diff options
Diffstat (limited to 'fg21sim/extragalactic')
| -rw-r--r-- | fg21sim/extragalactic/clusters/halo.py | 23 |
1 files changed, 17 insertions, 6 deletions
diff --git a/fg21sim/extragalactic/clusters/halo.py b/fg21sim/extragalactic/clusters/halo.py index f69c1cc..0b8446a 100644 --- a/fg21sim/extragalactic/clusters/halo.py +++ b/fg21sim/extragalactic/clusters/halo.py @@ -711,9 +711,21 @@ class RadioHalo: the electrons during the merging period, i.e., the acceleration timescale is set to be infinite after "t_merger + time_cross". - However, a zero diffusion coefficient may lead to unstable/wrong - results, so constrain the acceleration timescale to be a large - enough but finite number (e.g., 10 Gyr). + WARNING + ------- + A zero diffusion coefficient may lead to unstable/wrong results, + since it is not properly taken care of by the solver. Therefore + give the acceleration timescale a large enough but finite value + after turbulent acceleration. + Also note that a very large acceleration timescale (e.g., 1000 or + even 10000) will also cause problems (maybe due to some limitations + within the current calculation scheme), for example, the energy + losses don't seem to have effect in such cases, so the derived + initial electron spectrum is almost the same as the raw input one, + and the emissivity at medium/high frequencies even decreases when + the turbulence acceleration begins! + By carrying out some tests, the value of 10 [Gyr] is adopted for + the maximum acceleration timescale. Parameters ---------- @@ -734,9 +746,8 @@ class RadioHalo: Ref.[donnert2013],Eq.(15) """ if (t < self.age_merger) or (t > self.age_merger+self.time_crossing): - # NO acceleration; use a large enough timescale to avoid - # unstable results. - tau_acc = 100 # [Gyr] + # NO acceleration (see also the above NOTE and WARNING!) + tau_acc = 10 # [Gyr] else: # Turbulence acceleration tau_acc = self.tau_acceleration # [Gyr] |