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authorAaron LI <aaronly.me@outlook.com>2017-01-07 22:44:23 +0800
committerAaron LI <aly@aaronly.me>2017-06-01 16:33:38 +0800
commit659ef86e04124f1aa7fd4dc30f1612bf608d66a1 (patch)
tree43fefb3b6dfe329d2b2d3a85eecd49a1696ecfef /fg21sim/extragalactic
parent9d1fbf8d875d4ed754cbf6894109e3379c98b0bb (diff)
downloadfg21sim-659ef86e04124f1aa7fd4dc30f1612bf608d66a1.tar.bz2
cosmology.py: Only support flat ΛCDM cosmological model
Diffstat (limited to 'fg21sim/extragalactic')
-rw-r--r--fg21sim/extragalactic/clusters/cosmology.py118
1 files changed, 25 insertions, 93 deletions
diff --git a/fg21sim/extragalactic/clusters/cosmology.py b/fg21sim/extragalactic/clusters/cosmology.py
index bedb17e..5f7b283 100644
--- a/fg21sim/extragalactic/clusters/cosmology.py
+++ b/fg21sim/extragalactic/clusters/cosmology.py
@@ -2,7 +2,7 @@
# MIT license
"""
-Cosmological models
+Flat ΛCDM cosmological model.
"""
import logging
@@ -18,30 +18,30 @@ logger = logging.getLogger(__name__)
class Cosmology:
"""
- Cosmological model.
+ Flat ΛCDM cosmological model.
Attributes
----------
H0 : float
Hubble parameter at present day (z=0)
Om0 : float
- Density parameter of matter at present day
+ Density parameter of (dark and baryon) matter at present day
+ Ob0 : float
+ Density parameter of baryon at present day
Ode0 : float
Density parameter of dark energy at present day
- model : str
- Type of the current cosmological model:
- * open : Om0 < 1, Ode0 = 0
- * closed : Om0 > 1, Ode0 = 0
- * EdS (Einstein-de Sitter) : Om0 = 1, Ode0 = 0
- * flatLambdaCDM : Om0 + Ode0 = 1, Ode0 > 0
+ sigma8 : float
+ Present-day rms density fluctuation on a scale of 8 h^-1 Mpc.
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)
"""
-
- def __init__(self, H0=71.0, Om0=0.27, Ob0=0.046, Ode0=None, sigma8=None):
+ def __init__(self, H0=71.0, Om0=0.27, Ob0=0.046, Ode0=None, sigma8=0.834):
Ode0 = 1.0 - Om0 if Ode0 is None else Ode0
if (Ode0 > 0) and abs(Om0 + Ode0 - 1) > 1e-5:
raise ValueError("non-flat LambdaCDM model not supported!")
@@ -49,22 +49,8 @@ class Cosmology:
self.Om0 = Om0
self.Ob0 = Ob0
self.Ode0 = Ode0
- self._sigma8 = sigma8
+ self.sigma8 = sigma8
self.cosmo = LambdaCDM(H0=H0, Om0=Om0, Ob0=Ob0, Ode0=Ode0)
- logger.info("Cosmological model: {0}".format(self.model))
-
- @property
- def model(self):
- if self.Ode0 < 1e-5:
- if self.Om0 < 1:
- model = "open"
- elif self.Om0 == 1:
- model = "EdS"
- else:
- model = "closed"
- else:
- model = "flatLambdaCDM"
- return model
@property
def h(self):
@@ -74,32 +60,6 @@ class Cosmology:
return self.H0 / 100.0
@property
- def sigma8(self):
- """
- Present-day rms density fluctuation on a scale of 8 h^-1 Mpc.
-
- References
- ----------
- [1] Randall, Sarazin & Ricker 2002, ApJ, 577, 579
- http://adsabs.harvard.edu/abs/2002ApJ...577..579R
- Sec.2
- """
- if hasattr(self, "_sigma8"):
- return self._sigma8
- #
- if self.model == "open":
- sigma8 = 0.827
- elif self.model == "closed":
- raise NotImplementedError
- elif self.model == "EdS":
- sigma8 = 0.514
- elif self.model == "flatLambdaCDM":
- sigma8 = 0.834
- else:
- raise ValueError("unknown model: {0}".format(self.model))
- return sigma8
-
- @property
def M8(self):
"""
Mass contained in a sphere of radius of 8 h^-1 Mpc.
@@ -176,17 +136,8 @@ class Cosmology:
http://adsabs.harvard.edu/abs/2005MNRAS.357.1313C
Eqs.(10,A4)
"""
- if self.model == "open":
- raise NotImplementedError
- elif self.model == "closed":
- raise NotImplementedError
- elif self.model == "EdS":
- Delta_c = 18 * np.pi**2
- elif self.model == "flatLambdaCDM":
- omega_z = (1 / self.OmegaM(z)) - 1
- Delta_c = 18*np.pi**2 * (1 + 0.4093 * omega_z**0.9052)
- else:
- raise ValueError("unknown model: {0}".format(self.model))
+ omega_z = (1 / self.OmegaM(z)) - 1
+ Delta_c = 18*np.pi**2 * (1 + 0.4093 * omega_z**0.9052)
return Delta_c
def overdensity_crit(self, z):
@@ -200,21 +151,11 @@ class Cosmology:
http://adsabs.harvard.edu/abs/2002ApJ...577..579R
Appendix.A, Eq.(A1)
"""
- if self.model == "open":
- raise NotImplementedError
- elif self.model == "closed":
- raise NotImplementedError
- elif self.model == "EdS":
- coef = 3 * (12*np.pi) ** (2/3) / 20
- delta_c = coef * (self.age(0) / self.age(z)) ** (2/3)
- elif self.model == "flatLambdaCDM":
- coef = 3 * (12*np.pi) ** (2/3) / 20
- D0 = self.growth_factor(0)
- D_z = self.growth_factor(z)
- Om_z = self.OmegaM(z)
- delta_c = coef * (D0 / D_z) * (1 + 0.0123*np.log10(Om_z))
- else:
- raise ValueError("unknown model: {0}".format(self.model))
+ coef = 3 * (12*np.pi) ** (2/3) / 20
+ D0 = self.growth_factor(0)
+ D_z = self.growth_factor(z)
+ Om_z = self.OmegaM(z)
+ delta_c = coef * (D0 / D_z) * (1 + 0.0123*np.log10(Om_z))
return delta_c
def growth_factor(self, z):
@@ -227,19 +168,10 @@ class Cosmology:
http://adsabs.harvard.edu/abs/2002ApJ...577..579R
Appendix.A, Eq.(A7)
"""
- if self.model == "open":
- raise NotImplementedError
- elif self.model == "closed":
- raise NotImplementedError
- elif self.model == "EdS":
- raise NotImplementedError
- elif self.model == "flatLambdaCDM":
- x0 = (2 * self.Ode0 / self.Om0) ** (1/3)
- x = x0 / (1 + z)
- coef = np.sqrt(x**3 + 2) / (x**1.5)
- integral = integrate.quad(lambda y: y**1.5 * (y**3+2)**(-1.5),
- 0, x)[0]
- D = coef * integral
- else:
- raise ValueError("unknown model: {0}".format(self.model))
+ x0 = (2 * self.Ode0 / self.Om0) ** (1/3)
+ x = x0 / (1 + z)
+ coef = np.sqrt(x**3 + 2) / (x**1.5)
+ integral = integrate.quad(lambda y: y**1.5 * (y**3+2)**(-1.5),
+ a=0, b=x)[0]
+ D = coef * integral
return D