diff options
Diffstat (limited to 'fg21sim/extragalactic/clusters/halo.py')
| -rw-r--r-- | fg21sim/extragalactic/clusters/halo.py | 34 |
1 files changed, 15 insertions, 19 deletions
diff --git a/fg21sim/extragalactic/clusters/halo.py b/fg21sim/extragalactic/clusters/halo.py index 2236000..eac9501 100644 --- a/fg21sim/extragalactic/clusters/halo.py +++ b/fg21sim/extragalactic/clusters/halo.py @@ -73,8 +73,8 @@ logger = logging.getLogger(__name__) class RadioHalo: """ - Simulate the diffuse (giant) radio halo emission for a galaxy - cluster experiencing on-going/recent merger. + Simulate the radio halo properties for a galaxy cluster that is + experiencing an on-going merger or had a merger recently. Description ----------- @@ -168,7 +168,8 @@ class RadioHalo: def _set_solver(self): self.fpsolver = FokkerPlanckSolver( - xmin=self.gamma_min, xmax=self.gamma_max, + xmin=self.gamma_min, + xmax=self.gamma_max, x_np=self.gamma_np, tstep=self.time_step, f_advection=self.fp_advection, @@ -195,9 +196,9 @@ class RadioHalo: def time_turbulence(self, t=None): """ - The time duration the merger-induced turbulence persists, which - is used to approximate the effective turbulence acceleration - timescale. + The duration that the merger-induced turbulence persists, which + is used to approximate the lasting time of the effective turbulence + acceleration. Unit: [Gyr] """ @@ -298,16 +299,16 @@ class RadioHalo: mirror) rather than Coulomb scattering. Therefore, the fast modes damp by TTD (transit time damping) on relativistic rather than thermal particles, and the diffusion coefficient is given by: - D_pp = (2*p^2 * ζ / x_cr) * k_L * <v_turb^2>^2 / c_s^3 + D_pp = (4π * p^2 * ζ / X_cr / L_turb) * <v_turb^2>^2 / c_s^3 where: ζ: efficiency factor for the effectiveness of plasma instabilities - x_cr: relative energy density of cosmic rays - k_L = 2π/L: turbulence injection scale + X_cr: relative energy density of cosmic rays + L_turb: turbulence injection scale v_turb: turbulence velocity dispersion c_s: sound speed Thus the acceleration timescale is: τ_acc = p^2 / (4*D_pp) - = (x_cr * c_s^3 * L) / (16π * ζ * <v_turb^2>^2) + = (X_cr * c_s^3 * L_turb) / (16π * ζ * <v_turb^2>^2) WARNING ------- @@ -331,7 +332,6 @@ class RadioHalo: ------- tau : float The acceleration timescale at the requested time. - Return ``np.inf`` if no active turbulence at that time. Unit: [Gyr] References @@ -415,11 +415,9 @@ class RadioHalo: n0_e = n_inj * (self.age_begin - self.time_init) logger.debug("Derive the initial electron spectrum ...") - # NOTE: subtract ``time_step`` to avoid the acceleration at the - # last step at ``age_begin``. dt = self.time_step tstart = self.age_begin - self.time_init - dt - tstop = self.age_begin - dt + tstop = self.age_begin - dt # avoid acceleration at the ``age_begin`` # Use a bigger time step to save time self.fpsolver.tstep = 3 * dt n_e = self.fpsolver.solve(u0=n0_e, tstart=tstart, tstop=tstop) @@ -717,7 +715,7 @@ class RadioHalo: * synchrotron radiation * Coulomb collisions - Reference: Ref.[sarazin1999],Eq.(6,7,9) + Reference: Ref.[sarazin1999],Eqs.(6,7,9) Parameters ---------- @@ -746,10 +744,8 @@ class RadioHalo: class RadioHaloAM(RadioHalo): """ - Simulate the diffuse (giant) radio halo for a galaxy cluster - with all its on-going/recent merger events taken into account, - while the above ``RadioHalo`` class only considers the most - recent major/maximum merger event that is specified. + Simulate the radio halo properties for a galaxy cluster with all its + on-going merger and past merger events taken into account. Parameters ---------- |