def mc_errors(self, nsim=200):
""" Calculate the errors using MC simulations"""
errs = np.zeros((nsim, len(self.error)))
for i in range(nsim):
y = self.bestfit + np.random.normal(0, self.noise, len(
self.galaxy))
noise = np.ones_like(self.galaxy) * self.noise
sim = ppxf(self.bestfit_unbroad,
y,
noise,
velscale, [0, self.sol[1]],
goodpixels=self.goodpixels,
plot=False,
moments=4,
degree=-1,
mdegree=-1,
vsyst=self.vsyst,
lam=self.lam,
quiet=True,
bias=0.)
errs[i] = sim.sol
median = np.ma.median(errs, axis=0)
error = 1.4826 * np.ma.median(np.ma.abs(errs - median), axis=0)
# Here I am using always the maximum error between the simulated
# and the values given by pPXF.
self.error = np.maximum(error, self.error)
return
def run(self):
c = 299792.458 # speed of light in km/s
meps = np.finfo('float64').eps
dv = self.dv
velscale = self.velscale
templates = self.templates
lam_gal = self.lam_gal
mask = self.mask
wave_mask = self.wave_mask
use_mask = mask[wave_mask]
flux = ((self.flux)[wave_mask])
noise = ((self.ivar**(-0.5))[wave_mask])
nonzero_finite_bool = use_mask & (noise > 0) & (np.isfinite(noise))
igoodpixels = np.zeros(len(lam_gal)).astype(int)
igoodpixels[self.goodpixels] = 1
maskpixels = (igoodpixels & nonzero_finite_bool) > 0
noise[(noise <= 0) | ~np.isfinite(noise)] = meps
galaxy = flux / np.median(
flux[maskpixels]) # Normalize spectrum to avoid numerical issues
noise = noise / np.median(flux[maskpixels])
medsn = np.median(galaxy[maskpixels] / noise[maskpixels])
# Gas emission lines are excluded from the pPXF fit using the GOODPIXELS keyword.
# vel = c*np.log(1 + z) # eq.(8) of Cappellari (2017)
start = [0, 200.] # (km/s), starting guess for [V, sigma]
adegree = 0
mdegree = 0
pp = ppxf(templates,
galaxy,
noise,
velscale,
start,
mask=maskpixels,
plot=False,
quiet=True,
moments=2,
degree=adegree,
mdegree=mdegree,
vsyst=dv,
clean=False,
lam=lam_gal)
return pp, medsn
def ppxf_fit(self, spectrum, noise, verbose=False):
"""Run pPXF on one spaxel. Note: must run prepstellarfit() first!
Arguments:
spectrum, noise (1D array): Observed spectrum and variance array
verbose (bool): If 'True', make diagnostic plots
Returns:
params (float 1D array): Best fit velocity, velocity dispersion, velocity error, velocity dispersion error
"""
# Make sure spectrum and noise arrays are the right length
if spectrum.size != self.wvl_cropped.size:
raise ValueError('Size of spectrum array %s does not match size of wvl array %s' % (spectrum.size, self.wvl_cropped.size))
if noise.size != self.wvl_cropped.size:
raise ValueError('Size of noise array %s does not match size of wvl array %s' % (noise.size, self.wvl_cropped.size))
# Prep the observed spectrum
galspec = ndimage.gaussian_filter1d(spectrum, self.sigma)
galaxy, logLam1, velscale = util.log_rebin(self.lamRange1, galspec)
galaxy = galaxy/np.median(galaxy)
# Shift the template to fit the starting wavelength of the galaxy spectrum
c = 299792.458
dv = (self.logLam2[0] - logLam1[0])*c # km/s
goodPixels = util.determine_goodpixels(logLam1, self.lamRange2, 0)
# Here the actual fit starts. The best fit is plotted on the screen
start = [0., 200.] # (km/s), starting guess for [V, sigma]
if verbose: plot=True
else: plot=False
pp = ppxf(self.templates, galaxy, np.sqrt(noise), velscale, start,
goodpixels=goodPixels, plot=plot, moments=2,
degree=6, vsyst=dv, clean=False, quiet=True)
if verbose:
plt.show()
print("Formal errors:")
print(" dV dsigma")
print("".join("%8.2g" % f for f in pp.error*np.sqrt(pp.chi2)))
print('Best-fitting redshift z:', (self.z + 1)*(1 + pp.sol[0]/c) - 1)
return np.asarray([pp.sol[0], pp.sol[1], pp.error[0]*np.sqrt(pp.chi2), pp.error[1]*np.sqrt(pp.chi2), pp.chi2]), np.exp(logLam1), pp.bestfit, galaxy, noise
def mc_errors(self, nsim=200):
""" Calculate the errors using MC simulations"""
errs = np.zeros((nsim, len(self.error)))
for i in range(nsim):
y = self.bestfit + np.random.normal(0, self.noise,
len(self.galaxy))
noise = np.ones_like(self.galaxy) * self.noise
sim = ppxf(self.bestfit_unbroad, y, noise, velscale,
[0, self.sol[1]],
goodpixels=self.goodpixels, plot=False, moments=4,
degree=-1, mdegree=-1,
vsyst=self.vsyst, lam=self.lam, quiet=True, bias=0.)
errs[i] = sim.sol
median = np.ma.median(errs, axis=0)
error = 1.4826 * np.ma.median(np.ma.abs(errs - median), axis=0)
# Here I am using always the maximum error between the simulated
# and the values given by pPXF.
self.error = np.maximum(error, self.error)
return
def spectra_distance(star, template, mask, degree):
# Make ppxf fit without any velocity shift and with no sigma broadening.
# Only the polynomials are fitted.
velscale = 1. # Arbitrary number: we work in pixels units
start = [0, 1.] # Negligible sigma: OK with >2016 Fourier pPXF code
noise = np.ones_like(star)
pp = ppxf(template,
star,
noise,
velscale,
start,
moments=2,
degree=degree,
linear=True,
mask=mask)
resid = star - pp.bestfit
dist = np.percentile(np.abs(resid[mask]), 95.45) / np.mean(
star[mask]) * 50 # 2sigma/2 in %
return dist, pp
def fit_single_spectrum(lam_gal,
flux_gal,
templates,
velscale,
start,
velscale_ratio=1,
noise=None,
goodpixels=None,
dv=0,
add_poly_deg=4,
smooth=False,
smooth_sigma_pix=None,
clean=False,
plot=False):
"""
Fit a single spectrum with PPXF
:param lam_gal:
:param flux_gal:
:param templates:
:param velscale:
:param start:
:param velscale_ratio:
:param noise:
:param goodpixels:
:param dv:
:param add_poly_deg:
:return:
"""
# Smooth the spectrum to the resolution of the EMILES templates if requested
# The smoothing length should be provided by the user
if smooth:
flux_gal = ppxf_util.gaussian_filter1d(flux_gal, smooth_sigma_pix)
# Log rebin the spectrum to the given velocity scale
flux_rebin_gal, log_lam_gal, velscale = ppxf_util.log_rebin(
[lam_gal[0], lam_gal[-1]], flux_gal, velscale=velscale)
# Generate a default goodpixels vector
if goodpixels is None:
goodpixels = np.arange(len(flux_rebin_gal))
# Normalize the spectrum to avoid rounding error
norm = np.nanmedian(flux_rebin_gal)
flux_rebin_gal /= np.nanmedian(flux_rebin_gal)
# Generate a noise spectrum if noise is None. Use 15% of the flux
if noise is None:
noise = 0.15 * np.abs(flux_rebin_gal)
noise[np.isnan(noise) | (noise == 0)] = 1.0
# Remove NaNs and infs from goodpixels and change them to 0 in the spectrum
nonfinite_pix = ~np.isfinite(flux_rebin_gal)
flux_rebin_gal[nonfinite_pix] = 0.0
for i in range(len(nonfinite_pix)):
if nonfinite_pix[i]:
test = np.where(goodpixels == i)[0]
if len(test) > 0:
goodpixels = np.delete(goodpixels, test[0])
# Require at least 50% of the original pixels to do a fit
if np.float(len(goodpixels)) / np.float(len(log_lam_gal)) > 0.25:
# Run ppxf
pp = ppxf.ppxf(templates,
flux_rebin_gal,
noise,
velscale,
start,
plot=False,
moments=2,
degree=add_poly_deg,
vsyst=dv,
goodpixels=goodpixels,
velscale_ratio=velscale_ratio,
clean=clean)
vel = pp.sol[0]
disp = pp.sol[1]
chi2 = pp.chi2
temp_weights = pp.weights
gal = pp.galaxy
bestfit = pp.bestfit
stellar = pp.bestfit - pp.apoly
apoly = pp.apoly
residual = pp.galaxy - pp.bestfit
if plot:
pp.plot()
fig = plt.gcf()
return vel, disp, chi2, temp_weights, gal, bestfit, stellar, apoly, residual, norm, fig
else:
return vel, disp, chi2, temp_weights, gal, bestfit, stellar, apoly, residual, norm
else:
return 'Not enough pixels to fit.'
def fit_spectrum(spec,
zgal,
specresolution,
tie_balmer=False,
miles_dir=None,
rebin=True,
limit_doublets=False,
degree_add=None,
degree_mult=5,
**kwargs):
"""This is a wrapper for pPXF to fit stellar population models as well as
emission lines to galaxy spectra. Although pPXF allows otherwise, the
emission lines are kinematically fixed to one another as are the stellar
models, and the stars and gas independently vary with one another.
Please see the pPXF documentation for more details on the vast array of
parameters and options afforded by the software.
The pPXF software may be downloaded at
http://www-astro.physics.ox.ac.uk/~mxc/software/
Parameters
----------
spec : XSpectrum1D
Spectrum to be fitted
zgal : float
Redshift of galaxy
specresolution : float
Spectral resolution (R) of the data
tie_balmer : bool, optional
Assume intrinsic Balmer decrement. See documentation in ppxf_util.py,
as this has implications for the derived reddening.
limit_doublets : bool, optional
Limit the ratios of [OII] and [SII] lines to ranges allowed by atomic
physics. See documentation in ppxf_util.py, as this has implications
for getting the true flux values from those reported.
degree_add : int, optional
Degree of the additive Legendre polynomial used to modify the template
continuum in the fit.
degree_mult : int,optional
miles_dir: str, optional
Location of MILES models
Returns
-------
ppfit : ppxf
Object returned by pPXF; attributes are data pertaining to the fit
miles : miles
Contains information about the stellar templates used in the fit.
See the documentation in miles_util.py for full details
weights : 1d numpy vector
Weights of the *stellar* template components. Equivalent to the
first N elements of ppfit.weights where N is the number of stellar
templates used in the fit.
"""
if spec is None:
print('Galaxy has no spectrum associated')
return None
### Spectra must be rebinned to a log scale (in wavelength).
### pPXF provides a routine to do this, but the input spectra
### must be sampled uniformly linear. linetools to the rescue!
if rebin:
meddiff = np.median(spec.wavelength.value[1:] -
spec.wavelength.value[0:-1])
newwave = np.arange(spec.wavelength.value[0],
spec.wavelength.value[-1], meddiff)
spec = spec.rebin(newwave * units.AA, do_sig=True, grow_bad_sig=True)
# get data and transform wavelength to rest frame for template fitting
wave = spec.wavelength.to(units.Angstrom).value
flux = spec.flux.value
flux = flux * (1. + zgal)
noise = spec.sig.value
noise = noise * (1. + zgal)
wave = wave / (1. + zgal)
# transform to air wavelengths for MILES templates and get approx. FWHM
wave *= np.median(util.vac_to_air(wave) / wave)
# use only wavelength range covered by templates
mask = (wave > 3540) & (wave < 7409)
#mask = (wave > 1682) & (wave < 10000.)
maskidx = np.where(mask)[0]
# also deal with declared good regions of the spectrum
if 'goodpixels' in kwargs:
goodpix = kwargs['goodpixels']
pixmask = np.in1d(maskidx, goodpix)
newgoodpix = np.where(pixmask)[0]
kwargs['goodpixels'] = newgoodpix
wave = wave[mask]
flux = flux[mask]
noise = noise[mask]
# Nonnegative noise values are not allowed
noise[noise <= 0] = np.max(noise)
# pPXF requires the spectra to be log rebinned, so do it
flux, logLam, velscale = util.log_rebin(np.array([wave[0], wave[-1]]),
flux)
noise, junk1, junk2 = util.log_rebin(np.array([wave[0], wave[-1]]), noise)
### The following lines unnecessary for DEIMOS/Hecto spectra due to their
### units but rescaling may be necessary for some
# galaxy = flux / np.median(flux) # Normalize spectrum to avoid numerical issues
# print 'Scale flux by', round(np.median(flux),2)
galaxy = flux # use the native units
# pPXF wants the spectral resolution in units of wavelength
FWHM_gal = wave / specresolution
### Set up stellar templates
#miles_dir = resource_filename('ppxf', '/miles_models/')
#miles_dir = resource_filename('ppxf', '/emiles_padova_chabrier/')
if miles_dir is None:
miles_dir = resource_filename('ppxf', '/miles_padova_chabrier/')
#path4libcall = miles_dir + 'Mun1.30*.fits'
#path4libcall = miles_dir + 'Ech1.30*.fits'
path4libcall = miles_dir + 'Mch1.30*.fits'
miles = lib.miles(path4libcall, velscale, FWHM_gal, wave_gal=wave)
### Stuff for regularization dimensions
reg_dim = miles.templates.shape[1:]
stars_templates = miles.templates.reshape(miles.templates.shape[0], -1)
# See the pPXF documentation for the keyword REGUL
regul_err = 0.01 # Desired regularization error
### Now the emission lines! Only include lines in fit region.
if 'goodpixels' in kwargs:
gal_lam = wave[newgoodpix]
# Also, log rebinning the spectrum change which pixels are 'goodpixels'
newnewgoodpix = np.searchsorted(np.exp(logLam), gal_lam, side='left')
uqnewnewgoodpix = np.unique(newnewgoodpix)
if uqnewnewgoodpix[-1] == len(wave):
uqnewnewgoodpix = uqnewnewgoodpix[:-1]
kwargs['goodpixels'] = uqnewnewgoodpix
else:
gal_lam = wave
def FWHM_func(wave): # passed to generate emission line templates
return wave / specresolution
gas_templates, gas_names, line_wave = util.emission_lines_mask(
miles.log_lam_temp,
gal_lam,
FWHM_func,
tie_balmer=tie_balmer,
limit_doublets=limit_doublets)
# How many gas components do we have?
balmerlines = [ll for ll in gas_names if ll[0] == 'H']
numbalm = len(balmerlines)
numforbid = len(gas_names) - numbalm
# Stack all templates
templates = np.column_stack([stars_templates, gas_templates])
# other needed quantities
dv = c * (miles.log_lam_temp[0] - logLam[0])
### use the following line if not transforming to z=0 first
# vel = c * np.log(1 + zgal) # eq.(8) of Cappellari (2017)
vel = 0. # We already transformed to the restframe!
start = [vel, 25.] # (km/s), starting guess for [V, sigma]
### Set up combination of templates
n_temps = stars_templates.shape[1]
n_balmer = 1 if tie_balmer else numbalm # Number of Balmer lines included in the fit
n_forbidden = numforbid # Number of other lines included in the fit
# Assign component=0 to the stellar templates, component=1 to the Balmer
# emission lines templates, and component=2 to the forbidden lines.
# component = [0]*n_temps + [1]*n_balmer + [2]*n_forbidden
component = [0] * n_temps + [1] * (n_balmer + n_forbidden
) # tie the gas lines together
gas_component = np.array(
component) > 0 # gas_component=True for gas templates
# Fit (V, sig, h3, h4) moments=4 for the stars
# and (V, sig) moments=2 for the two gas kinematic components
if len(gas_names) > 0:
moments = [2, 2] # fix the gas kinematic components to one another
start = [[vel, 50.],
start] # Adopt different gas/stars starting values
else:
moments = [2] # only stars to be fit
start = [vel, 50.]
# If the Balmer lines are tied one should allow for gas reddening.
# The gas_reddening can be different from the stellar one, if both are fitted.
gas_reddening = 0 if tie_balmer else None
if degree_add is None:
degree_add = -1
t = time.time()
ppfit = ppxf.ppxf(templates,
galaxy,
noise,
velscale,
start,
plot=False,
moments=moments,
degree=degree_add,
vsyst=dv,
lam=np.exp(logLam),
clean=False,
regul=1. / regul_err,
reg_dim=reg_dim,
component=component,
gas_component=gas_component,
gas_names=gas_names,
gas_reddening=gas_reddening,
mdegree=degree_mult,
**kwargs)
print('Desired Delta Chi^2: %.4g' % np.sqrt(2 * galaxy.size))
print('Current Delta Chi^2: %.4g' % ((ppfit.chi2 - 1) * galaxy.size))
print('Elapsed time in PPXF: %.2f s' % (time.time() - t))
weights = ppfit.weights[
~gas_component] # Exclude weights of the gas templates
weights = weights.reshape(reg_dim) # Normalized
return ppfit, miles, weights
def ppxf_example_kinematics_sauron():
ppxf_dir = path.dirname(path.realpath(ppxf_package.__file__))
# Read a galaxy spectrum and define the wavelength range
#
cube_id = 468
cube_file = "data/cubes/cube_" + str(cube_id) + ".fits"
hdu = fits.open(cube_file)
gal_lin = hdu[0].data
h1 = hdu[0].header
cube_x_data = np.load("results/cube_" + str(int(cube_id)) + "/cube_" +
str(int(cube_id)) + "_cbd_x.npy")
cube_y_data = np.load("results/cube_" + str(int(cube_id)) + "/cube_" +
str(int(cube_id)) + "_cbs_y.npy")
mask = (cube_x_data > 5000) & (cube_x_data < 6000)
cube_y_data = cube_y_data[mask]
lamRange1 = h1['CRVAL1'] + np.array(
[0., np.abs(h1['CD1_1']) * (h1['NAXIS1'] - 1)])
FWHM_gal = 2.51 # SAURON has an instrumental resolution FWHM of 4.2A.
