params_cosmology.rst

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Cosmology Parameters

The default cosmological parameters in ARES are from Planck. Specifically, we take values from the last column of Table 4 in Planck XIII.

Note

Several input files (e.g., lookup tables for the halo mass function, initial conditions, etc.) depend on these vales. There currently is not a system in place to make sure there is a match between the parameters you pass at run-time and the lookup tables read-in from disk. Beware!

omega_m_0

Matter density, relative to the critical density.

Default: \Omega_{m,0} = 0.3089

omega_b_0

Baryon density, relative to the critical density.

Default: \Omega_{b,0} = 0.0486

omega_l_0

Dark energy density, relative to the critical density.

Default \Omega_{\Lambda,0} = 0.6911

hubble_0

Hubble parameter today.

Default: 0.6774 [100 \ \text{km} \ \text{s}^{-1} \ \text{Mpc}^{-1}]

helium_by_mass

Fractional helium abundance by mass.

Default: 0.2453

cmb_temp_0

Temperature of the cosmic microwave blackbody, today.

Default: 2.7255 [\text{K}]

sigma_8

Default: 0.8159

primordial_index

Default: 0.9667