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Table of contents

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Back to the main page 1. Compute Background Evolution 2. Compute Recombination History 3. Compute Perturbations 4. Compute Powerspectrum

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Compute Background Evolution

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Here you can select the cosmologically parameters and numerically compute the background evolution in $\Lambda$CDM and make some plots (dark energy density set from the stuff below as $\Omega_\Lambda = 1 - \sum_i \Omega_i$ and to use a pure cosmological constant as dark energy use $w_0 = -1$ and $w_a = 0$). We also show a comparison of the luminosity distance to supernova data (taken from Betoule et al. 2014). If you don't include neutrinos just put $N_{\rm eff} = 0.0$. The results using the fiducial parameters below can also be found here.

Background parameters
Hubble parameter ($H_0\equiv 100 h{\rm km/s/ Mpc}$):
$h$:
Baryon density:
$\Omega_b$:
CDM density:
$\Omega_{\rm CDM}$:
Curvature density ($\Omega_k \equiv -k/H_0^2$):
$\Omega_k$:
Temperature of the CMB today ($\Omega_\gamma \propto T_{\rm CMB}^4 / h^2$):
$T_{\rm CMB}$ (K):
Effective number of neutrinos ($\Omega_\nu \equiv N_{\rm eff}\frac{7}{8}\left(\frac{4}{11}\right)^{4/3}\Omega_\gamma$):
$N_{\rm eff}$:
Dark energy equation of state (CPL parametrisation) $w = w_0 + w_a(1-a)$:
$w_0$:
$w_a$:
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Answer to comment: "The Total matter density does not include non-relativistic neutrino. This caused a discrepancy between total matter as per Planck 2018 and the calculator!" - This calulator has not implemented massive neutrinos (see list of assumptions here). It assumes all neutrinos are massless and consequently the neutrinos does not contribute to the total matter density.

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