diff options
Diffstat (limited to 'fg21sim')
| -rw-r--r-- | fg21sim/galactic/freefree.py | 38 |
1 files changed, 24 insertions, 14 deletions
diff --git a/fg21sim/galactic/freefree.py b/fg21sim/galactic/freefree.py index 75dfbb7..2ea193c 100644 --- a/fg21sim/galactic/freefree.py +++ b/fg21sim/galactic/freefree.py @@ -168,6 +168,29 @@ class FreeFree: a = term1 * term2 return a + def _calc_halpha_to_freefree(self, nu): + """ + Calculate the conversion factor between Hα emission [Rayleigh] + to radio free-free emission [K] at frequency ν [MHz]. + + Parameters + ---------- + nu : float + The frequency where to calculate the conversion factor. + Unit: [MHz] + + Returns + ------- + h2f : float + The conversion factor between Hα emission and free-free emission. + + References: [dickinson2003],Eq.(11) + NOTE: The above referred formula has a superfluous "10^3" term! + """ + a = self._calc_factor_a(nu) + h2f = 38.86 * a * nu**(-2.1) * 10**(290/self.Te) * self.Te**0.667 + return h2f + def _make_filepath(self, **kwargs): """ Make the path of output file according to the filename pattern @@ -252,10 +275,6 @@ class FreeFree: """ Simulate the free-free map at the specified frequency. - References: [Dickinson2003], Eq.(11) - - NOTE: [Dickinson2003], Eq.(11) may wrongly have the "10^3" term. - Returns ------- skymap_f : 1D `~numpy.ndarray` @@ -268,16 +287,7 @@ class FreeFree: # logger.info("Simulating {name} map at {freq} ({unit}) ...".format( name=self.name, freq=frequency, unit=self.freq_unit)) - # Assumed electron temperature [ K ] - T4 = self.Te / 1e4 - nu = frequency * self.freq_unit.to(au.GHz) # frequency [ GHz ] - factor_a = self._calc_factor_a(frequency) - # NOTE: - # The referred formula has a superfluous "10^3" term. - ratio_mK_R = (8.396 * factor_a * nu**(-2.1) * - T4**0.667 * 10**(0.029/T4) * (1+0.08)) - # Use "Kelvin" as the brightness temperature unit - ratio_K_R = ratio_mK_R * au.mK.to(au.K) + ratio_K_R = self._calc_halpha_to_freefree(frequency) skymap_f = self.halphamap.data * ratio_K_R # if self.save: |