Resumen:
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 spectra) are discussed, and the procedures implemented
in INES to solve these problems are outlined.
The more relevant 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 reliable determination
of the background. The INES extraction also
includes a correction for the contamination by solar light
in long wavelength spectra. Examples showing the improvements
obtained in INES with respect to SWET are
described. Finally, the linearity and repeatability characteristics
of INES data are evaluated and the validity of
the errors provided in the extraction is discussed.