Make the Rosas-Guevara 2015 accretion model optional. Switched on in all the EAGLE examples

examples/EAGLE_ICs/EAGLE_100/eagle_100.yml

@@ -183,6 +183,7 @@ EAGLEAGN:
   subgrid_seed_mass_Msun:           1.5e5      # Black hole subgrid mass at creation time in solar masses.
   max_eddington_fraction:           1.0        # Maximal allowed accretion rate in units of the Eddington rate.
   eddington_fraction_for_recording: 0.1        # Record the last time BHs reached an Eddington ratio above this threshold.
+  with_angmom_limiter:              1          # Are we applying the Rosas-Guevara (2015) viscous time-scale reduction term?
   viscous_alpha:                    1e6        # Normalisation constant of the Bondi viscuous time-scale accretion reduction term
   radiative_efficiency:             0.1        # Fraction of the accreted mass that gets radiated.
   coupling_efficiency:              0.15       # Fraction of the radiated energy that couples to the gas in feedback events.

examples/EAGLE_ICs/EAGLE_12/eagle_12.yml

@@ -183,6 +183,7 @@ EAGLEAGN:
   subgrid_seed_mass_Msun:           1.5e5      # Black hole subgrid mass at creation time in solar masses.
   max_eddington_fraction:           1.0        # Maximal allowed accretion rate in units of the Eddington rate.
   eddington_fraction_for_recording: 0.1        # Record the last time BHs reached an Eddington ratio above this threshold.
+  with_angmom_limiter:              1          # Are we applying the Rosas-Guevara (2015) viscous time-scale reduction term?
   viscous_alpha:                    1e6        # Normalisation constant of the Bondi viscuous time-scale accretion reduction term
   radiative_efficiency:             0.1        # Fraction of the accreted mass that gets radiated.
   coupling_efficiency:              0.15       # Fraction of the radiated energy that couples to the gas in feedback events.

examples/EAGLE_ICs/EAGLE_25/eagle_25.yml

@@ -184,6 +184,7 @@ EAGLEAGN:
   subgrid_seed_mass_Msun:           1.5e5      # Black hole subgrid mass at creation time in solar masses.
   max_eddington_fraction:           1.0        # Maximal allowed accretion rate in units of the Eddington rate.
   eddington_fraction_for_recording: 0.1        # Record the last time BHs reached an Eddington ratio above this threshold.
+  with_angmom_limiter:              1          # Are we applying the Rosas-Guevara (2015) viscous time-scale reduction term?
   viscous_alpha:                    1e6        # Normalisation constant of the Bondi viscuous time-scale accretion reduction term
   radiative_efficiency:             0.1        # Fraction of the accreted mass that gets radiated.
   coupling_efficiency:              0.15       # Fraction of the radiated energy that couples to the gas in feedback events.

examples/EAGLE_ICs/EAGLE_50/eagle_50.yml

@@ -182,6 +182,7 @@ EAGLEAGN:
   subgrid_seed_mass_Msun:           1.5e5      # Black hole subgrid mass at creation time in solar masses.
   max_eddington_fraction:           1.0        # Maximal allowed accretion rate in units of the Eddington rate.
   eddington_fraction_for_recording: 0.1        # Record the last time BHs reached an Eddington ratio above this threshold.
+  with_angmom_limiter:              1          # Are we applying the Rosas-Guevara (2015) viscous time-scale reduction term?
   viscous_alpha:                    1e6        # Normalisation constant of the Bondi viscuous time-scale accretion reduction term
   radiative_efficiency:             0.1        # Fraction of the accreted mass that gets radiated.
   coupling_efficiency:              0.15       # Fraction of the radiated energy that couples to the gas in feedback events.

