diff options
| -rw-r--r-- | astro_params.py | 25 |
1 files changed, 20 insertions, 5 deletions
diff --git a/astro_params.py b/astro_params.py index b3b733b..bf7a0da 100644 --- a/astro_params.py +++ b/astro_params.py @@ -6,6 +6,9 @@ # # Change logs: # 2016-06-24: +# * Add some constants from `astropy.constants` +# * Add parameter 'mu' +# * Fix reference # * Add class 'ChandraPixel', moved from 'deproject_sbp.py' # @@ -15,6 +18,7 @@ and astrophysics. """ import astropy.units as au +import astropy.constants as ac from astropy.cosmology import FlatLambdaCDM @@ -22,20 +26,31 @@ class AstroParams: """ The parameters/constants used in astronomy. + NOTE: + The 'cgs' unit system is used. + References: - [1] ref. [4], eq.(9) below + [1] Ettori et al, 2013, Space Science Review, 177, 119-154 """ + # Gravitational constant + G = ac.G.cgs.value # [ cm^3 g^-1 s^-2 ] + # Boltzmann constant + k_B = ac.k_B.cgs.value # [ erg K^-1 ] + # Atomic mass unit (i.e., a.m.u) + m_atom = ac.u.cgs.value # [ g ] # 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 of electron density (n_e) to proton density (n_p) + # (Ref: [1], eq.(9) below) ratio_ne_np = 1.211 - # molecular weight per electron (0.3 solar abundance; grsa table) [1] + # molecular weight per electron (0.3 solar abundance; grsa table) + # (Ref: [1], eq.(9) below) mu_e = 1.155 - # atomic mass unit - m_atom = au.u.to(au.g) # [ g ] + # mean molecular weight (unit: a.m.u) [1] (Ref: [1], eq.(6) below) + mu = 0.6 class ChandraPixel: |