def get_photometric_error(mag, band, run=None, gamma=None, coadd=True):
"""
Calculate the photometric error
Returns
-------
The magnitude error in mag.
"""
bandpass_dir = '../throughputs/baseline' # hardcoded for my own system; not necessary for desc-stack
LSST_BandPass = BandpassDict.loadTotalBandpassesFromFiles(
bandpassDir=bandpass_dir)
bandpass_obj = LSST_BandPass[band]
phot_params_obj = PhotometricParameters()
# 5-sigma depth
if coadd:
m5 = dict(zip(list('ugrizy'), [26.1, 27.4, 27.5, 26.8, 26.1, 24.9]))
else:
# single visit (2 x 15s), for point sources
# from Ivezic et al 2018
m5 = dict(
zip(list('ugrizy'), [23, 78, 24.81, 24.35, 23.92, 23.34, 22.45]))
# Override if run is provided, meaning it's DC2
if run == '1.2i':
m5 = dict(zip(list('ugrizy'), [25.7, 25.7, 25.7, 25.7, 25.7, 25.7
])) #FIXME: only r correct for Run 1.2i
mag_err, gamma = calcMagError_m5(mag, bandpass_obj, m5[band],
phot_params_obj, gamma)
return mag_err
def convert_params_to_depths(params):
### Convert the number of visits in each band to 5sigma magnitude depths
# params = [ [vu,vg,vr,vi,vz,vy], years]
visits = params[0]
years = params[1]
print 'visits = ', visits
print 'years = ', years
filter_list = ['u', 'g', 'r', 'i', 'z', 'y']
filter_file = "/Users/melissagraham/Science/LSST/photoz_experiments/filters/LSSTcosmosJDEM.filt"
filters = OrderedDict({})
for filt in filter_list:
filters[filt] = importBandpass(filter_file, filt)
gamma = [0.037, 0.038, 0.039, 0.039, 0.04, 0.04] #Sam Schmidt
photParams = PhotometricParameters()
# m5sig_10year = np.asarray( (26.1,27.4,27.5,26.8,26.1,24.9), dtype='float' )
m5sig_1vis_lmags = np.asarray((23.9, 25.0, 24.7, 24.0, 23.3, 22.1),
dtype='float')
m5 = np.zeros(6, dtype='float')
for f, filt in enumerate(filter_list):
if visits[f] > 0:
m5[f] = m5sig_1vis_lmags[f] + (1.25 *
np.log10(visits[f] * years / 10.0))
if visits[f] <= 0: m5[f] = float('NaN')
# print 'm5: ',m5
return m5
def catsimBandFluxError(self, time, bandpassobject, m5,
fluxinMaggies=None,
magnitude=None,
photParams=None):
"""
return the flux uncertainty in the bandpass in units 'maggies'
(the flux the AB magnitude reference spectrum would have in the
same band.) for a source of given brightness. The source brightness
may be calculated, but the need for calculation is overridden by a
provided flux in bandpass (in units of maggies) which itself may be
overridden by a provided magnitude. If the provided/calculated flux
is 0. or negative the magnitude calculated is taken to be 200.0 rather
than a np.nan.
Parameters
----------
time: mandatory, float
MJD at which band fluxes are evaluated
bandpassobject: mandatory, `lsst.sims.photUtils.BandPass` object
A particular bandpass which is an instantiation of one of
(u, g, r, i, z, y)
m5 : float, mandatory
fiveSigma Depth for the sky observation
photParams : instance of `sims.photUtils.PhotometricParameters`, defaults to `None`
describes the hardware parameters of the Observing system
magnitude : float, defaults to None
AB magnitude of source in bandpass.
fluxinMaggies : float, defaults to None
flux in Maggies for source in bandpass
Returns
-------
float
Examples
--------
.. note: If there is an unphysical value of sed the fluxinMaggies might
be `np.nan`. The magnitude calculated from this is calculated using `noNan`
and is therefore 200.0 rather than `np.nan`.
"""
if fluxinMaggies is None:
fluxinMaggies = self.catsimBandFlux(time=time,
bandpassobject=bandpassobject)
if magnitude is None:
mag = self.catsimBandMag(time=time, fluxinMaggies=fluxinMaggies,
bandpassobject=bandpassobject, noNan=True)
else:
mag = magnitude
# recalculate fluxinMaggies as the previous one might have been `np.nan`
# the noise is contaminated if this is `np.nan`
fluxinMaggies = 10.0**(-0.4 * mag)
if photParams is None:
photParams = PhotometricParameters()
SNR, gamma = calcSNR_m5(magnitude=mag, bandpass=bandpassobject,
m5=m5, photParams=photParams)
return fluxinMaggies / SNR
def catsimBandMagError(self, time, bandpassobject, m5, photParams=None,
magnitude=None):
"""
return the 68 percent uncertainty on the magnitude in the bandpass
Parameters
----------
time: mandatory, float
MJD at which band fluxes are evaluated
bandpassobject: mandatory, `lsst.sims.photUtils.BandPass` object
A particular bandpass which is an instantiation of one of
(u, g, r, i, z, y)
m5 :
photParams :
magnitude :
Returns
-------
float
Examples
--------
.. note: If there is an unphysical value of sed in
the wavelength range, it produces a flux of `np.nan`
"""
if magnitude is None:
mag = self.catsimBandMag(time=time,
bandpassobject=bandpassobject,
noNan=True)
else:
mag = magnitude
bandpass = bandpassobject
if photParams is None:
photParams = PhotometricParameters()
magerr = calcMagError_m5(magnitude=mag,
bandpass=bandpassobject,
m5=m5,
photParams=photParams)
return magerr[0]
def setUp(self):
"""
Setup tests
SN_blank: A SNObject with no MW extinction
"""
mydir = get_config_dir()
print('===============================')
print('===============================')
print(mydir)
print('===============================')
print('===============================')
# A range of wavelengths in Ang
self.wave = np.arange(3000., 12000., 50.)
# Equivalent wavelenths in nm
self.wavenm = self.wave / 10.
# Time to be used as Peak
self.mjdobs = 571190
# Check that we can set up a SED
# with no extinction
self.SN_blank = SNObject()
self.SN_blank.setCoords(ra=30., dec=-60.)
self.SN_blank.set(z=0.96, t0=571181, x1=2.66, c=0.353, x0=1.796e-6)
self.SN_blank.set_MWebv(0.)
self.SN_extincted = SNObject(ra=30., dec=-60.)
self.SN_extincted.set(z=0.96,
t0=571181,
x1=2.66,
c=0.353,
x0=1.796112e-06)
self.SNCosmoModel = self.SN_extincted.equivalentSNCosmoModel()
self.rectify_photParams = PhotometricParameters()
self.lsstBandPass = BandpassDict.loadTotalBandpassesFromFiles()
self.SNCosmoBP = sncosmo.Bandpass(wave=self.lsstBandPass['r'].wavelen,
trans=self.lsstBandPass['r'].sb,
wave_unit=astropy.units.Unit('nm'),
name='lsst_r')