Lyon Data center for the Sciences of the Universe: LyDU

The PHOENIX archive of spectra contains collections of spectra computed under a variety of physical hypotheses and conditions for a wide range of parameters, from the hottest stars to giant planets. Together with the spectra, the atmosphere structures and the synthetic colours are available. In the mid term, the spectra will also be available through the POLLUX interface. The web interface provides added values services to evaluate the data, and transform them on-the-fly to suit special requirements. Beside this interface, the spectra can also be accessed from the Virtual Observatory.

The LySI spectrum interpolator is a service providing interpolated spectra based on empirical stellar libraries. It is instrumental to the elaboration of stellar population models (for example with PEGASE) and to the determination of the atmospheric parameters of stars.
LySI has been one of the first service in the Virtual Observatory delivering computed spectra.

ULySS, the University of Lyon Spectroscopic Software, is an analysis tools. It is intended to perform a full-spectrum fitting of an observation against any kind of models. It is essentially used to characterize the atmosphere of stars, and to study the history of the star formation and metal enhancement in galaxies.
It takes advantage of LySI and of the Phoenix spectra.

The Virtual Observatory is a global effort shared by the astronomical community to facilitate the exchange of data among the astronomers. It develops the tools and standards needed to achieve the interoperability of the many services offered by institutions around the world.
The LyDU services adopt those standards and are interoperable with all the other services of the Virtual observatory.