From f511d2b0403ad6a21de87fe0f36460fb2f906e12 Mon Sep 17 00:00:00 2001 From: Aaron LI Date: Tue, 25 Oct 2016 13:13:49 +0800 Subject: extragalactic/clusters.py: Speed up "calc_Tb()" significantly Avoid using "astropy.units" in "calc_Tb()", which significantly speeds up this method. NOTE: whether the distance given by the simulation needs additional conversion to derive the *luminosity distance* ?? --- fg21sim/extragalactic/clusters.py | 26 ++++++++++++++++---------- 1 file changed, 16 insertions(+), 10 deletions(-) (limited to 'fg21sim') diff --git a/fg21sim/extragalactic/clusters.py b/fg21sim/extragalactic/clusters.py index 7da778e..540ec52 100644 --- a/fg21sim/extragalactic/clusters.py +++ b/fg21sim/extragalactic/clusters.py @@ -417,12 +417,10 @@ class GalaxyClusters: Parameters ---------- luminosity : float - The luminosity density (unit: `self.units["luminosity"]`) at - the reference frequency (i.e., - `self.catalog_prop["luminosity_freq"]`). + The luminosity density (unit: [ W/Hz ]) at the reference + frequency (i.e., `self.catalog_prop["luminosity_freq"]`). distance : float - The luminosity distance (unit: `self.units["distance"]`) to the - object + The luminosity distance (unit: [ Mpc ]) to the object specindex : float The spectral index of the power-law spectrum. Note the *negative* sign in the formula. @@ -445,15 +443,23 @@ class GalaxyClusters: Therefore, the flux density at the requested frequency should first be calculated by extrapolating the spectrum, then convert the flux density to derive the brightness temperature. + + XXX/NOTE + -------- + The *luminosity distance* is required to calculate the flux density + from the luminosity density. + Whether the distance (i.e., ``self.catalog["distance"]``) is the + *comoving distance* ?? + Whether a conversion is required to get the *luminosity distance* ?? """ freq = frequency # [ MHz ] freq_ref = self.catalog_prop["luminosity_freq"].value - luminosity = luminosity * self.units["luminosity"] - Lnu = luminosity * (freq / freq_ref) ** (-specindex) - Fnu = Lnu / (4*np.pi * (distance*self.units["distance"])**2) - Fnu_Jy = Fnu.to(au.Jy).value # [ Jy ] + Lnu = luminosity * (freq / freq_ref) ** (-specindex) # [ W/Hz ] + # Conversion coefficient: [ W/Hz/Mpc^2 ] => [ Jy ] + coef = 1.0502650403056097e-19 + Fnu = coef * Lnu / (4*np.pi * distance**2) # [ Jy ] omega = size[0] * size[1] # [ deg^2 ] - Tb = Fnu_to_Tb_fast(Fnu_Jy, omega, freq) + Tb = Fnu_to_Tb_fast(Fnu, omega, freq) return Tb def _simulate_templates(self): -- cgit v1.2.2