diff options
Diffstat (limited to 'fg21sim')
| -rw-r--r-- | fg21sim/utils/cosmology.py | 102 |
1 files changed, 66 insertions, 36 deletions
diff --git a/fg21sim/utils/cosmology.py b/fg21sim/utils/cosmology.py index e4ac4d7..5d5e42f 100644 --- a/fg21sim/utils/cosmology.py +++ b/fg21sim/utils/cosmology.py @@ -3,6 +3,35 @@ """ Flat ΛCDM cosmological model. + +References +---------- +.. [unibonn-wiki] + https://astro.uni-bonn.de/~pavel/WIKIPEDIA/Lambda-CDM_model.html + +.. [wikipedia] + https://en.wikipedia.org/wiki/Lambda-CDM_model + +.. [randall2002] + Randall, Sarazin & Ricker 2002, ApJ, 577, 579 + http://adsabs.harvard.edu/abs/2002ApJ...577..579R + Sec.(2) + +.. [hogg1999] + Hogg 1999, arXiv:astro-ph/9905116 + http://adsabs.harvard.edu/abs/1999astro.ph..5116H + +.. [thomas2000] + Thomas & Kantowski 2000, Physical Review D, 62, 103507 + http://adsabs.harvard.edu/abs/2000PhRvD..62j3507T + +.. [ellis2007] + Ellis 2007, General Relativity and Gravitation, 39, 1047 + http://adsabs.harvard.edu/abs/2007GReGr..39.1047E + +.. [cassano2005] + Cassano & Brunetti 2005, MNRAS, 357, 1313 + http://adsabs.harvard.edu/abs/2005MNRAS.357.1313C """ import logging @@ -34,7 +63,7 @@ class Cosmology: Ode0 : float Density parameter of dark energy at present day sigma8 : float - Present-day rms density fluctuation on a scale of 8 h^-1 Mpc. + Present-day rms density fluctuation on a scale of 8 h^-1 [Mpc]. Internal attributes ------------------- @@ -42,14 +71,6 @@ class Cosmology: Astropy cosmology instance to help calculations. _growth_factor0 : float Present day (z=0) growth factor - - References - ---------- - [1] https://astro.uni-bonn.de/~pavel/WIKIPEDIA/Lambda-CDM_model.html - [2] https://en.wikipedia.org/wiki/Lambda-CDM_model - [3] Randall, Sarazin & Ricker 2002, ApJ, 577, 579 - http://adsabs.harvard.edu/abs/2002ApJ...577..579R - Sec.(2) """ # Present day (z=0) growth factor _growth_factor0 = None @@ -86,7 +107,7 @@ class Cosmology: @property def M8(self): """ - Mass contained in a sphere of radius of 8 h^-1 Mpc. + Mass contained in a sphere of radius of 8 h^-1 [Mpc]. Unit: [Msun] """ r = 8 * AUC.Mpc2cm / self.h # [cm] @@ -106,19 +127,44 @@ class Cosmology: """ return self.H0 * self.E(z) - def DL(self, z): + def DA(self, z): """ - Luminosity distance at redshift z. + Angular diameter distance at redshift z. Unit: [Mpc] + + Defined as the ratio of an object's physical transverse size + to its (observed) angular size (in radians). It is used to + convert the observed angular separations between sources into + their proper separations. + + NOTE + ---- + This distance is NOT increasing indefinitely as z -> ∞. + + Reference: Ref.[hogg1999] """ - return self._cosmo.luminosity_distance(z).value + return self._cosmo.angular_diameter_distance(z).value - def DA(self, z): + def DL(self, z): """ - Angular diameter distance at redshift z. + Luminosity distance at redshift z. Unit: [Mpc] + + Defined by the relationship between the measured bolometric + (i.e., integrated over all frequencies) flux S_bolo and the + object's intrinsic bolometric luminosity L_bolo. + + NOTE + ---- + DL = DA * (1+z)^2 + This is the general reciprocity theorem in General Relativity. + + Reference + --------- + * Ref.[hogg1999],Eq.(20,21) + * Ref.[ellis2007] """ - return self._cosmo.angular_diameter_distance(z).value + return self._cosmo.luminosity_distance(z).value @property def hubble_time(self): @@ -145,11 +191,7 @@ class Cosmology: Age of the universe (cosmic time) at the given redshift. Unit: [Gyr] - References - ---------- - [1] Thomas & Kantowski 2000, Physical Review D, 62, 103507 - http://adsabs.harvard.edu/abs/2000PhRvD..62j3507T - Eq.(18) + References: Ref.[thomas2000],Eq.(18) """ t_H = self.hubble_time t = (t_H * (2/3/np.sqrt(1-self.Om0)) * @@ -213,11 +255,7 @@ class Cosmology: Calculate the virial overdensity, which generally used to determine the virial radius of a cluster. - References - ---------- - [1] Cassano & Brunetti 2005, MNRAS, 357, 1313 - http://adsabs.harvard.edu/abs/2005MNRAS.357.1313C - Eqs.(10,A4) + References: Ref.[cassano2005],Eqs.(10,A4) """ omega_z = (1 / self.Om(z)) - 1 Delta_c = 18*np.pi**2 * (1 + 0.4093 * omega_z**0.9052) @@ -228,11 +266,7 @@ class Cosmology: Critical (linear) overdensity for a region to collapse at a redshift z. - References - ---------- - [1] Randall, Sarazin & Ricker 2002, ApJ, 577, 579 - http://adsabs.harvard.edu/abs/2002ApJ...577..579R - Appendix.A, Eq.(A1) + References: Ref.[randall2002],Eq.(A1) """ coef = 3 * (12*np.pi) ** (2/3) / 20 D0 = self.growth_factor0 @@ -245,11 +279,7 @@ class Cosmology: """ Growth factor at redshift z. - References - ---------- - [1] Randall, Sarazin & Ricker 2002, ApJ, 577, 579 - http://adsabs.harvard.edu/abs/2002ApJ...577..579R - Appendix.A, Eq.(A7) + References: Ref.[randall2002],Eq.(A7) """ x0 = (2 * self.Ode0 / self.Om0) ** (1/3) x = x0 / (1 + z) |