define_aperture

jwst.extract_1d.extract.define_aperture(input_model, slit, extract_params, exp_type)[source]

Define an extraction aperture from input parameters.

Parameters:

  • input_model (DataModel) – The input science model containing metadata information.

  • slit (DataModel or None) – One slit from a MultiSlitModel (or similar), or None. The spectral image and WCS information will be retrieved from slit unless slit is None. In that case, they will be retrieved from input_model.

  • extract_params (dict) – Extraction parameters, as created by get_extraction_parameters.

  • exp_type (str) – Exposure type for the input data.

Returns:

  • ra (float) – A representative RA value for the source centered in the aperture.

  • dec (float) – A representative Dec value for the source centered in the aperture.

  • wavelength (ndarray of float) – The 1D wavelength array, matching the dispersion dimension of the input spectral image, corresponding to the aperture. May contain NaNs for invalid dispersion elements.

  • profile (ndarray of float) – A 2D image containing pixel weights for the extraction aperture, matching the dimensions of the input spectral image. Values are between 0.0 (pixel not included in the extraction aperture) and 1.0 (pixel fully included in the aperture).

  • bg_profile (ndarray of float or None) – If background regions are specified in extract_params['bkg_coeff'], and extract_params['subtract_background'] is True, then bg_profile is a 2D image containing pixel weights for background regions, to be fit during extraction. Otherwise, bg_profile is None.

  • nod_profile (ndarray of float or None) – For optimal extraction, if nod subtraction was performed, a second spatial profile is generated, modeling the negative source in the slit. This second spatial profile is returned in nod_profile if generated. Otherwise, nod_profile is None.

  • limits (tuple of float) – Index limit values for the aperture, returned as (lower_limit, upper_limit, left_limit, right_limit). Upper/lower limits are along the cross-dispersion axis. Left/right limits are along the dispersion axis. All limits are inclusive and start at zero index value.