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Astron. Astrophys. Suppl. Ser. 141, 343-355

The INES system

III. Evaluation of IUE NEWSIPS high resolution spectra

R. González-Riestra1[*] - A. Cassatella2,3[*] - E. Solano1[*] - A. Altamore3 - W. Wamsteker4[*]

Send offprint request: R. González-Riestra,
e-mail: ch@laeff.esa.es


1 - Laboratorio de Astrofísica Espacial y Física Fundamental, VILSPA, P.O. Box 50727, E-28080 Madrid, Spain
2 - CNR, Istituto di Astrofisica Spaziale, Via del Fosso del Cavaliere, I-00133 Roma, Italy
3 - Dipartimento di Fisica E. Amaldi, Universitá Roma Tre, Via della Vasca Navale 84, I-00146 Roma, Italy
4 - ESA-IUE Observatory, VILSPA, P.O. Box 50727, E-28080 Madrid, Spain

Received July 23; accepted October 22, 1999

Abstract:

This paper discusses the overall quality of IUE high resolution data processed with the NEWSIPSsoftware 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 system provides the IUE high resolution data in two formats: the high resolution "concatenated'' spectra, in which the spectral orders are connected, eliminating the overlap regions through a procedure designed to optimize the signal-to-noise ratio at the edges of the orders, and the "rebinned'' spectra, i.e. the high resolution concatenated spectra resampled into the low resolution wavelength domain. Our study reveals the existence of a significant discrepancy in the wavelength scales of short and long wavelength NEWSIPS high resolution spectra. The INES processing applies a correction of +17.7 km s-1 to the wavelength scale of the high resolution SWP spectra in order to provide an internally consistent velocity scale. Similarly, suitable corrections have been applied to long wavelength small aperture spectra. The new wavelength scale is, within the errors, in good agreement with the optical velocity scale.

Key words: methods: data analysis; techniques: image processing; ultraviolet: general



 
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