Spoon or slide? The non-linear matter power spectrum in the presence of massive neutrinos

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  • Steen Hannestad
  • Amol Upadhye, Sydney Consortium for Particle Physics and Cosmology School of Physics, The University of New South Wales, Sydney NSW 2052, Australia a.upadhye@unsw.edu.au
  • ,
  • Yvonne Y. Y. Wong, Sydney Consortium for Particle Physics and Cosmology School of Physics, The University of New South Wales, Sydney NSW 2052, Australia yvonne.y.wong@unsw.edu.au
Numerical simulations of massive neutrino cosmologies consistently find a spoon-like feature in the non-linear matter power spectrum ratios of cosmological models that differ only in the neutrino mass fraction fN. Typically, the ratio approaches unity at low wave numbers k, decreases by ~ 10 fN at k ~ 1 h/Mpc, and turns up again at large k. Using the halo model of large-scale structure, we show that this spoon feature originates in the transition from the two-halo power spectrum to the one-halo power spectrum. The former's sensitivity to fN rises with k, while that of the latter decreases with k. The presence of this spoon feature is robust with respect to different choices of the halo mass function and the halo density profile, and does not require any parameter tuning within the halo model. We demonstrate that a standard halo model calculation is already able to predict the depth, width, and position of this spoon as well as its evolution with redshift z with remarkable accuracy. Predictions at z gtrsim 1 can be further improved using non-linear perturbative inputs.
Original languageEnglish
JournalJournal of Cosmology and Astroparticle Physics
Volume11
Issue11
Pages (from-to)62
ISSN1475-7516
DOIs
Publication statusPublished - 1 Nov 2020

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