Add a field to the black holes to store the last time they reached above a...

Add a field to the black holes to store the last time they reached above a given Eddington ratio. Set that threshold to 0.1 in all the examples.

examples/EAGLE_ICs/EAGLE_12/eagle_12.yml

@@ -176,6 +176,7 @@ EAGLEFeedback:
 EAGLEAGN:
   subgrid_seed_mass_Msun:           1.5e5      # Black hole subgrid mass at creation time in solar masses.
   max_eddington_fraction:           1.5        # 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.
   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

@@ -177,6 +177,7 @@ EAGLEFeedback:
 EAGLEAGN:
   subgrid_seed_mass_Msun:           1.5e5      # Black hole subgrid mass at creation time in solar masses.
   max_eddington_fraction:           1.5        # 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.
   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

@@ -177,6 +177,7 @@ EAGLEFeedback:
 EAGLEAGN:
   subgrid_seed_mass_Msun:           1.5e5      # Black hole subgrid mass at creation time in solar masses.
   max_eddington_fraction:           1.5        # 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.
   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_low_z/EAGLE_12/eagle_12.yml

@@ -171,6 +171,7 @@ EAGLEFeedback:
 EAGLEAGN:
   subgrid_seed_mass_Msun:           1.5e5      # Black hole subgrid mass at creation time in solar masses.
   max_eddington_fraction:           1.5        # 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.
   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_low_z/EAGLE_25/eagle_25.yml

@@ -179,6 +179,7 @@ EAGLEFeedback:
 EAGLEAGN:
   subgrid_seed_mass_Msun:           1.5e5      # Black hole subgrid mass at creation time in solar masses.
   max_eddington_fraction:           1.5        # 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.
   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_low_z/EAGLE_50/eagle_50.yml

@@ -170,6 +170,7 @@ EAGLEFeedback:
 EAGLEAGN:
   subgrid_seed_mass_Msun:           1.5e5      # Black hole subgrid mass at creation time in solar masses.
   max_eddington_fraction:           1.5        # 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.
   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_low_z/EAGLE_6/eagle_6.yml

@@ -180,6 +180,7 @@ EAGLEFeedback:
 EAGLEAGN:
   subgrid_seed_mass_Msun:           1.5e5      # Black hole subgrid mass at creation time in solar masses.
   max_eddington_fraction:           1.5        # 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.
   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

@@ -428,6 +428,7 @@ EAGLEFeedback:
 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.
   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/Default/black_holes.h

@@ -180,12 +180,14 @@ __attribute__((always_inline)) INLINE static void black_holes_swallow_bpart(
  * @param props The properties of the black hole scheme.
  * @param constants The physical constants (in internal units).
  * @param cosmo The cosmological model.
+ * @param time Time since the start of the simulation (non-cosmo mode).
+ * @param with_cosmology Are we running with cosmology?
  * @param dt The time-step size (in physical internal units).
  */
 __attribute__((always_inline)) INLINE static void black_holes_prepare_feedback(
     struct bpart* restrict bp, const struct black_holes_props* props,
     const struct phys_const* constants, const struct cosmology* cosmo,
-    const double dt) {}
+    const double time, const int with_cosmology, const double dt) {}
 
 /**
  * @brief Finish the calculation of the new BH position.

src/black_holes/EAGLE/black_holes.h

@@ -62,6 +62,9 @@ __attribute__((always_inline)) INLINE static void black_holes_first_init_bpart(
   bp->formation_time = -1.f;
   bp->cumulative_number_seeds = 1;
   bp->number_of_mergers = 0;
+  bp->last_high_Eddington_fraction_scale_factor = -1.f;
+
+  black_holes_mark_bpart_as_not_swallowed(&bp->merger_data);
 }
 
 /**
@@ -325,12 +328,14 @@ __attribute__((always_inline)) INLINE static void black_holes_swallow_bpart(
  * @param props The properties of the black hole scheme.
  * @param constants The physical constants (in internal units).
  * @param cosmo The cosmological model.
+ * @param time Time since the start of the simulation (non-cosmo mode).
+ * @param with_cosmology Are we running with cosmology?
  * @param dt The time-step size (in physical internal units).
  */
 __attribute__((always_inline)) INLINE static void black_holes_prepare_feedback(
     struct bpart* restrict bp, const struct black_holes_props* props,
     const struct phys_const* constants, const struct cosmology* cosmo,
-    const double dt) {
+    const double time, const int with_cosmology, const double dt) {
 
   if (dt == 0.) return;
 
@@ -342,6 +347,7 @@ __attribute__((always_inline)) INLINE static void black_holes_prepare_feedback(
 
   /* Gather the parameters of the model */
   const double f_Edd = props->f_Edd;
+  const double f_Edd_recording = props->f_Edd_recording;
   const double epsilon_r = props->epsilon_r;
   const double epsilon_f = props->epsilon_f;
   const double num_ngbs_to_heat = props->num_ngbs_to_heat;
@@ -409,6 +415,15 @@ __attribute__((always_inline)) INLINE static void black_holes_prepare_feedback(
   const double Eddington_rate =
       4. * M_PI * G * BH_mass * proton_mass / (epsilon_r * c * sigma_Thomson);
 
