diff options
| -rw-r--r-- | fg21sim/utils/cosmology.py | 26 |
1 files changed, 16 insertions, 10 deletions
diff --git a/fg21sim/utils/cosmology.py b/fg21sim/utils/cosmology.py index 8da335a..9c2ed0d 100644 --- a/fg21sim/utils/cosmology.py +++ b/fg21sim/utils/cosmology.py @@ -1,15 +1,15 @@ -# Copyright (c) 2016-2017 Weitian LI <liweitianux@live.com> -# MIT license +# Copyright (c) 2016-2017,2019 Weitian LI <wt@liwt.net> +# MIT License """ -Flat ΛCDM cosmological model. +Cosmology calculator in a flat ΛCDM universe. References ---------- .. [unibonn-wiki] https://astro.uni-bonn.de/~pavel/WIKIPEDIA/Lambda-CDM_model.html -.. [wikipedia] +.. [wikipedia-lcdm] https://en.wikipedia.org/wiki/Lambda-CDM_model .. [randall2002] @@ -32,6 +32,12 @@ References .. [cassano2005] Cassano & Brunetti 2005, MNRAS, 357, 1313 http://adsabs.harvard.edu/abs/2005MNRAS.357.1313C + +.. [wikipedia-virial] + https://en.wikipedia.org/wiki/Virial_mass + +.. [bryan1998] + http://adsabs.harvard.edu/abs/1998ApJ...495...80B """ import logging @@ -307,8 +313,6 @@ class Cosmology: def darkmatter_fraction(self): """ The cosmological mean dark matter fraction (w.r.t. matter). - - XXX: assumed to be *constant* regardless of redshifts! """ return 1 - self.baryon_fraction @@ -317,11 +321,13 @@ class Cosmology: Calculate the virial overdensity, which generally used to determine the virial radius of a cluster. - References: Ref.[cassano2005],Eqs.(10,A4) + References + ---------- + * Ref.[bryan1998],Eqs.(5,6) + * Ref.[wikipedia-virial] """ - omega_z = (1 / self.Om(z)) - 1 - Delta_c = 18*np.pi**2 * (1 + 0.4093 * omega_z**0.9052) - return Delta_c + x = self.Om(z) - 1 + return 18*np.pi**2 + 82*x - 39 * x**2 def overdensity_crit(self, z): """ |