def Msph(r, z, dr=0., ref='200c', unit='Msun', r_unit='kpc'):
"""
Calculates the mass of a cluster with radius r, assuming it is
spherical.
Supported units are Msun (for M) and {Mpc,kpc} for r.
"""
contrast = int(ref[:-1])
# [rho] = Msun·Mpc⁻³
rho = contrast * cosmology.density(z, ref=ref[-1], unit='astro')
# m = 4*pi/3 * rho*r**3
# --> r**3 = m / (4*pi/3) / rho
if r_unit == 'kpc':
r = r / 1000
m = rho * 4 * numpy.pi / 3 * r**3 # [M] = Msun
if dr != 0.:
dm = rho * 4 * numpy.pi * r**2 # [dM] = Msun
# later: include alternative units
if unit == 'Msun':
if dr != 0:
return m, dm
else:
return m
def rsph(m, z, dm=0., ref='200c', unit='Mpc'):
"""
Returns r, the radius that contains a density *contrast* times
the critical density, assuming a spherical distribution, given a
mass m,
m = (4·pi/3)·r³·(contrast·rho_c)
If an error on the mass is provided, also returns the error in r.
*Input:
m: the mass of the cluster, in solar masses. Can be an
uncertainties.ufloat as well, in which case *r* will be
returned with the same type.
z: the redshift of the cluster
dm: the uncertainty on the mass, in solar masses
contrast: the density contrast with respect to the critical (or
average) density of the Universe at redshift z.
*Returns:
r: the spherical radius, in kpc
dr: the uncertainty on r, in kpc -- if dm is given
"""
contrast = int(ref[:-1])
# [rho] = Msun·Mpc⁻³
rho = contrast * cosmology.density(z, ref=ref[-1], unit='astro')
# m = 4*pi/3 * rho*r**3
# --> r**3 = m / (4*pi/3) / rho
r = (m / (4 * numpy.pi / 3) / rho) ** (1. / 3.) # [r] = Mpc
if dm != 0. and type(m) != uncertainties.Variable:
dr = 1 / (4 * numpy.pi) * 1 / (rho * r ** 2) * dm # [dr] = Mpc
if unit == 'kpc':
return 1e3 * r, 1e3 * dr
if unit == 'Mpc':
return r, dr
if unit == 'kpc':
return 1e3 * r
if unit == 'Mpc':
return r
def nfw(m, z, dm=0, ref_in='200c', ref_out='500c',
c=1., err=1e-6, scaling='duffy08', full_output=False):
"""
Convert the mass of a cluster from one overdensity radius to another
assuming an NFW profile.
Parameters
----------
m : float
mass, in units of solar mass
z : float
redshift
dm : float (optional)
mass uncertainty
ref_in : {'2500c', '500c', '200c', '180c', '100c',
'500a', '200a', '100a'} (default '200c')
overdensity at which the input mass is measured.
The last letter indicates whether the overdensity
is with respect to the critical ('c') or average
('a') density of the Universe at redshift z.
ref_out : {'2500c', '500c', '200c', '180c', '100c',
'500a', '200a', '100a'} (default '500c')
overdensity at which the output mass is measured.
c : float (default 1)
either a fixed concentration or a correction factor
to the Duffy et al. relation (useful, e.g., for
estimating uncertainties due to the c-M relation).
See parameter duffy.
err : float (default 1e-6)
allowed difference for convergence
scaling : {'duffy08', 'dutton14'} (optional)
If given, use the corresponding concentration
relation with a correction factor *c*. If False,
the concentration is fixed to the value of *c*.
Only possible if ref_in is either '200c' or '200a'.
full_output : bool (default False)
If True, also return the concentration used.
Returns
-------
m_out : float
The mass at the output overdensity. If dm>0 then an
uncertainty on this mass is also returned (m_out is
then a tuple of length 2).
c : float (optional)
concentration. This is returned if full_output is
set to True.
"""
#if ref_in != '200c':
#return read_nfw(m, z, dm, ref_in=ref_in, ref_out=ref_out)
if ref_in not in ('200a', '200c'):
duffy = False
if not numpy.iterable(m):
m = numpy.array([m])
if not numpy.iterable(dm):
dm = numpy.array([dm])
# iteratively calculate output mass
def _mass(c, mx, scale, err):
mx_out = 0
mass = mx
while abs(mx_out/mass - 1) > err:
mx_out = mass
r_out = (3 * mx_out / (4 * numpy.pi * rho_out)) ** (1./3.)
x = r_out / scale
mass = mx * (numpy.log(1 + x) - x / (1 + x)) / \
(numpy.log(1 + c) - c / (1 + c))
return mass
# density contrasts
rho_in = int(ref_in[:-1]) * cosmology.density(z, ref=ref_in[-1])
rho_out = int(ref_out[:-1]) * cosmology.density(z, ref=ref_out[-1])
# radii
r_in = conversions.rsph(m, z, ref=ref_in, unit='Mpc')
if scaling in ('duffy08', 'dutton14'):
c = c * scalings.cM(m, z, ref=ref_in, scaling=scaling)
scale = r_in / c
# mass and uncertainty (if defined)
m_out = numpy.array([_mass(ci, mi, rs, err)
for ci, mi, rs in izip(c, m, scale)])
if numpy.any(dm > 0):
dm_hi = numpy.array([_mass(ci, mi+dmi, rs, err)
for ci, mi, dmi, rs in izip(c, m, dm, scale)])
dm_lo = numpy.array([_mass(ci, mi-dmi, rs, err)
for ci, mi, dmi, rs in izip(c, m, dm, scale)])
m_out = (m_out, (dm_hi+dm_lo)/2)
if full_output:
return m_out, c
return m_out