# If the galaxy is at significant redshift, one should bring the galaxy
# spectrum roughly to the rest-frame wavelength, before calling pPXF
# (See Sec2.4 of Cappellari 2017). In practice there is no
# need to modify the spectrum in any way, given that a red shift
# corresponds to a linear shift of the log-rebinned spectrum.
# One just needs to compute the wavelength range in the rest-frame
# and adjust the instrumental resolution of the galaxy observations.
# This is done with the following three commented lines:
#
# z = 1.23 # Initial estimate of the galaxy redshift
# lamRange1 = lamRange1/(1+z) # Compute approximate restframe wavelength range
# FWHM_gal = FWHM_gal/(1+z) # Adjust resolution in Angstrom
galaxy, logLam1, velscale = util.log_rebin(lamRange1, cube_y_data)
galaxy = galaxy / np.median(
galaxy) # Normalize spectrum to avoid numerical issues
noise = np.full_like(galaxy,
0.0047) # Assume constant noise per pixel here
print(galaxy)
# Read the list of filenames from the Single Stellar Population library
# by Vazdekis (2010, MNRAS, 404, 1639) http://miles.iac.es/. A subset
# of the library is included for this example with permission
vazdekis = glob.glob(ppxf_dir + '/miles_models/Mun1.30Z*.fits')
FWHM_tem = 2.51 # Vazdekis+10 spectra have a constant resolution FWHM of 2.51A.
velscale_ratio = 2 # adopts 2x higher spectral sampling for templates than for galaxy
# Extract the wavelength range and logarithmically rebin one spectrum
# to a velocity scale 2x smaller than the SAURON galaxy spectrum, to determine
# the size needed for the array which will contain the template spectra.
#
hdu = fits.open(vazdekis[0])
ssp = hdu[0].data
h2 = hdu[0].header
lamRange2 = h2['CRVAL1'] + np.array(
[0., h2['CDELT1'] * (h2['NAXIS1'] - 1)])
sspNew, logLam2, velscale_temp = util.log_rebin(lamRange2,
ssp,
velscale=velscale /
velscale_ratio)
templates = np.empty((sspNew.size, len(vazdekis)))
# Convolve the whole Vazdekis library of spectral templates
# with the quadratic difference between the SAURON and the
# Vazdekis instrumental resolution. Logarithmically rebin
# and store each template as a column in the array TEMPLATES.
# Quadratic sigma difference in pixels Vazdekis --> SAURON
# The formula below is rigorously valid if the shapes of the
# instrumental spectral profiles are well approximated by Gaussians.
#
FWHM_dif = np.sqrt(FWHM_gal**2 - FWHM_tem**2)
sigma = FWHM_dif / 2.355 / h2['CDELT1'] # Sigma difference in pixels
for j, file in enumerate(vazdekis):
hdu = fits.open(file)
ssp = hdu[0].data
ssp = ndimage.gaussian_filter1d(ssp, sigma)
sspNew, logLam2, velscale_temp = util.log_rebin(lamRange2,
ssp,
velscale=velscale /
velscale_ratio)
templates[:, j] = sspNew / np.median(sspNew) # Normalizes templates
# The galaxy and the template spectra do not have the same starting wavelength.
# For this reason an extra velocity shift DV has to be applied to the template
# to fit the galaxy spectrum. We remove this artificial shift by using the
# keyword VSYST in the call to PPXF below, so that all velocities are
# measured with respect to DV. This assume the redshift is negligible.
# In the case of a high-redshift galaxy one should de-redshift its
# wavelength to the rest frame before using the line below (see above).
#
c = 299792.458
if velscale_ratio > 1:
dv = (np.mean(logLam2[:velscale_ratio]) - logLam1[0]) * c # km/s
else:
dv = (logLam2[0] - logLam1[0]) * c # km/s
z = 0.0015 # Initial redshift estimate of the galaxy
goodPixels = util.determine_goodpixels(logLam1, lamRange2, z)
# Here the actual fit starts. The best fit is plotted on the screen.
# Gas emission lines are excluded from the pPXF fit using the GOODPIXELS keyword.
#
vel = c * np.log(1 + z) # eq.(8) of Cappellari (2017)
start = [vel, 200.] # (km/s), starting guess for [V, sigma]
t = clock()
pp = ppxf(templates,
galaxy,
noise,
velscale,
start,
goodpixels=goodPixels,
plot=True,
moments=4,
degree=4,
vsyst=dv,
velscale_ratio=velscale_ratio)
print("Formal errors:")
print(" dV dsigma dh3 dh4")
print("".join("%8.2g" % f for f in pp.error * np.sqrt(pp.chi2)))
print('Elapsed time in pPXF: %.2f s' % (clock() - t))
def apply_pPXF(spectra_file,
fwhm_instrument,
redshift,
noise,
vel_ratio=1,
template_dir=None,
fwhm_templates=None,
templates=None,
logLam2=None):
"""
Function to fit galaxy spectra using pPXF.
If provided with the template directory and resolution, this function will run the degrade_templates()
function in order to match the resolution of the observation and the templates. Else, if the degraded
templates are already provided, this function will just use the templates provided to fit the observed
galaxy spectra.
:param spectra_file: A string describing the path to the SimSpin spectra file.
:param fwhm_instrument: A float describing the resolution of the observed spectra.
:param redshift: A float describing the redshift, z, of the observed galaxy.
:param noise: A float describing the level of noise within the observed spectra.
:param vel_ratio: A float describing the sampling rate of the templates relative
to the observed spectra. Default value is 1.
If wishing to degrade templates to the appropriate resolution,
:param template_dir: A string describing the path to the directory in which the template files are
located. Default is None.
:param fwhm_templates: A float describing the resolution of the template spectra. Default
is None.
If you have already degraded the templates to the appropriate resolution for a previous
fit, you can provide these variables directly to the function to avoid recalculating the
comupationally expensive degradation and rebinning:
:param templates: A matrix containing the rebinned and degraded templates. Default is None.
:param logLam2: An array describing the wavelength labels of the templates. Default is None.
"""
hdu = fits.open(spectra_file)
dim = hdu[0].data.shape
mid = np.array([round(dim[1] / 2), round(dim[2] / 2)])
gal_lin = hdu[0].data # pulling in the spectra for each pixel
h1 = hdu[0].header
lamRange1 = h1['CRVAL3'] + (np.array([-h1['CRPIX3'], h1['CRPIX3']]) *
h1['CDELT3']) # wavelength range
FWHM_gal = fwhm_instrument # SAMI has an instrumental resolution FWHM of 2.65A.
z = redshift # Initial estimate of the galaxy redshift
lamRange1 = lamRange1 / (
1 + z) # Compute approximate restframe wavelength range
FWHM_gal = FWHM_gal / (1 + z) # Adjust resolution in Angstrom
galaxy, logLam1, velscale = util.log_rebin(lamRange1, gal_lin[:, mid[0],
mid[1]])
if not templates or not logLam2:
assert isinstance(template_dir, str) and isinstance(
fwhm_templates, float
), 'Please provide the path to the template directory and template resolution'
templates, logLam2 = degrade_templates(template_dir,
fwhm_templates,
FWHM_observation=FWHM_gal,
velscale_obs=velscale,
vel_ratio=vel_ratio)
velocity = np.empty([dim[1], dim[2]])
dispersion = np.empty([dim[1], dim[2]])
for x in range(0, dim[1]):
for y in range(0, dim[2]):
if all(np.isnan(gal_lin[:, x, y])):
velocity[x, y] = None
dispersion[x, y] = None
else:
galaxy, logLam1, velscale = util.log_rebin(
lamRange1, gal_lin[:, x, y])
galaxy = galaxy / np.median(
galaxy) # Normalize spectrum to avoid numerical issues
noise = np.full_like(
galaxy, noise) # Assume constant noise per pixel here
if velscale_ratio > 1:
dv = (np.mean(logLam2[:velscale_ratio]) -
logLam1[0]) * c # km/s
else:
dv = (logLam2[0] - logLam1[0]) * c # km/s
start = [100, 200.] # (km/s), starting guess for [V, sigma]
pp = ppxf.ppxf(templates,
galaxy,
noise,
velscale,
start,
plot=False,
moments=2,
quiet=True,
degree=4,
vsyst=dv,
velscale_ratio=vel_ratio)
velocity[x, y] = pp.sol[0]
dispersion[x, y] = pp.sol[1]
return velocity, dispersion
def ppxf_example_sky_and_symmetric_losvd():
ppxf_dir = path.dirname(path.realpath(ppxf_package.__file__))
# Solar metallicity, Age=12.59 Gyr
hdu = fits.open(
ppxf_dir +
'/miles_models/Mun1.30Zp0.00T12.5893_iPp0.00_baseFe_linear_FWHM_2.51.fits'
)
ssp = hdu[0].data
h = hdu[0].header
lamRange = h['CRVAL1'] + np.array([0., h['CDELT1'] * (h['NAXIS1'] - 1)])
velscale = 70. # km/s
star, logLam, velscale = util.log_rebin(lamRange, ssp, velscale=velscale)
star /= np.mean(star)
# Adopted input parameters =================================================
vel = 200. / velscale # Velocity of 1st spectrum in pixels (2nd has -vel)
sigma = 300. / velscale # Dispersion of both spectra in pixels
h3 = 0.1 # h3 of 1st spectrum (2nd has -h3)
h4 = 0.1
sn = 40.
moments = 4
deg = 4
vshift = 10 # Adopted systemic velocity in pixels
vsyst = vshift * velscale # Adopted systemic velocity in km/s
# Generate input Sky =======================================================
# For illustration, the sky is modelled as two Gaussian emission lines
n = star.size
x = np.arange(n)
sky1 = np.exp(-0.5 * (x - 1000)**2 / 100)
sky2 = np.exp(-0.5 * (x - 2000)**2 / 100)
# Generate input LOSVD =====================================================
dx = int(abs(vel) + 5 * sigma)
v = np.linspace(-dx, dx, 2 * dx + 1)
w = (v - vel) / sigma
w2 = w**2
gauss = np.exp(-0.5 * w2)
gauss /= np.sum(gauss)
h3poly = w * (2 * w2 - 3) / np.sqrt(3)
h4poly = (w2 * (4 * w2 - 12) + 3) / np.sqrt(24)
losvd = gauss * (1 + h3 * h3poly + h4 * h4poly)
# Generate first synthetic spectrum ========================================
# The template is convolved with the LOSVD
x = np.linspace(-1, 1, n)
galaxy1 = signal.fftconvolve(star, losvd, mode="same")
galaxy1 = np.roll(galaxy1, vshift) # Mimic nonzero systemic velocity
galaxy1 *= legendre.legval(
x, np.append(1,
np.random.uniform(-0.1, 0.1,
deg - 1))) # Multiplicative polynomials
galaxy1 += legendre.legval(x,
np.random.uniform(-0.1, 0.1,
deg)) # Additive polynomials
galaxy1 += sky1 + 2 * sky2 # Add two sky lines
galaxy1 = np.random.normal(galaxy1, 1 / sn) # Add noise
# Generate symmetric synthetic spectrum ====================================
# The same template is convolved with a reversed LOSVD
# and different polynomials and sky lines are included
galaxy2 = signal.fftconvolve(star, np.flip(losvd, 0), mode="same")
galaxy2 = np.roll(galaxy2, vshift) # Mimic nonzero systemic velocity
galaxy2 *= legendre.legval(
x, np.append(1,
np.random.uniform(-0.1, 0.1,
deg - 1))) # Multiplicative polynomials
galaxy2 += legendre.legval(x,
np.random.uniform(-0.1, 0.1,
deg)) # Additive polynomials
galaxy2 += 2 * sky1 + sky2 # Add two sky lines
galaxy2 = np.random.normal(galaxy2, 1 / sn) # Add noise
# Load spectral templates ==================================================
vazdekis = glob.glob(ppxf_dir + '/miles_models/Mun1.30Z*.fits')
templates = np.empty((n, len(vazdekis)))
for j, file in enumerate(vazdekis):
hdu = fits.open(file)
ssp = hdu[0].data
sspNew, logLam2, velscale = util.log_rebin(lamRange,
ssp,
velscale=velscale)
templates[:, j] = sspNew / np.median(sspNew) # Normalize templates
# Do the fit ===============================================================
# Input both galaxy spectra simultaneously to pPXF
galaxy = np.column_stack([galaxy1, galaxy2])
# Use two sky templates for each galaxy spectrum
sky = np.column_stack([sky1, sky2])
# Randomized starting guess
vel0 = vel + np.random.uniform(-1, 1)
sigma0 = sigma * np.random.uniform(0.8, 1.2)
start = np.array([vel0, sigma0]) * velscale # Convert to km/s
goodpixels = np.arange(50, n - 50)
print(
"\nThe input values are: Vel=%0.0f, sigma=%0.0f, h3=%0.1f, h4=%0.1f\n"
% (vel * velscale, sigma * velscale, h3, h4))
t = clock()
pp = ppxf(templates,
galaxy,
np.full_like(galaxy, 1 / sn),
velscale,
start,
goodpixels=goodpixels,
plot=1,
moments=moments,
vsyst=vsyst,
mdegree=deg,
degree=deg,
sky=sky)
print('Elapsed time in pPXF: %.2f s' % (clock() - t))
plt.pause(1)
def ppxf_example_population_gas_sdss(tie_balmer, limit_doublets):
ppxf_dir = path.dirname(path.realpath(ppxf_package.__file__))
cube_id = 468
# reading cube_data
cube_file = "data/cubes/cube_" + str(cube_id) + ".fits"
hdu = fits.open(cube_file)
t = hdu[0].data
# using our redshift estimate from lmfit
cube_result_file = ("results/cube_" + str(cube_id) + "/cube_" +
str(cube_id) + "_lmfit.txt")
cube_result_file = open(cube_result_file)
line_count = 0
for crf_line in cube_result_file:
if (line_count == 20):
curr_line = crf_line.split()
z = float(curr_line[1])
line_count += 1
cube_x_data = np.load("results/cube_" + str(int(cube_id)) + "/cube_" +
str(int(cube_id)) + "_cbd_x.npy")
cube_y_data = np.load("results/cube_" + str(int(cube_id)) + "/cube_" +
str(int(cube_id)) + "_cbs_y.npy")
# Only use the wavelength range in common between galaxy and stellar library.
#
mask = (cube_x_data > 3540) & (cube_x_data < 7409)
flux = cube_y_data[mask]
galaxy = flux / np.median(
flux) # Normalize spectrum to avoid numerical issues
wave = cube_x_data[mask]
# The SDSS wavelengths are in vacuum, while the MILES ones are in air.
# For a rigorous treatment, the SDSS vacuum wavelengths should be
# converted into air wavelengths and the spectra should be resampled.
# To avoid resampling, given that the wavelength dependence of the
# correction is very weak, I approximate it with a constant factor.
#
wave *= np.median(util.vac_to_air(wave) / wave)
# The noise level is chosen to give Chi^2/DOF=1 without regularization (REGUL=0).
# A constant noise is not a bad approximation in the fitted wavelength
# range and reduces the noise in the fit.
#
noise = np.full_like(galaxy,
0.01635) # Assume constant noise per pixel here
# The velocity step was already chosen by the SDSS pipeline
# and we convert it below to km/s
#
c = 299792.458 # speed of light in km/s
velscale = c * np.log(wave[1] / wave[0]) # eq.(8) of Cappellari (2017)
FWHM_gal = 2.76 # SDSS has an approximate instrumental resolution FWHM of 2.76A.
