clusters/halo: Set fixed radius for RadioHaloAM

Since the halo radius is related to the turbulence injection region size
which is further related to the stripping radius, it varies along the
cluster growth as mergers happen.  Therefore, the finally radio halo
radius is determined otherwise and just specified here.

1 files changed, 14 insertions, 2 deletions

diff --git a/fg21sim/extragalactic/clusters/halo.py b/fg21sim/extragalactic/clusters/halo.py
index b9b99aa..c367eb5 100644
--- a/fg21sim/extragalactic/clusters/halo.py
+++ b/fg21sim/extragalactic/clusters/halo.py
@@ -811,16 +811,28 @@ class RadioHaloAM(RadioHalo):
         The redshifts at each merger event, from small to large.
     merger_num : int
         Number of merger events traced for the cluster.
+    radius : float
+        The radius of the radio halo.
+        Unit: [kpc]
     """
     def __init__(self, M_obs, z_obs, M_main, M_sub, z_merger,
-                 merger_num, configs=CONFIGS):
-        self.merger_num = merger_num
+                 merger_num, radius, configs=CONFIGS):
         M_main = np.asarray(M_main[:merger_num])
         M_sub = np.asarray(M_sub[:merger_num])
         z_merger = np.asarray(z_merger[:merger_num])
         super().__init__(M_obs=M_obs, z_obs=z_obs,
                          M_main=M_main, M_sub=M_sub,
                          z_merger=z_merger, configs=configs)
+        self.merger_num = merger_num
+        self.radius_ = radius  # [kpc]
+
+    @property
+    def radius(self):
+        """
+        The radius of the final radio halo.
+        Unit: [kpc]
+        """
+        return self.radius_
 
     @property
     def age_begin(self):