deproject_sbp.py: split "AstroParams" to module "astro_params.py"

2 files changed, 41 insertions, 18 deletions

diff --git a/astro_params.py b/astro_params.py
new file mode 100644
index 0000000..a272ba4
--- /dev/null
+++ b/astro_params.py
@@ -0,0 +1,33 @@
+# -*- mode: python -*-
+#
+# Weitian LI
+# Created: 2016-06-24
+# Updated: 2016-06-24
+#
+
+"""
+This module contains the parameters/constants used in astronomy
+and astrophysics.
+"""
+
+import astropy.units as au
+
+
+class AstroParams:
+    """
+    The parameters/constants used in astronomy.
+
+    References:
+    [1] ref. [4], eq.(9) below
+    """
+    # Hubble constant at z=0
+    H0 = 71.0  # [ km/s/Mpc ]
+    # density of non-relativistic matter in units of the critical density
+    # at z=0
+    OmegaM0 = 0.27
+    # ratio of electron density (n_e) to proton density (n_p) [1]
+    ratio_ne_np = 1.211
+    # molecular weight per electron (0.3 solar abundance; grsa table) [1]
+    mu_e = 1.155
+    # atomic mass unit
+    m_atom = au.u.to(au.g)  # [ g ]
diff --git a/deproject_sbp.py b/deproject_sbp.py
index 9d87ac2..2f9c3f4 100755
--- a/deproject_sbp.py
+++ b/deproject_sbp.py
@@ -2,9 +2,11 @@
 #
 # Weitian LI
 # Created: 2016-06-10
-# Updated: 2016-06-23
+# Updated: 2016-06-24
 #
 # Change logs:
+# 2016-06-24:
+#   * Split class 'AstroParams' to separate module 'astro_params.py'
 # 2016-06-23:
 #   * Add configuration parameter 'sbpexp_rcut'
 #   * Allow extrapolate the cooling function profile
@@ -155,22 +157,9 @@ from matplotlib.backends.backend_agg import FigureCanvasAgg as FigureCanvas
 from matplotlib.figure import Figure
 from configobj import ConfigObj
 
-plt.style.use("ggplot")
-
-
-class AstroParams:
-    """
-    The parameters/constants used in astronomy.
+from astro_params import AstroParams
 
-    References:
-    [1] ref. [4], eq.(9) below
-    """
-    # ratio of electron density (n_e) to proton density (n_p) [1]
-    ratio_ne_np = 1.211
-    # molecular weight per electron (0.3 solar abundance; grsa table) [1]
-    mu_e = 1.155
-    # atomic mass unit
-    m_atom = au.u.to(au.g)  # [ g ]
+plt.style.use("ggplot")
 
 
 class Projection:
@@ -966,9 +955,10 @@ class ChandraPixel:
     # length of one pixel at the given redshift
     length = None
 
-    def __init__(self, z=None, H0=71, OmegaM0=0.27):
+    def __init__(self, z=None):
         self.z = z
-        self.cosmo = FlatLambdaCDM(H0=H0, Om0=OmegaM0)
+        self.cosmo = FlatLambdaCDM(H0=AstroParams.H0,
+                                   Om0=AstroParams.OmegaM0)
         if z is not None:
             self.D_A = self.cosmo.angular_diameter_distance(z)
             self.length = self.D_A * self.angle.to(au.radian).value