Non-linear evolution of suppressed dark matter primordial power spectra |
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| Authors: | C Boehm H Mathis J Devriendt J Silk |
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| Institution: | University of Oxford, Astrophysics, Keble Road, Oxford OX1 3RH |
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| Abstract: | We address the degree and rapidity of generation of small-scale power over the course of structure formation in cosmologies where the primordial power spectrum is strongly suppressed beyond a given wavenumber. We first summarize the situations where one expects such suppressed power spectra and point out their diversity. We then employ an exponential cut-off, which characterizes warm dark matter (WDM) models, as a template for the shape of the cut-off and focus on damping scales ranging from 106 to 109 h −1 M⊙ . Using high-resolution simulations, we show that the suppressed part of the power spectrum is quickly (re)generated and catches up with both the linear and the non-linear evolution of the unsuppressed power spectrum. From z = 2 onwards, a power spectrum with a primordial cut-off at 109 h −1 M⊙ becomes virtually indistinguishable from an evolved cold dark matter (CDM) power spectrum. An attractor such as that described in Zaldarriaga, Scoccimarro & Hui for power spectra with different spectral indices also emerges in the case of truncated power spectra. Measurements of z ∼ 0 non-linear power spectra at ∼100 h −1 kpc cannot rule out the possibility of linear power spectra damped below ∼109 h −1 M⊙ . Therefore, WDM or scenarios with similar features should be difficult to exclude in this way. |
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| Keywords: | methods: N-body simulations cosmology: theory dark matter large-scale structure of Universe |
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