find_lines_derivative¶
- specutils.fitting.find_lines_derivative(spectrum, flux_threshold=None)[source]¶
Find the emission and absorption lines in a spectrum. The method here is based on finding the zero crossings in the derivative of the spectrum.
- Parameters:
- spectrum
Spectrum1D
The spectrum object over which the equivalent width will be calculated.
- flux_thresholdfloat,
Quantity
or None The threshold a pixel must be above to be considered part of a line. If a float, will assume the same units as
spectrum.flux
. This threshold is above and beyond the derivative searching step. Default is None so no thresholding. The threshold is positive for emission lines and negative for absorption lines.
- spectrum
- Returns:
- qtable:
QTable
Table of emission and absorption lines. Line center (
line_center
), line type (line_type
) and index of line center (line_center_index
) are stored for each line.
- qtable: