def extract(spectrum_data, x_range):
''' Extracts a region from a spectrum.
Paramaters
----------
spectrum_data: SpectrumData
Contains the spectrum to be extracted.
w_range: tuple
A spectral coordinate range as in (wave1, wave2)
Returns
-------
SpectrumData with extracted region.
'''
x = spectrum_data.x.data
y = spectrum_data.y.data
slice = (x >= x_range[0]) & (x < x_range[1])
result = SpectrumData()
result.set_x(x[slice], unit=spectrum_data.x.unit)
result.set_y(y[slice], unit=spectrum_data.y.unit)
return result
def read_image(image, flux_unit=None, dispersion_unit=None, **kwargs):
"""Read 1D image
Parameters
----------
image: FITS Image HDU
Returns
-------
SpectrumData
Notes
-----
Assumes ONLY 1D and that the WCS has the dispersion
definition. If not, its just pixels.
"""
if len(image.data.shape) > 1:
raise RuntimeError('Attempting to read an image with more than one '
'dimension.')
wcs = WCS(image.header)
spectrum = SpectrumData()
unit = flux_unit if flux_unit else DEFAULT_FLUX_UNIT
spectrum.set_y(image.data, unit=unit)
unit = wcs.wcs.cunit[0] if not dispersion_unit else dispersion_unit
spectrum.set_x(wcs.all_pix2world(range(image.data.shape[0]), 1)[0],
unit=unit)
return spectrum
def read_table(table,
flux='flux', dispersion='wavelength',
flux_unit=None, dispersion_unit=None):
"""Read FITS table
Parameters
----------
table: FITS table
dispersion: str
Name of column containing the dispersion axis.
flux: str
Name of column containing the flux axis.
dispersion_unit: str
Unit of dispersion
flux_unit: str
Unit of flux
Returns
-------
SpectrumData
'"""
if dispersion_unit is None:
try:
dispersion_unit = table.columns[table.names.index(dispersion.upper())].unit
if dispersion_unit is None:
raise ValueError
except ValueError:
dispersion_unit = DEFAULT_DISPERSION_UNIT
if flux_unit is None:
try:
flux_unit = table.columns[table.names.index(flux.upper())].unit
if flux_unit is None:
raise ValueError
except ValueError:
flux_unit = DEFAULT_FLUX_UNIT
spectrum = SpectrumData()
spectrum.set_x(table[dispersion], unit=dispersion_unit)
spectrum.set_y(table[flux], unit=flux_unit)
return spectrum
def read_image(image, flux_unit=None, dispersion_unit=None, **kwargs):
"""Read 1D image
Parameters
----------
image: FITS Image HDU
Returns
-------
SpectrumData
Notes
-----
Assumes ONLY 1D and that the WCS has the dispersion
definition. If not, its just pixels.
"""
if len(image.data.shape) > 1:
raise RuntimeError('Attempting to read an image with more than one '
'dimension.')
wcs = WCS(image.header)
spectrum = SpectrumData()
unit = flux_unit if flux_unit else DEFAULT_FLUX_UNIT
spectrum.set_y(image.data, unit=unit)
unit = wcs.wcs.cunit[0] if not dispersion_unit else dispersion_unit
spectrum.set_x(wcs.all_pix2world(range(image.data.shape[0]), 1)[0],
unit=unit)
return spectrum
def extract(spectrum_data, x_range):
''' Extracts a region from a spectrum.
Paramaters
----------
spectrum_data: SpectrumData
Contains the spectrum to be extracted.
w_range: tuple
A spectral coordinate range as in (wave1, wave2)
Returns
-------
SpectrumData with extracted region.
'''
x = spectrum_data.x.data
y = spectrum_data.y.data
slice = (x >= x_range[0]) & (x < x_range[1])
result = SpectrumData()
result.set_x(x[slice], unit=spectrum_data.x.unit)
result.set_y(y[slice], unit=spectrum_data.y.unit)
return result
def read_table(table,
flux='flux',
dispersion='wavelength',
flux_unit=None,
dispersion_unit=None):
"""Read FITS table
Parameters
----------
table: FITS table
dispersion: str
Name of column containing the dispersion axis.
flux: str
Name of column containing the flux axis.
dispersion_unit: str
Unit of dispersion
flux_unit: str
Unit of flux
Returns
-------
SpectrumData
'"""
if dispersion_unit is None:
try:
dispersion_unit = table.columns[table.names.index(
dispersion.upper())].unit
if dispersion_unit is None:
raise ValueError
except ValueError:
dispersion_unit = DEFAULT_DISPERSION_UNIT
if flux_unit is None:
try:
flux_unit = table.columns[table.names.index(flux.upper())].unit
if flux_unit is None:
raise ValueError
except ValueError:
flux_unit = DEFAULT_FLUX_UNIT
spectrum = SpectrumData()
spectrum.set_x(table[dispersion], unit=dispersion_unit)
spectrum.set_y(table[flux], unit=flux_unit)
return spectrum
# Example usage
def print_results(wave, flux, converted_wave, converted_flux):
for k in range(4):
print(wave[k], " ", converted_wave[k])
for k in range(4):
print(flux[k], " ", converted_flux[k])
import test_data
if __name__ == "__main__":
# real emission line from UV spectrum of NGC3516
x, y, e = test_data.get_data()
# test conversions from SpectrumData objects.
sp_data = SpectrumData()
sp_data.set_x(x, unit="Angstrom")
sp_data.set_y(y, unit="erg.s-1.cm**-2.Angstrom-1") # flam
converter = UnitsConverter(u.micron, u.Jy)
converter.convertSpectrumData(sp_data)
print(sp_data.x.unit, " ", sp_data.y.unit)
for k in range(4):
print(sp_data.x.data[k], " ", sp_data.y.data[k])
# test conversions from Quantity objects.
wave = test_data.get_data()[0] * u.Unit('angstrom')
flux = test_data.get_data()[1] * u.Unit("erg / (Angstrom cm2 s)")
converter = UnitsConverter(u.micron, u.Jy)
# Example usage
def print_results(wave, flux, converted_wave, converted_flux):
for k in range(4):
print(wave[k], " ", converted_wave[k])
for k in range(4):
print(flux[k], " ", converted_flux[k])
import test_data
if __name__ == "__main__":
# real emission line from UV spectrum of NGC3516
x,y,e = test_data.get_data()
# test conversions from SpectrumData objects.
sp_data = SpectrumData()
sp_data.set_x(x, unit="Angstrom")
sp_data.set_y(y, unit="erg.s-1.cm**-2.Angstrom-1") # flam
converter = UnitsConverter(u.micron, u.Jy)
converter.convertSpectrumData(sp_data)
print(sp_data.x.unit, " ", sp_data.y.unit)
for k in range(4):
print(sp_data.x.data[k], " ", sp_data.y.data[k])
# test conversions from Quantity objects.
wave = test_data.get_data()[0] * u.Unit('angstrom')
flux = test_data.get_data()[1] * u.Unit("erg / (Angstrom cm2 s)")