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-rw-r--r--fg21sim/extragalactic/clusters/formation.py75
1 files changed, 34 insertions, 41 deletions
diff --git a/fg21sim/extragalactic/clusters/formation.py b/fg21sim/extragalactic/clusters/formation.py
index 2089ef8..f8e1b27 100644
--- a/fg21sim/extragalactic/clusters/formation.py
+++ b/fg21sim/extragalactic/clusters/formation.py
@@ -32,13 +32,13 @@ logger = logging.getLogger(__name__)
class ClusterFormation:
"""
- Simulate the cluster formation (i.e., merging history) using the extended
- Press-Schechter formalism by Monte Carlo methods.
+ Simulate the cluster formation (i.e., merging history) by employing
+ the extended Press-Schechter formalism.
Parameters
----------
M0 : float
- Cluster mass at redshift z0
+ Cluster total mass at redshift ``z0``
Unit: [Msun]
z0 : float
Redshift from where to simulate former merging history.
@@ -49,14 +49,6 @@ class ClusterFormation:
Minimum mass change to be regarded as a merger event instead of
accretion.
Unit: [Msun]
-
- Attributes
- ----------
- mtree : `~MergerTree`
- Merging history of this cluster.
- recent_major_merger : dict, or None
- An dictionary containing the properties of the found most recent
- major merger event, or ``None`` if not found.
"""
def __init__(self, M0, z0, zmax=3.0, merger_mass_min=1e12):
self.M0 = M0 # [Msun]
@@ -78,8 +70,8 @@ class ClusterFormation:
def f_sigma(self, mass):
"""
- Current rms density fluctuations within a sphere of specified
- mass (unit: Msun).
+ Current r.m.s. density fluctuations within a sphere of the given
+ mean /dark matter/ mass (unit: [Msun]).
It is generally sufficient to consider a power-law spectrum of
density perturbations, which is consistent with the CDM models.
@@ -127,9 +119,8 @@ class ClusterFormation:
def calc_mass(self, S):
"""
- Calculate the mass corresponding to the given S.
-
- S = sigma(M)^2
+ Calculate the /dark matter/ mass corresponding to the given S,
+ which is defined as: S = sigma(M)^2
References: Ref.[randall2002],Sec.(3)
"""
@@ -296,16 +287,17 @@ class ClusterFormation:
def _trace_main(self):
"""
- Iteratively trace the merger and accretion events of the
- main cluster/halo.
+ Iteratively trace the merger and accretion events of the main
+ cluster/halo only.
"""
# Initial properties
zc = self.z0
- Mc = self.M0
- mtree_root = MergerTree(data={"mass": Mc,
+ Mc_cl = self.M0 # cluster total mass
+ Mc = Mc_cl * COSMO.baryon_fraction # dark matter mass
+ mtree_root = MergerTree(data={"mass": Mc_cl,
"z": zc,
"age": COSMO.age(zc)})
- logger.debug("[main] z=%.4f : mass=%g [Msun]" % (zc, Mc))
+ logger.debug("[main] z=%.4f : mass=%g [Msun]" % (zc, Mc_cl))
mtree = mtree_root
while True:
@@ -333,37 +325,38 @@ class ClusterFormation:
M_min = min(M1, dM)
if M_min <= self.merger_mass_min:
# Accretion
- M_main = Mc - M_min
+ M_main_cl = (Mc - M_min) / COSMO.baryon_fraction
# NOTE: no sub node
else:
- # Merger event
- M_main = max(M1, dM)
- M_sub = M_min
- mtree.sub = MergerTree(data={"mass": M_sub,
+ # Merger
+ M_main_cl = max(M1, dM) / COSMO.baryon_fraction
+ M_sub_cl = M_min / COSMO.baryon_fraction
+ mtree.sub = MergerTree(data={"mass": M_sub_cl,
"z": z1,
"age": age1})
- logger.debug("[sub] z=%.4f : mass=%g [Msun]" % (z1, M_sub))
+ logger.debug("[sub] z=%.4f : mass=%g [Msun]" % (z1, M_sub_cl))
# Update main cluster
- mtree.main = MergerTree(data={"mass": M_main,
+ mtree.main = MergerTree(data={"mass": M_main_cl,
"z": z1,
"age": age1})
- logger.debug("[main] z=%.4f : mass=%g [Msun]" % (z1, M_main))
+ logger.debug("[main] z=%.4f : mass=%g [Msun]" % (z1, M_main_cl))
# Update for next iteration
- Mc = M_main
+ Mc_cl = M_main_cl
zc = z1
mtree = mtree.main
return mtree_root
- def _trace_formation(self, M, _z=None, zmax=None):
+ def _trace_formation(self, M_cl, _z=None, zmax=None):
"""
- Recursively trace the cluster formation and thus simulate its
- merger tree.
+ Recursively trace the cluster/halo formation and thus simulate
+ its merger tree.
"""
z = 0.0 if _z is None else _z
- node_data = {"mass": M, "z": z, "age": COSMO.age(z)}
+ M = M_cl * COSMO.baryon_fraction # dark matter mass
+ node_data = {"mass": M_cl, "z": z, "age": COSMO.age(z)}
# Whether to stop the trace
if self.zmax is not None and z > self.zmax:
@@ -388,18 +381,18 @@ class ClusterFormation:
M_min = min(M1, dM)
if M_min <= self.merger_mass_min:
# Accretion
- M_new = M - M_min
+ M_new_cl = (M - M_min) / COSMO.baryon_fraction
return MergerTree(
data=node_data,
- main=self._trace_formation(M_new, _z=z1),
+ main=self._trace_formation(M_new_cl, _z=z1),
sub=None
)
else:
- # Merger event
- M_main = max(M1, dM)
- M_sub = M_min
+ # Merger
+ M_main_cl = max(M1, dM) / COSMO.baryon_fraction
+ M_sub_cl = M_min / COSMO.baryon_fraction
return MergerTree(
data=node_data,
- main=self._trace_formation(M_main, _z=z1),
- sub=self._trace_formation(M_sub, _z=z1)
+ main=self._trace_formation(M_main_cl, _z=z1),
+ sub=self._trace_formation(M_sub_cl, _z=z1)
)