def setUp(self):
self.bb = S.BlackBody(5000)
self.em = S.GaussianSource(3300, 1, 1)
self.flat = S.FlatSpectrum(10)
self.pl = S.PowerLaw(5000, -2)
self.tspec = S.ArraySpectrum(self.bb.wave,
self.bb.flux,
fluxunits=self.bb.fluxunits)
self.pl.writefits('ac_pl.fits')
self.fspec = S.FileSpectrum('ac_pl.fits')
def test_conversion1(self):
pl = S.PowerLaw(6000, -4, 'angstrom', 'photlam')
angflux = pl.sample(self.wave)
pl.convert('nm')
nmflux = pl.sample(self.wave / 10.)
self.assertEqualNumpy(nmflux, angflux)
def test_conversion2(self):
pl = S.PowerLaw(6000, -4, 'angstrom', 'photlam')
self.assertEqualNumpy(
pl.sample(self.wave)[:10], pl.sample(self.wave[:10]))
pl.convert('nm')
self.assertEqualNumpy(
pl.sample(self.wave)[:10], pl.sample(self.wave[:10]))
def test_values(self):
ref = np.array([
16., 15.78843266, 15.58035072, 15.37568551, 15.17436992,
14.97633838, 14.78152682, 14.5898726, 14.40131453, 14.21579277
])
pl = S.PowerLaw(6000, -4, 'angstrom', 'photlam')
test = pl.sample(self.wave[:10])
self.assertApproxNumpy(test, ref)
def __init__(self, refwave, beta, redshift, A=1.0, verbose=False):
self.rspec = S.PowerLaw(refwave,
beta,
waveunits='angstrom',
fluxunits='flam')
# self.factory = FileSED.GalaxySEDFactory(spec=rspec)
# Redshift the spectrum & add IGM attenuation
# self.rspec = self.factory.redshift(redshift) # the reference spectrum
mag = S.Observation(self.rspec, filters['f160w']).effstim('abmag')
# normalize reference spectrum to 25.0 mag in F160W to minimize
# round-off errors later in fitting
dmag = 25.0 - mag
self.rspec = 10.**(-0.4 * dmag) * self.rspec
A = np.abs(A)
self.rspec = A * self.rspec
self.beta = beta
self.A = A
self.verbose = verbose
def read_source(sourcespec):
"""
Read a spectrum
Parameters
----------
sourcespec : str
Source spectrum specification string. Acceptable options are:
* BB<Temperature>
* PL<Reference Wave Angstrom>_<PL Index>
* Flat<AB magnitude>
* ckmod<Temperature>_<logZ>_<logg>
Returns
-------
source : :py:class:`pysynphot.spectrum.ArraySourceSpectrum`
The spectrum data.
Has ``dtype=[('wave', '<f8'), ('flux', '<f8')]``
Raises
------
ValueError
If attempting to use this routine to load a file, or if source spectrum
specification string is invalid
Notes
-----
The source spectrum specification string parsing is basic. Strings are
checked to see if they start with an acceptable prefix, and then split.
The individual constituents are converted to float, and passed to
pysynphot. There is no checking of the values, only that they can be
properly typecast into float. Making sure the value is accepted is left
to the user.
"""
if os.path.exists(sourcespec):
message = 'File spectrum parsing is complex and requires pre-processing. Use source_synphot.source routines'
raise ValueError(message)
else:
# assume sourcespec is a string and parse it, trying to interpret as:
# simple blackbody spectrum
if sourcespec.startswith('BB'):
temp = sourcespec.lstrip('BB')
try:
temp = float(temp)
except (TypeError, ValueError) as e:
message = 'Source temperature {} cannot be interpreted as a float'.format(sourcespec)
raise ValueError(message)
bb = S.Blackbody(temp)
bb.convert('flam')
spec = {'wave':bb.wave, 'flux':bb.flux}
# power-law spectrum
elif sourcespec.startswith('PL'):
refwave, plindex = sourcespec.lstrip('PL').split('_')
try:
refwave = float(refwave)
except (TypeError, ValueError) as e:
message = 'Reference wavelength {} cannot be interpreted as a float'.format(sourcespec)
raise ValueError(message)
try:
plindex = float(plindex)
except (TypeError, ValueError) as e:
message = 'Power law index {} cannot be interpreted as a float'.format(sourcespec)
raise ValueError(message)
pl = S.PowerLaw(refwave, plindex)
pl.convert('flam')
spec = {'wave':pl.wave, 'flux':pl.flux}
# flat spectrum (in f_lam, not f_nu) normalized to some ABmag
elif sourcespec.startswith('Flat'):
abmag = sourcespec.replace('Flat','')
try:
abmag = float(abmag)
except (TypeError, ValueError) as e:
message = 'AB mag {} cannot be interpreted as a float'.format(sourcespec)
raise ValueError(message)
flat = S.FlatSpectrum(abmag, fluxunits='abmag')
flat.convert('flam')
spec = {'wave':flat.wave, 'flux':flat.flux}
# a Castelli-Kurucz model
elif sourcespec.startswith('ckmod'):
teff, logZ, logg = sourcespec.replace('ckmod','').split('_')
try:
teff = float(teff)
except (TypeError, ValueError) as e:
message = 'Source temperature {} cannot be interpreted as a float'.format(sourcespec)
raise ValueError(message)
try:
logZ = float(logZ)
except (TypeError, ValueError) as e:
message = 'Abundance {} cannot be interpreted as a float'.format(sourcespec)
raise ValueError(message)
try:
logg = float(logg)
except (TypeError, ValueError) as e:
message = 'Surface gravity {} cannot be interpreted as a float'.format(sourcespec)
raise ValueError(message)
ckmod = S.Icat('ck04models',teff, logZ,logg)
ckmod.convert('flam')
spec = {'wave':ckmod.wave, 'flux':ckmod.flux}
# else give up
else:
message = 'Source spectrum {} cannot be parsed as input file or pre-defined type (BB, PL, Flat, ckmod)'.format(sourcespec)
raise ValueError(message)
spec = S.ArraySpectrum(spec['wave'], spec['flux'], name=sourcespec)
return spec
def specFromSpectralType(sptype, return_list=False, catalog=None):
"""Get Pysynphot Spectrum object from a user-friendly spectral type string.
