The INES system - III. Evaluation of IUE NEWSIPS high resolution spectra

This paper discusses the overall quality of IUE high resolution data proces sed with the NEWSIPS software in terms of flux and wavelength accuracy. It also describes the processing of NEWSIPS high resolution spectra within the framework of the ESA "IUE Newly. Extracted Spectra" (INES) System. This sy stem provides the IUE high resolution data in two formats: the high resolut ion "concatenated" spectra: in which the spectral orders are connected; eli minating the overlap regions through a procedure designed to optimize the s ignal-to-noise ratio at the edges of the orders, and the "rebinned" spectra , i.e. the high resolution concatenated spectra resampled into the low reso lution wavelength domain. Our study reveals the existence of a significant discrepancy in the wavelength scales of short and long wavelength NEWSIPS h igh resolution spectra. The INES processing applies a correction of +17.7 k m s(-1) to the wavelength scale of the high resolution SWP spectra in order to provide an internally consistent velocity scale. Similarly, suitable co rrections have been applied to long wavelength small aperture spectra. The new wavelength scale is, within the error:;, in good agreement with the opt ical velocity scale.