+  /* Shall we record this high rate? */
+  if (Bondi_rate > f_Edd_recording * Eddington_rate) {
+    if (with_cosmology) {
+      bp->last_high_Eddington_fraction_scale_factor = cosmo->a;
+    } else {
+      bp->last_high_Eddington_fraction_time = time;
+    }
+  }
+
   /* Limit the accretion rate to the Eddington fraction */
   const double accr_rate = min(Bondi_rate, f_Edd * Eddington_rate);
   bp->accretion_rate = accr_rate;
@@ -555,6 +570,9 @@ INLINE static void black_holes_create_from_gas(
   const struct chemistry_part_data* p_chem = &p->chemistry_data;
   chemistry_bpart_from_part(bp_chem, p_chem, gas_mass);
 
+  /* Last time this BH had a high Eddington fraction */
+  bp->last_high_Eddington_fraction_scale_factor = -1.f;
+
   /* First initialisation */
   black_holes_init_bpart(bp);
 

src/black_holes/EAGLE/black_holes_io.h

@@ -114,7 +114,7 @@ INLINE static void black_holes_write_particles(const struct bpart* bparts,
                                                int with_cosmology) {
 
   /* Say how much we want to write */
-  *num_fields = 14;
+  *num_fields = 15;
 
   /* List what we want to write */
   list[0] = io_make_output_field_convert_bpart(
@@ -180,11 +180,26 @@ INLINE static void black_holes_write_particles(const struct bpart* bparts,
       cumulative_number_seeds,
       "Total number of BH seeds that have merged into this black hole");
 
-  list[13] = io_make_output_field("NumberOfMergers", INT, 1, UNIT_CONV_NO_UNITS,
-                                  0.f, bparts, number_of_mergers,
-                                  "Number of mergers black holes went through. "
-                                  "This does not include the number of mergers "
-                                  "accumulated by any merged black hole.");
+  list[13] =
+      io_make_output_field("NumberOfMergers", INT, 1, UNIT_CONV_NO_UNITS, 0.f,
+                           bparts, number_of_mergers,
+                           "Number of mergers the black holes went through. "
+                           "This does not include the number of mergers "
+                           "accumulated by any merged black hole.");
+
+  if (with_cosmology) {
+    list[14] = io_make_output_field(
+        "LastHighEddingtonFractionScaleFactors", FLOAT, 1, UNIT_CONV_NO_UNITS,
+        0.f, bparts, last_high_Eddington_fraction_scale_factor,
+        "Scale-factors at which the black holes last reached an Eddington "
+        "ratio > 0.1. -1 if never reached.");
+  } else {
+    list[14] = io_make_output_field(
+        "LastHighEddingtonFractionTimes", FLOAT, 1, UNIT_CONV_TIME, 0.f, bparts,
+        last_high_Eddington_fraction_time,
+        "Times at which the black holes last reached an Eddington ratio > 0.1. "
+        "-1 if never reached.");
+  }
 
 #ifdef DEBUG_INTERACTIONS_BLACK_HOLES
 

src/black_holes/EAGLE/black_holes_part.h

@@ -111,6 +111,16 @@ struct bpart {
   /*! Total number of BH merger events (i.e. not including all progenies) */
   int number_of_mergers;
 
+  /*! Union for the last high Eddington ratio point in time */
+  union {
+
+    /*! Last time the BH had a a high Eddington fraction */
+    float last_high_Eddington_fraction_time;
+
+    /*! Last scale factor the BH had a a high Eddington fraction */
+    float last_high_Eddington_fraction_scale_factor;
+  };
+
   /*! Properties used in the feedback loop to distribute to gas neighbours. */
   struct {
 

src/black_holes/EAGLE/black_holes_properties.h

@@ -66,6 +66,9 @@ struct black_holes_props {
   /*! Normalisation of the viscuous angular momentum accretion reduction */
   float alpha_visc;
 
+  /*! Eddington fraction threshold for recording */
+  float f_Edd_recording;
+
   /* ---- Properties of the feedback model ------- */
 
   /*! Temperature increase induced by AGN feedback (Kelvin) */
@@ -148,6 +151,8 @@ INLINE static void black_holes_props_init(struct black_holes_props *bp,
   /* Accretion parameters ---------------------------------- */
 
   bp->f_Edd = parser_get_param_float(params, "EAGLEAGN:max_eddington_fraction");
+  bp->f_Edd_recording =
+      parser_get_param_float(params, "EAGLEAGN:eddington_fraction_for_recording");
   bp->epsilon_r =
       parser_get_param_float(params, "EAGLEAGN:radiative_efficiency");
   bp->epsilon_f =

src/runner_ghost.c

@@ -838,7 +838,8 @@ void runner_do_black_holes_swallow_ghost(struct runner *r, struct cell *c,
 
         /* Compute variables required for the feedback loop */
         black_holes_prepare_feedback(bp, e->black_holes_properties,
-                                     e->physical_constants, e->cosmology, dt);
+                                     e->physical_constants, e->cosmology,
+                                     e->time, with_cosmology, dt);
       }
     }
   }