SpectralElement¶

class
synphot.spectrum.
SpectralElement
(modelclass, clean_meta=False, **kwargs)[source]¶ Bases:
synphot.spectrum.BaseUnitlessSpectrum
Class to handle instrument filter bandpass.
 Parameters
 modelclass, kwargs
See
BaseSpectrum
.
Methods Summary
check_overlap
(other[, wavelengths, threshold])Check for wavelength overlap between two spectra.
efficiency
([wavelengths])Calculate dimensionless efficiency.
emflx
(area[, wavelengths])Calculate equivalent monochromatic flux.
equivwidth
(**kwargs)Calculate bandpass equivalent width.
from_file
(filename, **kwargs)Creates a bandpass from file.
from_filter
(filtername, **kwargs)fwhm
(**kwargs)Calculate FWHM of equivalent gaussian.
photbw
([wavelengths, threshold])Calculate the bandpass RMS width as in IRAF SYNPHOT.
rectwidth
([wavelengths])Calculate bandpass rectangular width.
rmswidth
([wavelengths, threshold])Calculate the bandpass RMS width.
tlambda
(**kwargs)Calculate throughput at bandpass average wavelength.
to_fits
(filename[, wavelengths])Write the bandpass to a FITS file.
tpeak
([wavelengths])Calculate peak bandpass throughput.
unit_response
(area[, wavelengths])Calculate unit response of this bandpass.
wpeak
([wavelengths])Calculate wavelength at peak throughput.
Methods Documentation

check_overlap
(other, wavelengths=None, threshold=0.01)[source]¶ Check for wavelength overlap between two spectra.
Only wavelengths where
self
throughput is nonzero are considered.Example of full overlap:
 other   self 
Examples of partial overlap:
 self   other   other   self   self   other 
Examples of no overlap:
 self   other   other   self 
 Parameters
 other
BaseSpectrum
 wavelengthsarraylike,
Quantity
, orNone
Wavelength values for integration. If not a Quantity, assumed to be in Angstrom. If
None
,waveset
is used. thresholdfloat
If less than this fraction of flux or throughput falls outside wavelength overlap, the lack of overlap is insignificant. This is only used when partial overlap is detected. Default is 1%.
 other
 Returns
 result{‘full’, ‘partial_most’, ‘partial_notmost’, ‘none’}
‘full’ 
self
coverage is within or same asother
‘partial_most’  Less than
threshold
fraction ofself
flux is outside the overlapping wavelength region, i.e., the lack of overlap is insignificant‘partial_notmost’ 
self
partially overlaps withother
but does not qualify for ‘partial_most’‘none’ 
self
does not overlapother
 Raises
 synphot.exceptions.SynphotError
Invalid inputs.

efficiency
(wavelengths=None)[source]¶ Calculate dimensionless efficiency.

emflx
(area, wavelengths=None)[source]¶ Calculate equivalent monochromatic flux.
 Parameters
 area, wavelengths
See
unit_response()
.
 Returns
 em_flux
Quantity
Equivalent monochromatic flux.
 em_flux

equivwidth
(**kwargs)[source]¶ Calculate bandpass equivalent width.
 Parameters
 kwargsdict
See
integrate()
.
 Returns
 equvw
Quantity
Bandpass equivalent width.
 equvw

classmethod
from_file
(filename, **kwargs)[source]¶ Creates a bandpass from file.
If filename has ‘fits’ or ‘fit’ suffix, it is read as FITS. Otherwise, it is read as ASCII.
 Parameters
 filenamestr
Bandpass filename.
 kwargsdict
Keywords acceptable by
read_fits_spec()
(if FITS) orread_ascii_spec()
(if ASCII).
 Returns
 bp
SpectralElement
Empirical bandpass.
 bp

classmethod
from_filter
(filtername, **kwargs)[source]¶ Load predefined filter bandpass.
 Parameters
 filternamestr
Filter name. Choose from ‘bessel_j’, ‘bessel_h’, ‘bessel_k’, ‘cousins_r’, ‘cousins_i’, ‘johnson_u’, ‘johnson_b’, ‘johnson_v’, ‘johnson_r’, ‘johnson_i’, ‘johnson_j’, or ‘johnson_k’.
 kwargsdict
Keywords acceptable by
read_remote_spec()
.
 Returns
 bp
SpectralElement
Empirical bandpass.
 bp
 Raises
 synphot.exceptions.SynphotError
Invalid filter name.

photbw
(wavelengths=None, threshold=None)[source]¶ Calculate the bandpass RMS width as in IRAF SYNPHOT.
This is a compatibility function. To calculate the actual bandpass RMS width, use
rmswidth()
. Parameters
 wavelengthsarraylike,
Quantity
, orNone
Wavelength values for sampling. If not a Quantity, assumed to be in Angstrom. If
None
,self.waveset
is used. thresholdfloat or
Quantity
, optional Data points with throughput below this value are not included in the calculation. By default, all data points are included.
 wavelengthsarraylike,
 Returns
 bandw
Quantity
IRAF SYNPHOT RMS width of the bandpass.
 bandw
 Raises
 synphot.exceptions.SynphotError
Threshold is invalid.

rectwidth
(wavelengths=None)[source]¶ Calculate bandpass rectangular width.

rmswidth
(wavelengths=None, threshold=None)[source]¶ Calculate the bandpass RMS width. Not to be confused with
photbw()
. Parameters
 wavelengthsarraylike,
Quantity
, orNone
Wavelength values for sampling. If not a Quantity, assumed to be in Angstrom. If
None
,self.waveset
is used. thresholdfloat or
Quantity
, optional Data points with throughput below this value are not included in the calculation. By default, all data points are included.
 wavelengthsarraylike,
 Returns
 rms_width
Quantity
RMS width of the bandpass.
 rms_width
 Raises
 synphot.exceptions.SynphotError
Threshold is invalid.

tlambda
(**kwargs)[source]¶ Calculate throughput at bandpass average wavelength.

to_fits
(filename, wavelengths=None, **kwargs)[source]¶ Write the bandpass to a FITS file.
Throughput column is automatically named ‘THROUGHPUT’.
 Parameters
 filenamestr
Output filename.
 wavelengthsarraylike,
Quantity
, orNone
Wavelength values for sampling. If not a Quantity, assumed to be in Angstrom. If
None
,self.waveset
is used. kwargsdict
Keywords accepted by
write_fits_spec()
.

tpeak
(wavelengths=None)[source]¶ Calculate peak bandpass throughput.

unit_response
(area, wavelengths=None)[source]¶ Calculate unit response of this bandpass.
 Parameters
 Returns
 uresp
Quantity
Flux (in FLAM) of a star that produces a response of one photon per second in this bandpass.
 uresp

wpeak
(wavelengths=None)[source]¶ Calculate wavelength at peak throughput.
If there are multiple data points with peak throughput value, only the first match is returned.