Constants

colibri.constants.explanatory()[source]

This file contains a series of physical constants and conversion factors which are used in the other codes. Also useful quantities not strictly related to cosmology are defined.

Conversion factors, distance

  • km_to_cm: 1 km in cm

  • km_to_m: 1 km in m

  • pc_to_cm: 1 pc in cm

  • pc_to_m: 1 pc in m

  • pc_to_km: 1 pc in km

  • kpc_to_cm: 1 kpc in cm

  • kpc_to_m: 1 kpc in m

  • kpc_to_km: 1 kpc in km

  • Mpc_to_cm: 1 Mpc in cm

  • Mpc_to_m: 1 Mpc in m

  • Mpc_to_km: 1 Mpc in km

Conversion factors, time

  • yr_to_s: 1 yr in s

  • Myr_to_s: 1 Myr in s

Conversion factors, energy

  • eV: electron-Volt in \(\mathrm{J}\)

  • keV: kilo Electron-Volt in \(\mathrm{J}\)

  • MeV: mega Electron-Volt in \(\mathrm{J}\)

  • GeV: giga Electron-Volt in \(\mathrm{J}\)

  • TeV: tera Electron-Volt in \(\mathrm{J}\)

Proton & electron mass & charges

  • mp: proton mass in \(\mathrm{eV}\)

  • mp_g: proton mass in \(\mathrm{g}\)

  • mp_J: proton mass in \(\mathrm{J}\)

  • me: eletron mass in \(\mathrm{eV^2}\)

  • me_g: eletron mass in \(\mathrm{g}\)

  • me_J: eletron mass in \(\mathrm{J}\)

  • q: electron/proton charge in \(\mathrm{C}\)

Neutrino properties

  • Delta_m21_squared: difference of squared masses in \(\mathrm{eV^2}\)

  • Delta_m32_squared_IH: difference of squared masses in \(\mathrm{eV^2}\)

  • Delta_m32_squared_NH: difference of squared masses in \(\mathrm{eV^2}\)

  • sin_theta_21_squared: sine squared of mixing angle

  • sin_theta_23_squared_IH: sine squared of mixing angle, inverted hierarchy

  • sin_theta_23_squared_NH: sine squared of mixing angle, normal hierarchy

  • sin_theta_13_squared: sine squared of mixing angle

Constants of physics

  • G: Newton’s gravitational constant in units of \(\mathrm{Mpc} \ M_\odot (\mathrm{km/s})^2\)

  • eps_0: vacuum permittivity in \(\mathrm{F/m = C/V \ m}\)

  • mu_0: magnetic permeability in \(\mathrm{H/m = T \ m^2/A = V \ s/A}\)

  • kB: Boltzmann constant in \(\mathrm{eV/K}\)

  • c: speed of light in \(\mathrm{km/s}\)

  • hP: Planck constant in units of \(\mathrm{eV \ s}\)

  • sSB: Stefan-Boltzmann constant in \(\mathrm{W \ m^{-2} \ K^{-4}}\)

  • N_A: Avogadro constant in \(\mathrm{mol^{-1}}\)

Derived constants

  • e2: electron/proton charge (squared!) in CGS units

  • hPb: reduced Planck constant (\(\bar{h}\)) in \(\mathrm{eV \ s}\)

  • hPJ: Planck constant in \(\mathrm{J \ s}\)

  • hPJb: reduced Planck constant (\(\bar{h}\)) in \(\mathrm{J \ s}\)

  • sSB_eV: Stefan-Boltzmann constant in \(\mathrm{eV \ m^{-2} \ K^{-4}}\)

  • alpha_BB: constant for blackbody energy density in \(\mathrm{J \ m^{-3} \ K^{-4}}\)

  • R: perfect gas constant in \(\mathrm{J \ mol^{-1} \ K^{-1}}\)

  • alpha_EM: fine structure constant

  • lambda_e: Compton wavelength for electron in \(\mathrm{m}\)

  • r_e: electron classical radius in \(\mathrm{m}\)

  • sigma_T: Thomson scattering cross section in \(\mathrm{m}^2\)

  • rhoch2: critical density of the Universe \(h^2 \ M_\odot \ \mathrm{Mpc}^{-3}\)

Planck units

  • l_Pl: Planck length in \(\mathrm{m}\)

  • t_Pl: Planck time in \(\mathrm{s}\)

  • m_Pl: Planck mass in \(\mathrm{g}\)

  • T_Pl: Planck temperatur in \(\mathrm{K}\)

  • q_Pl: Planck charge in \(\mathrm{C}\)

Solar units

  • Msun: solar mass in \(\mathrm{g}\)

  • Rsun: solar radius in \(\mathrm{cm}\)

  • Tsun: solar surface temperature in \(\mathrm{K}\)

  • Lsun: solar luminosity in \(\mathrm{erg \ s^{-1}}\)