Since the arrival of new generations of terrestrial and satellite telescopes, observation of the Universe has moved away from the 'age of the eye' to that of the detection of its many invisible rays. This technological change is giving rise to such a mass of digital data that it requires a new tool – the Astrophysical Virtual Observatory (AVO) – to manage it.
Three images of the same galaxy are the result of different telescopic approaches using the spectrum of visible waves, radio wavelengths and X-rays. Each one gives rise to interpretations which increase our knowledge.
The Universe has never come in for such scrutiny – from satellites such as the Hubble, the Infrared Space Observatory (ISO) and the XMM-Newton X-Ray Telescope, as well as such high-tech terrestrial installations as the Very Large Telescope (VLT) at the European Southern Observatory's Chile site. The sophisticated sensors fitted to the telescopes continuously record billions of observations of invisible rays which are stored in huge databases. New equipment already being prepared at the international level – such as the Next Generation Space Telescope or the Atacama Large Millimetre Array (ALMA), a complex of 64 dishes measuring 100 metres in diameter being planned for Chile – will further increase this explosion in astrophysical data.
The sky on screen Astronomers no longer look at the sky, but at computer screens, as they face an increasingly daunting task. 'The performances of astronomical instruments and detectors double every year, those of computers every 18 months, and of data transmission networks every 20 months,' stresses Lars Christensen of the ESA (SC-ECF). 'The telescopes we will be using 10 years from now will provide us with such a mass of images in a single night that it would take us more than a month to transfer them using the present Internet configuration.'
How do you manage and use this growing flow of data effectively? This is a question, first and foremost, for the information and communication technologies – and one posed not only by astrophysics but by disciplines such as particle physics and genomics too. The answer lies in using the Grid. This new concept is a kind of 'super-Internet' designed to share the archiving and processing of vast quantities of data between host computers at different locations, thereby pooling power and capacity.
Customised data mining and archiving It is against this background that the Astrophysical Virtual Observatory (AVO) is being set up. Launched at the end of 2001, the initiative has a budget of approximately €5 million, including a Union contribution of €2 million. It is a partnership of six of Europe's best astronomy centres under the management of the ESO.
This interactive structure will enable researchers to identify, for example, in which galaxies black holes can be identified which correspond to specific characteristics. The system will explore the data available in all the interconnected databases before making a summary of their processing using, in parallel, the capacities of the networked computers.
The researcher will then receive an analysis of the results without having to undertake the long and laborious task of decoding and listing. At the same time, another scientist working on different questions but drawing on data used for the first request will, in turn, receive a reply customised to his own needs.
Note: the AVO is being developed in close co-operation with two sister initiatives, Astrogrid in the United Kingdom and the National Virtual Observatory (NVO) in the United States.
Partners in the AVO project
Institute for Astronomy (University of Edinburgh) and Jordell Bank Observatory (Victoria University of Manchester – UK)
Institut d'astrophysique de Paris and the Observatoire astronomique de Strasbourg ...