#------------------- Setup templates -----------------------
pathname = ppxf_dir + '/miles_models/Mun1.30*.fits'
miles = lib.miles(pathname, velscale, FWHM_gal)
# The stellar templates are reshaped below into a 2-dim array with each
# spectrum as a column, however we save the original array dimensions,
# which are needed to specify the regularization dimensions
#
reg_dim = miles.templates.shape[1:]
stars_templates = miles.templates.reshape(miles.templates.shape[0], -1)
# See the pPXF documentation for the keyword REGUL,
regul_err = 0.013 # Desired regularization error
# Construct a set of Gaussian emission line templates.
# Estimate the wavelength fitted range in the rest frame.
#
lam_range_gal = np.array([np.min(wave), np.max(wave)]) / (1 + z)
gas_templates, gas_names, line_wave = util.emission_lines(
miles.log_lam_temp,
lam_range_gal,
FWHM_gal,
tie_balmer=tie_balmer,
limit_doublets=limit_doublets)
# Combines the stellar and gaseous templates into a single array.
# During the PPXF fit they will be assigned a different kinematic
# COMPONENT value
#
templates = np.column_stack([stars_templates, gas_templates])
#-----------------------------------------------------------
# The galaxy and the template spectra do not have the same starting wavelength.
# For this reason an extra velocity shift DV has to be applied to the template
# to fit the galaxy spectrum. We remove this artificial shift by using the
# keyword VSYST in the call to PPXF below, so that all velocities are
# measured with respect to DV. This assume the redshift is negligible.
# In the case of a high-redshift galaxy one should de-redshift its
# wavelength to the rest frame before using the line below as described
# in PPXF_EXAMPLE_KINEMATICS_SAURON and Sec.2.4 of Cappellari (2017)
#
c = 299792.458
dv = c * (miles.log_lam_temp[0] - np.log(wave[0])
) # eq.(8) of Cappellari (2017)
vel = c * np.log(1 + z) # eq.(8) of Cappellari (2017)
start = [vel, 180.] # (km/s), starting guess for [V, sigma]
n_temps = stars_templates.shape[1]
n_forbidden = np.sum(["[" in a
for a in gas_names]) # forbidden lines contain "[*]"
n_balmer = len(gas_names) - n_forbidden
# Assign component=0 to the stellar templates, component=1 to the Balmer
# gas emission lines templates and component=2 to the forbidden lines.
component = [0] * n_temps + [1] * n_balmer + [2] * n_forbidden
gas_component = np.array(
component) > 0 # gas_component=True for gas templates
# Fit (V, sig, h3, h4) moments=4 for the stars
# and (V, sig) moments=2 for the two gas kinematic components
moments = [4, 2, 2]
# Adopt the same starting value for the stars and the two gas components
start = [start, start, start]
# If the Balmer lines are tied one should allow for gas reddeining.
# The gas_reddening can be different from the stellar one, if both are fitted.
gas_reddening = 0 if tie_balmer else None
# Here the actual fit starts.
#
# IMPORTANT: Ideally one would like not to use any polynomial in the fit
# as the continuum shape contains important information on the population.
# Unfortunately this is often not feasible, due to small calibration
# uncertainties in the spectral shape. To avoid affecting the line strength of
# the spectral features, we exclude additive polynomials (DEGREE=-1) and only use
# multiplicative ones (MDEGREE=10). This is only recommended for population, not
# for kinematic extraction, where additive polynomials are always recommended.
#
t = clock()
pp = ppxf(templates,
galaxy,
noise,
velscale,
start,
plot=False,
moments=moments,
degree=-1,
mdegree=10,
vsyst=dv,
lam=wave,
clean=False,
regul=1. / regul_err,
reg_dim=reg_dim,
component=component,
gas_component=gas_component,
gas_names=gas_names,
gas_reddening=gas_reddening)
# When the two Delta Chi^2 below are the same, the solution
# is the smoothest consistent with the observed spectrum.
#
print('Desired Delta Chi^2: %.4g' % np.sqrt(2 * galaxy.size))
print('Current Delta Chi^2: %.4g' % ((pp.chi2 - 1) * galaxy.size))
print('Elapsed time in PPXF: %.2f s' % (clock() - t))
weights = pp.weights[
~gas_component] # Exclude weights of the gas templates
weights = weights.reshape(reg_dim) / weights.sum() # Normalized
miles.mean_age_metal(weights)
miles.mass_to_light(weights, band="r")
# Plot fit results for stars and gas.
plt.clf()
plt.subplot(211)
pp.plot()
# Plot stellar population mass fraction distribution
plt.subplot(212)
miles.plot(weights)
plt.tight_layout()
#plt.pause(1)
plt.show()
#Randomize numpy seeds. Otherwise all processes will give exact same values.
#This seed depends on exact system time
np.random.seed(seed=microsecond)
normal = np.random.normal(size=noise.shape) * noise
galaxy = gal + normal
goodPixels = np.arange(len(galaxy))
em_lam = np.array([4363, 5007, 4861, 6548, 6562, 6584, 6717, 6731])
goodPixels = [x for x in range(len(lam)) if ~((lam[x] < (em_lam + 10)) & (lam[x] > (em_lam - 10))).all()]
goodPixels = np.array(goodPixels)
degrees = [10,10]
degrees = minimize_leg(galname, templates, galaxy, noise, velscale, start,
goodPixels, dv, velscale_ratio, iterations, RunMC,
find_min = True)
ppxf_obj = ppxf.ppxf(templates, galaxy, noise, velscale, start,
goodpixels=goodPixels, plot=False, moments=4,
degree=degrees[0],vsyst=dv,
velscale_ratio = velscale_ratio,
mdegree=degrees[1], clean=False)
redshift = ppxf_obj.sol[0]
vel_disp = ppxf_obj.sol[1]
vel_disp_err = ppxf_obj.error[1]*np.sqrt(ppxf_obj.chi2)
print("Minimization took %s minutes to complete"
%int(round((time.time() - stime) / 60.)))
ppxf_obj.plot()
def cal_veldis(self,
temp_spec=None,
lib_path=None,
temp_array=None,
informat='text',
temp_num=None,
sig_ins=None,
rand_temp=False,
fwhm_temp=None,
doplot=True,
verbose=True,
moments=4,
plot=True,
degree=None,
mask_reg=None,
quiet=False,
show_weight=False,
clean=False):
"""
This function calculates velocity dispersion using 'ppxf'
method.
"""
"""First Setup some parameters """
if temp_spec is None:
self.temp_spec = self.gen_rebinned_temp(lib_path=lib_path,
temp_array=temp_array,
informat=informat,
temp_num=temp_num,
sig_ins=sig_ins,
rand_temp=rand_temp,
fwhm_temp=fwhm_temp,
doplot=doplot,
verbose=verbose)
else:
self.temp_spec = temp_spec
if mask_reg is not None:
self.mask_region = self.masking(pixel_range=mask_reg)
if degree is None:
deg = np.arange(4, 6)
else:
deg = np.arange(degree[0], degree[1])
"""Setup the containers to store velocity dispersion and error
values """
vel_dis = np.zeros(len(deg))
error = np.zeros(len(deg))
best_fit = []
"""good pixels are the pixels which have been used in the fit"""
good_pixels = []
"""Do the velocity dispersion calculation """
for i, d in enumerate(deg):
print('\ndegree : %d' % d)
if mask_reg is None:
pp = ppxf(self.temp_spec,
self.flux_rebinned,
self.noise_rebinned,
self.v,
self.start,
moments=moments,
plot=plot,
vsyst=self.vsyst,
degree=d,
quiet=quiet,
clean=clean,
lam=np.exp(self.wav_rebinned))
else:
pp = ppxf(self.temp_spec,
self.flux_rebinned,
self.noise_rebinned,
self.v,
self.start,
moments=moments,
plot=plot,
vsyst=self.vsyst,
degree=d,
mask=self.mask_region,
quiet=quiet,
lam=np.exp(self.wav_rebinned),
clean=clean)
vel_dis[i] = pp.sol[1]
error[i] = pp.error[1]
best_fit.append(pp.bestfit)
good_pixels.append(pp.goodpixels)
if plot:
plt.figure()
if show_weight:
[print('%d, %f'%(i,w)) for i,w in enumerate(pp.weights)\
if w>10]
self.vel_dis = vel_dis
self.error = error
self.deg = deg
self.best_fit = best_fit
self.goodpixels = good_pixels
def stellarfit(self, plot=True):
""" Fit stellar continuum of integrated spectra, return stellar kinematics,
and subtract continuum/absorption features.
Args:
plot (bool): if 'True', make plots
Returns:
kinematics (array): [vel, veldisp, vel_err, veldisp_err, wvlarray, fitspectrum, obsspectrum, obsspectrum_err]
"""
print('Preparing templates for stellar kinematics fit...')
# Define path to pPXF directory
ppxf_dir = path.dirname(path.realpath(ppxf_package.__file__))
print(ppxf_dir)
# Define spectrum
spectrum = self.totalspec[self.goodwvl]
noise = self.totalvar[self.goodwvl]
wvl = self.wvl_zcorr[self.goodwvl]
print(spectrum.shape, noise.shape, wvl.shape)
# Define wavelength range
lamRange1 = [wvl[0], wvl[-1]]
fwhm_gal = 2.4 / (1 + self.z) # KCWI instrumental FWHM of ~2.4A
# Rebin spectrum into log scale to get initial velocity scale
galaxy, logLam1, velscale = util.log_rebin(lamRange1, spectrum)
# Read the list of filenames from template library
vazdekis = glob.glob(
ppxf_dir +
'/miles_models/Mun1.30*.fits') # From E-MILES SSP library
#vazdekis = glob.glob(ppxf_dir + '/miles_stellar/s*.fits') # From MILES stellar library
fwhm_tem = 2.51 # Vazdekis+10 spectra have a constant resolution FWHM of 2.51A.
# Open template spectrum in order to get the size of the template array
hdu = fits.open(vazdekis[0])
ssp = hdu[0].data
h2 = hdu[0].header
lamRange2 = h2['CRVAL1'] + np.array(
[0., h2['CDELT1'] * (h2['NAXIS1'] - 1)])
sspNew, logLam2, velscale_temp = util.log_rebin(lamRange2,
ssp,
velscale=velscale)
templates = np.empty((sspNew.size, len(vazdekis)))
# Convolve observed spectrum with quadratic difference between observed and template resolution.
# (This is valid if shapes of instrumental spectral profiles are well approximated by Gaussians.)
fwhm_dif = np.sqrt(np.abs(fwhm_gal**2 - fwhm_tem**2))
sigma = fwhm_dif / 2.355 / h2['CDELT1'] # Sigma difference in pixels
galspec = ndimage.gaussian_filter1d(spectrum, sigma)
# Now logarithmically rebin this new observed spectrum
galaxy, logLam1, velscale = util.log_rebin(lamRange1,
galspec,
velscale=velscale)
# TEST: log-rebin the error spectrum too?
noise, _, _ = util.log_rebin(lamRange1, noise, velscale=velscale)
# Open and normalize all the templates
for j, file in enumerate(vazdekis):
hdu = fits.open(file)
ssp = hdu[0].data
sspNew, logLam2, velscale_temp = util.log_rebin(lamRange2,
ssp,
velscale=velscale)
templates[:,
j] = sspNew / np.median(sspNew) # Normalizes templates
# Prep the observed spectrum
galaxy = galaxy / np.median(galaxy)
print('Doing stellar kinematics fit...')
print(galaxy.shape, noise.shape)
# Shift the template to fit the starting wavelength of the galaxy spectrum
c = 299792.458
dv = (logLam2[0] - logLam1[0]) * c # km/s
goodPixels = util.determine_goodpixels(logLam1, lamRange2, 0)
# Here the actual fit starts. The best fit is plotted on the screen
start = [0., 200.] # (km/s), starting guess for [V, sigma]
pp = ppxf(templates,
galaxy,
np.sqrt(noise),
velscale,
start,
goodpixels=goodPixels,
plot=plot,
moments=2,
degree=6,
vsyst=dv,
clean=False,
quiet=True)
if plot:
plt.show()
print('Chi2:', pp.chi2)
print('Best-fitting redshift z:',
(self.z + 1) * (1 + pp.sol[0] / c) - 1)
print('Final solution:', pp.sol)
print("Errors:", pp.error * np.sqrt(pp.chi2))
if plot:
plt.figure(figsize=(9, 3))
lines = np.array([
3726.03, 3728.82, 3970.08, 4101.76, 4340.47, 4363.21, 4861.33,
4958.92, 5006.84, 6300.30, 6548.03, 6583.41, 6562.80, 6716.47,
6730.85
])
for line in lines:
if line < np.exp(logLam1)[-1]:
plt.axvspan(line - 10.,
line + 10.,
color='gray',
alpha=0.25)
plt.fill_between(np.exp(logLam1),
galaxy - np.sqrt(noise),
galaxy + np.sqrt(noise),
color='r',
alpha=0.8)
plt.plot(np.exp(logLam1), pp.bestfit, 'k-')
plt.xlabel(r'$\lambda (\AA)$', fontsize=14)
plt.ylabel(r'Normalized flux', fontsize=14)
plt.ylim(-0.05, 2.0)
plt.savefig('figures/' + self.galaxyname + '/' + 'intspec.png',
bbox_inches='tight')
plt.show()
# Subtract stellar contribution from spectrum
print('Normalizing data by best-fit stellar template...')
self.spectrum_norm = galaxy - pp.bestfit * np.median(galaxy)
self.kinematics_wvl = np.exp(logLam1)
np.save('output/' + self.galaxyname + '/intspec_norm',
self.spectrum_norm)
np.save('output/' + self.galaxyname + '/intspec_wvl',
self.kinematics_wvl)
# Plot image for testing
if plot:
# Plot example spectrum
plt.figure(figsize=(9, 3))
lines = np.array([
3726.03, 3728.82, 3970.08, 4101.76, 4340.47, 4363.21, 4861.33,
4958.92, 5006.84, 6300.30, 6548.03, 6583.41, 6562.80, 6716.47,
6730.85
])
for line in lines:
if line < np.exp(logLam1)[-1]:
plt.axvspan(line - 10.,
line + 10.,
color='gray',
alpha=0.25)
plt.fill_between(np.exp(logLam1),
self.spectrum_norm - np.sqrt(noise),
self.spectrum_norm + np.sqrt(noise),
color='r',
alpha=0.8)
plt.plot(np.exp(logLam1), self.spectrum_norm, 'k-')
plt.xlabel(r'$\lambda (\AA)$', fontsize=14)
plt.ylabel(r'Normalized flux', fontsize=14)
plt.xlim(3500, 5100)
plt.savefig('figures/' + self.galaxyname + '/' +
'intspec_norm.png',
bbox_inches='tight')
plt.show()
return np.asarray([
pp.sol[0], pp.sol[1], pp.error[0] * np.sqrt(pp.chi2),
pp.error[1] * np.sqrt(pp.chi2)
]), np.exp(logLam1), pp.bestfit, galaxy, noise
def ppxf_single(object_id,
z_init,
lambda_spec,
galaxy_lin,
error_lin,
cars_model,
emsub_specfile=None,
plotfile=None,
outfile=None,
outfile_spec=None,
mpoly=None,
apoly=None,
reflines=None):
# Speed of light
c = 299792.458
#h_spec = spec_hdu[0].header
#Ang_air = h_spec['CRVAL3'] + np.arange(0,h_spec['CDELT3']*(h_spec['NAXIS3']),h_spec['CDELT3'])
#s = 10**4/Ang_air
#n = 1 + 0.00008336624212083 + 0.02408926869968 / (130.1065924522 - s**2) + 0.000159740894897 / (38.92568793293 - s**2)
#lambda_spec = Ang_air*n
#wave = h_spec['CRVAL3'] + np.arange(0,h_spec['CDELT3']*(h_spec['NAXIS3']),h_spec['CDELT3'])
#lambda_spec = vactoair(wave)
#lambda_spec = h_spec['CRVAL3'] + np.arange(0,h_spec['CDELT3']*(h_spec['NAXIS3']),h_spec['CDELT3'])
# Crop to finite
use = (np.isfinite(galaxy_lin) & (galaxy_lin > 0.0))
# Making a "use" vector
use_indices = np.arange(galaxy_lin.shape[0])[use]
galaxy_lin = (galaxy_lin[use_indices.min():(use_indices.max() + 1)])[2:-3]
error_lin = (error_lin[use_indices.min():(use_indices.max() + 1)])[2:-3]
lambda_spec = (lambda_spec[use_indices.min():(use_indices.max() +
1)])[2:-3]
lamRange_gal = np.array([np.min(lambda_spec), np.max(lambda_spec)])
# New resolution estimate = 0.9 \AA (sigma), converting from sigma to FWHM
FWHM_gal = 2.355 * (np.max(lambda_spec) -
np.min(lambda_spec)) / len(lambda_spec)
print('FWHM', FWHM_gal)
lamRange_gal = lamRange_gal / (
1 + float(z_init)) # Compute approximate restframe wavelength range
FWHM_gal = FWHM_gal / (1 + float(z_init)) # Adjust resolution in Angstrom
sigma_gal = FWHM_gal / (2.3548 * 4500.0) * c # at ~4500 \AA
# log rebinning for the fits
galaxy, logLam_gal, velscale = util.log_rebin(np.around(lamRange_gal,
decimals=3),
galaxy_lin,
flux=True)
noise, logLam_noise, velscale = util.log_rebin(np.around(lamRange_gal,decimals=3), error_lin, \
velscale=velscale, flux=True)
# correcting for infinite or zero noise
noise[np.logical_or((noise == 0.0), np.isnan(noise))] = 1.0
galaxy[np.logical_or((galaxy < 0.0), np.isnan(galaxy))] = 0.0
if galaxy.shape != noise.shape:
galaxy = galaxy[:-1]
logLam_gal = logLam_gal[:-1]
# Define lamRange_temp and logLam_temp
#lamRange_temp, logLam_temp = setup_spectral_library_conroy(velscale[0], FWHM_gal)
# Construct a set of Gaussian emission line templates.
# Estimate the wavelength fitted range in the rest frame.
#
gas_templates, line_names, line_wave = util.emission_lines(
logLam_gal, lamRange_gal, FWHM_gal)
goodpixels = np.arange(galaxy.shape[0])
wave = np.exp(logLam_gal)
# crop very red end (only affects a very small subsample)
# goodpixels = goodpixels[wave <= 5300]
# exclude lines at the edges (where things can go very very wrong :))
include_lines = np.where((line_wave > (wave.min() + 10.0))
& (line_wave < (wave.max() - 10.0)))
if line_wave[include_lines[0]].shape[0] < line_wave.shape[0]:
line_wave = line_wave[include_lines[0]]
line_names = line_names[include_lines[0]]
gas_templates = gas_templates[:, include_lines[0]]
#reg_dim = stars_templates.shape[1:]
reg_dim = gas_templates.shape[1:]
templates = gas_templates
#np.hstack([gas_templates, gas_templates])
dv = 0 #(logLam_temp[0]-logLam_gal[0])*c # km/s
vel = 0 #np.log(z_init + 1)*c # Initial estimate of the galaxy velocity in km/s
#z = np.exp(vel/c) - 1 # Relation between velocity and redshift in pPXF
# Here the actual fit starts. The best fit is plotted on the screen.
# Gas emission lines are excluded from the pPXF fit using the GOODPIXELS keyword.
#
t = clock()
nNLines = gas_templates.shape[1]
component = [0] * nNLines
start_gas = [vel, 100.]
