The IUE INES system: Improved data extraction procedures for IUE

We present the extraction and processing of the IUE Low Dispersion spectra within the framework of the ESA "IUE Newly Extracted Spectra" (INES) System . Weak points of SWET, the optimal extraction implementation to produce the NEWSIPS output products (extracted spectral are discussed, and the procedu res implemented in INES to solve these problems are outlined. The more rele vant modifications are: 1) the use of a new noise model, 2) a more accurate representation of the spatial profile of the spectrum and 3) a more reliab le determination of the background. The INES extraction also includes a cor rection for the contamination by solar light in long wavelength spectra. Ex amples showing the improvements obtained in INES with respect to SWET are d escribed. Finally, the linearity and repeatability characteristics of INES data are evaluated and the validity of the errors provided in the extractio n is discussed.