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: http://www.adass.org/adass/proceedings/adass03/P3-3/
Дата изменения: Sat Aug 14 03:53:42 2004 Дата индексирования: Tue Oct 2 04:32:45 2012 Кодировка: |
The acquisition rate of astronomical data, both from space and ground-based observatories, has increased enormously in the last years. The possibility of studying regions of the electromagnetic spectrum that could not be reached until very recently has led to a spectacular growth of the multi-wavelength astronomy. However, a negative aspect affecting this growth is the lack of homogeneity that astronomical archives currently show. Historically, astronomical archives have been built independently of each other and this has meant that their remote interoperability is neither easy nor efficient, as demonstrated by the fact that the queries to multiple databases are done, most of the times, by hand. Interoperability is, therefore, one of the fundamental aspects for the Virtual Observatory (VO) and an essential requirement for the multi-wavelength astrophysical research.
Since January 2002 LAEFF has been developing, in the framework of the VO, a multi-mission data server to provide easy, efficient and uniform access to astronomical databases. A primary goal of this project is the implementation of science-driven tools. In this context, MMDSL provides an excellent framework to check the performance of utilities before their inclusion in the VO structure. This is a fundamental step in order to manage properly the huge flow of data expected from the VO federation of archive centres.
In this paper, the main functionalities and contents of the system are presented. The first version is foreseen to be released at the beginning of 2004 and will be available at http://sdc.laeff.inta.es
In the first phase, the system focuses on the integration of the ultraviolet archives maintained at LAEFF (EURDand INES) with the ESA astronomical archives hosted at VILSPA (XMM-Newton and ISO). The coverage in the optical range is given by flux-calibrated Strömgren and Geneva photometry.
At the time of writing we are working on the implementation of the 2MASS Point-Source Catalogue. To give a coverage as complete as possible in the UV, future plans imply access to the ultraviolet missions available in MAST.
The development of analysis tools for their further implementation in the Data Server constitutes an important added-value to the system and is in agreement with the Virtual Observatory goal that Data Centres should not be simple data repositories but they must incorporate tools to help users in the analysis. This will permit to transfer only results and not pre-analyzed data, a non negligible aspect given the vast amount of data handled in the Virtual Observatory federation of Archives. Implemented in the Data Centre the analysis tools can be shared and re-used and the expertise requirements on the user's side greatly reduced. It is clear that a Data Centre cannot cope with all potential scientific cases but this situation can be alleviated if collaboration with scientists in universities or research centres, acting as software tools writers, are established.
At present, MMDSL allows for comparisons between the observed spectral energy distribution of a stellar object and synthetic models. Another important facility implemented in the system is the determination of the physical parameters of early and mid-type stars from the Strömgren photometry using the most updated calibrations. Similarly, physical parameters of late-type stars will be derived from V-Johnson and 2MASS photometry following the method described in Ribas et al. (2003). Subsequent releases of the system will include the use of data mining tools for spectral classification and characterization of the observed spectral energy distributions.
Ribas, I., Solano, E., Massana, E. & Giménez, A., 1993, A&A, 411, L501