diff options
Diffstat (limited to 'fg21sim/extragalactic/clusters/halo.py')
| -rw-r--r-- | fg21sim/extragalactic/clusters/halo.py | 62 |
1 files changed, 38 insertions, 24 deletions
diff --git a/fg21sim/extragalactic/clusters/halo.py b/fg21sim/extragalactic/clusters/halo.py index 1481899..f8902a3 100644 --- a/fg21sim/extragalactic/clusters/halo.py +++ b/fg21sim/extragalactic/clusters/halo.py @@ -285,9 +285,7 @@ class RadioHalo: z = COSMO.redshift(t) return helper.kT_cluster(mass=mass, z=z, configs=self.configs) - @property - @lru_cache() - def tau_acceleration(self): + def tau_acceleration(self, t=None): """ Calculate the electron acceleration timescale due to turbulent waves, which describes the turbulent acceleration efficiency. @@ -310,13 +308,37 @@ class RadioHalo: τ_acc = p^2 / (4*D_pp) = (η_e * c_s^3 * L) / (16π * ζ * <v_turb^2>^2) - Unit: [Gyr] + NOTE + ---- + Considering that the turbulence acceleration is a 2nd-order Fermi + process, it has only an effective acceleration time ~<1 Gyr. + Therefore, only during the period that strong turbulence persists + in the ICM that the turbulence could effectively accelerate the + relativistic electrons. + + Parameters + ---------- + t : float, optional + The cosmic time when to determine the acceleration timescale. + Default: ``self.age_obs`` + + Returns + ------- + tau : float + The acceleration timescale at the requested time. + Return ``np.inf`` if no active turbulence at that time. + Unit: [Gyr] - Reference - --------- + References + ---------- * Ref.[pinzke2017],Eq.(37) * Ref.[miniati2015],Eq.(29) """ + if t is None: + t = self.age_begin + if t > self.age_begin + self.time_turbulence: + return np.inf + R_vir = helper.radius_virial(mass=self.M_main, z=self.z_merger) L = self.f_lturb * R_vir # [kpc] cs = helper.speed_sound(self.kT_main()) # [km/s] @@ -500,14 +522,6 @@ class RadioHalo: which is described by the ``tau_acc`` acceleration timescale parameter. - NOTE - ---- - Considering that the turbulence acceleration is a 2nd-order Fermi - process, it has only an effective acceleration time ~<1 Gyr. - Therefore, only during the period that strong turbulence persists - in the ICM that the turbulence could effectively accelerate the - relativistic electrons. - WARNING ------- A zero diffusion coefficient may lead to unstable/wrong results, @@ -545,12 +559,12 @@ class RadioHalo: # Maximum acceleration timescale when no turbulence acceleration # NOTE: see the above WARNING! tau_max = 10.0 # [Gyr] - if (t < self.age_begin) or (t > self.age_begin+self.time_turbulence): - # NO active turbulence acceleration + if t < self.age_begin: + # To derive the initial electron spectrum tau_acc = tau_max else: - # Turbulence acceleration - tau_acc = self.tau_acceleration # [Gyr] + # Turbulence acceleration and beyond + tau_acc = self.tau_acceleration(t=t) # Impose the maximum acceleration timescale if tau_acc > tau_max: tau_acc = tau_max @@ -577,12 +591,12 @@ class RadioHalo: """ if t < self.age_begin: # To derive the initial electron spectrum - advection = (abs(self._loss_ion(gamma, self.age_begin)) + - abs(self._loss_rad(gamma, self.age_begin))) + advection = (abs(self._loss_ionization(gamma, self.age_begin)) + + abs(self._loss_radiation(gamma, self.age_begin))) else: # Turbulence acceleration and beyond - advection = (abs(self._loss_ion(gamma, t)) + - abs(self._loss_rad(gamma, t)) - + advection = (abs(self._loss_ionization(gamma, t)) + + abs(self._loss_radiation(gamma, t)) - (self.fp_diffusion(gamma, t) * 2 / gamma)) return advection @@ -677,7 +691,7 @@ class RadioHalo: v2_turb = v2_vir * (self.eta_turb / fmass) * (self.M_sub / mass) return np.sqrt(v2_turb) - def _loss_ion(self, gamma, t): + def _loss_ionization(self, gamma, t): """ Energy loss through ionization and Coulomb collisions. @@ -706,7 +720,7 @@ class RadioHalo: loss = -3.79e4 * n_th * (1 + np.log(gamma/n_th) / 75) return loss - def _loss_rad(self, gamma, t): + def _loss_radiation(self, gamma, t): """ Energy loss via synchrotron emission and inverse Compton scattering off the CMB photons. |