start = start_gas # adopt the same starting value for both gas (BLs and NLs) and stars
moments = [
2
] # fit (V,sig,h3,h4) for the stars and (V,sig) for the gas' broad and narrow components
fixed = None
## Additive polynomial degree
if apoly is None:
degree = int(
np.ceil((lamRange_gal[1] - lamRange_gal[0]) /
(100.0 * (1. + float(z_init)))))
else:
degree = int(apoly)
if mpoly is None: mdegree = 3
else: mdegree = int(mpoly)
# Trying: sigmas must be kinematically decoupled
# #Trying: velocities must be kinematically decoupled
#A_ineq = [[0,0,2,0,-1,0]]
#b_ineq = [0]
bounds_gas = [[-1000, 1000], [0, 1000]]
bounds = bounds_gas
pp = ppxf.ppxf(templates,
galaxy,
noise,
velscale,
start,
fixed=fixed,
plot=False,
moments=moments,
mdegree=mdegree,
degree=degree,
vsyst=dv,
reg_dim=reg_dim,
goodpixels=goodpixels,
bounds=bounds)
#component=component,
# redshift_to_newtonian:
# return (v-astropy.constants.c.to('km/s').value*redshift)/(1.0+redshift)
# "v" from above is actually the converted velocity which is
# (np.exp(v_out/c) - 1)*c
v_gas = pp.sol[0]
ev_gas = pp.error[0]
conv_vel_gas = (np.exp(pp.sol[0] / c) - 1) * c
vel_gas = (1 + z_init) * (conv_vel_gas - c * z_init)
sigma_gas = pp.sol[1] #first # is template, second # is the moment
esigma_gas = pp.error[1] #*np.sqrt(pp.chi2)
zfit_gas = (z_init + 1) * (1 + pp.sol[0] / c) - 1
zfit_stars = z_init
ezfit_gas = (z_init + 1) * pp.error[0] * np.sqrt(pp.chi2) / c
if plotfile is not None:
#
### All of the rest of this plots and outputs the results of the fit
### Feel free to comment anything out at will
#
maskedgalaxy = np.copy(galaxy)
lowSN = np.where(noise > (0.9 * np.max(noise)))
maskedgalaxy[lowSN] = np.nan
wave = np.exp(logLam_gal) * (1. + z_init) / (1. + zfit_stars)
fig = plt.figure(figsize=(12, 7))
ax1 = fig.add_subplot(211)
# plotting smoothed spectrum
smoothing_fact = 3
ax1.plot(wave,
convolve(maskedgalaxy, Box1DKernel(smoothing_fact)),
color='Gray',
linewidth=0.5)
ax1.plot(wave[goodpixels],
convolve(maskedgalaxy[goodpixels],
Box1DKernel(smoothing_fact)),
'k',
linewidth=1.)
label = "Best fit template from high res Conroy SSPs + emission lines at z={0:.3f}".format(
zfit_stars)
# overplot stellar templates alone
ax1.plot(wave, pp.bestfit, 'r', linewidth=1.0, alpha=0.75, label=label)
ax1.set_ylabel('Flux')
ax1.legend(loc='upper right', fontsize=10)
ax1.set_title(object_id)
xmin, xmax = ax1.get_xlim()
ax2 = fig.add_subplot(413, sharex=ax1, sharey=ax1)
# plotting emission lines if included in the fit
gas = pp.matrix[:, -nNLines:].dot(pp.weights[-nNLines:])
ax2.plot(wave, gas, 'b', linewidth=2,\
label = '$\sigma_{gas}$'+'={0:.0f}$\pm${1:.0f} km/s'.format(sigma_gas, esigma_gas)+', $V_{gas}$'+'={0:.0f}$\pm${1:.0f} km/s'.format(v_gas, ev_gas)) # overplot emission lines alone
cars_model = (cars_model[use_indices.min():(use_indices.max() +
1)])[2:-3]
ax2.plot(np.array(lambda_spec)/(1+z_init), cars_model, color='orange', linewidth=1,\
label = 'CARS Model')
#(lambda_spec[use_indices.min():(use_indices.max()+1)])[2:-3]
stars = pp.bestfit - gas
#if (ymax > 3.0*np.median(stars)): ymax = 3.0*np.median(stars)
#if (ymin < -0.5): ymin = -0.5
ax2.set_ylabel('Best Fits')
ax2.legend(loc='upper left', fontsize=10)
# Plotting the residuals
ax3 = fig.add_subplot(817, sharex=ax1)
ax3.plot(wave[goodpixels],
(convolve(maskedgalaxy, Box1DKernel(smoothing_fact)) -
pp.bestfit)[goodpixels],
'k',
label='Fit Residuals')
#ax3.set_yticks([-0.5,0,0.5])
ax3.set_ylabel('Residuals')
ax4 = fig.add_subplot(818, sharex=ax1)
ax4.plot(wave, noise, 'k', label='Flux Error')
ax4.set_ylabel('Noise')
ax4.set_xlabel('Rest Frame Wavelength [$\AA$]')
#ax4.set_yticks(np.arange(0,0.5,0.1))
'''if reflines is not None:
for i,w,label in zip(range(len(reflines)),reflines['wave'],reflines['label']):
if ((w > xmin) and (w < xmax)):
# ax1.text(w,ymin+(ymax-ymin)*(0.03+0.08*(i % 2)),'$\mathrm{'+label+'}$',fontsize=10,\
# horizontalalignment='center',\
# bbox=dict(boxstyle='round', facecolor='white', alpha=0.5))
print(label.decode("utf-8"))
ax1.text(w,ymin+(ymax-ymin)*(0.03+0.08*(i % 2)),'$\mathrm{'+label.decode("utf-8")+'}$',fontsize=10,\
horizontalalignment='center',\
bbox=dict(boxstyle='round', facecolor='white', alpha=0.5))
ax1.plot([w,w],[ymin,ymax],':k',alpha=0.5)'''
fig.subplots_adjust(hspace=0.05)
plt.setp([a.get_xticklabels() for a in fig.axes[:-1]], visible=False)
#print('Saving figure to {0}'.format(plotfile))
ax1.set_xlim([6450, 6750])
ax2.set_xlim([6450, 6750])
#ymin, ymax = ax1.get_ylim([])
plt.savefig(plotfile, dpi=150)
plt.close()
return v_gas, vel_gas, sigma_gas, pp.chi2
# print('# id z_stars ez_stars sigma_stars esigma_stars z_gas ez_gas sigma_gas esigma_gas SN_median SN_rf_4000 SN_obs_8030 chi2dof')
print('{0:d} {1:.6f} {2:.6f} {3:.1f} {4:.1f} {5:.6f} {6:.6f} {7:.1f} {8:.1f} {9:.1f} {10:.1f} {11:.1f} {12:.2f}\n'.format(\
object_id,zfit_stars,ezfit_stars, sigma_stars,esigma_stars,\
zfit_gas, ezfit_gas, sigma_gas, esigma_gas, SN_median, SN_rf_4000, SN_obs_8030, pp.chi2))
## This prints the fit parameters to an open file object called outfile
if outfile is not None:
outfile.write('{0:d} {1:d} {2:.6f} {3:.6f} {4:.1f} {5:.1f} {6:.6f} {7:.6f} {8:.1f} {9:.1f} {10:.1f} {11:.1f} {12:.1f} {13:.2f}\n'.format(\
object_id, row2D, zfit_stars, ezfit_stars, sigma_stars,esigma_stars,\
zfit_gas, ezfit_gas, sigma_gas, esigma_gas, SN_median, SN_rf_4000, SN_obs_8030, pp.chi2))
## This outputs the spectrum and best-fit model to an open file object called outfile_spec
if outfile_spec is not None:
outfile_spec.write(
'# l f ef f_stars f_gas f_model_tot used_in_fit add_poly mult_poly\n'
)
for i in np.arange(wave.shape[0]):
isgood = 0
if goodpixels[goodpixels == i].shape[0] == 1: isgood = 1
outfile_spec.write(
'{0:0.4f} {1:0.4f} {2:0.4f} {3:0.4f} {4:0.4f} {5:0.4f} {6} {7:0.4f} {8:0.4f}\n'
.format(wave[i], galaxy[i], noise[i], stars[i], gas[i],
pp.bestfit[i], isgood, add_polynomial[i],
mult_polynomial[i]))
# ## This outputs the best-fit emission-subtracted spectrum to a fits file
# ## but I've commented it out since you are unlikely to need this!
# if emsub_specfile is not None:
# wave = np.exp(logLam_gal)*(1.+z_init)
# if include_gas:
# emsub = galaxy - gas
# else:
# emsub = galaxy
# col1 = fits.Column(name='wavelength', format='E', array=wave)
# col2 = fits.Column(name='flux',format='E',array=galaxy)
# col3 = fits.Column(name='error',format='E',array=noise)
# col4 = fits.Column(name='flux_emsub',format='E',array=emsub)
# cols = fits.ColDefs([col1,col2,col3,col4])
# tbhdu = fits.BinTableHDU.from_columns(cols)
# # delete old file if it exists
# if os.path.isfile(emsub_specfile): os.remove(emsub_specfile)
# tbhdu.writeto(emsub_specfile)
# return zfit_stars, ezfit_stars, sigma_stars, esigma_stars, zfit_gas, ezfit_gas, \
# sigma_gas, esigma_gas, SN_median, SN_rf_4000, SN_obs_8030, pp.chi2
return zfit_stars, sigma_stars, sigma_blr, wave, pp.bestfit
def rv_fit(self, guesses, niter=10000, line_sigma=3,\
n_CPU=-1, line_significants=5, RV_guess_var=0.):
"""
The module runs the radial velocity fit using `ppxf`_ and the
:ref:`Monte Carlo`.
Args:
guesses : :func:`numpy.array`
The initial guesses for the the radial velocity fit guesses in
the form [RV,sepctral_dispersion]
Kwargs:
niter : :obj:`int` (optional, default: 10000)
number of iterations to bootstrap the spectrum
line_sigma: :obj:`int` (optional, default: 3):
sigma for the RV clipping for the individual lines
n_CPU : :obj:`float` (optional, default: -1)
Setting the number of CPUs used for the parallelization. If set
to -1 all available system resources are used. Maximum number
of CPUs is the number of spectral lines the fit is performed
to.
line_significants: :obj:`int` (optional, default: 5)
The sigma-level for the spectral line to be above the continuum
in order to be considered *valid*
RV_guess_var : :obj:`float` (optional, default: 0)
The maximum variation the RV guess will be varied using a
uniform distribution.
"""
self.logger.info('Starting the RV fitting')
self.logger.info('Settings: niter=' + str(niter)\
+ '; sigma RV for excluding lines: ' + str(line_sigma))
start_time = time.time()
if self.loglevel == "DEBUG":
n_CPU = 1
if n_CPU == -1:
n_CPU = cpu_count()
self.logger.info('Max number of cores: '\
+ str(n_CPU))
### transfer the spectrum to log-space
log_spec_f, logspec_lambda, velscale_spec\
= ppxf_util.log_rebin([self.spec_lambda[0],\
self.spec_lambda[-1]], self.spec_f)
log_template_f, log_template_lambda, velscale_template\
= ppxf_util.log_rebin([self.spec_lambda[0],\
self.spec_lambda[-1]], self.template_f)
log_spec_err, log_spec_err_lambda, velscale_spec_err\
= ppxf_util.log_rebin([self.spec_lambda[0],\
self.spec_lambda[-1]], self.spec_err)
log_spec_err[~np.isfinite(log_spec_err)] = 1.
# This happens if AO was used and there is a gap in the spec
exponent = int(np.log10(np.nanmedian(log_spec_f)) - 4.)
# Obtain larger flux numbers to make it numerically stable
factor = float(10**(exponent * (-1)))
log_spec_f = log_spec_f * factor
log_template_f = log_template_f * factor
log_spec_err = log_spec_err * factor
l_fit = self.cat.loc[:, 'l_fit'].values.astype(np.float64)
l_lab = self.cat.loc[:, 'l_lab'].values.astype(np.float64)
line_name = self.cat.index
fwhm_g, fwhm_l, fwhm_v\
= voigt_FWHM(self.cat.loc[:, 'sg_fit'].values.astype(np.float64),\
self.cat.loc[:, 'sl_fit'].values.astype(np.float64))
used = np.where(self.cat.loc[:, 'used'] == 'f')
l_fit = np.delete(l_fit, used)
l_lab = np.delete(l_lab, used)
line_name = np.delete(line_name, used)
fwhm_g = np.delete(fwhm_g, used)
fwhm_l = np.delete(fwhm_l, used)
fwhm_v = np.delete(fwhm_v, used)
v = np.zeros_like(l_lab)
ev = np.zeros_like(l_lab)
for i, line in enumerate(l_lab):
self.logger.info('Started line ' + line_name[i])
if self.cat.loc[line_name[i], 'significance'] > line_significants:
mask = np.zeros(len(log_template_f), dtype=bool)
ind_min = np.argmin(np.abs(log_template_lambda\
- np.log(line - 0.5 * fwhm_v[i]))) - 1
ind_max = np.argmin(np.abs(log_template_lambda\
- np.log(line + 0.5 * fwhm_v[i]))) + 1
ind_center = np.argmin(np.abs(log_template_lambda\
- np.log(line)))
mask[ind_min:ind_max + 1] = True
log_spec_f[~np.isfinite(log_spec_f)] = 0.
pp_outliers_init = ppxf.ppxf(log_template_f, log_spec_f,\
log_spec_err, velscale_spec, guesses,\
mask=mask, degree=-1, clean=False, quiet=True,\
plot=False, fixed=[0, 1])
self.logger.info('RV guess variation line ' + line_name[i]\
+ ': ' + str('{:4.2f}'.format(RV_guess_var)) + 'km/s')
v[i], ev[i] = ppxf_MC(log_template_f, log_spec_f,\
log_spec_err, velscale_spec, guesses, nrand=0.5 * niter,\
goodpixels=pp_outliers_init.goodpixels, degree=-1,\
moments=2, RV_guess_var=RV_guess_var, n_CPU=n_CPU)
self.logger.info('Finished line ' + line_name[i]\
+ ': RV=(' + str('{:4.2f}'.format(v[i])) + '+-'\
+ str('{:4.3f}'.format(ev[i])) + ')km/s')
else:
self.logger.info(line_name[i]\
+ ': Line not significant [level ='\
+ str(line_significants) + ']')
ev[i] = np.nan
v[i] = np.nan
self.cat.loc[line_name[i], 'RV'] = v[i]
self.cat.loc[line_name[i], 'eRV'] = ev[i]
remaining_lines = line_clipping(self, v, line_significants,\
sigma=line_sigma)
if remaining_lines.mask.all():
self.logger.error('NO USABLE LINE FOUND WITH SET PARAMETER !!')
else:
self.cat.loc[line_name[~remaining_lines.mask], 'used'] = 'x'
l_fit = l_fit[~remaining_lines.mask]
fwhm_v = fwhm_v[~remaining_lines.mask]
rv_var_lines = MAD(self.cat.loc[line_name[~remaining_lines.mask],\
'RV'])
RV_guess_var_min = RV_guess_var
if rv_var_lines > RV_guess_var:
RV_guess_var = rv_var_lines
self.logger.info('RV guess variation: min = '\
+ str(RV_guess_var_min) + 'km/s; used = '\
+ str('{:4.2f}'.format(RV_guess_var)) + 'km/s')
mask = np.zeros(len(self.spec_lambda), dtype=bool)
for i, line in enumerate(l_fit):
ind_min = np.argmin(np.abs(logspec_lambda\
- np.log(line - 0.5 * fwhm_v[i]))) - 1
ind_max = np.argmin(np.abs(logspec_lambda\
- np.log(line + 0.5 * fwhm_v[i]))) + 1
ind_center = np.argmin(np.abs(logspec_lambda - np.log(line)))
mask[ind_min:ind_max + 1] = True
# pp_final_plot = plt.figure(str(self.spec_id)\
# + '_ppxf_fit_final', figsize=(10, 3))
if len(l_lab) > 1:
pp_final_init = ppxf.ppxf(log_template_f, log_spec_f,\
log_spec_err, velscale_spec, guesses, degree=-1, clean=False,\
mask=mask, quiet=True, fixed=[0, 1])
if len(l_lab) == 1:
pp_final_init = pp_outliers_init
# pp_final_init.plot()
# # plt.tight_layout()
# plt.savefig(self.spec_id + '_ppxf_fit_final.png', dpi=600)
# plt.close()
self.logger.info('Started final RV fit')
self.rv, self.erv = ppxf_MC(log_template_f, log_spec_f,\
log_spec_err, velscale_spec, guesses,\
nrand=niter, goodpixels=pp_final_init.goodpixels, degree=-1,\
moments=2, spec_id=self.spec_id, RV_guess_var=RV_guess_var,\
n_CPU=n_CPU)
elapsed_time = time.time() - start_time
self.logger.info('Used lines for RV fit: '\
+ ', '.join(line_name[~remaining_lines.mask]))
self.logger.info('Finished RV fitting: RV=('\
+ str('{:4.2f}'.format(self.rv)) + '+-'\
+ str('{:4.3f}'.format(self.erv)) + ')km/s based on '\
+ str(len(l_fit)) + '/' + str(len(line_name)) + ' lines')
self.logger.info('Elapsed time: '\
+ time.strftime("%H:%M:%S", time.gmtime(elapsed_time)))
def ppxf_L_tot(int_spec, header, redshift, vel, dist_mod, dM_err=[0.1, 0.1]):
"""Take in collapsed galaxy spectra, with vel and distance modulus, to calculate L_bol based on various filter bands. \
Also returns Vega mangitudes for g,r and Johnson V bands, along with sigma (LOSVD).
Parameters
----------
int_spec : float, array
Collapsed spectra of the galaxy.
header : Fits header object
galaxy's Fits file header, containing information for the function.
redshift : float
Redshift of the galaxy, from recession velocity
vel : float
recession velocity of the galaxy, in km/s
dist_mod : float
Distance modulus for use in the calculation of Lbol and magnitudes
dM_err : list, optional
Error in distance modulus, by default [0.1,0.1]
Returns
-------
dict
lum_bol_g, lum_bol_g_u, lum_bol_g_l, mag_g, mag_r, mag_v, fit_sigma
"""
# Read a galaxy spectrum and define the wavelength range
lamRange1 = header['CRVAL3'] + np.array([
0., header['CD3_3'] * (header['NAXIS3'] - 1)
]) #IMPORTANTE: EL RANGO DE LAMBDAS ESTA EN ESCALA LOGARITMICA
#Transformamos los pixeles en lambdas:
#lam=np.linspace(lamRange1[0],lamRange[1],len(gal_lin[0,:]))
FWHM_gal = 2.81 # SAURON has an instrumental resolution FWHM of 4.2A.
