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| Paper: |
Sky Subtraction for Observations without Plain Sky Information |
| Volume: |
485, Astronomical Data Analysis Software and Systems XXIII |
| Page: |
99 |
| Authors: |
Noll, S.; Kausch, W.; Szyszka, C.; Jones, A. M.; Barden, M.; Kimeswenger, S. |
| Abstract: |
In the near-IR, the sky background is dominated by highly variable
airglow emission lines. This is an issue for the sky subtraction in
spectra without plain sky, where reference sky spectra taken at a
different time as the object spectrum are required. For this reason, we
have developed the instrument-independent sky subtraction code SKYCORR,
which uses physically motivated line group scaling in the reference sky
spectrum by a fitting approach for an improved sky line removal in the
object spectrum. Possible wavelength shifts between both spectra are
corrected by fitting Chebyshev polynomials and advanced rebinning
without resolution decrease. For the correction, the optimised sky line
spectrum and the automatically separated sky continuum (without scaling)
is subtracted from the input object spectrum. Tests show that SKYCORR
performs well (percent level residuals) for data in different
wavelength regimes and of different resolution, even in the cases of
relatively long time lags between the object and the reference sky
spectrum. Lower quality results are mainly restricted to wavelengths
not dominated by airglow lines or pseudo continua by unresolved strong
emission bands. |
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