DESI DR1 Lyman-alpha data yields Δ²★=0.379±0.032 and n★=-2.309±0.019 at k★=0.009 km⁻¹s and z=3, sharpening N_eff, α_s, and β_s constraints by factors of 1.18-1.90 when combined with other probes.
Transients from Initial Conditions in Cosmological Simulations
4 Pith papers cite this work. Polarity classification is still indexing.
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abstract
We study the impact of setting initial conditions in numerical simulations using the standard procedure based on the Zel'dovich approximation (ZA). As it is well known from perturbation theory, ZA initial conditions have incorrect second and higher-order growth and therefore excite long-lived transients in the evolution of the statistical properties of density and velocity fields. We also study the improvement brought by using more accurate initial conditions based on second-order Lagrangian perturbation theory (2LPT). We show that 2LPT initial conditions reduce transients significantly and thus are much more appropriate for numerical simulations devoted to precision cosmology. Using controlled numerical experiments with ZA and 2LPT initial conditions we show that simulations started at redshift z_i=49 using the ZA underestimate the power spectrum in the nonlinear regime by about 2,4,8 % at z=0,1,3 respectively, whereas the mass function of dark matter halos is underestimated by 5% at m=10^15 M_sun/h (z=0) and 10% at m=2x10^14M_sun/h (z=1). The clustering of halos is also affected to the few percent level at z=0. These systematics effects are typically larger than statistical uncertainties in recent mass function and power spectrum fitting formulae extracted from numerical simulations. At large scales, the measured transients in higher-order correlations can be understood from first principle calculations based on perturbation theory.
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astro-ph.CO 4representative citing papers
Galaxy pairwise peculiar velocities from Cosmicflows-4 yield M_ν = 0.24^{+0.34}_{-0.18} eV and η² = 2.14^{+0.30}_{-0.32} (7σ non-zero asymmetry) in the CMB framework, consistent with prior Planck results.
Projection-induced selection bias causes 20-50% overestimation of weak lensing masses for optically selected galaxy clusters, larger on scales >3 Mpc.
The parity-odd intrinsic alignment power spectrum probes the collapsed limit of the parity-odd primordial trispectrum and can tighten constraints on parity-violating PNG when bias parameters are calibrated from N-body simulations.
citing papers explorer
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Cosmological analysis of the DESI DR1 Lyman alpha 1D power spectrum
DESI DR1 Lyman-alpha data yields Δ²★=0.379±0.032 and n★=-2.309±0.019 at k★=0.009 km⁻¹s and z=3, sharpening N_eff, α_s, and β_s constraints by factors of 1.18-1.90 when combined with other probes.
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Measuring neutrino mass and asymmetry through galaxy pairwise peculiar velocity
Galaxy pairwise peculiar velocities from Cosmicflows-4 yield M_ν = 0.24^{+0.34}_{-0.18} eV and η² = 2.14^{+0.30}_{-0.32} (7σ non-zero asymmetry) in the CMB framework, consistent with prior Planck results.
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Impact of projection-induced optical selection bias on the weak lensing mass calibration of galaxy clusters
Projection-induced selection bias causes 20-50% overestimation of weak lensing masses for optically selected galaxy clusters, larger on scales >3 Mpc.
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Parity Violation in Galaxy Shapes: Primordial Non-Gaussianity
The parity-odd intrinsic alignment power spectrum probes the collapsed limit of the parity-odd primordial trispectrum and can tighten constraints on parity-violating PNG when bias parameters are calibrated from N-body simulations.