kinextract.fortran_rebin_after_redshift

kinextract.fortran_rebin_after_redshift(x: ndarray, flux: ndarray, step: float, extra_arrays: dict | None = None) → tuple[ndarray, ndarray, dict][source]

Resample a de-redshifted spectrum onto a uniform wavelength grid.

After dividing the observed wavelength array by 1 + zgal, the pixel spacing is no longer exactly uniform in the rest frame. This reproduces the legacy Fortran imfit behavior of re-gridding onto a strictly uniform step (starting at the first rest-frame wavelength) via linear interpolation, which several downstream steps (e.g. the LOSVD convolution machinery) assume.

Parameters:

  • x (ndarray) – De-redshifted (rest-frame) wavelength array (Å), non-uniformly spaced.

  • flux (ndarray) – Flux array corresponding to x.

  • step (float) – Desired uniform wavelength step (Å) of the output grid.

  • extra_arrays (dict, optional) – Additional named arrays (e.g. flux errors, continuum estimates) to resample onto the same new grid using the same linear interpolation and edge-fill rule. Entries with value None are passed through as None in the output.

Returns:

  • x_new (ndarray) – Uniformly spaced rest-frame wavelength grid (Å), same length as the input x, starting at x[0].

  • flux_new (ndarray) – Flux linearly interpolated onto x_new, with edge values held constant beyond the original range.

  • extra_new (dict) – Each array in extra_arrays similarly resampled onto x_new.