def __init__(self, **kwargs):
IGMSurvey.__init__(self, 'DLA', **kwargs)
# define the cosmology (for H0)
try:
_ = self.cosmo
except ValueError:
self.cosmo = acc.FlatLambdaCDM(70., 0.3)
def cosm_xz(z, cosmo=None, zmin=0., flg=0):
""" Calculates X(z) -- absorption path length or dXdz
Parameters:
z: float or ndarray
Redshift to evaluate at. May be an array
cosmo: astropy.cosmology
Cosmological model to adopt
zmin: float (0.)
Minimum redshift to evaluate at
flg: int (0)
Flag controlling the output
0 = X(z)
1 = dX/dz at z
Returns:
Xz or dXdz:
Absorption path or its derivative
ToDo:
JXP 08 Nov 2014
"""
# Cosmology
if cosmo == None:
from astropy.cosmology import core as acc
cosmo = acc.FlatLambdaCDM(70., 0.3)
#cosmo = Planck13
# Flat?
if cosmo.Ok(0.) == 0:
if flg == 0: # X(z)
rslt = cosmo.absorption_distance(z)
elif flg == 1: # dX/dz
rslt = cosmo._xfunc(z)
else:
raise ValueError('igm_utils.cosm_xz: Bad flg %d' % flg)
else:
raise ValueError(
'igm_utils.cosm_xz: Not prepared for non-flat cosmology')
#
return rslt
def cosm_xz(z, cosmo=None, flg_return=0):
""" Calculates X(z) -- absorption path length or dXdz
Parameters
----------
z : float or ndarray
Redshift to evaluate at. May be an array
cosmo : astropy.cosmology
Cosmological model to adopt
flg_return : int, optional (0)
Flag controlling the output
0 = X(z)
1 = dX/dz at z
Returns
-------
Xz or dXdz :
Absorption path or its derivative
Set by flag
"""
# Cosmology
if cosmo is None:
from astropy.cosmology import core as acc
cosmo = acc.FlatLambdaCDM(70., 0.3)
# Flat?
if cosmo.Ok(0.) == 0:
if flg_return == 0: # X(z)
rslt = cosmo.absorption_distance(z)
elif flg_return == 1: # dX/dz
try:
rslt = cosmo.abs_distance_integrand(z)
except AttributeError:
rslt = cosmo._xfunc(z)
else:
raise ValueError('pyigm.utils.cosm_xz: Bad flg {:d}'.format(flg_return))
else:
raise ValueError('pyigm.utils.cosm_xz: Not prepared for non-flat cosmology')
#
return rslt
def cosm_xz(z, cosmo=None, flg_return=0):
""" Calculates X(z) -- absorption path length or dXdz
Parameters
----------
z : float or ndarray
Redshift to evaluate at. May be an array
cosmo : astropy.cosmology
Cosmological model to adopt
flg_return : int, optional (0)
Flag controlling the output
0 = X(z)
1 = dX/dz at z
Returns
-------
Xz or dXdz :
Absorption path or its derivative
Set by flag
"""
# Cosmology
if cosmo is None:
from astropy.cosmology import core as acc
cosmo = acc.FlatLambdaCDM(H0=70., Om0=0.3)
# Flat?
if flg_return == 0: # X(z)
rslt = cosmo.absorption_distance(z)
elif flg_return == 1: # dX/dz
try:
rslt = cosmo.abs_distance_integrand(z)
except AttributeError: # Deprecated in astropy
rslt = cosmo._xfunc(z)
#
return rslt