SOPHIE : Final reduction stepsExtracted spectra in wavelength spaceThis page illustrates some of the final steps in the reduction of SOPHIE spectra. We have selected three orders from the observation of HD 34078 done on 2007-02-10 in HR mode. The first row shows the extracted data for each order in the e2ds file, plotted vs. wavelength, obtained from the associated wave file, while the second row shows the same data after division by the associated blaze file. Note that the standard e2ds data product is not de-blazed.
De-blazed, rebinned spectra after order reconnectionThe third row shows the same wavelength intervals from the deblazed, reconnected and rebinned s1d file. Note how the reconnection improves the S/N ratio in the intervals corresponding to the order edges, thanks to a substantial order overlap. Note that s1d spectra have not been corrected neither for atmospheric extinction nor for the instrument response. The flux given is relative to the flat-field lamp energy distribution.
Spectral sampling and correction for Earth's velocityUsers should be aware that the s1d data product as delivered has a 0.01 Å wavelength step. This is smaller than the actual sampling done by the CCD, which is 0.019 Å/pixel near 3900Å, 0.024 Å/pixel near 5000Å and 0.034 Å/pixel near 6900Å. Note that the s1d spectra have been corrected for the Doppler shift of the telescope relative to the barycenter of the Solar System, and that the lines are thus not at the same wavelength as in the e2ds spectra. The fourth row illustrates this in the case of HD 34078 for two different interstellar CH absorption lines.
23.03.07
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