clusters: Update radio halo radius estimation

The simulated radio halo is assumed to have a radius of the falling
sub-cluster; while previously it is assumed to be 1/4 of the virial radius of
the merged cluster.

The new estimation can agree better with the currently observed radio halos,
which generally have a angular diameter size of ~2-7 [arcmin].

1 files changed, 8 insertions, 4 deletions

diff --git a/fg21sim/extragalactic/clusters/halo.py b/fg21sim/extragalactic/clusters/halo.py
index 832371e..6bfa4ca 100644
--- a/fg21sim/extragalactic/clusters/halo.py
+++ b/fg21sim/extragalactic/clusters/halo.py
@@ -166,13 +166,17 @@ class RadioHalo:
     @property
     def radius(self):
         """
-        The halo radius derived from the virial radius by a scaling
-        relation.
+        The estimated radius for the simulated radio halo.
+
+        NOTE
+        ----
+        The halo radius is assumed to be the virial radius of the falling
+        sub-cluster.  See ``helper.radius_halo()`` for more details.
 
         Unit: [kpc]
         """
-        mass = self.M_main + self.M_sub  # [Msun]
-        r_halo = helper.radius_halo(mass, self.z_merger)  # [kpc]
+        r_halo = helper.radius_halo(self.M_main, self.M_sub,
+                                    self.z_merger)
         return r_halo
 
     @property