diff options
| -rw-r--r-- | fg21sim/extragalactic/clusters/formation.py | 43 |
1 files changed, 42 insertions, 1 deletions
diff --git a/fg21sim/extragalactic/clusters/formation.py b/fg21sim/extragalactic/clusters/formation.py index 59c8cbe..c1a93bf 100644 --- a/fg21sim/extragalactic/clusters/formation.py +++ b/fg21sim/extragalactic/clusters/formation.py @@ -49,6 +49,11 @@ class ClusterFormation: zmax : float, optional The maximum redshift/age when to stop the formation trace. Default: 3.0 (i.e., looking back time ~11.5 Gyr) + ratio_major : float, optional + The mass ratio of the main and sub clusters to define whether + the merger is a major event or a minor one. + If ``M_main/M_sub < ratio_major``, then it is a major merger event. + Default: 3.0 cosmo : `~Cosmology`, optional Adopted cosmological model with custom utility functions. merger_mass_min : float, optional @@ -61,11 +66,12 @@ class ClusterFormation: mtree : `~MergerTree` Merging history of this cluster. """ - def __init__(self, M0, z0, zmax=3.0, + def __init__(self, M0, z0, zmax=3.0, ratio_major=3.0, cosmo=Cosmology(), merger_mass_min=1e12): self.M0 = M0 # [Msun] self.z0 = z0 self.zmax = zmax + self.ratio_major = ratio_major self.cosmo = cosmo self.merger_mass_min = merger_mass_min @@ -196,6 +202,41 @@ class ClusterFormation: logger.info("Simulated cluster formation with merger tree") return self.mtree + @property + def last_major_merger(self): + """ + Identify and return the last major merger event + + Returns + ------- + event : + An dictionary containing the properties of the found major + event: + ``{"M_main": M_main, "M_sub": M_sub, "z": z, "age": age}``; + ``None`` if no major event found. + """ + mtree = self.mtree + event = None + while mtree and mtree.main: + if mtree.sub is None: + mtree = mtree.main + continue + + M_main = mtree.main["mass"] + M_sub = mtree.sub["mass"] + z = mtree.main["z"] + age = mtree.main["age"] + if M_main / M_sub < self.ratio_major: + # Found a major merger event + event = {"M_main": M_main, "M_sub": M_sub, + "z": z, "age": age} + break + + # A minor merger event, continue + mtree = mtree.main + + return event + def _trace_main(self): """ Iteratively trace the merger and accretion events of the |