ISO Status Report - April 2003
A new approach to the assessment of data quality has been laid down, upgrading from a small set of technical quality flags to a well-structured quality report, which often includes a scientific assessment. This approach is the same as that foreseen for the XMM-NEWTON Science Archive. Its implementation is foreseen for version 7 of the ISO archive, planned for end 2003. Work on documentation continues well. The legacy versions of the remaining ISO Handbook volumes (ISOCAM and ISO) are being finalised.
ISO continues to have a significant presence in the refereed literature with, up to now, about one thousand articles drawing upon ISO data having appeared since late 1996! In 2002, there were 143 refereed papers based on ISO data; the rate for 2003 (43 published up to March 2003) extrapolates to a similar amount for the current year. ISO papers cover almost all areas of astronomy. Recent results include:
A complete ISO view of Palomar-Green (PG) quasars, based on 64 infrared spectral energy distributions between 5 and 200 micron. Not only coarse IR differences between ULIRGs and quasars are seen, known from earlier IRAS studies, but also the details and a possible evolution of the dust distribution and emission even among the optically selected Palomar-Green quasar sample. During such an evolution the dust distribution rearranges, settling more and more into a torus/disk like configuration. During the evolution the AGN strength grows, then stays high and finally declines. As a relict a "dead quasar" remains with a starved black hole sitting in a bright host galaxy.
A more precise thermal and compositional knowledge of Titan's stratosphere, obtained from spectra in the range 7-30 micron, by three of the ISO instruments (SWS, CAM and PHT). With the high spectral resolution achieved by the SWS (much higher than that of the Voyager 1 IRIS spectrometer) it was possible to detect and separate the contributions of most of the atmospheric gases present on Titan and to determine disk-averaged mole fractions.