dsf.utils.converters module

Useful unit and cosmology conversions.

dsf.utils.converters.arcmin2_per_steradian()[source]

Return the number of square arcminutes in one steradian.

Returns:

Number of square arcminutes in one steradian.

Return type:

float

dsf.utils.converters.comoving_delta_sigma_to_proper(func)[source]

Convert a comoving Delta Sigma function to a proper Delta Sigma function.

The wrapped function should accept comoving projected radius r and scale factor a. The returned wrapper accepts proper projected radius r and returns proper \(\Delta\Sigma\).

Parameters:

func (Callable[[...], ndarray[tuple[Any, ...], dtype[float64]]]) – Function computing comoving \(\Delta\Sigma\).

Returns:

Function computing proper \(\Delta\Sigma\).

Return type:

Callable[[…], ndarray[tuple[Any, …], dtype[float64]]]

dsf.utils.converters.comoving_distance_h(cosmo, z, *, h)[source]

Return the comoving radial distance in Mpc/h.

Parameters:

  • cosmo (Cosmology) – Cosmology used to evaluate the distance.

  • z (ndarray[tuple[Any, ...], dtype[float64]]) – Redshift value or array of redshift values.

  • h (float) – Dimensionless Hubble parameter.

Returns:

Comoving radial distance in Mpc/h.

Return type:

float | ndarray[tuple[Any, …], dtype[float64]]

dsf.utils.converters.deg2_to_arcmin2(area_deg2)[source]

Convert square degrees to square arcminutes.

Parameters:

area_deg2 (float) – Area in square degrees.

Returns:

Area in square arcminutes.

Return type:

float

dsf.utils.converters.hubble_constant_per_s_per_mpc(h)[source]

Return the Hubble constant as an Astropy quantity.

Parameters:

h (float) – Reduced Hubble parameter.

Returns:

Hubble constant in km/s/Mpc.

Return type:

Quantity

dsf.utils.converters.hubble_over_c_cubed(h)[source]

Return \((H_0 / c)^3\) in inverse cubic Mpc.

Parameters:

h (float) – Reduced Hubble parameter.

Returns:

Value of \((H_0 / c)^3\) in \(Mpc^{-3}\).

Return type:

float

dsf.utils.converters.power_spectrum_to_correlation(power_spectrum, a, k=None)[source]

Convert a power spectrum to a correlation function using FFTLog.

Parameters:

  • power_spectrum (Callable[[...], ndarray[tuple[Any, ...], dtype[float64]]]) – Power spectrum function with arguments k and a.

  • a (float) – Scale factor.

  • k (ndarray[tuple[Any, ...], dtype[float64]] | None) – Wavenumber array. If not provided, a default logarithmic grid is used.

Returns:

Function returning \(\xi(r)\) evaluated at the requested radii.

Return type:

Callable[[ndarray[tuple[Any, …], dtype[float64]]], ndarray[tuple[Any, …], dtype[float64]]]

dsf.utils.converters.redshift_to_scale_factor(z)[source]

Convert redshift to scale factor.

Parameters:

z (float | ndarray[tuple[Any, ...], dtype[float64]]) – Redshift or array of redshifts.

Returns:

Scale factor or array of scale factors.

Return type:

float | ndarray[tuple[Any, …], dtype[float64]]

dsf.utils.converters.resolve_h(cosmo, h)[source]

Return the supplied Hubble parameter or read it from the CCL cosmology.

Parameters:

  • cosmo (Cosmology) – CCL cosmology object.

  • h (float | None) – Dimensionless Hubble parameter.

Returns:

Hubble parameter or read it from the CCL cosmology.

Return type:

float

dsf.utils.converters.resolve_omega_m(cosmo, omega_m)[source]

Return supplied Omega_m or read it from the CCL cosmology.

Parameters:

  • cosmo (Cosmology)

  • omega_m (float | None)

Return type:

float

dsf.utils.converters.rho_critical_comoving_msun_mpc3(cosmo, *, h=None)[source]

Return critical density in comoving Msun / Mpc^3.

Parameters:

  • cosmo (Cosmology) – CCL cosmology object.

  • h (float | None) – Optional dimensionless Hubble parameter. If omitted, it is read from cosmo.

Returns:

Critical density in Msun / Mpc^3.

Return type:

float

dsf.utils.converters.rho_critical_projected_msun_pc2_per_mpc(cosmo, *, h=None)[source]

Return critical density in projected DeltaSigma units.

Parameters:

  • cosmo (Cosmology) – CCL cosmology object.

  • h (float | None) – Optional dimensionless Hubble parameter. If omitted, it is read from cosmo.

Returns:

Critical density in Msun / pc^2 / Mpc.

Return type:

float

dsf.utils.converters.scale_factor_to_redshift(a)[source]

Convert scale factor to redshift.

Parameters:

a (float | ndarray[tuple[Any, ...], dtype[float64]]) – Scale factor or array of scale factors.

Returns:

Redshift or array of redshifts.

Return type:

float | ndarray[tuple[Any, …], dtype[float64]]

dsf.utils.converters.sigma_crit_prefactor_msun_h_pc2()[source]

Return the Sigma_crit prefactor for comoving distances in Mpc / h.

This is the inverse of the prefactor used to compute comoving Sigma_crit^{-1} in units of pc^2 / (Msol h). It is intended for calculations where distances are supplied in Mpc / h and DeltaSigma-like quantities are expressed in Msol h / pc^2.

Return type:

float

dsf.utils.converters.speed_of_light_mpc_per_s()[source]

Return the speed of light in Mpc/s.

Returns:

Speed of light in Mpc/s.

Return type:

float