Given a spectral type such as 'A0IV' or 'G2V', this uses a fixed lookup table
to determine an appropriate spectral model from Castelli & Kurucz 2004 or
the Phoenix model grids. Depends on pysynphot and CDBS. This is just a
convenient access function.
Parameters
-----------
catalog: str
'ck04' for Castelli & Kurucz 2004, 'phoenix' for Phoenix models.
If not set explicitly, the code will check if the phoenix models are
present inside the $PYSYN_CDBS directory. If so, those are the default;
otherwise, it's CK04.
"""
import pysynphot
if catalog is None:
import os
cdbs = os.getenv('PYSYN_CDBS')
if os.path.exists( os.path.join(os.getenv('PYSYN_CDBS'), 'grid', 'phoenix')):
catalog='phoenix'
elif os.path.exists( os.path.join(os.getenv('PYSYN_CDBS'), 'grid', 'ck04models')):
catalog='ck04'
else:
raise IOError("Could not find either phoenix or ck04models subdirectories of $PYSYN_CDBS/grid")
if catalog.lower() =='ck04':
catname='ck04models'
# Recommended lookup table into the CK04 models (from
# the documentation of that catalog?)
lookuptable = {
"O3V": (50000, 0.0, 5.0),
"O5V": (45000, 0.0, 5.0),
"O6V": (40000, 0.0, 4.5),
"O8V": (35000, 0.0, 4.0),
"O5I": (40000, 0.0, 4.5),
"O6I": (40000, 0.0, 4.5),
"O8I": (34000, 0.0, 4.0),
"B0V": (30000, 0.0, 4.0),
"B3V": (19000, 0.0, 4.0),
"B5V": (15000, 0.0, 4.0),
"B8V": (12000, 0.0, 4.0),
"B0III": (29000, 0.0, 3.5),
"B5III": (15000, 0.0, 3.5),
"B0I": (26000, 0.0, 3.0),
"B5I": (14000, 0.0, 2.5),
"A0V": (9500, 0.0, 4.0),
"A5V": (8250, 0.0, 4.5),
"A0I": (9750, 0.0, 2.0),
"A5I": (8500, 0.0, 2.0),
"F0V": (7250, 0.0, 4.5),
"F5V": (6500, 0.0, 4.5),
"F0I": (7750, 0.0, 2.0),
"F5I": (7000, 0.0, 1.5),
"G0V": (6000, 0.0, 4.5),
"G5V": (5750, 0.0, 4.5),
"G0III": (5750, 0.0, 3.0),
"G5III": (5250, 0.0, 2.5),
"G0I": (5500, 0.0, 1.5),
"G5I": (4750, 0.0, 1.0),
"K0V": (5250, 0.0, 4.5),
"K5V": (4250, 0.0, 4.5),
"K0III": (4750, 0.0, 2.0),
"K5III": (4000, 0.0, 1.5),
"K0I": (4500, 0.0, 1.0),
"K5I": (3750, 0.0, 0.5),
"M0V": (3750, 0.0, 4.5),
"M2V": (3500, 0.0, 4.5),
"M5V": (3500, 0.0, 5.0),
"M0III": (3750, 0.0, 1.5),
"M0I": (3750, 0.0, 0.0),
"M2I": (3500, 0.0, 0.0)}
elif catalog.lower() =='phoenix':
catname='phoenix'
# lookup table used in JWST ETCs
lookuptable = {
"O3V": (45000, 0.0, 4.0),
"O5V": (41000, 0.0, 4.5),
"O7V": (37000, 0.0, 4.0),
"O9V": (33000, 0.0, 4.0),
"B0V": (30000, 0.0, 4.0),
"B1V": (25000, 0.0, 4.0),
"B3V": (19000, 0.0, 4.0),
"B5V": (15000, 0.0, 4.0),
"B8V": (12000, 0.0, 4.0),
"A0V": (9500, 0.0, 4.0),
"A1V": (9250, 0.0, 4.0),
"A3V": (8250, 0.0, 4.0),
"A5V": (8250, 0.0, 4.0),
"F0V": (7250, 0.0, 4.0),
"F2V": (7000, 0.0, 4.0),
"F5V": (6500, 0.0, 4.0),
"F8V": (6250, 0.0, 4.5),
"G0V": (6000, 0.0, 4.5),
"G2V": (5750, 0.0, 4.5),
"G5V": (5750, 0.0, 4.5),
"G8V": (5500, 0.0, 4.5),
"K0V": (5250, 0.0, 4.5),
