diff options
Diffstat (limited to 'fg21sim')
| -rw-r--r-- | fg21sim/configs/10-galactic.conf.spec | 5 | ||||
| -rw-r--r-- | fg21sim/galactic/freefree.py | 33 |
2 files changed, 28 insertions, 10 deletions
diff --git a/fg21sim/configs/10-galactic.conf.spec b/fg21sim/configs/10-galactic.conf.spec index 1ef15eb..b082a5d 100644 --- a/fg21sim/configs/10-galactic.conf.spec +++ b/fg21sim/configs/10-galactic.conf.spec @@ -62,6 +62,11 @@ # The unit of the above dust map (e.g., "MJy/sr") dustmap_unit = string(default=None) + # The electron temperature assumed for the ionized interstellar medium + # that generating H{\alpha} emission. + # Unit: [K] + electron_temperature = float(default=7000.0, min=1000) + # Filename prefix for this component prefix = string(default="gfree") # Whether save this component to disk diff --git a/fg21sim/galactic/freefree.py b/fg21sim/galactic/freefree.py index 41e84e6..a4d8ad6 100644 --- a/fg21sim/galactic/freefree.py +++ b/fg21sim/galactic/freefree.py @@ -75,6 +75,7 @@ class FreeFree: self.dustmap_path = self.configs.get_path(comp+"/dustmap") self.dustmap_unit = au.Unit( self.configs.getn(comp+"/dustmap_unit")) + self.Te = self.configs.getn(comp+"/electron_temperature") # [K] self.prefix = self.configs.getn(comp+"/prefix") self.save = self.configs.getn(comp+"/save") self.output_dir = self.configs.get_path(comp+"/output_dir") @@ -143,15 +144,27 @@ class FreeFree: self._dust_corrected = True logger.info("Done dust absorption correction") - def _calc_ratio_a(self, Te, nu_GHz): - """Calculate the ratio factor a(T, nu), which will be used to - transform the Halpha emission (Rayleigh) to free-free emission - brightness temperature (mK). + def _calc_factor_a(self, nu): + """ + Calculate the ratio factor a(Te, ν), which will be used to + convert the Halpha emission [Rayleigh] to free-free emission + brightness temperature [K]. + + Parameters + ---------- + nu : float + The frequency where to calculate the factor a(nu). + Unit: [MHz] + + Returns + ------- + a : float + The factor for Hα to free-free conversion. - References: [Dickinson2003], Eq.(8) + References: [dickinson2003],Eq.(8) """ - term1 = 0.366 * nu_GHz**0.1 * Te**(-0.15) - term2 = np.log(4.995e-2 / nu_GHz) + 1.5*np.log(Te) + term1 = 0.183 * nu**0.1 * self.Te**(-0.15) + term2 = 3.91 - np.log(nu) + 1.5*np.log(self.Te) a = term1 * term2 return a @@ -256,12 +269,12 @@ class FreeFree: logger.info("Simulating {name} map at {freq} ({unit}) ...".format( name=self.name, freq=frequency, unit=self.freq_unit)) # Assumed electron temperature [ K ] - Te = 7000.0 - T4 = Te / 1e4 + T4 = self.Te / 1e4 nu = frequency * self.freq_unit.to(au.GHz) # frequency [ GHz ] - ratio_a = self._calc_ratio_a(Te, nu) # NOTE: ignored the "10^3" term in the referred equation ratio_mK_R = (8.396 * ratio_a * nu**(-2.1) * + factor_a = self._calc_factor_a(frequency) + 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) |