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| author | Aaron LI <aly@aaronly.me> | 2019-01-25 16:17:23 +0800 |
|---|---|---|
| committer | Aaron LI <aly@aaronly.me> | 2019-01-25 16:17:48 +0800 |
| commit | 2ad2169909838a6a8055fc69541a1cde8ffe8391 (patch) | |
| tree | 2f1ae8641f62cf7d8ab731637b66af1df694e25d | |
| parent | 8ab2148f9871920e81562a88f491456fcca4b8b5 (diff) | |
| download | fg21sim-2ad2169909838a6a8055fc69541a1cde8ffe8391.tar.bz2 | |
clusters/halo: Account for mass scaling in tau_acceleration()
Add configuration option "mass_index" to specify the scaling index.
| -rw-r--r-- | fg21sim/configs/config.spec | 4 | ||||
| -rw-r--r-- | fg21sim/extragalactic/clusters/halo.py | 18 |
2 files changed, 22 insertions, 0 deletions
diff --git a/fg21sim/configs/config.spec b/fg21sim/configs/config.spec index adc4134..f68b2e1 100644 --- a/fg21sim/configs/config.spec +++ b/fg21sim/configs/config.spec @@ -398,6 +398,10 @@ stream = option("stderr", "stdout", "", default="stderr") # Electron injection, which is assumed to have a constant injection # rate and a power-law spectrum. injection_index = float(default=2.3, min=2.1, max=3.0) + # The scaling index of the diffusion coefficient (D_γγ) w.r.t. the + # mass of the main cluster. + mass_index = float(default=0, min=0, max=2) + # Minimum and maximum Lorentz factor (i.e., energy) of the relativistic # electron spectrum. diff --git a/fg21sim/extragalactic/clusters/halo.py b/fg21sim/extragalactic/clusters/halo.py index 4e87f3f..56c8622 100644 --- a/fg21sim/extragalactic/clusters/halo.py +++ b/fg21sim/extragalactic/clusters/halo.py @@ -154,6 +154,7 @@ class RadioHalo1M: self.eta_turb = configs.getn(comp+"/eta_turb") self.eta_e = configs.getn(comp+"/eta_e") self.x_cr = configs.getn(comp+"/x_cr") + self.mass_index = configs.getn(comp+"/mass_index") self.gamma_min = configs.getn(comp+"/gamma_min") self.gamma_max = configs.getn(comp+"/gamma_max") self.gamma_np = configs.getn(comp+"/gamma_np") @@ -293,6 +294,18 @@ class RadioHalo1M: τ'_acc = γ^2 / (4 * D'_γγ) = X_cr * c_s^3 / (8 * ζ * k_L * v_t^4) + Previous studies show that more massive clusters are more efficient + to accelerate electrons to be radio bright. To further account for + this scaling relation: + D_γγ = D'_γγ * f_m * (M_main / 1e15)^m + where: + m: scaling index + f_m: normalization + Therefore, the final acceleration timescale is: + τ_acc = τ'_acc * (M_main / 1e15)^(-m) / f_m + = X_cr * c_s^3 * (M_main/1e15)^(-m) / (8*f_acc * k_L * v_t^4) + with: f_acc = f_m * ζ + WARNING ------- Tests show that a very large acceleration timescale (e.g., @@ -335,6 +348,11 @@ class RadioHalo1M: v_t = self._velocity_turb(t_merger) # [km/s] tau = self.x_cr * cs**3 / (8*k_L * v_t**4) tau *= AUC.s2Gyr * AUC.kpc2km # [s kpc/km] -> [Gyr] + + # Mass scaling + M_main = self.mass_main(t) + f_mass = (M_main / 1e15) ** (-self.mass_index) + tau *= f_mass tau /= self.f_acc # tune factor (folded with "zeta_ins") # Impose the maximum acceleration timescale |