"K2V": (4750, 0.0, 4.5),
"K5V": (4250, 0.0, 4.5),
"K7V": (4000, 0.0, 4.5),
"M0V": (3750, 0.0, 4.5),
"M2V": (3500, 0.0, 4.5),
"M5V": (3500, 0.0, 5.0),
"B0III": (29000, 0.0, 3.5),
"B5III": (15000, 0.0, 3.5),
"G0III": (5750, 0.0, 3.0),
"G5III": (5250, 0.0, 2.5),
"K0III": (4750, 0.0, 2.0),
"K5III": (4000, 0.0, 1.5),
"M0III": (3750, 0.0, 1.5),
"O6I": (39000, 0.0, 4.5),
"O8I": (34000, 0.0, 4.0),
"B0I": (26000, 0.0, 3.0),
"B5I": (14000, 0.0, 2.5),
"A0I": (9750, 0.0, 2.0),
"A5I": (8500, 0.0, 2.0),
"F0I": (7750, 0.0, 2.0),
"F5I": (7000, 0.0, 1.5),
"G0I": (5500, 0.0, 1.5),
"G5I": (4750, 0.0, 1.0),
"K0I": (4500, 0.0, 1.0),
"K5I": (3750, 0.0, 0.5),
"M0I": (3750, 0.0, 0.0),
"M2I": (3500, 0.0, 0.0)}
if return_list:
sptype_list = lookuptable.keys()
def sort_sptype(typestr):
letter = typestr[0]
lettervals = {'O':0, 'B': 10, 'A': 20,'F': 30, 'G':40, 'K': 50, 'M':60}
value = lettervals[letter]*1.0
value += int(typestr[1])
if "III" in typestr: value += .3
elif "I" in typestr: value += .1
elif "V" in typestr: value += .5
return value
sptype_list.sort(key=sort_sptype)
sptype_list.insert(0,"Flat spectrum in F_nu")
sptype_list.insert(0,"Flat spectrum in F_lambda")
# add a variety of spectral type slopes, per request from Dean Hines
for slope in [-3, -2, -1.5, -1, -0.75, -0.5, 0.5, 0.75, 1.0, 1.5, 2, 3]:
sptype_list.insert(0,"Power law F_nu ~ nu^(%s)" % str(slope))
#sptype_list.insert(0,"Power law F_nu ~ nu^(-0.75)")
#sptype_list.insert(0,"Power law F_nu ~ nu^(-1.0)")
#sptype_list.insert(0,"Power law F_nu ~ nu^(-1.5)")
#sptype_list.insert(0,"Power law F_nu ~ nu^(-2.0)")
return sptype_list
if "Flat" in sptype:
if sptype == "Flat spectrum in F_nu": spec = pysynphot.FlatSpectrum( 1, fluxunits = 'fnu')
elif sptype == "Flat spectrum in F_lambda": spec= pysynphot.FlatSpectrum( 1, fluxunits = 'flam')
spec.convert('flam')
return spec*(1./spec.flux.mean())
if 'Power law' in sptype:
import re
ans = re.search('\((.*)\)', sptype)
if ans is None: raise ValueError("Invalid power law specification cannot be parsed to get exponent")
exponent = float(ans.groups(0)[0])
# note that Pysynphot's PowerLaw class implements a power law in terms of lambda, not nu.
# but since nu = clight/lambda, it's just a matter of swapping the sign on the exponent.
spec = pysynphot.PowerLaw(1, (-1)*exponent, fluxunits='fnu')
spec.convert('flam')
spec *= (1./spec.flux.mean())
spec.name = sptype
return spec
else:
keys = lookuptable[sptype]
try:
return pysynphot.Icat(catname,keys[0], keys[1], keys[2])
except:
errmsg = "Could not find a match in catalog {0} for key {1}. Check that is a valid name in the lookup table, and/or that pysynphot is installed properly.".format(catname, sptype)
_log.critical(errmsg)
raise LookupError(errmsg)
def setUp(self):
self.sp=S.PowerLaw(10000,0.5)