From 1200e50fd24451ed7b56d137a20106c18c0e0153 Mon Sep 17 00:00:00 2001
From: Aaron LI <aly@aaronly.me>
Date: Tue, 16 Jan 2018 09:23:52 +0800
Subject: clusters: minor updates
---
fg21sim/configs/20-extragalactic.conf.spec | 2 ++
fg21sim/extragalactic/clusters/helper.py | 9 ++++-----
2 files changed, 6 insertions(+), 5 deletions(-)
diff --git a/fg21sim/configs/20-extragalactic.conf.spec b/fg21sim/configs/20-extragalactic.conf.spec
index cb11bd8..7de9eb1 100644
--- a/fg21sim/configs/20-extragalactic.conf.spec
+++ b/fg21sim/configs/20-extragalactic.conf.spec
@@ -132,6 +132,8 @@
# The fraction of the magnetic field energy density w.r.t. the ICM
# thermal energy density, which is used to determine the mean magnetic
# field strength within the ICM and is also assumed to be uniform.
+ # * ~< 0.4% (Ref: Pfrommer & Ensslin 2004, MNRAS)
+ # * ~0.3%-1% (Ref: Bohringer et al. 2016, A&A)
eta_b = float(default=0.001, min=1e-5, max=0.1)
# The temperature of the outer gas surrounding the cluster. Accretion
diff --git a/fg21sim/extragalactic/clusters/helper.py b/fg21sim/extragalactic/clusters/helper.py
index 39cee12..8d6db09 100644
--- a/fg21sim/extragalactic/clusters/helper.py
+++ b/fg21sim/extragalactic/clusters/helper.py
@@ -2,7 +2,7 @@
# MIT license
"""
-Helper functions
+Functions to help simulate galaxy cluster diffuse emissions.
References
----------
@@ -295,8 +295,7 @@ def speed_sound(kT):
Reference: Ref.[zhuravleva2014],Appendix(Methods)
"""
- # The gas adiabatic index
- gamma = AC.gamma
+ gamma = AC.gamma # gas adiabatic index
cs = np.sqrt(gamma * kT*AUC.keV2erg / (AC.mu * AC.u)) # [cm/s]
return cs * AUC.cm2km # [km/s]
@@ -377,12 +376,12 @@ def time_crossing(M_main, M_sub, z=0.0):
def time_turbulence(M_main, M_sub, z=0.0, configs=CONFIGS):
"""
- The timescale that the compressive turbulence persists, which is
+ The duration that the compressive turbulence persists, which is
estimated as:
τ_turb ≅ 2*d / v_impact,
where d ≅ L ≅ R_vir / 3,
and L is also the turbulence injection scale.
- During this timescale, the merger-induced turbulence is regarded
+ During this period, the merger-induced turbulence is regarded
to accelerate the relativistic electrons effectively.
Unit: [Gyr]
--
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