`astra.utils.continuum.sines_and_cosines`¶

Continuum-normalization using sines and cosines.

Module Contents¶

Functions¶

`normalize`(dispersion, flux, ivar, continuum_regions=None, L=1400, order=3, regions=([3000, 10000], [15090, 15822], [15823, 16451], [16452, 16971]), fill_value=1.0, **kwargs)	Pseudo-continuum-normalize the flux using a defined set of continuum pixels and a sum of sine
`sines_and_cosines`(dispersion, flux, ivar, continuum_pixels, L=1400, order=3, regions=None, fill_value=1.0, **kwargs)	Fit the flux values of pre-defined continuum pixels using a sum of sine and
`_continuum_design_matrix`(dispersion, L, order)	Build a design matrix for the continuum determination, using sines and

astra.utils.continuum.sines_and_cosines.normalize(dispersion, flux, ivar, continuum_regions=None, L=1400, order=3, regions=([3000, 10000], [15090, 15822], [15823, 16451], [16452, 16971]), fill_value=1.0, **kwargs)¶

Pseudo-continuum-normalize the flux using a defined set of continuum pixels and a sum of sine and cosine functions.

Parameters:

Parameters:	dispersion – The dispersion values. flux – The flux values for all pixels, as they correspond to the `dispersion` array. ivar – The inverse variances for all pixels, as they correspond to the `dispersion` array. continuum_regions – [optional] A list of two-length tuples that describe the start and end of regions that should be treated as continuum. L – [optional] The length scale for the sines and cosines. order – [optional] The number of sine/cosine functions to use in the fit. regions – [optional] Specify sections of the spectra that should be fitted separately in each star. This may be due to gaps between CCDs, or some other physically- motivated reason. These values should be specified in the same units as the `dispersion`, and should be given as a list of `[(start, end), ...]` values. For example, APOGEE spectra have gaps near the following wavelengths which could be used as `regions`: >> regions = ([15090, 15822], [15823, 16451], [16452, 16971]) fill_value – [optional] The continuum value to use for when no continuum was calculated for that particular pixel (e.g., the pixel is outside of the `regions`). full_output – [optional] If set as True, then a metadata dictionary will also be returned.
Returns:	The continuum values for all pixels, and a dictionary that contains metadata about the fit.

dispersion – The dispersion values.
flux – The flux values for all pixels, as they correspond to the dispersion array.
ivar – The inverse variances for all pixels, as they correspond to the dispersion array.
continuum_regions – [optional] A list of two-length tuples that describe the start and end of regions that should be treated as continuum.
L – [optional] The length scale for the sines and cosines.
order – [optional] The number of sine/cosine functions to use in the fit.
regions –
[optional] Specify sections of the spectra that should be fitted separately in each star. This may be due to gaps between CCDs, or some other physically- motivated reason. These values should be specified in the same units as the dispersion, and should be given as a list of [(start, end), ...] values. For example, APOGEE spectra have gaps near the following wavelengths which could be used as regions:

>> regions = ([15090, 15822], [15823, 16451], [16452, 16971])
fill_value – [optional] The continuum value to use for when no continuum was calculated for that particular pixel (e.g., the pixel is outside of the regions).
full_output – [optional] If set as True, then a metadata dictionary will also be returned.

Returns:

The continuum values for all pixels, and a dictionary that contains metadata about the fit.

astra.utils.continuum.sines_and_cosines.sines_and_cosines(dispersion, flux, ivar, continuum_pixels, L=1400, order=3, regions=None, fill_value=1.0, **kwargs)¶

Fit the flux values of pre-defined continuum pixels using a sum of sine and cosine functions.

Parameters:

Parameters:	dispersion – The dispersion values. flux – The flux values for all pixels, as they correspond to the `dispersion` array. ivar – The inverse variances for all pixels, as they correspond to the `dispersion` array. continuum_pixels – A mask that selects pixels that should be considered as ‘continuum’. L – [optional] The length scale for the sines and cosines. order – [optional] The number of sine/cosine functions to use in the fit. regions – [optional] Specify sections of the spectra that should be fitted separately in each star. This may be due to gaps between CCDs, or some other physically- motivated reason. These values should be specified in the same units as the `dispersion`, and should be given as a list of `[(start, end), ...]` values. For example, APOGEE spectra have gaps near the following wavelengths which could be used as `regions`: >> regions = ([15090, 15822], [15823, 16451], [16452, 16971]) fill_value – [optional] The continuum value to use for when no continuum was calculated for that particular pixel (e.g., the pixel is outside of the `regions`). full_output – [optional] If set as True, then a metadata dictionary will also be returned.
Returns:	The continuum values for all pixels, and a dictionary that contains metadata about the fit.

dispersion – The dispersion values.
flux – The flux values for all pixels, as they correspond to the dispersion array.
ivar – The inverse variances for all pixels, as they correspond to the dispersion array.
continuum_pixels – A mask that selects pixels that should be considered as ‘continuum’.
L – [optional] The length scale for the sines and cosines.
order – [optional] The number of sine/cosine functions to use in the fit.
regions –
[optional] Specify sections of the spectra that should be fitted separately in each star. This may be due to gaps between CCDs, or some other physically- motivated reason. These values should be specified in the same units as the dispersion, and should be given as a list of [(start, end), ...] values. For example, APOGEE spectra have gaps near the following wavelengths which could be used as regions:

>> regions = ([15090, 15822], [15823, 16451], [16452, 16971])
fill_value – [optional] The continuum value to use for when no continuum was calculated for that particular pixel (e.g., the pixel is outside of the regions).
full_output – [optional] If set as True, then a metadata dictionary will also be returned.

Returns:

The continuum values for all pixels, and a dictionary that contains metadata about the fit.

astra.utils.continuum.sines_and_cosines._continuum_design_matrix(dispersion, L, order)¶

Build a design matrix for the continuum determination, using sines and cosines.

Parameters:	dispersion – An array of dispersion points. L – The length-scale for the sine and cosine functions. order – The number of sines and cosines to use in the fit.

astra.utils.continuum.sines_and_cosines¶

Module Contents¶

Functions¶

`astra.utils.continuum.sines_and_cosines`¶