def find_virial_radius(ds,center):
z = ds.current_redshift
co = Cosmology(hubble_constant=ds.hubble_constant, omega_matter=ds.omega_matter,
omega_lambda=ds.omega_lambda, omega_curvature=0.0)
rho_c = co.critical_density(z=z)
r = 0
rs = []
densities = []
density = np.inf
while density > 200*rho_c:
r+=5
rs.append(r)
sp = ds.sphere(center,(r,'kpc'))
cell_mass,particle_mass = sp.quantities.total_mass()
volume = 4/3*np.pi*ds.arr(r,'kpc')**3
new_density = (cell_mass+particle_mass)/volume
if new_density > density:
print('density not decreasing!')
break
density = new_density.in_units('g/cm**3')
densities.append(density)
toprint = (r,cell_mass+particle_mass,(cell_mass+particle_mass).units,particle_mass,particle_mass.units,cell_mass,cell_mass.units)
rs = np.array(rs)
densities = np.array(densities)
Rvir = np.interp(200*rho_c,np.flip(densities),np.flip(rs))
Mvir = cell_mass+particle_mass
return ds.arr(Rvir,'kpc'),ds.arr(Mvir,'g')
def find_radius_mass(m_r, delta, z=0.0, cosmo=None):
"""
Given a mass profile and an overdensity, find the radius
and mass (e.g. M200, r200)
Parameters
----------
m_r : RadialProfile
The mass profile.
delta : float
The overdensity to compute the mass and radius for.
z : float, optional
The redshift of the halo formation. Default: 0.0
cosmo : yt ``Cosmology`` object
The cosmology to be used when computing the critical
density. If not supplied, a default one from yt will
be used.
"""
from yt.utilities.cosmology import Cosmology
from scipy.optimize import bisect
if cosmo is None:
cosmo = Cosmology()
rho_crit = cosmo.critical_density(z).to_value("Msun/kpc**3")
f = lambda r: 3.0*m_r(r)/(4.*np.pi*r**3) - delta*rho_crit
r_delta = bisect(f, 0.01, 10000.0)
return r_delta, m_r(r_delta)
def nfw_scale_density(conc, z=0.0, delta=200.0, cosmo=None):
"""
Compute a scale density parameter for an NFW profile
given a concentration parameter, and optionally
a redshift, overdensity, and cosmology.
Parameters
----------
conc : float
The concentration parameter for the halo, which should
correspond the selected overdensity (which has a default
of 200).
z : float, optional
The redshift of the halo formation. Default: 0.0
delta : float, optional
The overdensity parameter for which the concentration
is defined. Default: 200.0
cosmo : yt Cosmology object
The cosmology to be used when computing the critical
density. If not supplied, a default one from yt will
be used.
"""
from yt.utilities.cosmology import Cosmology
if cosmo is None:
cosmo = Cosmology()
rho_crit = cosmo.critical_density(z).to_value("Msun/kpc**3")
rho_s = delta*rho_crit*conc**3*_nfw_factor(conc)/3.
return rho_s
def _set_code_unit_attributes(self):
# First try to set units based on parameter file
if self.cosmological_simulation:
mu = self.parameters.get("dMsolUnit", 1.0)
self.mass_unit = self.quan(mu, "Msun")
lu = self.parameters.get("dKpcUnit", 1000.0)
# In cosmological runs, lengths are stored as length*scale_factor
self.length_unit = self.quan(lu, "kpc") * self.scale_factor
density_unit = self.mass_unit / (self.length_unit / self.scale_factor) ** 3
if "dHubble0" in self.parameters:
# Gasoline's internal hubble constant, dHubble0, is stored in
# units of proper code time
self.hubble_constant *= np.sqrt(G * density_unit)
# Finally, we scale the hubble constant by 100 km/s/Mpc
self.hubble_constant /= self.quan(100, "km/s/Mpc")
# If we leave it as a YTQuantity, the cosmology object
# used below will add units back on.
self.hubble_constant = self.hubble_constant.to_value("")
else:
mu = self.parameters.get("dMsolUnit", 1.0)
self.mass_unit = self.quan(mu, "Msun")
lu = self.parameters.get("dKpcUnit", 1.0)
self.length_unit = self.quan(lu, "kpc")
# If unit base is defined by the user, override all relevant units
if self._unit_base is not None:
for my_unit in ["length", "mass", "time"]:
if my_unit in self._unit_base:
my_val = self._unit_base[my_unit]
my_val = (
self.quan(*my_val)
if isinstance(my_val, tuple)
else self.quan(my_val)
)
setattr(self, f"{my_unit}_unit", my_val)
# Finally, set the dependent units
if self.cosmological_simulation:
cosmo = Cosmology(
hubble_constant=self.hubble_constant,
omega_matter=self.omega_matter,
omega_lambda=self.omega_lambda,
)
self.current_time = cosmo.lookback_time(self.current_redshift, 1e6)
# mass units are rho_crit(z=0) * domain volume
mu = (
cosmo.critical_density(0.0)
* (1 + self.current_redshift) ** 3
* self.length_unit ** 3
)
self.mass_unit = self.quan(mu.in_units("Msun"), "Msun")
density_unit = self.mass_unit / (self.length_unit / self.scale_factor) ** 3
# need to do this again because we've modified the hubble constant
self.unit_registry.modify("h", self.hubble_constant)
else:
density_unit = self.mass_unit / self.length_unit ** 3
if not hasattr(self, "time_unit"):
self.time_unit = 1.0 / np.sqrt(density_unit * G)
def find_overdensity_radius(m, delta, z=0.0, cosmo=None):
"""
Given a mass value and an overdensity, find the radius
that corresponds to that enclosed mass.
Parameters
----------
m : float
The enclosed mass.
delta : float
The overdensity to compute the radius for.
z : float, optional
The redshift of the halo formation. Default: 0.0
cosmo : yt ``Cosmology`` object
The cosmology to be used when computing the critical
density. If not supplied, a default one from yt will
be used.
"""
from yt.utilities.cosmology import Cosmology
if cosmo is None:
cosmo = Cosmology()
rho_crit = cosmo.critical_density(z).to_value("Msun/kpc**3")
return (3.0*m/(4.0*np.pi*delta*rho_crit))**(1./3.)
proton_electron_mass_ratio = 1836.
proton_mass = 1.67e-24 # g
hubble_constant = 67.11 # H_0 in km / s / Mpc
outer_scale_0_IGM = 1e6 # pc ## from Ryu+ 2008 ## global outer scale assumed to compute SM, choose other values by SM*L0**(-2/3)
## cosmic functions
co = Cosmology(hubble_constant=h,
omega_matter=omega_matter,
omega_lambda=omega_lambda,
omega_curvature=omega_curvature)
comoving_radial_distance = co.comoving_radial_distance ## comoving distance z0 to z1
luminosity_distance = co.luminosity_distance ## proper distance z0 to z1
CriticalDensity = lambda redshift: co.critical_density(redshift).in_cgs(
).value * 1
critical_density = CriticalDensity(0)
def GasDensity(z):
return critical_density * omega_baryon * (1 + z)**3
## redshift <-> time
z_from_t = co.z_from_t
t_from_z = co.t_from_z
## Geometry
def GetDirection(x, y, z):
