The Short Wavelength Spectrometer (SWS) provides medium and high spectral resolution in the infrared. Its grating spectrometers cover the wavelength region 2.38-45.2 m, with an overall spectral resolution of 1,000-2,000 , i.e., corresponding to a velocity resolution of 300-150 km s . By inserting Fabry-Pérot (F-P) filters for the wavelength regions 15-26 m and 26-35 m, the resolution can be boosted to , i.e., corresponding to a velocity resolution 10 km s . Limiting flux densities for 10-minute observations at a signal-to-noise ratio SNR = 20 in the standard grating mode (Astronomical Observation Template SWS06) range from 2 Jy at 2.38 m to 8 Jy at 45.2 m for a wavelength range of 8 resolution elements. Limiting fluxes for 10-minute observations at SNR = 20 in the standard F-P mode (AOT SWS07) of an unresolved line are of the order of 2 Wm .
The SWS wavelength range is of great scientific interest, not only because it is here that cool objects in the temperature range 1500-80 K radiate the bulk of their energy, but also because of its rich variety of atomic, ionic, molecular and solid-state spectral features. These provide unique and excellent tools for studies of the physical and chemical processes in the universe, especially of those regions optically hidden by interstellar dust. The SWS spectral resolution allows probing of kinematic processes in a variety of objects ranging from nuclei of galaxies to planetary atmospheres. With the SWS sensitivity, line studies of extragalactic objects out to the distance of the Virgo cluster, and even beyond in the case of IRAS galaxies, can be carried out. Direct observation of ground state in the interstellar medium is possible. With the SWS over 100,000 objects -- including many galaxies -- are within reach for detailed spectroscopic studies.
The scope of this document is to provide to instrument team
investigators and guest investigators an ISO-SWS observer's manual,
giving a general introduction to the SWS instrument and operations, and
recipes for planning of individual observations.