Merge pull request #3477 from aconley/planck2015

Add Planck 2015 cosmology
astropy · Feb 24, 2015 · 8f149fe · 8f149fe
2 parents 688e70d + 33e3e51
commit 8f149fe
Show file tree

Hide file tree

Showing 4 changed files with 58 additions and 20 deletions.
diff --git a/CHANGES.rst b/CHANGES.rst
@@ -18,6 +18,8 @@ New Features
 
 - ``astropy.cosmology``
 
+  - Add Planck 2015 cosmology [#3476]
+
 - ``astropy.io.ascii``
 
   - Automatically use ``guess=False`` when reading if the file ``format`` is

diff --git a/astropy/cosmology/core.py b/astropy/cosmology/core.py
@@ -26,7 +26,7 @@
 
 __all__ = ["FLRW", "LambdaCDM", "FlatLambdaCDM", "wCDM", "FlatwCDM",
            "Flatw0waCDM", "w0waCDM", "wpwaCDM", "w0wzCDM", "WMAP5", "WMAP7",
-           "WMAP9", "Planck13", "default_cosmology"]
+           "WMAP9", "Planck13", "Planck15", "default_cosmology"]
 
 __doctest_requires__ = {'*': ['scipy.integrate']}
 
@@ -76,7 +76,8 @@ class FLRW(Cosmology):
 
     Om0 : float
         Omega matter: density of non-relativistic matter in units of the
-        critical density at z=0.
+        critical density at z=0.  Note that this does not include
+        massive neutrinos.
 
     Ode0 : float
         Omega dark energy: density of dark energy in units of the critical
@@ -448,7 +449,7 @@ def w(self, z):
           The dark energy equation of state
 
         Notes
-        ------
+        -----
         The dark energy equation of state is defined as
         :math:`w(z) = P(z)/\\rho(z)`, where :math:`P(z)` is the
         pressure at redshift z and :math:`\\rho(z)` is the density
@@ -472,6 +473,11 @@ def Om(self, z):
         Om : ndarray, or float if input scalar
           The density of non-relativistic matter relative to the critical
           density at each redshift.
+
+        Notes
+        -----
+        This does not include neutrinos, even if non-relativistic
+        at the redshift of interest; see `Onu`.
         """
 
         if isiterable(z):
@@ -522,6 +528,10 @@ def Odm(self, z):
         ------
         ValueError
           If Ob0 is None.
+        Notes
+        -----
+        This does not include neutrinos, even if non-relativistic
+        at the redshift of interest.
         """
 
         if self._Odm0 is None:
@@ -603,7 +613,8 @@ def Ogamma(self, z):
         return self._Ogamma0 * (1. + z) ** 4 * self.inv_efunc(z) ** 2
 
     def Onu(self, z):
-        """ Return the density parameter for massless neutrinos at redshift ``z``.
+        """ Return the density parameter for massless neutrinos at
+        redshift ``z``.
 
         Parameters
         ----------

diff --git a/astropy/cosmology/parameters.py b/astropy/cosmology/parameters.py
@@ -24,6 +24,9 @@
 The list of cosmologies available are given by the tuple
 `available`. Current cosmologies available:
 
+Planck 15 parameters from Planck Collaboration 2015, arXiv: 1502.01589
+ (Paper XIII), Table 4 (TT, TE, EE + lowP + lensing + ext)
+
 Planck13 parameters from Planck Collaboration 2013, arXiv:1303.5076
  (Paper XVI), Table 5 (Planck + WP + highL + BAO)
 
@@ -48,9 +51,29 @@
 
 # Note: if you add a new cosmology, please also update the table
 # in the 'Built-in Cosmologies' section of astropy/docs/cosmology/index.rst
-# in addition to the list above.
+# in addition to the list above.  You also need to add them to
+# __all__ in core.py
+
+# Planck 2015 paper XII Table 4 final column (best fit)
+Planck15 = dict(
+    Oc0=0.2589,
+    Ob0=0.04860,
+    Om0=0.3075,
+    H0=67.74,
+    n=0.9667,
+    sigma8=0.8159,
+    tau=0.066,
+    z_reion=8.8,
+    t0=13.799,
+    Tcmb0=2.7255,
+    Neff=3.046,
+    flat=True,
+    m_nu=[0., 0., 0.06],
+    reference=("Planck Collaboration 2015, Paper XII, arXiv:1502.01589"
+               " Table 4 (TT, TE, EE + lowP + lensing + ext)")
+)
 
-# Ade et al. Planck 2013 paper XVI Table 5 penultimate column (best fit)
+# Planck 2013 paper XVI Table 5 penultimate column (best fit)
 Planck13 = dict(
     Oc0=0.25886,
     Ob0=0.048252,

diff --git a/docs/cosmology/index.rst b/docs/cosmology/index.rst
@@ -241,14 +241,15 @@ the WMAP and Planck satellite data. For example,
 A full list of the pre-defined cosmologies is given by
 ``cosmology.parameters.available``, and summarized below:
 
-========  ============================= ====  ===== =======
-Name      Source                        H0    Om    Flat
-========  ============================= ====  ===== =======
-WMAP5     Komatsu et al. 2009           70.2  0.277 Yes
-WMAP7     Komatsu et al. 2011           70.4  0.272 Yes
-WMAP9     Hinshaw et al. 2013           69.3  0.287 Yes
-Planck13  Planck Collab 2013, Paper XVI 67.8  0.307 Yes
-========  ============================= ====  ===== =======
+========  ============================== ====  ===== =======
+Name      Source                         H0    Om    Flat
+========  ============================== ====  ===== =======
+WMAP5     Komatsu et al. 2009            70.2  0.277 Yes
+WMAP7     Komatsu et al. 2011            70.4  0.272 Yes
+WMAP9     Hinshaw et al. 2013            69.3  0.287 Yes
+Planck13  Planck Collab 2013, Paper XVI  67.8  0.307 Yes
+Planck15  Planck Collab 2015, Paper XIII 67.7  0.307 Yes
+========  ============================== ====  ===== =======
 
 Currently, all are instances of `~astropy.cosmology.FlatLambdaCDM`.
 More details about exactly where each set of parameters come from
@@ -308,8 +309,9 @@ This is not the simple
 :math:`\Omega_{\nu 0} h^2 = \sum_i m_{\nu\, i} / 93.04\,\mathrm{eV}`
 approximation.  Also note that the values of :math:`\Omega_{\nu}(z)`
 include both the kinetic energy and the rest-mass energy components,
-and that the Planck13 cosmology includes a single species of neutrinos
-with non-zero mass (which is not included in :math:`\Omega_{m0}`).
+and that the Planck13 and Planck15 cosmologies includes a single
+species of neutrinos with non-zero mass (which is not included in
+:math:`\Omega_{m0}`).
 
 The contribution of photons and neutrinos to the total mass-energy density
 can be found as a function of redshift::
@@ -437,10 +439,10 @@ please let us know by `opening an issue at the github repository
 The built in cosmologies use the parameters as listed in the
 respective papers.  These provide only a limited range of precision,
 and so you should not expect derived quantities to match beyond
-that precision.  For example, the Planck 2013 results only provide the
-Hubble constant to 4 digits.  Therefore, the Planck13 built-in
-cosmology should only be expected to match the age of the Universe
-quoted by the Planck team to 4 digits, although they provide 5 in the paper.
+that precision.  For example, the Planck 2013 and 2015 results only provide the
+Hubble constant to 4 digits.  Therefore, they shouldn't be expected
+to match the age quoted by the Planck team to better than that, despite
+the fact that 5 digits are quoted in the papers.
 
 Reference/API
 =============