# -*- coding: utf-8 -*-
import numpy as np
from scipy import special
from astropy.io import fits
from copy import deepcopy
try:
import bottleneck as bn
except ImportError:
import numpy as bn
from .galaxy_parameters import GalaxyParameters
from .model_utilities import modelPlots, ModelExt
from .model_class import Model
from .math_utils import flux_sersic
# LOGGING CONFIGURATION
import logging
logging.basicConfig(level=logging.INFO)
logger = logging.getLogger('GalPaK: DiskModel ')
[docs]class ModelSersic(Model,modelPlots, ModelExt):
"""
The first and default galpak `Model` (when unspecified).
It simulates a simple disk galaxy using `DiskParameters`.
flux_profile: 'exponential' | 'gaussian' | 'de_vaucouleurs' | 'sersicN2' | 'user'
The flux profile of the observed galaxy. The default is 'exponential'.
See http://en.wikipedia.org/wiki/Sersic%27s_law
If 'user' provided flux map, specify flux_image. Currently unsupported
thickness_profile: 'gaussian' [default] | 'exponential' | 'sech2' | 'none'
The perpendicular flux profile of the disk galaxy.
The default is 'gaussian'.
If none. the galaxy will become a cylinder.
rotation_curve: 'arctan' | 'exponential' | 'tanh' [default] |
'isothermal' | 'NFW' | 'Burkert' |
'mass' | 'Freeman' | 'Spano'
The profile of the velocity v(r) can be in (with X=r/rV where rV=turnover radius):
- arctan : Vmax arctan(X),
- tanh : Vmax tanh(X),
- exponential : inverted exponential, Vmax (1-exp(-X))
- isothermal : for an isothermal halo, Vmax [1-arctan(X)/X)]^0.5
- NFW : for a NFW halo, Vmax {[ln(1+X) - X/(1+X)]/X}^0.5
- Burkert : for a Burkert halo, Vmax {[ln(1 + X) + 0.5 ln (1 + X^2) - arctan(X)]/X}^0.5
- Freeman : a Freeman disk with Vmax=V2.2
- mass : a constant light-to-mass ratio v(r)=sqrt(G m(<r) / r); where m(<r) is the cumulative mass profile with m(<r) = \int I(r) 2 pi r dr
- Spano: for a Spano 2008 profile, Vmax {arcsinh(X)/X - 1/sqrt(1+X2)}
See https://doi.org/10.1093/mnras/stz1969
The default is 'tanh'.
dispersion_profile: 'thick' [default] | 'thin'
The local disk dispersion from the rotation curve and disk thickness
from Binney & Tremaine 2008, see Genzel et al. 2008.
GalPak has 3 components for the dispersion:
- a component from the rotation curve arising from mixing velocities
of a disk with non-zero thickness.
- a component from the local disk dispersion specified by
`disk_dispersion`
- a spatially constant dispersion,
which is the output parameter `velocity_dispersion`.
line: None[default] | dict to fit doublets, use a dictionary with
- line['wave']=[l, lref] eg. [3726.2, 3728.9] # Observed or Rest
- line['ratio']=[0.8, 1.0] eg. [0.8, 1.0] # The primary line for redshifts is the reddest
redshift: float
The redshift of the observed galaxy, used in mass calculus.
Will override the redshift provided at init ; this is a convenience parameter.
If this is not set anywhere, GalPak will not try to compute the mass.
