The model has been accessible over the World-Wide Web since 1996. Parameters for the simulation are passed through web forms and the result is retrieved through ftp. In the framework of the VO, the Galaxy model can be useful to complement observational data to interpolate stellar statistics at new wavelengths or at directions where no data are available yet. We are also implementing a Bayesian classification tool to apply to observational data, based on probabilities computed by the galactic model assuming given observational parameters (Robin et al. 2002b).
To fulfill these goals, the database presents the following functionalities: () it incorporates catalogues from all observational categories; () it is interfaced (or will be in the near future) to other more specialized binary star databases such as Cracow (eclipsing binaries), SIDONIE (visual) and SB9 (spectroscopic); () a specific Java tool has been developed to compare numerical data from several catalogues with Digitized Sky Survey and CCD images (from a European Network) of visual binaries; and () the database will provide some tools specific to double stars such as ephemeris for eclipsing binaries. The database can be queried through web forms and mail-supplied lists of stars.
The idea is to have a dynamical database that allows the user to read, transform or create more data (if allowed by the available codes). We are currently calculating the collisional excitation rates of HO by H; some of the results are already published (Dubernet & Grosjean 2002) and we intend to start the database with our own results on the HO + H system. The fitted coefficients and functions of the collisional rates will be available as well as the Fortran code used to rebuild the collisional rates. The cross-section (tables and graphs) will be available in order for a user to check the completeness of the data and to complete the data if necessary.
A bibliographic database on ro-vibrational excitation processes has been built. It contains about 400 references from physical and chemical journals, with specific keywords added to all references. It gives the possibility to choose the molecules and atoms in collision, the origin of the data (theoretical, experimental), the type of processes (rotational excitation, vibrational excitation, etc.), the type of data (probabilities, cross-sections, collisional rates, etc.) and the usual information (author, year since 1974). The database can be updated automatically via a web page. All the papers providing data relevant to astrophysical use will be linked to files containing the traceability and validation of the data, as well as fits or links of/to the data.
The databases have three main goals: exploitation of observational data, in particular data that will be provided by HERSCHEL/ALMA or existing data from SWAS/ISO, modeling of cometary, planetary and interstellar media, and maximum of information given to theoreticians wishing to do calculations.
Thanks to our experience in discovery and follow-up of TNOs with the CFH12k (Petit et al. 2001), Besançon Observatory is actively participating in the definition of the strategy of the Ultra-Wide component of the CFHT Legacy Survey, aimed at discovering all TNOs around the ecliptic down to magnitude . In collaboration with CADC and Department of Physics and Astronomy of the University of British Columbia, we will prepare the observations and data processing and will participate in the additional observations required to determine the orbital parameters of the detected objects.
The outcome of this programme will be an orbital database of more than 1000 TNOs, all discovered in a well characterized survey. In addition, all the TNOs discovered in this survey will be followed to the third opposition, to avoid follow-up bias which is impossible to model. For each discovered TNO, the database will contain: () the field coordinates and size, with ``filling factor'' for a mosaic camera, () the exposure time, () the efficiency curve versus magnitude of discovery observations, together with range of rate of motion of validity, () all astrometric measurements, at discovery and recoveries, () the estimated orbit, and () for objects not yet with three oppositions, the full history of recovery attempts, in particular, the failing observations with circumstances.
One of the basic concepts of the Virtual Observatory is to use recent technology to enable access to data spread worldwide, keeping them where the relevant scientific expertise resides. In this framework, the Besançon Observatory will make available experimental or simulated data as well as scientific added value to the astronomical community more efficiently through the different facilities described above which have been accessed so far through the World-Wide Web. This makes necessary to broaden the operation methods implemented so far (web pages and forms, HTML or flat files output, http or ftp retrieval); this implies definition of metadata, broader query modes, extraction of large amount of data, on-the-fly analysis tools, etc. Some particular milestones of this process have been laid, namely: () XML formatted output of the data of the BDB database, with interoperability in mind (Debray 2002); while initial developments were done following the Astrores DTD, full final implementation will use the VOTables format (Ochsenbein et al. 2002); () planned implementation of the bibcode (Schmitz et al. 1995) within the bibliographic database of the BASECOL facility; it aims mainly at allowing both direct access to the bibliographic services such as ADS, and external retrieval of the keywords added in BASECOL used to classify the compiled references.
To implement VO concepts and standards in the future, we need them to comprehensively account for the scientific and technical requirements of our facilities, for instance, the definition of unambiguous metadata for the description of both services and data. Some requirements are already addressed by present definitions of Unified Column Descriptors (UCDs, see Derrière et al. 2002); more specific metadata are however needed for, e.g., the observational log of trans-neptunian objects or the parameters of simulated stellar populations.
On the other hand, our facilities (the Galactic simulation model mainly, but not exclusively) require that emerging protocols properly consider that a request issued by a remote service (web server, remote program) may require a long computing time before the output is sent back; simple http requests do not properly handle this case. Lastly, the VO will likely increase significantly the access rate to our services; replications via mirror sites have to be envisaged.
Robin, A. C. , Reylé, C., Derrière, S., & Picaud, S. 2002a, A&A, submitted
Robin, A. C., Reylé, C., Picaud, S., & Debray, B. 2002b, in Toward an International Virtual Observatory, ESO Astrophysics Symposia, ed. K.M. Górski & P. J. Quinn (Berlin: Springer-Verlag), in press
Oblak, E., Debray, B., Lastennet, E., & Kundera, T. 2002, in SF2A 2002: Semaine de l'Astrophysique Française, EDP-Sciences, ed. F. Combes & D. Barret, in press
Dubernet, M.-L., Grosjean, A. 2002, A&A, 390, 793
Petit, J.-M., et al. 2001, BAAS, 33, 1030
Debray, B. 2002, in Toward an International Virtual Observatory, Scientific Motivation, ESO Astrophysics Symposia, ed. K.M. Górski & P. J. Quinn (Berlin: Springer-Verlag), in press
Ochsenbein, F., et al. 2002, in Toward an International Virtual Observatory, ESO Astrophysics Symposia, ed. K.M. Górski & P. J. Quinn (Berlin: Springer-Verlag), in press
Schmitz, M., et al. 1995, Vistas Astron. 39, 272
Derrière, S., Ochsenbein, F., & Ortiz, P. 2002, in Toward an International Virtual Observatory, ESO Astrophysics Symposia, ed. K.M. Górski & P.J. Quinn (Berlin: Springer-Verlag), in press