TY - JOUR

T1 - Constraints on small-scale cosmological fluctuations from SNe lensing dispersion

AU - Ben-Dayan, Ido

AU - Takahashi, Ryuichi

N1 - Publisher Copyright:
© 2015 The Authors.

PY - 2016/1/1

Y1 - 2016/1/1

N2 - We provide predictions on small-scale cosmological density power spectrum from supernova lensing dispersion. Parametrizing the primordial power spectrum with running a and running of running β of the spectral index, we exclude large positive α and β parameters which induce too large lensing dispersions over current observational upper bound. We ran cosmological N-body simulations of collisionless dark matter particles to investigate non-linear evolution of the primordial power spectrum with positive running parameters. The initial small-scale enhancement of the power spectrum is largely erased when entering into the non-linear regime. For example, even if the linear power spectrum at k > 10 h Mpc-1 is enhanced by 1-2 orders of magnitude, the enhancement much decreases to a factor of 2-3 at late time (z ≤ 1.5). Therefore, the lensing dispersion induced by the dark matter fluctuations weakly constrains the running parameters. When including baryon-cooling effects (which strongly enhance the small-scale clustering), the constraint is comparable to the Planck constraint, depending on the UV cut-off. Further investigations of the non-linear matter spectrum with baryonic processes is needed to reach a firm constraint.

AB - We provide predictions on small-scale cosmological density power spectrum from supernova lensing dispersion. Parametrizing the primordial power spectrum with running a and running of running β of the spectral index, we exclude large positive α and β parameters which induce too large lensing dispersions over current observational upper bound. We ran cosmological N-body simulations of collisionless dark matter particles to investigate non-linear evolution of the primordial power spectrum with positive running parameters. The initial small-scale enhancement of the power spectrum is largely erased when entering into the non-linear regime. For example, even if the linear power spectrum at k > 10 h Mpc-1 is enhanced by 1-2 orders of magnitude, the enhancement much decreases to a factor of 2-3 at late time (z ≤ 1.5). Therefore, the lensing dispersion induced by the dark matter fluctuations weakly constrains the running parameters. When including baryon-cooling effects (which strongly enhance the small-scale clustering), the constraint is comparable to the Planck constraint, depending on the UV cut-off. Further investigations of the non-linear matter spectrum with baryonic processes is needed to reach a firm constraint.

KW - Cosmological parameters

KW - Cosmology

KW - Gravitational lensing

KW - Inflation

KW - Large-scale structure of Universe

KW - Theory

KW - Weak

UR - http://www.scopus.com/inward/record.url?scp=84958260652&partnerID=8YFLogxK

U2 - 10.1093/mnras/stv2356

DO - 10.1093/mnras/stv2356

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AN - SCOPUS:84958260652

SN - 0035-8711

VL - 455

SP - 552

EP - 562

JO - Monthly Notices of the Royal Astronomical Society

JF - Monthly Notices of the Royal Astronomical Society

IS - 1

ER -