examples/parameter_example.yml

@@ -481,6 +481,7 @@ EAGLEAGN:
   subgrid_seed_mass_Msun:           1.5e5      # Black hole subgrid mass at creation time in solar masses.
   max_eddington_fraction:           1.         # Maximal allowed accretion rate in units of the Eddington rate.
   eddington_fraction_for_recording: 0.1        # Record the last time BHs reached an Eddington ratio above this threshold.
+  with_angmom_limiter:              1          # Are we applying the Rosas-Guevara (2015) viscous time-scale reduction term?
   viscous_alpha:                    1e6        # Normalisation constant of the Bondi viscuous time-scale accretion reduction term
   radiative_efficiency:             0.1        # Fraction of the accreted mass that gets radiated.
   coupling_efficiency:              0.15       # Fraction of the radiated energy that couples to the gas in feedback events.

src/black_holes.h

@@ -30,7 +30,7 @@
 #include "./black_holes/EAGLE/black_holes.h"
 #include "./black_holes/EAGLE/black_holes_iact.h"
 #else
-#error "Invalid choice of star model"
+#error "Invalid choice of black hole model"
 #endif
 
 #endif

src/black_holes/EAGLE/black_holes.h

@@ -453,17 +453,19 @@ __attribute__((always_inline)) INLINE static void black_holes_prepare_feedback(
                       denominator_inv * denominator_inv * denominator_inv;
 
   /* Compute the reduction factor from Rosas-Guevara et al. (2015) */
-  const double Bondi_radius = G * BH_mass / gas_c_phys2;
-  const double Bondi_time = Bondi_radius / gas_c_phys;
-  const double r_times_v_tang = Bondi_radius * tangential_velocity;
-  const double r_times_v_tang_3 =
-      r_times_v_tang * r_times_v_tang * r_times_v_tang;
-  const double viscous_time = 2. * M_PI * r_times_v_tang_3 /
-                              (1e-6 * alpha_visc * G * G * BH_mass * BH_mass);
-  const double f_visc = max(Bondi_time / viscous_time, 1.);
-
-  /* Limit the Bondi rate by the Bondi viscuous time ratio */
-  Bondi_rate *= f_visc;
+  if (props->with_angmom_limiter) {
+    const double Bondi_radius = G * BH_mass / gas_c_phys2;
+    const double Bondi_time = Bondi_radius / gas_c_phys;
+    const double r_times_v_tang = Bondi_radius * tangential_velocity;
+    const double r_times_v_tang_3 =
+        r_times_v_tang * r_times_v_tang * r_times_v_tang;
+    const double viscous_time = 2. * M_PI * r_times_v_tang_3 /
+                                (1e-6 * alpha_visc * G * G * BH_mass * BH_mass);
+    const double f_visc = max(Bondi_time / viscous_time, 1.);
+
+    /* Limit the Bondi rate by the Bondi viscuous time ratio */
+    Bondi_rate *= f_visc;
+  }
 
   /* Compute the Eddington rate (internal units) */
   const double Eddington_rate =

src/black_holes/EAGLE/black_holes_properties.h

@@ -63,6 +63,9 @@ struct black_holes_props {
   /*! Feedback coupling efficiency of the black holes. */
   float epsilon_f;
 
+  /*! Are we using the Rosas-Guevara et al. (2015) term? */
+  int with_angmom_limiter;
+
   /*! Normalisation of the viscuous angular momentum accretion reduction */
   float alpha_visc;
 
@@ -165,7 +168,12 @@ INLINE static void black_holes_props_init(struct black_holes_props *bp,
       parser_get_param_float(params, "EAGLEAGN:radiative_efficiency");
   bp->epsilon_f =
       parser_get_param_float(params, "EAGLEAGN:coupling_efficiency");
-  bp->alpha_visc = parser_get_param_float(params, "EAGLEAGN:viscous_alpha");
+
+  /* Rosas-Guevara et al. (2015) model */
+  bp->with_angmom_limiter =
+      parser_get_param_int(params, "EAGLEAGN:with_angmom_limiter");
+  if (bp->with_angmom_limiter)
+    bp->alpha_visc = parser_get_param_float(params, "EAGLEAGN:viscous_alpha");
 
   /* Feedback parameters ---------------------------------- */