JENAM 2008 Theory Standards for the Virtual Observatory SimDB + SimDAP

JENAM 2008 Complex observations John Hibbard NASA/CXC/SAO/G. Fabbiano et al. electron densitygas pressuregas temperature Courtesy Alexis Finoguenov, Ulrich Briel, Peter Schuecker, (MPE)

JENAM 2008 require complex models Toomre & Toomre, 1972 Di Matteo, Springel and Hernquist, 2005 Courtesy Volker Springel

JENAM 2008 Survey planning Observed galaxy catalogues and synthetic counterparts from Millennium Run see: garching.mpg.de/millennium Model fitting HST observation of the PN central star LSV4621 vs. a theoretical SED which considers all elements H - Ni. Courtesy Thomas Rauch

JENAM 2008 Existing DAL standards can be used, sometimes If end products similar SSAP theory spectra SCS-like mock catalogues SIAP-like visualisation services

JENAM 2008 New, theory specific standards in progress: SimDB + SimDAP Discovery: Simulation Database (SimDB) Publish Describe Search Compare Access: Simulation Data Access Protocol (SimDAP) Retrieve Filter Analyse Visualise Combine

JENAM 2008 SimDB Supports discovery of interesting simulation results. and links to (SimDAP) services for accessing them Rich data model describing simulations and post-processing products Focused on 3+1D simulations but easily extended

JENAM 2008 SimDB approach Build a model containing the required features Create representations in standard modelling languages Define access services for publishing and querying Here we explain the model in some detail. See for details

JENAM 2008 Model must support common questions What was simulated? LSS, galaxy merger, rings of Saturn What physics was included? gravity only, hydrodynamics, chemistry How is the world represented? N bodies, adaptive mesh, spherically symmetric 1D What properties are calculated? position, velocity, mass, temperature, density, chemical abundances How do I get access? etc.

JENAM 2008 File Somewhere there is a file containing data of interest

JENAM 2008 Storage The data may also reside in a database. In general, there is some storage container somewhere.

JENAM 2008 Results of Experiments In our model, the data is of interest because it is the result of an astronomical experiment.

JENAM 2008 Experiments For SimDB, we consider for example Simulation and ClusterExtraction as special cases of such experiments. We could also consider observations, but that is a different model.

JENAM 2008 Protocol Experiments are performed according to a well defined protocol. Examples of this are simulator codes. The same protocol can be reused for describing many experiments done with it.

JENAM 2008 Parameters Protocols define input parameters, different experiments will give different values to these parameters.

JENAM 2008 Target For search purposes it is important to be able to describe the goal of an experiment. We model this using a collection of targets. These describe scientific content of the experiments. E.g. a galaxy merger was simulated, or a stellar spectrum.

JENAM 2008 Web service In reality the results of experiments are hardly ever stored simply, in a standardised manner. So we introduce web services that can be called to access specific experiments and their results.

JENAM 2008 The SimDB data model (in progress)data model In reality the final model deviates in the details, but the philosophy is the same.

JENAM 2008 Complex? Registry data model Spectrum Data Model STC SDSS SkyServer etc. The SimDB data model is not more complex than other models in the VO.

JENAM 2008 Representations (Generated)* XML Schemas Protocol: PDR code (courtesy Franck LePetit + Laurent Bourges) Simulation: Millennium Run Ideally generated from simulation and post-processing pipe-lines Relational Database Schema Java code HTML * To work with the model we need ot define representations of it in specific languages.

JENAM 2008 E.g.: XML Representation

JENAM 2008 Implementation protoypes CNRS GalMER: ITVO Trieste: Catania: Under development SimCat (UCSD) PDR/SimDB (Paris) Horizon/GalICS (Lyon) GAVO (Generated)