"""
# fixme: use integers instead of strings here and enjoy the performance gain
FLUX_VALID = ['gaussian', 'exponential', 'de_vaucouleurs', 'sersicN2', 'user']
THICKNESS_VALID = [ 'gaussian', 'exponential', 'sech2', 'none']
DISPERSION_VALID = [ 'thick', 'thin']
CURVE_VALID = ['arctan', 'exponential', 'tanh', \
'isothermal', 'NFW', 'Burkert', 'Freeman', 'mass', 'Spano' ]
logger = logger
def __init__(self,
flux_profile='exponential',
thickness_profile='gaussian',
dispersion_profile='thick',
rotation_curve= 'tanh',
flux_image=None,
line=None,
aspect=None,
redshift=None,
pixscale=None,
cosmology='planck15'):
if flux_profile in self.FLUX_VALID:
self.flux_profile = flux_profile
else:
raise ValueError("Flux parameter should be one of self.FLUX_VALID",self.FLUX_VALID)
if rotation_curve in self.CURVE_VALID:
self.rotation_curve = rotation_curve
else:
raise ValueError("Rotation curve should be one of self.CURVE_VALID", self.CURVE_VALID)
if thickness_profile in self.THICKNESS_VALID:
self.thickness_profile = thickness_profile
if self.thickness_profile == 'exponential':
self.logger.warning("Exponential thickness profile will be deprecated")
else:
raise ValueError("Thickness profile should be one of self.THICKNESS_VALID", self.THICKNESS_VALID)
if dispersion_profile in self.DISPERSION_VALID:
self.dispersion_profile = dispersion_profile
else:
raise ValueError('Dispersion profile should be one of self.DISPERSION_VALID', self.DISPERSION_VALID)
self.line = line
self.aspect = aspect
self.redshift = redshift
self.pixscale = pixscale
self.cosmology= cosmology
self.logger = logging.getLogger('GalPaK: DiskModel')
if self.rotation_curve == 'Freeman' and self.flux_profile != 'exponential':
self.logger.warning("You have selected a Freeman disk and a flux profile that is not exponential. Use this at your own risks.")
if self.rotation_curve == 'mass':
self.logger.warning("You have selected the mass disk profile; which only works for gaussian/exponential/sersicN2 flux profile")
#fluxmap user
if self.flux_profile == 'user':
if isinstance(flux_image, str):
try:
self.flux_map_user = fits.open(flux_image)['DATA'].data
except KeyError:
self.flux_map_user = fits.open(flux_image)[0].data
else:
raise ValueError('Flux user image should have data in DATA or extention 0')
elif isinstance(flux_image, np.ndarray):
self.flux_map_user = flux_image
else:
self.logger.error("Flux image should be an array or a string")
if self.redshift != None :
if self.cosmology is not None:
self.set_cosmology(self.cosmology)
else:
self.set_cosmology() #using default
if self.aspect is not None:
self.q = self.aspect
else:
self.q = 0.15 #default aspect ratio
#self.logger.info("Set up model: %s" % (self.__str__()))
def initial_parameters(self, runner):
"""
Returns an instance of a class extending `ModelParameters`.
You may omit parameters, they will be automatically set to the mean of
the max and min.
"""
# Default initial parameters
init = self.parameters_class()(
radius=3.0,
turnover_radius=1.0,
inclination=30,
pa=np.random.uniform(0,360),
maximum_velocity=100.0,
velocity_dispersion=5.0,
flux=runner.flux_est
)
return init
def min_boundaries(self, runner):
"""
Returns an instance of a class extending `ModelParameters`.
You MUST provide all the parameters.
"""
# Default boundaries
return GalaxyParameters(
x=runner.cube.shape[2] / 3.,
y=runner.cube.shape[1] / 3.,
z=runner.cube.shape[0] / 3.,
flux=0.,
radius=0.8,
inclination=-5,
pa=-40,
turnover_radius=0.01,
maximum_velocity=10.,
velocity_dispersion=0.
)
def max_boundaries(self, runner):
"""
Returns an instance of a class extending `ModelParameters`.
You MUST provide all the parameters.
"""
# changed max radius to 3/8th of cube size.
return GalaxyParameters(
x=runner.cube.shape[2] * 2 / 3.,
y=runner.cube.shape[1] * 2 / 3.,
z=runner.cube.shape[0] * 2 / 3.,
flux=3. * runner.flux_est,
radius= 0.5 * (runner.cube.shape[1]+runner.cube.shape[2]) * 3 / 8.,
inclination=90.5,
pa=400,
turnover_radius=0.5 * (runner.cube.shape[1]+runner.cube.shape[2]) * 3 / 8. / 2.,
maximum_velocity=350.,
velocity_dispersion=180.
)
def setup_random_amplitude(self, amplitude):
"""
Mutates the random `amplitude` of the parameter jump with custom logic.
This is called during the setup of the MCMC runner.