# If the galaxy is at a significant redshift (z > 0.03), one would need to apply
# a large velocity shift in PPXF to match the template to the galaxy spectrum.
# This would require a large initial value for the velocity (V > 1e4 km/s)
# in the input parameter START = [V,sig]. This can cause PPXF to stop!
# The solution consists of bringing the galaxy spectrum roughly to the
# rest-frame wavelength, before calling PPXF. In practice there is no
# need to modify the spectrum before the usual LOG_REBIN, given that a
# red shift corresponds to a linear shift of the log-rebinned spectrum.
# One just needs to compute the wavelength range in the rest-frame
# and adjust the instrumental resolution of the galaxy observations.
# This is done with the following three commented lines:
#
# z = 1.23 # Initial estimate of the galaxy redshift
# lamRange1 = lamRange1/(1+z) # Compute approximate restframe wavelength range
# FWHM_gal = FWHM_gal/(1+z) # Adjust resolution in Angstrom
galaxy, logLam1, velscale = util.log_rebin(lamRange1, int_spec)
cond = np.exp(logLam1) <= 6900
# Getting the apparent magnitude of the galaxy in the g, r and V bands
mag_g, Flux_g = library(np.exp(logLam1[cond]),
galaxy[cond] * 1.0e-20,
filt="SDSS",
band="g")
mag_r, Flux_r = library(np.exp(logLam1[cond]),
galaxy[cond] * 1.0e-20,
filt="SDSS",
band="r")
mag_v, Flux_v = library(np.exp(logLam1[cond]),
galaxy[cond] * 1.0e-20,
filt="GROUND_JOHNSON",
band="V")
# Converting to absolute magnitude
M_g = mag_g - dist_mod #
M_g_u = mag_g - (dist_mod + dM_err[0]) # upper distance M_g
M_g_l = mag_g - (dist_mod - dM_err[1]) # lower distance M_g
# M_r = mag_r - dist_mod
# M_r_u = mag_r - (dist_mod + dM_err[0]) # upper distance M_g
# M_r_l = mag_r - (dist_mod - dM_err[1])
# M_v = mag_v - dist_mod
# M_v_u = mag_v - (dist_mod + dM_err[0]) # upper distance M_g
# M_v_l = mag_v - (dist_mod - dM_err[1])
galaxy = galaxy / np.median(
galaxy) # Normalize spectrum to avoid numerical issues
noise = np.full_like(galaxy,
redshift) # Assume constant noise per pixel here
# Read the list of filenames from the Single Stellar Population library
# by Vazdekis (2010, MNRAS, 404, 1639) http://miles.iac.es/. A subset
# of the library is included for this example with permission
vazdekis = glob.glob(
'emiles/Ekb1.30*') # PUT HERE THE DIRECTORY TO EMILES_STARS
FWHM_tem = 2.51 # Vazdekis+10 spectra have a constant resolution FWHM of 2.51A.
velscale_ratio = 2 # adopts 2x higher spectral sampling for templates than for galaxy
miles_path = path.expanduser("emiles/Ekb1.30Z*.fits")
miles = lib.miles(miles_path, velscale, FWHM_tem)
stars_templates = miles.templates.reshape(miles.templates.shape[0], -1)
reg_dim = miles.templates.shape[1:]
# Extract the wavelength range and logarithmically rebin one spectrum
# to a velocity scale 2x smaller than the SAURON galaxy spectrum, to determine
# the size needed for the array which will contain the template spectra.
#
hdu = fits.open(vazdekis[0])
ssp = hdu[0].data
h2 = hdu[0].header
lamRange2 = h2['CRVAL1'] + np.array(
[0., h2['CDELT1'] * (h2['NAXIS1'] - 1)])
sspNew, logLam2, velscale_temp = util.log_rebin(lamRange2,
ssp,
velscale=velscale /
velscale_ratio)
templates = np.empty(
(sspNew.size, len(vazdekis))) # PUT HERE THE DIRECTORY TO MILES_STARS
# Extract the wavelength range and logarithmically rebin one spectrum
# to a velocity scale 2x smaller than the SAURON galaxy spectrum, to determine
# the size needed for the array which will contain the template spectra.
#
hdu = fits.open(vazdekis[0])
ssp = hdu[0].data
h2 = hdu[0].header
lamRange2 = h2['CRVAL1'] + np.array(
[0., h2['CDELT1'] * (h2['NAXIS1'] - 1)])
sspNew, logLam2, velscale_temp = util.log_rebin(lamRange2,
ssp,
velscale=velscale /
velscale_ratio)
templates = np.empty((sspNew.size, len(vazdekis)))
# Convolve the whole Vazdekis library of spectral templates
# with the quadratic difference between the SAURON and the
# Vazdekis instrumental resolution. Logarithmically rebin
# and store each template as a column in the array TEMPLATES.
# Quadratic sigma difference in pixels Vazdekis --> SAURON
# The formula below is rigorously valid if the shapes of the
# instrumental spectral profiles are well approximated by Gaussians.
#
FWHM_dif = np.sqrt(FWHM_gal**2 - FWHM_tem**2)
sigma = FWHM_dif / 2.355 / h2['CDELT1'] # Sigma difference in pixels
for j, vazd in enumerate(vazdekis):
hdu = fits.open(vazd)
ssp = hdu[0].data
ssp = ndimage.gaussian_filter1d(ssp, sigma)
sspNew, logLam2, velscale_temp = util.log_rebin(lamRange2,
ssp,
velscale=velscale /
velscale_ratio)
templates[:, j] = sspNew / np.median(sspNew) # Normalizes templates
# The galaxy and the template spectra do not have the same starting wavelength.
# For this reason an extra velocity shift DV has to be applied to the template
# to fit the galaxy spectrum. We remove this artificial shift by using the
# keyword VSYST in the call to PPXF below, so that all velocities are
# measured with respect to DV. This assume the redshift is negligible.
# In the case of a high-redshift galaxy one should de-redshift its
# wavelength to the rest frame before using the line below (see above).
#
c = 299792.458 # in km/s
#c = 299792458.0 # speed of light
dv = (logLam2[0] - logLam1[0]) * c # km/s
z = np.exp(vel / c) - 1 # Relation between velocity and redshift in pPXF
cond = np.exp(logLam1) <= 7810 #6900
logLam1 = logLam1[cond]
galaxy = galaxy[cond]
noise = noise[cond]
goodPixels = util.determine_goodpixels(logLam1, lamRange2, z)
# Here the actual fit starts. The best fit is plotted on the screen.
# Gas emission lines are excluded from the pPXF fit using the GOODPIXELS keyword.
#
start = [vel, 200.] # (km/s), starting guess for [V, sigma]
t = clock()
galaxy[np.where(np.isfinite(galaxy) == False)] = 0.0
noise[np.where(np.isfinite(noise) == False)] = 0.0
templates[np.where(np.isfinite(templates) == False)] = 0.0
pp = ppxf(templates,
galaxy,
noise * 0.0 + 1.0,
velscale,
start,
goodpixels=goodPixels,
plot=True,
moments=4,
mdegree=15,
vsyst=dv,
velscale_ratio=velscale_ratio)
weights = pp.weights
normalized_weights = weights / np.sum(weights)
# Use miles_utils to get metallicity
weights = pp.weights
weights = weights.reshape(reg_dim) / weights.sum() # Normalized
miles.mean_age_metal(weights)
fit_sigma = pp.sol
optimal_template = np.zeros(templates.shape[0])
for j in range(0, templates.shape[1]):
optimal_template = optimal_template + templates[:,
j] * normalized_weights[
j]
print("Formal errors:")
print(" dV dsigma dh3 dh4")
print("".join("%8.2g" % f for f in pp.error * np.sqrt(pp.chi2)))
print('Elapsed time in PPXF: %.2f s' % (clock() - t))
# Pass the optimal template to get the bolometric correction for the g-band
BC_g = transmission(np.exp(logLam2), optimal_template, band="g")
# BC_r = transmission(np.exp(logLam2), optimal_template, band="r")
# BC_v = transmission(np.exp(logLam2), optimal_template, band="V")
# Obtaining the bolometric correction of the Sun
BC_sun_g, M_sun_g = library(0, 0, filt="SDSS", band="g", get_sun='Y')
# BC_sun_r, M_sun_r = library(0,0,filt="SDSS", band="r",get_sun='Y')
# BC_sun_v, M_sun_v = library(0,0,filt="GROUND_JOHNSON", band="V",get_sun='Y')
# Getting the bolometric luminosity (in solar luminosity) for the g-band
lum_bol_g = 10.0**(-0.4 * (M_g - M_sun_g)) * 10.0**(-0.4 *
(BC_g - BC_sun_g))
lum_bol_g_u = 10.0**(-0.4 * (M_g_u - M_sun_g)) * 10.0**(
-0.4 * (BC_g - BC_sun_g)) # upper dM L
lum_bol_g_l = 10.0**(-0.4 * (M_g_l - M_sun_g)) * 10.0**(
-0.4 * (BC_g - BC_sun_g)) # lower dM L
# lum_bol_r = 10.0**(-0.4*(M_r-M_sun_r)) * 10.0**(-0.4*(BC_r-BC_sun_r))
# lum_bol_r_u = 10.0**(-0.4*(M_r_u-M_sun_r)) * 10.0**(-0.4*(BC_r-BC_sun_r)) # upper dM L
# lum_bol_r_l = 10.0**(-0.4*(M_r_l-M_sun_r)) * 10.0**(-0.4*(BC_r-BC_sun_r)) # lower dM L
# lum_bol_v = 10.0**(-0.4*(M_v-M_sun_v)) * 10.0**(-0.4*(BC_v-BC_sun_v))
# lum_bol_v_u = 10.0**(-0.4*(M_v_u-M_sun_v)) * 10.0**(-0.4*(BC_v-BC_sun_v)) # upper dM L
# lum_bol_v_l = 10.0**(-0.4*(M_v_l-M_sun_v)) * 10.0**(-0.4*(BC_v-BC_sun_v)) # lower dM L
#lum_bol_r, [lum_bol_r_u, lum_bol_r_l], lum_bol_v, [lum_bol_v_u, lum_bol_v_l],
result_dict = {
"Lbol": lum_bol_g,
"Lbol_err_up": lum_bol_g_u,
"Lbol_err_lo": lum_bol_g_l,
"mag_g": mag_g,
"mag_r": mag_r,
"mag_v": mag_v,
"sigma": fit_sigma[1]
}
return result_dict
def ppxf_example_simulation():
ppxf_dir = path.dirname(path.realpath(ppxf_package.__file__))
hdu = fits.open(
ppxf_dir +
'/miles_models/Mun1.30Zp0.00T12.5893_iPp0.00_baseFe_linear_FWHM_2.51.fits'
) # Solar metallicitly, Age=12.59 Gyr
ssp = hdu[0].data
h = hdu[0].header
lamRange = h['CRVAL1'] + np.array([0., h['CDELT1'] * (h['NAXIS1'] - 1)])
c = 299792.458 # speed of light in km/s
velscale = c * h['CDELT1'] / max(
lamRange) # Do not degrade original velocity sampling
star, logLam, velscale = util.log_rebin(lamRange, ssp, velscale=velscale)
# The finite sampling of the observed spectrum is modeled in detail:
# the galaxy spectrum is obtained by oversampling the actual observed spectrum
# to a high resolution. This represent the true spectrum, which is later resampled
# to lower resolution to simulate the observations on the CCD. Similarly, the
# convolution with a well-sampled LOSVD is done on the high-resolution spectrum,
# and later resampled to the observed resolution before fitting with PPXF.
factor = 10 # Oversampling integer factor for an accurate convolution
starNew = ndimage.interpolation.zoom(
star, factor,
order=3) # This is the underlying spectrum, known at high resolution
star = rebin(
starNew, factor
) # Make sure that the observed spectrum is the integral over the pixels
h3 = 0.1 # Adopted G-H parameters of the LOSVD
h4 = 0.1
sn = 30. # Adopted S/N of the Monte Carlo simulation
m = 300 # Number of realizations of the simulation
moments = 4
velV = np.random.rand(m) # velocity in *pixels* [=V(km/s)/velScale]
sigmaV = np.linspace(
0.5, 4, m) # Range of sigma in *pixels* [=sigma(km/s)/velScale]
result = np.zeros((m, moments)) # This will store the results
t = clock()
for j, (vel, sigma) in enumerate(zip(velV, sigmaV)):
dx = int(
abs(vel) +
5 * sigma) # Sample the Gaussian and GH at least to vel+5*sigma
x = np.linspace(
-dx, dx, 2 * dx * factor +
1) # Evaluate the Gaussian using steps of 1/factor pixels.
w = (x - vel) / sigma
w2 = w**2
gauss = np.exp(-0.5 * w2)
gauss /= np.sum(gauss) # Normalized total(gauss)=1
h3poly = w * (2. * w2 - 3.) / np.sqrt(3.) # H3(y)
h4poly = (w2 * (4. * w2 - 12.) + 3.) / np.sqrt(24.) # H4(y)
losvd = gauss * (1. + h3 * h3poly + h4 * h4poly)
galaxy = signal.fftconvolve(
starNew, losvd, mode="same") # Convolve the oversampled spectrum
galaxy = rebin(
galaxy, factor) # Integrate spectrum into original spectral pixels
noise = galaxy / sn # 1sigma error spectrum
galaxy = np.random.normal(galaxy,
noise) # Add noise to the galaxy spectrum
start = np.array([
vel + np.random.uniform(-1, 1),
sigma * np.random.uniform(0.8, 1.2)
]) * velscale # Convert to km/s
pp = ppxf(star,
galaxy,
noise,
velscale,
start,
goodpixels=np.arange(dx, galaxy.size - dx),
plot=False,
moments=moments,
bias=0.2)
result[j, :] = pp.sol
print('Calculation time: %.2f s' % (clock() - t))
plt.clf()
plt.subplot(221)
plt.plot(sigmaV * velscale, result[:, 0] - velV * velscale, '+k')
plt.axhline(0, color='r')
plt.axvline(velscale, linestyle='dashed')
plt.axvline(2 * velscale, linestyle='dashed')
plt.ylim(-20, 20)
plt.xlabel(r'$\sigma_{\rm in}\ (km\ s^{-1})$')
plt.ylabel(r'$V - V_{\rm in}\ (km\ s^{-1})$')
plt.text(2.05 * velscale, -15, r'2$\times$velscale')
plt.subplot(222)
plt.plot(sigmaV * velscale, result[:, 1] - sigmaV * velscale, '+k')
plt.axhline(0, color='r')
plt.axvline(velscale, linestyle='dashed')
plt.axvline(2 * velscale, linestyle='dashed')
plt.ylim(-20, 20)
plt.xlabel(r'$\sigma_{in}\ (km\ s^{-1})$')
plt.ylabel(r'$\sigma - \sigma_{\rm in}\ (km\ s^{-1})$')
plt.text(2.05 * velscale, -15, r'2$\times$velscale')
plt.subplot(223)
plt.plot(sigmaV * velscale, result[:, 2], '+k')
plt.axhline(h3, color='r')
plt.axhline(0, linestyle='dotted', color='limegreen')
plt.axvline(velscale, linestyle='dashed')
plt.axvline(2 * velscale, linestyle='dashed')
plt.ylim(-0.2 + h3, 0.2 + h3)
plt.xlabel(r'$\sigma_{\rm in}\ (km\ s^{-1})$')
plt.ylabel('$h_3$')
plt.text(2.05 * velscale, h3 - 0.15, r'2$\times$velscale')
plt.subplot(224)
plt.plot(sigmaV * velscale, result[:, 3], '+k')
plt.axhline(h4, color='r')
plt.axhline(0, linestyle='dotted', color='limegreen')
plt.axvline(velscale, linestyle='dashed')
plt.axvline(2 * velscale, linestyle='dashed')
plt.ylim(-0.2 + h4, 0.2 + h4)
plt.xlabel(r'$\sigma_{\rm in}\ (km\ s^{-1})$')
plt.ylabel('$h_4$')
plt.text(2.05 * velscale, h4 - 0.15, r'2$\times$velscale')
plt.tight_layout()
plt.pause(1)
def ppxf_example_kinematics_sdss():
ppxf_dir = path.dirname(path.realpath(ppxf_package.__file__))
# Read SDSS DR12 galaxy spectrum taken from here http://dr12.sdss3.org/
# The spectrum is *already* log rebinned by the SDSS DR12
# pipeline and log_rebin should not be used in this case.
file = ppxf_dir + '/spectra/NGC4636_SDSS_DR12.fits'
hdu = fits.open(file)
t = hdu['COADD'].data
z = 0.003129 # SDSS redshift estimate
# Only use the wavelength range in common between galaxy and stellar library.
mask = (t['loglam'] > np.log10(3540)) & (t['loglam'] < np.log10(7409))
flux = t['flux'][mask]
galaxy = flux / np.median(
flux) # Normalize spectrum to avoid numerical issues
loglam_gal = t['loglam'][mask]
lam_gal = 10**loglam_gal
noise = np.full_like(galaxy,
0.0166) # Assume constant noise per pixel here
c = 299792.458 # speed of light in km/s
frac = lam_gal[1] / lam_gal[0] # Constant lambda fraction per pixel
dlam_gal = (frac - 1) * lam_gal # Size of every pixel in Angstrom
wdisp = t['wdisp'][
mask] # Intrinsic dispersion of every pixel, in pixels units
fwhm_gal = 2.355 * wdisp * dlam_gal # Resolution FWHM of every pixel, in Angstroms
velscale = np.log(
frac) * c # Velocity scale in km/s per pixel (eq.8 of Cappellari 2017)
# If the galaxy is at significant redshift, one should bring the galaxy
# spectrum roughly to the rest-frame wavelength, before calling pPXF
# (See Sec.2.4 of Cappellari 2017). In practice there is no
# need to modify the spectrum in any way, given that a red shift
# corresponds to a linear shift of the log-rebinned spectrum.
# One just needs to compute the wavelength range in the rest-frame
# and adjust the instrumental resolution of the galaxy observations.
# This is done with the following three commented lines:
#
# lam_gal = lam_gal/(1+z) # Compute approximate restframe wavelength
# fwhm_gal = fwhm_gal/(1+z) # Adjust resolution in Angstrom
# Read the list of filenames from the Single Stellar Population library
# by Vazdekis (2010, MNRAS, 404, 1639) http://miles.iac.es/. A subset
# of the library is included for this example with permission
vazdekis = glob.glob(ppxf_dir + '/miles_models/Mun1.30Z*.fits')
fwhm_tem = 2.51 # Vazdekis+10 spectra have a constant resolution FWHM of 2.51A.
