of Smith and Takahashi (both combined with the Bird correction), with an overall agreement of 2% for all the cosmological scenarios considered. Concerning emulators, we find that, especially at low redshifts, EuclidEmulator2 remarkably agrees with the simulated spectra at ≲ 1% level in scenarios with dynamical dark energy and massless neutrinos, reaching a maximum difference of ∼ 2% atz= 2.baccoemuhas a similar behaviour as EuclidEmulator2, except for a couple of dark energy models. In cosmologies with massive neutrinos, atz= 0 all the nonlinear prescriptions improve their agreement with respect to the massless neutrino case, except for the Bird and TakaBird models which, however, are not tailored tow0–wamodels. Atz> 0 we do not find a similar improvement when including massive neutrinos, probably due to the lower impact of neutrino free-streaming at higher redshifts; rather atz= 2 EuclidEmulator2 exceeds 2% agreement for some dark energy equation of state. When considering ratios between the matter power spectrum computed in a given cosmological model and its ΛCDM counterpart, all the tested prescriptions agree with simulated data, at sub-percent or percent level, depending onz. Finally, we also test how nonlinear prescriptions compare against simulations when computing cosmic shear and angular galaxy clustering spectra. For the former, we find a 2–3% agreement for HMcode,baccoemu, EuclidEmulator2 andReACT; for the latter, due to the minimum stellar mass of the simulated galaxies, shot noise highly affects the signal and makes the discrepancies as high as 5%.
Institutions: Roma Tre University, Scuola Internazionale Superiore di Studi Avanzati, Istituto Nazionale di Fisica Nucleare, Trieste Astronomical Observatory, Istituto Nazionale di Fisica Nucleare, Sezione di Roma Tre, Institute for Fundamental Physics of the Universe, University of Genoa, National Institute for Astrophysics, Istituto di Astrofisica Spaziale e Fisica Cosmica di Milano, Centre National de la Recherche Scientifique, Université de Toulon, Aix-Marseille Université, University of Geneva, University of Zurich, Royal Observatory, University of Edinburgh, Osservatorio Astronomico della Regione Autonoma Valle d'Aosta, University of Milan, University of Oxford, Donostia International Physics Center
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W4288726760