The amplitude is already filled with :
sqrt((min_boundaries - max_boundaries) ** 2 / 12.) * p / v
where
p = number of parameters in the model
v = number of voxels in the cube
"""
amplitude['flux'] *= 0.5 # flux since we start at ~flux since flux is an integrated quantity
amplitude['pa'] *= 1.5
amplitude['maximum_velocity'] *= 1.5 #
amplitude['velocity_dispersion'] *= 1.5 # velocity dispersion
amplitude *= 3 # fixme: document this coefficient
#CUSTOM METHODS
def set_flux_profile(self, galaxy, radius_cube):
"""
creates a flux_cube in 3D (x,y,z)
returns flux_cube
"""
rhalf = galaxy['radius']
if self.flux_profile == 'de_vaucouleurs':
flux_cube = flux_sersic(radius_cube, rhalf, 4.0)
elif self.flux_profile == 'gaussian':
flux_cube = flux_sersic(radius_cube, rhalf, 0.5)
elif self.flux_profile == 'exponential':
flux_cube = flux_sersic(radius_cube, rhalf, 1.0)
elif self.flux_profile == 'sersicN2':
flux_cube = flux_sersic(radius_cube, rhalf, 2.0)
elif self.flux_profile == 'user':
if len(radius_cube.shape)==1:
#then measure 1D profile from parameters
flux_cube = self._user_profile(parameters, radius_cube)
elif len(radius_cube.shape)==3:
flux_cube = self.flux_map_user[None, :, :] # @fixme need thickness?
else:
raise ValueError("set profile with a 1d vector or 3d cube")
else:
raise ValueError("Flux profile is invalid. Should be one of '%s' ." % self.FLUX_VALID)
return flux_cube
def set_velocity_profile(self, galaxy, radius_cube):
"""
creates a velocity profile for circular orbits
return v_profile
"""
max_vel = galaxy['maximum_velocity']
rt = galaxy['turnover_radius']
x = radius_cube / rt
# Flat rotation curve
if self.rotation_curve == 'arctan':
v_profile = np.arctan(x) * max_vel * 2. / np.pi
#
elif self.rotation_curve == 'tanh':
v_profile = max_vel * np.tanh(x)
# For Feng's inv_exp profile
elif self.rotation_curve == 'exponential':
v_profile = max_vel * (1.0 - np.exp(-x))
# ISOTHERMAL rotation curve;
elif self.rotation_curve == 'isothermal' :
v_profile = max_vel * np.sqrt(1 - np.arctan(x)/x)
elif self.rotation_curve == 'NFW':
v_sq = ( np.log(1+x) - x / (1+x) ) / x #peaks at x=2.16
v_sq /= ( np.log(1+2.16) - 2.16 / (1+2.16)) / 2.16
v_profile = max_vel * np.sqrt(v_sq)
elif self.rotation_curve == 'Burkert':
v_sq = (np.log(1+x)+0.5*np.log(1+x**2)-np.arctan(x)) / x # peaks at x=3.24
v_sq /= (np.log(4.24)+0.5*np.log(1+3.24**2)-np.arctan(3.24)) / 3.24
v_profile = max_vel * np.sqrt(v_sq)
elif self.rotation_curve == 'mass':
v_profile = self._fv_newton(radius_cube, galaxy['radius'], max_vel)
elif self.rotation_curve == 'Freeman':
#Using Freeman disk. Vmax = V2.2
v_sq = self._v_disk_sq(galaxy, radius_cube)
v_profile = np.sqrt(v_sq)
elif self.rotation_curve == 'Spano':
# From Spano et al. 2008: https://doi.org/10.1111/j.1365-2966.2007.12545.x
# and Hernandez-Hernandez et al. 2019 https://doi.org/10.1093/mnras/stz1969
v_sq = 1/x * np.vectorize(np.math.asinh)(x) - 1. / (1+x**2)
v_profile = max_vel * np.sqrt(v_sq)
else:
raise NotImplementedError("Rotational Curve not supported. Should be '%s' " %
self.CURVE_VALID)
return v_profile
#Private methods
def _v_disk_sq(self, parameters, radius):
##disk Freeman model
y = 1.68 * radius / parameters['radius'] / 2.
B = special.i0(y) * special.k0(y) \
- special.i1(y) * special.k1(y) #
# Swinbank
# V(r)^2 = 0.5 (GMd/Rd) * (3.6*x)^2 * (I0K0-I1K1)
#
# Eq. 2.165. BinneyTremaine 2008
# Vsq = 2 * (G Md/Rd) y**2 [I0K0-I1K1]
# Vsq = 4 * (G Md/Rd) 0.5 * y**2 [I0K0-I1K1]
B1 = 0.1934 #y^2 B(y) peaks at y=1.1;
v_disk_sq = parameters['maximum_velocity']**2. * (y)**2. * B / B1
# 2 Vdisk_sq * B1 = Vmax_sq
return v_disk_sq