# Extract the wavelength range and logarithmically rebin one spectrum
# to the same velocity scale of the SDSS galaxy spectrum, to determine
# the size needed for the array which will contain the template spectra.
#
hdu = fits.open(vazdekis[0])
ssp = hdu[0].data
h2 = hdu[0].header
lam_temp = h2['CRVAL1'] + h2['CDELT1'] * np.arange(h2['NAXIS1'])
lamRange_temp = [np.min(lam_temp), np.max(lam_temp)]
sspNew = util.log_rebin(lamRange_temp, ssp, velscale=velscale)[0]
templates = np.empty((sspNew.size, len(vazdekis)))
# Interpolates the galaxy spectral resolution at the location of every pixel
# of the templates. Outside the range of the galaxy spectrum the resolution
# will be extrapolated, but this is irrelevant as those pixels cannot be
# used in the fit anyway.
fwhm_gal = np.interp(lam_temp, lam_gal, fwhm_gal)
# Convolve the whole Vazdekis library of spectral templates
# with the quadratic difference between the SDSS and the
# Vazdekis instrumental resolution. Logarithmically rebin
# and store each template as a column in the array TEMPLATES.
# Quadratic sigma difference in pixels Vazdekis --> SDSS
# The formula below is rigorously valid if the shapes of the
# instrumental spectral profiles are well approximated by Gaussians.
#
# In the line below, the fwhm_dif is set to zero when fwhm_gal < fwhm_tem.
# In principle it should never happen and a higher resolution template should be used.
#
fwhm_dif = np.sqrt((fwhm_gal**2 - fwhm_tem**2).clip(0))
sigma = fwhm_dif / 2.355 / h2['CDELT1'] # Sigma difference in pixels
for j, fname in enumerate(vazdekis):
hdu = fits.open(fname)
ssp = hdu[0].data
ssp = util.gaussian_filter1d(
ssp, sigma) # perform convolution with variable sigma
sspNew = util.log_rebin(lamRange_temp, ssp, velscale=velscale)[0]
templates[:, j] = sspNew / np.median(sspNew) # Normalizes templates
# The galaxy and the template spectra do not have the same starting wavelength.
# For this reason an extra velocity shift DV has to be applied to the template
# to fit the galaxy spectrum. We remove this artificial shift by using the
# keyword VSYST in the call to PPXF below, so that all velocities are
# measured with respect to DV. This assume the redshift is negligible.
# In the case of a high-redshift galaxy one should de-redshift its
# wavelength to the rest frame before using the line below (see above).
#
c = 299792.458
dv = np.log(lam_temp[0] / lam_gal[0]) * c # km/s
goodpixels = util.determine_goodpixels(np.log(lam_gal), lamRange_temp, z)
# Here the actual fit starts. The best fit is plotted on the screen.
# Gas emission lines are excluded from the pPXF fit using the GOODPIXELS keyword.
#
vel = c * np.log(1 + z) # eq.(8) of Cappellari (2017)
start = [vel, 200.] # (km/s), starting guess for [V, sigma]
t = clock()
pp = ppxf(templates,
galaxy,
noise,
velscale,
start,
goodpixels=goodpixels,
plot=True,
moments=4,
degree=12,
vsyst=dv,
clean=False,
lam=lam_gal)
print("Formal errors:")
print(" dV dsigma dh3 dh4")
print("".join("%8.2g" % f for f in pp.error * np.sqrt(pp.chi2)))
print('Elapsed time in PPXF: %.2f s' % (clock() - t))
def apply_ppxf(self,
galnoise,
FWHM_gal,
FWHM_tem,
z,
moments,
plot=False,
directory_plots=''):
"""This is the method that uses the PPxF package and applies it to the trimmed
data. It saves the results in the class variable 'results_ppxf'. It also has the
possibility of saving the plots that it produces.
Parameters
----------
galnoise : float
Noise in the galaxy's data.
FWHM_gal : float
Full width-half maximum of the galaxy.
FWHM_tem : float
Full width-half maximum of the templates.
z : float
The galaxy's redshift.
moments : int
The number of moments that should be used with PPxF.
plot : boolean, optional
Boolean to determine if the plots should be saved.
directory_plots : String
String that represents the absolute path where the plots are
to be saved at.
"""
# make sure that the list of results is empty
self.results_ppxf = []
temp_header, ssp = self.templates[self.templates_names[0]]
CRVAL1h3 = temp_header["CRVAL1"]
CRPIX1h3 = temp_header["CRPIX1"]
CDELT1h3 = temp_header["CDELT1"]
NAXIS1h3 = temp_header["NAXIS1"]
# calculate the wavelenght range from the templates
lamRange2 = (CRVAL1h3 - CRPIX1h3 * CDELT1h3) + np.array(
[0., (CDELT1h3 * NAXIS1h3 - 1.0)])
# speed of light
c = 299792.458
# Initial estimate of the galaxy's velocity in km/s
vel = c * z
# I NEED TO UNDERSTAND WHAT THE FOLLOWING TWO LINES MEAN
goodPixels = np.arange(
1150,
1820) #(1150,1820) #[1150,1820] or perhaps an np.arange(1150,1820)
start = [vel, 120.]
# The current pixel being worked on
number_of_pixel = 1
### Start nested loop
for i in np.arange(self.cube.trimmed_data.shape[1]):
for j in np.arange(self.cube.trimmed_data.shape[2]):
# the spectrum corresponding to these pixel coordinates
spec = self.cube.trimmed_data[:, i, j]
galaxy, logLam1, velscale = util.log_rebin(
self.cube.wavelength_range, spec)
galaxy = galaxy / np.median(galaxy) # Normalizing the spectrum
noise = galaxy * 0 + galnoise # Assuming constant noise per pixel here
sspNew, logLam2, velscale = util.log_rebin(lamRange2,
ssp,
velscale=velscale)
templates = np.zeros((sspNew.shape[0], self.ntemplates))
FWHM_dif = np.sqrt((FWHM_gal**2 - FWHM_tem**2))
sigma = FWHM_dif / 2.355 / CDELT1h3
#list_of_templates_names = list(templates_dictionary.keys())
k = 0
while k < self.ntemplates:
h3, ssp = self.templates[self.templates_names[k]]
ssp = util.gaussian_filter1d(
ssp, sigma) # perform convolution with variable
sspNew = util.log_rebin(lamRange2, ssp,
velscale=velscale)[0]
templates[:, k] = sspNew / np.median(sspNew)
k += 1
dv = (logLam2[0] - logLam1[0]) * c # km/s
pp = ppxf(templates,
galaxy,
noise,
velscale,
start,
goodpixels=goodPixels,
plot=False,
moments=moments,
degree=4,
mdegree=0,
vsyst=dv)
self.results_ppxf.append(pp)
if plot:
plt.rcParams['figure.figsize'] = (32, 20)
myplt = pp.plot()
plt.savefig(directory_plots + str(number_of_pixel) +
".pdf")
plt.clf()
number_of_pixel += 1
def fit(self, wavelength, data, mask=None, initial_velocity=0.0, initial_sigma=150.0, fwhm_gal=2, fwhm_model=1.8,
noise=0.05, plot_fit=False, quiet=False, deg=4, moments=4, **kwargs):
"""
Performs the pPXF fit.
Parameters
----------
wavelength : numpy.ndarray
Wavelength coordinates of the data.
data : numpy.ndarray
Input spectrum flux vector.
mask : list
List of masked regions, as pairs of wavelength coordinates.
initial_velocity : float
Initial guess for radial velocity.
initial_sigma : float
Initial guess for the velocity dispersion.
fwhm_gal : float
Full width at half maximum of a resolution element in the observed spectrum in units of pixels.
fwhm_model : float
The same as the above for the models.
noise : float or numpy.ndarray
If float it as assumed as the signal to noise ratio, and will be horizontally applied to the whole
spectrum. If it is an array, it will be interpreted as individual noise values for each pixel.
plot_fit : bool
Plots the resulting fit.
quiet : bool
Prints information on the fit.
deg : int
Degree of polynomial function to be fit in addition to the stellar population spectrum.
moments : int
Number of moments in the Gauss-Hermite polynomial. A simple Gaussian would be 2.
kwargs
Additional keyword arguments passed directly to ppxf.
Returns
-------
pp
pPXF output object.
See Also
--------
ppxf, ppxf_util
"""
self.mask = mask
fw = (wavelength >= self.fitting_window[0]) & (wavelength < self.fitting_window[1])
lam_range1 = wavelength[fw][[0, -1]]
gal_lin = copy.deepcopy(data[fw])
self.obs_flux = gal_lin
galaxy, log_lam1, velscale = ppxf_util.log_rebin(lam_range1, gal_lin)
# Here we use the goodpixels as the fitting window
gp = np.arange(len(log_lam1))
lam1 = np.exp(log_lam1)
self.obs_wavelength = lam1
if self.mask is not None:
if len(self.mask) == 1:
gp = gp[(lam1 < self.mask[0][0]) | (lam1 > self.mask[0][1])]
else:
m = np.array([(lam1 < i[0]) | (lam1 > i[1]) for i in self.mask])
gp = gp[np.sum(m, 0) == m.shape[0]]
self.good_pixels = gp
lam_range2 = self.base_wavelength[[0, -1]]
ssp = self.base[0]
ssp_new, log_lam2, velscale = ppxf_util.log_rebin(lam_range2, ssp, velscale=velscale)
templates = np.empty((ssp_new.size, len(self.base)))
fwhm_dif = np.sqrt(fwhm_gal ** 2 - fwhm_model ** 2)
# Sigma difference in pixels
sigma = fwhm_dif / 2.355 / self.base_delta
for j in range(len(self.base)):
ssp = self.base[j]
ssp = gaussian_filter(ssp, sigma)
ssp_new, log_lam2, velscale = ppxf_util.log_rebin(lam_range2, ssp, velscale=velscale)
# Normalizes templates
templates[:, j] = ssp_new / np.median(ssp_new)
c = constants.c.value * 1.e-3
dv = (log_lam2[0] - log_lam1[0]) * c # km/s
# z = np.exp(vel/c) - 1
# Here the actual fit starts.
start = [initial_velocity, initial_sigma] # (km/s), starting guess for [V,sigma]
# Assumes uniform noise accross the spectrum
def make_noise(galaxy, noise):
noise = galaxy * noise
noise_mask = (~np.isfinite(noise)) | (noise <= 0.0)
mean_noise = np.mean(noise[~noise_mask])
noise[noise_mask] = mean_noise
return noise
if isinstance(noise, float):
noise = make_noise(galaxy, noise)
elif isinstance(noise, np.ndarray):
noise, log_lam1, velscale = ppxf_util.log_rebin(lam_range1, copy.deepcopy(noise)[fw])
self.noise = noise
self.normalization_factor = np.nanmean(galaxy)
galaxy = copy.deepcopy(ma.getdata(galaxy / self.normalization_factor))
noise = copy.deepcopy(ma.getdata(np.abs(noise / self.normalization_factor)))
assert np.all((noise > 0) & np.isfinite(noise)), 'Invalid values encountered in noise spectrum.'
if len(gp.shape) > 1:
gp = gp[0]
pp = ppxf.ppxf(templates, galaxy, noise, velscale, start, goodpixels=gp, moments=moments, degree=deg, vsyst=dv,
quiet=quiet, **kwargs)
self.solution = pp
if plot_fit:
self.plot_fit()
return pp
def ppxf_wifis(spectrumfl, z_guess=0.004, sigma_guess=170.):
ppxf_dir = path.dirname(path.realpath(ppxf_package.__file__))
# Read a galaxy spectrum and define the wavelength range
#
hdu = fits.open(spectrumfl)
gal_lin = hdu[0].data
wl_lin = hdu[1].data
noise_lin = hdu[2].data
#wh_fit = np.where((wl_lin >= 11600) & (wl_lin <= 13000))[0]
wh_fit = np.where((wl_lin >= 11600) & (wl_lin <= 13000))[0]
gal_lin = gal_lin[wh_fit]
wl_lin = wl_lin[wh_fit]
noise_lin = noise_lin[wh_fit]
#lamRange1 = h1['CRVAL1'] + np.array([0., h1['CDELT1']*(h1['NAXIS1'] - 1)])
lamRange1 = [wl_lin[0], wl_lin[-1]]
#FWHM_gal = 6.06 # SAURON has an instrumental resolution FWHM of 4.2A.
#FWHM_gal = 5.08 # SAURON has an instrumental resolution FWHM of 4.2A.
FWHM_gal = 4.68 # SAURON has an instrumental resolution FWHM of 4.2A.
# If the galaxy is at significant redshift, one should bring the galaxy
# spectrum roughly to the rest-frame wavelength, before calling pPXF
# (See Sec2.4 of Cappellari 2017). In practice there is no
# need to modify the spectrum in any way, given that a red shift
# corresponds to a linear shift of the log-rebinned spectrum.
# One just needs to compute the wavelength range in the rest-frame
# and adjust the instrumental resolution of the galaxy observations.
# This is done with the following three commented lines:
#
# z = 1.23 # Initial estimate of the galaxy redshift
# lamRange1 = lamRange1/(1+z) # Compute approximate restframe wavelength range
# FWHM_gal = FWHM_gal/(1+z) # Adjust resolution in Angstrom
galaxy, logLam1, velscale = util.log_rebin(lamRange1, gal_lin)
noise, logLam1, velscale = util.log_rebin(lamRange1, noise_lin)
galaxy = galaxy / np.median(
galaxy) # Normalize spectrum to avoid numerical issues
noise = noise / np.median(noise)
#noise = np.full_like(galaxy, 0.0047) # Assume constant noise per pixel here
# Read the list of filenames from the Single Stellar Population library
# by Vazdekis (2010, MNRAS, 404, 1639) http://miles.iac.es/. A subset
# of the library is included for this example with permission
#vazdekis = glob.glob('/home/elliot/mcmcgemini/spec/vcj_ssp/*t05.0*Zp0.0*.s100')
vazdekis = glob.glob('/home/elliot/mcmcgemini/spec/vcj_ssp/*.s100')
FWHM_tem = 1.63 # Vazdekis+10 spectra have a constant resolution FWHM of 2.51A.
#FWHM_tem = 3 # Vazdekis+10 spectra have a constant resolution FWHM of 2.51A.
