Theory Standards for the Virtual ObservatorySimDB + SimDAP

Complex observations ...

... require complex modelsToomre & Toomre, 1972Di Matteo, Springel and Hernquist, 2005Courtesy Volker SpringelCourtesy Volker Springel

Survey planningObserved galaxy catalogues and synthetic counterparts from Millennium Run see: http://www.mpa-garching.mpg.de/millennium Model fittingHST observation of the PN central star LSV4621 vs. a theoretical SED which considers all elements H - Ni. Courtesy Thomas Rauch

Existing DAL standardscan be used, sometimesIf end products similarSSAPtheory spectra SCS-likemock cataloguesSIAP-likevisualisation services

New, theory specific standards in progress: SimDB + SimDAPDiscovery: Simulation Database (SimDB)PublishDescribeSearchCompareAccess: Simulation Data Access Protocol (SimDAP)RetrieveFilterAnalyseVisualiseCombine

SimDBSupports discovery of interesting simulation results.and links to (SimDAP) services for accessing themRich data model describing simulations and post-processing productsFocused on 3+1D simulationsbut easily extended

SimDB approachBuild a model containing the required featuresCreate representations in standard modelling languagesDefine access services for publishing and queryingHere we explain the model in some detail.See http://code.google.com/p/volute/wiki/TheoryHome for details

Model must support common questionsWhat was simulated?LSS, galaxy merger, rings of SaturnWhat physics was included?gravity only, hydrodynamics, chemistryHow is the world represented?N bodies, adaptive mesh, spherically symmetric 1DWhat properties are calculated?position, velocity, mass, temperature, density, chemical abundancesHow do I get access?etc.

FileSomewhere there is a file containing data of interest

StorageThe data may also reside in a database.In general, there is some storage container somewhere.

Results of ExperimentsIn our model, the data is of interest because it is the result of an astronomical experiment.

ExperimentsFor 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.

ProtocolExperiments 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.

ParametersProtocols define input parameters, different experiments will give different values to these parameters.

TargetFor 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.

Web serviceIn 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.

The SimDB data model (in progress)The SimDB ata model deviates in the details, but the philosophy is the same.

Complex?Registry data model

Spectrum Data ModelSTC SDSS SkyServer

etc.The SimDB data model is not more complex than other models in the VO.

Representations(Generated)*XML SchemasProtocol: PDR code (courtesy Franck LePetit + Laurent Bourges)Simulation: Millennium Run Ideally generated from simulation and post-processing pipe-linesRelational Database SchemaJava codeHTML* http://code.google.com/p/volute/wiki/TheoryHome To work with the model we need ot define representations of it in specific languages.

E.g.: XML Representation

Implementation prototypesCNRSGalMER: http://galmer.obspm.fr/ ITVOTrieste: http://wwwas.oats.inaf.it/IA2/ITVOCatania: http://itvo.oact.inaf.it Under developmentSimCat (UCSD)PDR/SimDB (Paris)Horizon/GalICS (Lyon)MPA Simulations (GAVO, Generated)