INFO 33-1998: The Universe as seen by ISO
15 October 1998
The latest results from the Infrared Space Observatory (ISO) are being presented at an International meeting in Paris, 20-23 October. Nearly 400 hundred infrared astronomers will attend the conference.This is the first major scientific conference devoted to ISO since the end of its in-orbit mission last May. Thus, it is a long-awaited occasion for the scientists to come to conclusions and start picturing the infrared face of the universe in detail.
The meeting will be held at UNESCO, Place de Fontenoy, Paris, where nearly 300 scientific papers ranging over all fields of astronomy, from solar system to cosmology, will be presented and analysed by infrared astronomers.
Background
The infrared universe is relatively poorly known because infrared light comes from dusty and cold regions that are invisible to other telescopes. ISO, the best infrared space telescope so far, finally has swept away the dust and seen all the way through. ISO scientists, therefore, are ready for surprises. The recent discovery by ISO of the presence of water throughout the universe was already a hint of what is still to come. More findings can be expected from this meeting, and a few results are already summarized below.ISO unveils the hidden rings of Andromeda
The Andromeda galaxy, one of the closest companions of our own galaxy, has been hiding from the astronomers' eyes one of its secrets: while always considered a typical spiral galaxy, ISO sees it now as a spectacular ringed galaxy. Andromeda is thus structured in multiple concentric rings, made of very cold dust ~ -260 °C. The cold dust cannot be seen by optical telescopes, that's the reason why the rings have always remained hidden in the common views of the galaxy. The new data suggest that Andromeda might be undergoing a transition phase to become a ringed galaxy which would be seen as such also by conventional telescopes in the distant future.
Infrared bright gravitational arcs
ISO has detected the first known infrared-bright gravitational arcs, which may be the distorted and magnified images of distant young galaxies in collision. Before ISO no gravitational arc had been detected at these wavelengths, so these results make a nice victory for those who, against all pessimistic predictions, bet on ISO's sensitivity to detect gravitational arcs by infrared light. The newly-observed arcs number more than thirty, and the galaxies they reveal are some of the farthest objects ever seen in the mid-infrared. To all other telescopes these objects have remained deeply obscured by dust. This means that ISO is unveiling the hidden side of the early universe, the processes that took place when the cosmos was about one third of its present age or even younger.
ISO sees a ring of organic matter surrounding a star
A huge ring of organic matter surrounding a young star has been observed by ISO. This kind of structure has never been detected before. With this finding ISO shows again a clear example of how the stars and their environment work as the Nature's chemical factories: not only water is being produced there - as ISO demonstrated--, but also complex organic molecules are present; these molecules are, essentially, the basic building blocks of all living organisms.