velscale_ratio = 3 # adopts 2x higher spectral sampling for templates than for galaxy
# Extract the wavelength range and logarithmically rebin one spectrum
# to a velocity scale 2x smaller than the SAURON galaxy spectrum, to determine
# the size needed for the array which will contain the template spectra.
#
hdu = np.loadtxt(vazdekis[0])
ssp = hdu[:, 74]
modelwl = hdu[:, 0]
wh_wifis = np.where((modelwl >= 8000) & (modelwl <= 13500))[0]
modelwl_wifis = modelwl[wh_wifis]
wl_rebin = np.linspace(modelwl_wifis[0],
modelwl_wifis[-1],
num=len(modelwl_wifis))
ssp_rebin = np.interp(wl_rebin, modelwl_wifis, ssp[wh_wifis])
lamRange2 = [wl_rebin[0], wl_rebin[-1]]
sspNew, logLam2, velscale_temp = util.log_rebin(lamRange2,
ssp_rebin,
velscale=velscale /
velscale_ratio)
#h2 = hdu[0].header
#lamRange2 = h2['CRVAL1'] + np.array([0., h2['CDELT1']*(h2['NAXIS1'] - 1)])
fullage = np.array([1.0, 3.0, 5.0, 7.0, 9.0, 11.0, 13.5])
#fullZ = np.array([-1.5, -1.0, -0.5, 0.0, 0.2])
fullZ = np.array([-0.5, 0.0, 0.2])
#templates = np.empty((sspNew.size, len(vazdekis)))
templates = np.empty((sspNew.size, len(fullage), len(fullZ)))
conroydict = {}
for fl in vazdekis:
flspl = fl.split('/')[-1]
mnamespl = flspl.split('_')
age = float(mnamespl[3][1:])
Zsign = mnamespl[4][1]
Zval = float(mnamespl[4][2:5])
if Zsign == "m":
Zval = -1.0 * Zval
conroydict[(age, Zval)] = fl
# Convolve the whole Vazdekis library of spectral templates
# with the quadratic difference between the SAURON and the
# Vazdekis instrumental resolution. Logarithmically rebin
# and store each template as a column in the array TEMPLATES.
# Quadratic sigma difference in pixels Vazdekis --> SAURON
# The formula below is rigorously valid if the shapes of the
# instrumental spectral profiles are well approximated by Gaussians.
#
FWHM_dif = np.sqrt(FWHM_gal**2 - FWHM_tem**2)
#sigma = FWHM_dif/2.355/h2['CDELT1'] # Sigma difference in pixels
sigma = FWHM_dif / 2.355 / (wl_rebin[1] - wl_rebin[0]
) # Sigma difference in pixels
for j in range(len(fullage)):
for k in range(len(fullZ)):
#for j, file in enumerate(vazdekis):
x = pd.read_csv(conroydict[(fullage[j], fullZ[k])],
delim_whitespace=True,
header=None)
hdu = np.array(x)
#hdu = np.loadtxt(conroydict[(fullage[j],fullZ[j])])
ssp = hdu[:, 73]
ssp_rebin = np.interp(wl_rebin, modelwl_wifis, ssp[wh_wifis])
ssp = ndimage.gaussian_filter1d(ssp_rebin, sigma)
sspNew, logLam2, velscale_temp = util.log_rebin(lamRange2,
ssp,
velscale=velscale /
velscale_ratio)
templates[:, j,
k] = sspNew / np.median(sspNew) # Normalizes templates
# The galaxy and the template spectra do not have the same starting wavelength.
# For this reason an extra velocity shift DV has to be applied to the template
# to fit the galaxy spectrum. We remove this artificial shift by using the
# keyword VSYST in the call to PPXF below, so that all velocities are
# measured with respect to DV. This assume the redshift is negligible.
# In the case of a high-redshift galaxy one should de-redshift its
# wavelength to the rest frame before using the line below (see above).
#
c = 299792.458
dv = (np.mean(logLam2[:velscale_ratio]) - logLam1[0]) * c # km/s
z = z_guess # Initial redshift estimate of the galaxy
goodPixels = util.determine_goodpixels(logLam1, lamRange2, z)
# Here the actual fit starts. The best fit is plotted on the screen.
# Gas emission lines are excluded from the pPXF fit using the GOODPIXELS keyword.
#
vel = c * np.log(1 + z) # eq.(8) of Cappellari (2017)
start = [vel, sigma_guess] # (km/s), starting guess for [V, sigma]
t = clock()
pp = ppxf(templates,
galaxy,
noise,
velscale,
start,
goodpixels=goodPixels,
plot=True,
moments=2,
degree=4,
vsyst=dv,
velscale_ratio=velscale_ratio)
print("Formal errors:")
print(" dV dsigma dh3 dh4")
print("".join("%8.2g" % f for f in pp.error * np.sqrt(pp.chi2)))
print('Elapsed time in pPXF: %.2f s' % (clock() - t))
# If the galaxy is at significant redshift z and the wavelength has been
# de-redshifted with the three lines "z = 1.23..." near the beginning of
# this procedure, the best-fitting redshift is now given by the following
# commented line (equation 2 of Cappellari et al. 2009, ApJ, 704, L34;
# http://adsabs.harvard.edu/abs/2009ApJ...704L..34C)
#
# print('Best-fitting redshift z:', (z + 1)*(1 + pp.sol[0]/c) - 1)
return pp
def run_ppxf(fields, w1, w2, targetSN, tempfile, logdir, redo=False,
ncomp=2, **kwargs):
""" New function to run pPXF. """
global velscale
stars = pf.getdata(tempfile, 0)
emission = pf.getdata(tempfile, 1)
logLam_temp = wavelength_array(tempfile, axis=1, extension=0)
ngas = len(emission)
nstars = len(stars)
templates = np.column_stack((stars.T, emission.T))
##########################################################################
# Set components
if ncomp == 1:
components = np.zeros(nstars + ngas)
kwargs["component"] = components
elif ncomp == 2:
components = np.hstack((np.zeros(nstars), np.ones(ngas))).astype(int)
kwargs["component"] = components
##########################################################################
for f in fields:
print "Working on Field {0}".format(f[-1])
os.chdir(os.path.join(data_dir, "combined_{0}".format(f)))
outdir = os.path.join(os.getcwd(), logdir)
if not os.path.exists(outdir):
os.mkdir(outdir)
fits = "binned_sn{0}_res2.95.fits".format(targetSN)
data = pf.getdata(fits, 0)
w = wavelength_array(fits, axis=1, extension=0)
bins = wavelength_array(fits, axis=2, extension=0)
######################################################################
# Slice array before fitting
idx = np.where(np.logical_and(w >= w1, w <= w2))[0]
data = data[:,idx]
w = w[idx]
######################################################################
for i,bin in enumerate(bins):
output = os.path.join(outdir, "{1}_bin{2:04d}.pkl".format(targetSN,
f, bin))
outroot = output.replace(".pkl", "")
if os.path.exists(output) and not redo:
continue
print "PPXF run {0}/{1}".format(i+1, len(bins))
spec = data[i,:]
signal, noise, sn = snr(spec)
galaxy, logLam, vtemp = util.log_rebin([w[0], w[-1]], \
spec, velscale=velscale)
dv = (logLam_temp[0]-logLam[0])*c
lam = np.exp(logLam)
name = "{0}_bin{1:04d}".format(f, bin)
noise = np.ones_like(galaxy) * noise
kwargs["lam"] = lam
###################################################################
# Masking bad pixels
skylines = np.array([5577,5889, 6300, 6863])
goodpixels = np.arange(len(lam))
for line in skylines:
sky = np.argwhere((lam < line - 10) | (lam > line + 10)).ravel()
goodpixels = np.intersect1d(goodpixels, sky)
kwargs["goodpixels"] = goodpixels
###################################################################
kwargs["vsyst"] = dv
pp = ppxf(templates, galaxy, noise, velscale, **kwargs)
title = "Field {0} Bin {1}".format(f[-1], bin)
pp.name = name
# Adding other things to the pp object
pp.has_emission = True
pp.dv = dv
pp.w = np.exp(logLam)
pp.velscale = velscale
pp.ngas = ngas
pp.ntemplates = nstars
pp.templates = 0
pp.id = id
pp.name = name
pp.title = title
ppsave(pp, outroot=outroot)
ppf = ppload(outroot)
ppf = pPXF(ppf, velscale)
ppf.plot("{1}/{0}.png".format(name, outdir))
return
def minimize_leg(galname, templates, galaxy, noise, velscale, start, goodPixels,
dv, velscale_ratio, iterations, useMC, find_min=True):
#Minimizes ppxf uncertainty using legendre polynomials
#find_min=True will force the program to find the minimum again
value_range = range(5,23)
if useMC == False: #so that you don't double up on the multiprocessing and kill the server
#iterations
feeds = []
for ad in value_range:
for md in value_range:
feeds.append([(ad, md), i, iterations, templates, galaxy,
noise, velscale, start, goodPixels, dv, velscale_ratio])
P = mp.Pool(iterations)
outputs = P.map(min_worker, feeds)
outputs = np.array(outputs)
degrees = outputs[:,0]
errors = outputs[:,1]
deg = degrees[np.argmin(errors)]
print(' ')
print('Deg is:')
print(deg)
print(' ')
return deg
else: #serial version
stime = time.time()
deg_used = []
errors = []
if find_min or np.any(np.isnan(degrees)):
#Sample parameter space within $value_range to find minimum uncertainty
minimum = 1e10
degrees = [0,0] #ad, md
for ad in value_range: #degree of additive legendre polynomial
for md in value_range: #degree of multiplicative legendre polynomial
print('degrees of %i additive, %i multiplicative'%(ad, md))
#print((ad, md))
ppxf_obj = ppxf.ppxf(templates, galaxy, noise, velscale,
start, goodpixels=goodPixels,
plot=False, moments=4, degree=ad,
vsyst=dv,
velscale_ratio = velscale_ratio,
mdegree=md, clean=False)
error = ppxf_obj.error[1]*np.sqrt(ppxf_obj.chi2)
deg_used.append((ad,md))
errors.append(error)
#error = ppxf_obj.chi2
print('Uncertainty is ' + str(round(float(error), 2)) + ' km/s')
if error < minimum:
minimum = error
degrees[0] = ad
degrees[1] = md
print('')
print('Degree of Linear Legendre Polynomial is: ' + str(degrees[0]))
print('')
print('Degree of Multiplicative Legendre Polynomial is: ' + str(degrees[1]))
print('')
print('Took %s seconds to complete'%int(round(time.time() - stime)))
print('')
return degrees
def ppxf_example_two_components():
ppxf_dir = path.dirname(path.realpath(ppxf_package.__file__))
hdu = fits.open(
ppxf_dir +
'/miles_models/Mun1.30Zp0.00T12.5893_iPp0.00_baseFe_linear_FWHM_2.51.fits'
) # Solar metallicitly, Age=12.59 Gyr
gal_lin = hdu[0].data
h1 = hdu[0].header
lamRange1 = h1['CRVAL1'] + np.array(
[0., h1['CDELT1'] * (h1['NAXIS1'] - 1)])
c = 299792.458 # speed of light in km/s
velscale = c * h1['CDELT1'] / max(
lamRange1) # Do not degrade original velocity sampling
model1, logLam1, velscale = util.log_rebin(lamRange1,
gal_lin,
velscale=velscale)
model1 /= np.median(model1)
hdu = fits.open(
ppxf_dir +
'/miles_models/Mun1.30Zp0.00T01.0000_iPp0.00_baseFe_linear_FWHM_2.51.fits'
) # Solar metallicitly, Age=1.00 Gyr
gal_lin = hdu[0].data
model2, logLam1, velscale = util.log_rebin(lamRange1,
gal_lin,
velscale=velscale)
model2 /= np.median(model2)
model = np.column_stack([model1, model2])
galaxy = np.empty_like(model)
# These are the input values in spectral pixels
# for the (V,sigma) of the two kinematic components
#
vel = np.array([0., 300.]) / velscale
sigma = np.array([200., 100.]) / velscale
# The synthetic galaxy model consists of the sum of two
# SSP spectra with age of 1Gyr and 13Gyr respectively
# with different velocity and dispersion
#
for j in range(len(vel)):
dx = int(abs(vel[j]) +
4. * sigma[j]) # Sample the Gaussian at least to vel+4*sigma
v = np.linspace(-dx, dx, 2 * dx + 1)
losvd = np.exp(-0.5 * ((v - vel[j]) / sigma[j])**2) # Gaussian LOSVD
losvd /= np.sum(losvd) # normalize LOSVD
galaxy[:, j] = signal.fftconvolve(model[:, j], losvd, mode="same")
galaxy[:, j] /= np.median(model[:, j])
galaxy = np.sum(galaxy, axis=1)
sn = 100.
noise = galaxy / sn
galaxy = np.random.normal(galaxy, noise) # add noise to galaxy
# Adopts two templates per kinematic component
#
templates = np.column_stack([model1, model2, model1, model2])
# With multiple stellar kinematic components a good starting velocity is essential.
# Starting too far from the solution pPXF may *not* converge to the global minimum.
# Giving the same starting point for both components should be generally avoided and
# and is used below just to illustrate how one can swap the components using constr_kinem.
# In general one should explore a grid of starting velocities as illustrated
# e.g. in Sec.3.3 of Mitzkus et al. (2017 https://ui.adsabs.harvard.edu/abs/2017MNRAS.464.4789M)
start = [[100, 100], [100, 100]]
goodPixels = np.arange(20, 6000)
t = clock()
plt.clf()
print("\n++++++++++++++++++++++++++++++++++++++++++++++\n"
" No constraints on the kinematics\n"
"----------------------------------------------")
plt.subplot(211)
plt.title("Two components pPXF fit")
pp = ppxf(templates,
galaxy,
noise,
velscale,
start,
goodpixels=goodPixels,
plot=True,
degree=4,
moments=[2, 2],
component=[0, 0, 1, 1])
print("\n++++++++++++++++++++++++++++++++++++++++++++++\n"
"Force sigma(component=0) >= sigma(component=1)\n"
"----------------------------------------------")
# Note the swapping of the two components in the solution
# with respect to the previous uncostrained fit
A_ineq = [[0, -1, 0, 1]] # -sigma0 + sigma1 <= 0
b_ineq = [0]
constr_kinem = {"A_ineq": A_ineq, "b_ineq": b_ineq}
pp = ppxf(templates,
galaxy,
noise,
velscale,
start,
goodpixels=goodPixels,
degree=4,
moments=[2, 2],
component=[0, 0, 1, 1],
constr_kinem=constr_kinem)
print("\n++++++++++++++++++++++++++++++++++++++++++++++\n"
" Single component pPXF fit\n"
"----------------------------------------------")
plt.subplot(212)
plt.title("Single component pPXF fit")
start = start[0]
pp = ppxf(templates,
galaxy,
noise,
velscale,
start,
goodpixels=goodPixels,
plot=True,
degree=4,
moments=2)
print("==============================================")
print("Total elapsed time %.2f s" % (clock() - t))
plt.tight_layout()
plt.pause(1)
def ppxf_fit_spec(galaxy,
noise,
templates,
fit_range,
lamRange2,
logLam1,
logLam2,
velscale,
start,
sky=None,
plot=True,
moments=4,
degree=-1,
mdegree=4,
goodpixels=None):
"""Use pPXF to fit kinematics to a spectrum. This function masks the templates so they're the appropriate lengths (a bit longer than the galaxy spectrum) then
runs pPXF
inputs:
galaxy- a full length galaxy spectrum (i.e 4112 pixels for SWIFT)
noise- noise spectrum, same length as galaxy
templates- array of templates
lamRange2- wavelength range of the templates, pre masking
logLam1- log rebinned wavelength array for galaxy
logLam2- log rebinned wavelength array for templates
fit_range- range over which you want to fit the galaxy
start- starting guess for V and Sigma (or h3, h4, etc if you want higher moments)
sky- optionally fit a sky spectra at the same time. Set to None if you're not using
outputs:
pp- the ppxf class
sky- the input sky spectrum, but masked. If sky=None, then this is None
galaxy- the input galaxy spectrum, but masked
noise- the input noise spectrum, but masked
"""
#We need to pad the templates for ~100 angstroms each side of the galaxy spectrum.
lower_lam, upper_lam = np.array(fit_range)
#print(upper_lam)
#print(lamRange2)
pad = 300
#make the template mask
tmask = np.where((logLam2 >= np.log((lower_lam - pad)))
& (logLam2 <= np.log((upper_lam + pad))))[0]
#mask the wavelength range and the templates
logLam2 = logLam2[tmask]
templates = templates[tmask, :]
#make the mask for the galaxy spectrum
#mask=np.where((logLam1 >= np.log(lower_lam)) & (logLam1 <= np.log(upper_lam)))[0]
#mask the galaxy, sky and variance, plus the wavelengh ranges
"""
logLam1=logLam1[mask]
galaxy=galaxy[mask]
if SKY_FLAG:
sky=sky[mask, :]
noise=noise[mask]
"""
#################################################################################
# The galaxy and the template spectra do not have the same starting wavelength.
# For this reason an extra velocity shift DV has to be applied to the template
# to fit the galaxy spectrum. We remove this artificial shift by using the
# keyword VSYST in the call to PPXF below, so that all velocities are
# measured with respect to DV. This assume the redshift is negligible.
# In the case of a high-redshift galaxy one should de-redshift its
# wavelength to the rest frame before using the line below (see above).
#
c = 299792.458
#print("logam2[0] is {}, loglam1[0] is {}, logLam1/(1+z) is {}".format(logLam2[0], logLam1[0],logLam1[0]/(1+z)))
dv = (logLam2[0] - logLam1[0]) * c # km/s
vel, sigma = start
z_ppxf = np.exp(
vel / c) - 1 # Relation between velocity and redshift in pPXF
if goodpixels is None:
goodpixels = util.determine_goodpixels(logLam1, lamRange2, z_ppxf)
print("#########################################################")
print("Velocity shift DV is {}".format(dv))
print("The templates are shape {}".format(np.shape(templates)))
print("The galaxy is shape {}".format(np.shape(galaxy)))
print("#########################################################")
# Here the actual fit starts. The best fit is plotted on the screen.
# Gas emission lines are excluded from the pPXF fit using the GOODPIXELS keyword.
#
t = clock()
if sky is not None:
pp = ppxf(templates,
galaxy,
noise,
velscale,
start,
goodpixels=goodpixels,
plot=plot,
moments=moments,
degree=degree,
mdegree=mdegree,
vsyst=dv,
sky=sky)
else:
pp = ppxf(templates,
galaxy,
noise,
velscale,
start,
goodpixels=goodpixels,
plot=plot,
moments=moments,
degree=degree,
mdegree=mdegree,
vsyst=dv)
print("Formal errors:")
print(" dV dsigma dh3 dh4")
print("".join("%8.2g" % f for f in pp.error * np.sqrt(pp.chi2)))
print('Elapsed time in PPXF: %.2f s' % (clock() - t))
return (pp, sky, galaxy, noise)
def ppxf_example_two_components():
ppxf_dir = path.dirname(path.realpath(ppxf_package.__file__))
hdu = fits.open(
ppxf_dir +
'/miles_models/Mun1.30Zp0.00T12.5893_iPp0.00_baseFe_linear_FWHM_2.51.fits'
) # Solar metallicitly, Age=12.59 Gyr
gal_lin = hdu[0].data
h1 = hdu[0].header
lamRange1 = h1['CRVAL1'] + np.array(
[0., h1['CDELT1'] * (h1['NAXIS1'] - 1)])
c = 299792.458 # speed of light in km/s
velscale = c * h1['CDELT1'] / max(
lamRange1) # Do not degrade original velocity sampling
model1, logLam1, velscale = util.log_rebin(lamRange1,
gal_lin,
velscale=velscale)
model1 /= np.median(model1)
hdu = fits.open(
ppxf_dir +
'/miles_models/Mun1.30Zp0.00T01.0000_iPp0.00_baseFe_linear_FWHM_2.51.fits'
) # Solar metallicitly, Age=1.00 Gyr
gal_lin = hdu[0].data
model2, logLam1, velscale = util.log_rebin(lamRange1,
gal_lin,
velscale=velscale)
model2 /= np.median(model2)
model = np.column_stack([model1, model2])
galaxy = np.empty_like(model)
# These are the input values in spectral pixels
# for the (V,sigma) of the two kinematic components
#
vel = np.array([0., 300.]) / velscale
sigma = np.array([200., 100.]) / velscale
# The synthetic galaxy model consists of the sum of two
# SSP spectra with age of 1Gyr and 13Gyr respectively
# with different velocity and dispersion
#
for j in range(len(vel)):
dx = int(abs(vel[j]) +
4. * sigma[j]) # Sample the Gaussian at least to vel+4*sigma
v = np.linspace(-dx, dx, 2 * dx + 1)
losvd = np.exp(-0.5 * ((v - vel[j]) / sigma[j])**2) # Gaussian LOSVD
losvd /= np.sum(losvd) # normaize LOSVD
galaxy[:, j] = signal.fftconvolve(model[:, j], losvd, mode="same")
galaxy[:, j] /= np.median(model[:, j])
galaxy = np.sum(galaxy, axis=1)
sn = 100.
noise = galaxy / sn
galaxy = np.random.normal(galaxy, noise) # add noise to galaxy
# Adopts two templates per kinematic component
#
templates = np.column_stack([model1, model2, model1, model2])
# Start both kinematic components from the same guess.
# With multiple stellar kinematic components
# a good starting guess is essential
#
start = [np.mean(vel) * velscale, np.mean(sigma) * velscale]
start = [start, start]
goodPixels = np.arange(20, 6000)
t = clock()
plt.clf()
plt.subplot(211)
plt.title("Two components pPXF fit")
print("+++++++++++++++++++++++++++++++++++++++++++++")
pp = ppxf(templates,
galaxy,
noise,
velscale,
start,
goodpixels=goodPixels,
plot=True,
degree=4,
moments=[2, 2],
component=[0, 0, 1, 1])
plt.subplot(212)
plt.title("Single component pPXF fit")
print("---------------------------------------------")
start = start[0]
pp = ppxf(templates,
galaxy,
noise,
velscale,
start,
goodpixels=goodPixels,
plot=True,
degree=4,
moments=2)
print("=============================================")
print("Total elapsed time %.2f s" % (clock() - t))
plt.tight_layout()
plt.pause(1)
def kinematics_sdss(cube_id, y_data_var, fit_range):
file_loc = "ppxf_results" + "/cube_" + str(int(cube_id))
if not os.path.exists(file_loc):
os.mkdir(file_loc)
# reading cube_data
cube_file = (
"/Volumes/Jacky_Cao/University/level4/project/cubes_better/cube_" +
str(cube_id) + ".fits")
hdu = fits.open(cube_file)
t = hdu[1].data
spectra = cube_reader.spectrum_creator(cube_file)
# using our redshift estimate from lmfit
cube_result_file = ("cube_results/cube_" + str(cube_id) + "/cube_" +
str(cube_id) + "_lmfit.txt")
cube_result_file = open(cube_result_file)
line_count = 0
for crf_line in cube_result_file:
if (line_count == 20):
curr_line = crf_line.split()
z = float(curr_line[1])
line_count += 1
cube_x_data = np.load("cube_results/cube_" + str(int(cube_id)) + "/cube_" +
str(int(cube_id)) + "_cbd_x.npy")
if (np.sum(y_data_var) == 0):
cube_y_data = np.load("cube_results/cube_" + str(int(cube_id)) +
"/cube_" + str(int(cube_id)) + "_cbs_y.npy")
else:
cube_y_data = y_data_var
cube_x_original = cube_x_data
cube_y_original = cube_y_data
# masking the data to ignore initial 'noise' / non-features
initial_mask = (cube_x_data > 3540 * (1 + z))
cube_x_data = cube_x_original[initial_mask]
cube_y_data = cube_y_original[initial_mask]
# calculating the signal to noise
sn_region = np.array([4000, 4080]) * (1 + z)
sn_region_mask = ((cube_x_data > sn_region[0]) &
(cube_x_data < sn_region[1]))
cube_y_sn_region = cube_y_data[sn_region_mask]
cy_sn_mean = np.mean(cube_y_sn_region)
cy_sn_std = np.std(cube_y_sn_region)
cy_sn = cy_sn_mean / cy_sn_std
#print("s/n:")
#print(cy_sn, cy_sn_mean, cy_sn_std)
# cube noise
cube_noise_data = cube_noise()
spectrum_noise = cube_noise_data['spectrum_noise']
spec_noise = spectrum_noise[initial_mask]
# will need this for when we are considering specific ranges
if (isinstance(fit_range, str)):
pass
else:
rtc = fit_range * (1 + z
) # create a new mask and mask our x and y data
rtc_mask = ((cube_x_data > rtc[0]) & (cube_x_data < rtc[1]))
cube_x_data = cube_x_data[rtc_mask]
cube_y_data = cube_y_data[rtc_mask]
spec_noise = spec_noise[rtc_mask]
lamRange = np.array([np.min(cube_x_data), np.max(cube_x_data)])
specNew, logLam, velscale = log_rebin(lamRange, cube_y_data)
lam = np.exp(logLam)
loglam = np.log10(lam)
# Only use the wavelength range in common between galaxy and stellar library.
mask = (loglam > np.log10(3540)) & (loglam < np.log10(9464))
flux = specNew[mask]
galaxy = flux / np.median(
flux) # Normalize spectrum to avoid numerical issues
loglam_gal = loglam[mask]
lam_gal = 10**loglam_gal
# galaxy spectrum not scaled
galaxy_ns = flux
segmentation_data = hdu[2].data
seg_loc_rows, seg_loc_cols = np.where(segmentation_data == cube_id)
signal_pixels = len(seg_loc_rows)
spec_noise = spec_noise[mask]
noise = (spec_noise * np.sqrt(signal_pixels)) / np.median(flux)
# sky noise
sky_noise = cube_reader.sky_noise("data/skyvariance_csub.fits")
skyNew, skyLogLam, skyVelScale = log_rebin(lamRange,
sky_noise[initial_mask])
skyNew = skyNew[mask]
c = 299792.458 # speed of light in km/s
frac = lam_gal[1] / lam_gal[0] # Constant lambda fraction per pixel
dlam_gal = (frac - 1) * lam_gal # Size of every pixel in Angstrom
data_shape = np.shape(galaxy)
wdisp = np.full(data_shape, 1,
dtype=float) # Intrinsic dispersion of every pixel
fwhm_gal = 2.51 * wdisp * dlam_gal # Resolution FWHM of every pixel, in Angstroms
velscale = np.log(frac) * c # Constant velocity scale in km/s per pixel
# If the galaxy is at significant redshift, one should bring the galaxy
# spectrum roughly to the rest-frame wavelength, before calling pPXF
# (See Sec2.4 of Cappellari 2017). In practice there is no
# need to modify the spectrum in any way, given that a red shift
# corresponds to a linear shift of the log-rebinned spectrum.
# One just needs to compute the wavelength range in the rest-frame
# and adjust the instrumental resolution of the galaxy observations.
# This is done with the following three commented lines:
#
#lam_gal = lam_gal/(1+z) # Compute approximate restframe wavelength
#fwhm_gal = fwhm_gal/(1+z) # Adjust resolution in Angstrom
# Read the list of filenames from the Single Stellar Population library
# by Vazdekis (2010, MNRAS, 404, 1639) http://miles.iac.es/. A subset
# of the library is included for this example with permission
#template_set = glob.glob('miles_models/Mun1.30Z*.fits')
#template_set = glob.glob('jacoby_models/jhc0*.fits')
#fwhm_tem = 4.5 # instrumental resolution in Ångstroms.
# NOAO Coudé templates
template_set = glob.glob("noao_templates/*.fits")
fwhm_tem = 1.35
# Extract the wavelength range and logarithmically rebin one spectrum
# to the same velocity scale of the SDSS galaxy spectrum, to determine
# the size needed for the array which will contain the template spectra.
#
#hdu = fits.open(template_set[0])
#ssp = hdu[0].data
#h2 = hdu[0].header
#lam_temp = h2['CRVAL1'] + h2['CDELT1']*np.arange(h2['NAXIS1'])
hdu = fits.open(template_set[0])
noao_data = hdu[1].data[0]
ssp = noao_data[1]
lam_temp = noao_data[0]
lamRange_temp = [np.min(lam_temp), np.max(lam_temp)]
sspNew = util.log_rebin(lamRange_temp, ssp, velscale=velscale)[0]
templates = np.empty((sspNew.size, len(template_set)))
# Interpolates the galaxy spectral resolution at the location of every pixel
# of the templates. Outside the range of the galaxy spectrum the resolution
# will be extrapolated, but this is irrelevant as those pixels cannot be
# used in the fit anyway.
fwhm_gal = np.interp(lam_temp, lam_gal, fwhm_gal)
# Convolve the whole Vazdekis library of spectral templates
# with the quadratic difference between the SDSS and the
# Vazdekis instrumental resolution. Logarithmically rebin
# and store each template as a column in the array TEMPLATES.
# Quadratic sigma difference in pixels Vazdekis --> SDSS
# The formula below is rigorously valid if the shapes of the
# instrumental spectral profiles are well approximated by Gaussians.
#
# In the line below, the fwhm_dif is set to zero when fwhm_gal < fwhm_tem.
# In principle it should never happen and a higher resolution template should be used.
#
fwhm_dif = np.sqrt((fwhm_gal**2 - fwhm_tem**2).clip(0))
#sigma = fwhm_dif/2.355/h2['CDELT1'] # Sigma difference in pixels
spacing = lam_temp[1] - lam_temp[0]
sigma = fwhm_dif / 2.355 / spacing # Sigma difference in pixels
for j, fname in enumerate(template_set):
hdu = fits.open(fname)
#ssp = hdu[0].data
noao_data = hdu[1].data[0]
ssp = noao_data[1]
ssp = util.gaussian_filter1d(
ssp, sigma) # perform convolution with variable sigma
sspNew = util.log_rebin(lamRange_temp, ssp, velscale=velscale)[0]
templates[:, j] = sspNew / np.median(sspNew) # Normalizes templates
# The galaxy and the template spectra do not have the same starting wavelength.
# For this reason an extra velocity shift DV has to be applied to the template
# to fit the galaxy spectrum. We remove this artificial shift by using the
# keyword VSYST in the call to PPXF below, so that all velocities are
# measured with respect to DV. This assume the redshift is negligible.
# In the case of a high-redshift galaxy one should de-redshift its
# wavelength to the rest frame before using the line below (see above).
#
c = 299792.458
dv = np.log(lam_temp[0] / lam_gal[0]) * c # km/s
#lam_gal_alt = lam_gal * (1+z)
#lamRange_temp = [np.min(lam_temp), np.max(lam_temp)]
goodpixels = util.determine_goodpixels(np.log(lam_gal), lamRange_temp, z)
# Here the actual fit starts. The best fit is plotted on the screen.
# Gas emission lines are excluded from the pPXF fit using the GOODPIXELS keyword.
#
vel = c * np.log(1 + z) # eq.(8) of Cappellari (2017)
start = [vel, 200.] # (km/s), starting guess for [V, sigma]
t = process_time()
f = io.StringIO()
with redirect_stdout(f):
pp = ppxf(templates,
galaxy,
noise,
velscale,
start,
sky=skyNew,
goodpixels=goodpixels,
plot=True,
moments=4,
degree=12,
vsyst=dv,
clean=False,
lam=lam_gal)
ppxf_variables = pp.sol
ppxf_errors = pp.error
red_chi2 = pp.chi2
best_fit = pp.bestfit
x_data = cube_x_data[mask]
y_data = cube_y_data[mask]
print(ppxf_variables)
#plt.show()
if ((np.sum(y_data_var) == 0) and isinstance(fit_range, str)):
np.save(file_loc + "/cube_" + str(int(cube_id)) + "_lamgal", lam_gal)
np.save(file_loc + "/cube_" + str(int(cube_id)) + "_flux", flux)
np.save(file_loc + "/cube_" + str(int(cube_id)) + "_x", x_data)
np.save(file_loc + "/cube_" + str(int(cube_id)) + "_y", y_data)
np.save(file_loc + "/cube_" + str(int(cube_id)) + "_noise", noise)
# if best fit i.e. perturbation is 0, save everything
kinematics_file = open(
file_loc + "/cube_" + str(int(cube_id)) + "_kinematics.txt", 'w')
np.save(file_loc + "/cube_" + str(int(cube_id)) + "_model", best_fit)
print("Rough reduced chi-squared from ppxf: " + str(pp.chi2))
data_to_file = f.getvalue()
kinematics_file.write(data_to_file)
kinematics_file.write("")
kinematics_file.write("Formal errors: \n")
kinematics_file.write(" dV dsigma dh3 dh4 \n")
kinematics_file.write("".join("%8.2g" % f
for f in pp.error * np.sqrt(pp.chi2)) +
"\n")
kinematics_file.write('Elapsed time in PPXF: %.2f s' %
(process_time() - t) + "\n")
plt.tight_layout()
graph_loc = "ppxf_results" + "/cube_" + str(int(cube_id))
if not os.path.exists(graph_loc):
os.mkdir(graph_loc)
kinematics_graph = (graph_loc + "/cube_" + str(int(cube_id)) +
"_kinematics.pdf")
plt.savefig(kinematics_graph)
#plt.show()
plt.close("all")
if not isinstance(fit_range, str):
# saving graphs if not original range
fit_range = fit_range * (1 + z)
fitting_plotter(cube_id, fit_range, x_data, y_data, best_fit, noise)
# If the galaxy is at significant redshift z and the wavelength has been
# de-redshifted with the three lines "z = 1.23..." near the beginning of
# this procedure, the best-fitting redshift is now given by the following
# commented line (equation 2 of Cappellari et al. 2009, ApJ, 704, L34):
#
#print, 'Best-fitting redshift z:', (z + 1)*(1 + sol[0]/c) - 1
return {
'reduced_chi2': red_chi2,
'noise': noise,
'variables': ppxf_variables,
'y_data': galaxy,
'x_data': lam_gal,
'redshift': z,
'y_data_original': cube_y_original,
'non_scaled_y': galaxy_ns,
'model_data': best_fit,
'noise_original': spec_noise,
'errors': ppxf_errors
}
def run_ppxf(group,
specs,
redo=False,
ncomp=2,
logdir="ppxf",
window=50,
w1=None,
w2=None,
**kwargs):
""" New function to run pPXF. """
global velscale
tempfile = os.path.join(
home, "MILES/templates/"
"templates_w3540.5_7409.6_res4.7.fits")
stars = pf.getdata(tempfile, 0)
emission = pf.getdata(tempfile, 1)
logLam_temp = wavelength_array(tempfile, axis=1, extension=0)
ngas = len(emission)
nstars = len(stars)
templates = np.column_stack((stars.T, emission.T))
##########################################################################
# Set components
if ncomp == 1:
components = np.zeros(nstars + ngas)
kwargs["component"] = components
elif ncomp == 2:
components = np.hstack((np.zeros(nstars), np.ones(ngas))).astype(int)
kwargs["component"] = components
##########################################################################
for spec in specs:
os.chdir(os.path.join(data_dir, group))
outdir = os.path.join(os.getcwd(), logdir)
if not os.path.exists(outdir):
os.mkdir(outdir)
data = pf.getdata(spec)
w = wavelength_array(spec)
if w1 == None:
w1 = w[0]
if w2 == None:
w2 = w[-1]
idx = np.where((w >= w1) & (w <= w2))[0]
data = data[idx]
w = w[idx]
#######################################################################
# Preparing output
output = os.path.join(outdir, spec.replace(".fits", ".pkl"))
outroot = output.replace(".pkl", "")
if os.path.exists(output) and not redo:
continue
print group, spec
signal, noise, sn = snr(data)
galaxy, logLam, vtemp = util.log_rebin([w[0], w[-1]],
data,
velscale=velscale)
lam = np.exp(logLam)
###################################################################
# Trimming spectra
idx = np.where(np.exp(logLam) > np.exp(logLam_temp[0]))[0]
didx = int(1500. / velscale) # Space in the beginning of the spec
idx = idx[didx:]
galaxy = galaxy[idx]
lam = lam[idx]
logLam = logLam[idx]
#######################################################################
# Masking bad pixels
goodpixels = np.arange(len(lam), dtype=float)
gaps = set_badpixels(group)
for gap in gaps:
idx = np.where((lam > gap[0] - window / 2.)
& (lam < gap[1] + window / 2.))[0]
goodpixels[idx] = np.nan
goodpixels = goodpixels[~np.isnan(goodpixels)].astype(int)
kwargs["goodpixels"] = goodpixels
#######################################################################
kwargs["lam"] = lam
dv = (logLam_temp[0] - logLam[0]) * c
kwargs["vsyst"] = dv
noise = np.ones_like(galaxy) * noise
# First fitting to obtain realistic noise
pp0 = ppxf(templates, galaxy, noise, velscale, **kwargs)
pp0.has_emission = True
pp0.dv = dv
pp0.w = np.exp(logLam)
pp0.velscale = velscale
pp0.ngas = ngas
pp0.ntemplates = nstars
pp0.templates = 0
pp0.name = spec
pp0.title = ""
pp0 = pPXF(pp0, velscale)
pp0.calc_sn()
res = (pp0.galaxy - pp0.bestfit)
noise = rolling_std(res, window, center=True)
noise[:window / 2] = noise[window + 1]
noise[-window / 2 + 1:] = noise[-window / 2]
# Second fitting using results from first interaction
pp = ppxf(templates, galaxy, noise, velscale, **kwargs)
title = "Group {} , Spectrum {}".format(
group.upper(),
spec.replace(".fits", "").replace("spec", ""))
# Adding other things to the pp object
pp.has_emission = True
pp.dv = dv
pp.w = np.exp(logLam)
pp.velscale = velscale
pp.ngas = ngas
pp.ntemplates = nstars
pp.templates = 0
pp.id = id
pp.name = spec
pp.title = title
ppsave(pp, outroot=outroot)
ppf = ppload(outroot)
ppf = pPXF(ppf, velscale)
ppf.plot("{1}/{0}.png".format(pp.name.replace(".fits", ""), outdir))
return