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Enrique Solano (LAEFF/SVO)

Interop., Kyoto, May 2005. TSAP: an SVO-ESAVO collaboration to develop a protocol to access theoretical data. Application to PGos3. Enrique Solano (LAEFF/SVO). SVO Carlos Rodrigo Miguel Cerviño. ESAVO Jesús Sal gado Isa Barbarisi Pedro Osuna. Interop., Kyoto, May 2005.

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Enrique Solano (LAEFF/SVO)

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  1. Interop., Kyoto, May 2005 TSAP: an SVO-ESAVO collaboration to develop a protocol to access theoretical data. Application to PGos3 Enrique Solano (LAEFF/SVO) SVO • Carlos Rodrigo • Miguel Cerviño ESAVO • Jesús Salgado • Isa Barbarisi • Pedro Osuna

  2. Interop., Kyoto, May 2005 Theory in the VO  Final goal:To ensure a real interoperability between observational and theoretical data.  Basic requirement: Specific VO-theory standards must be defined. Some already existing VO standards are useful (VOTables, UCDs, data models,..) but some others are not (e.g. access protocols). “In the light of the positive experience of the approach in the IVOA it will likely be very useful to define some simple query protocols for simulations as well and this effort should be one of the first for the TVO to undertake” . (Lemson & Colberg, Theory in the VO white paper)  Definition of a new protocol for theoretical data

  3. Interop., Kyoto, May 2005 Theory in the VO  The problem: • Observational data can be unambiguously defined by their coordinates. They are, therefore, prime parameters for SIAP, SSAP AND Conesearch. • For most of the theoretical data, Cone Search, SSA, SIAP cannot be applied as absolute positions on the sky are irrelevant. Moreover, the input parameters are model-dependent: there is not a common set that can play the role of the coordinates for the observational data.

  4. Interop., Kyoto, May 2005 TSAP: an access protocol for theoretical data •  The answer: the “three-steps” process: • The server accepts the “FORMAT=METADATA” request giving back the list of input parameters (and appropriate descriptions) in VOTable. • The client shows them to the user who makes the selection (fixed values or ranges of values). • A new SSAP-like query is submitted and the results are obtained.  TSAP sounds familiar (very much like SIAP or SSAP) and it is simple and easy to implement.

  5. Curation fields • DataID fields • Spectral coordinates and flux values. Interop., Kyoto, May 2005 Data model for theoretical spectra • To ensure an efficient comparison, it is advisable that any data structure proposed in the theoretical domain resembles that proposed for observational data.  The output VOTable is as close as possible to the IVOA SED Data Model v0.93. Although Coverage and Frame are meaningless fields…

  6. Interop., Kyoto, May 2005 A practical case  The client:  The server:

  7. Name resolved by SIMBAD Selection of input parameters Description attached to each parameter Interop., Kyoto, May 2005 Registry Access (SSA) + Theoretical services

  8. Model data scaling Interop., Kyoto, May 2005 Comparison of observational and theoretical spectra using VOSpec

  9. Interop., Kyoto, May 2005 What’s next?Application I: accretion disk models

  10. http://ov.inaoep.mx Interop., Kyoto, May 2005 Application II: PGos3 • Federative project that plans to include public codes related to the modelling of stellar populations in galaxies. • Beta version. The development and implementation phase began in July 2004 during the Guillermo Haro Workshop: “Violent Star Formation and the Legacy Tool” held at INAOE, Mexico. • Synergy between astrophysicist ands computer scientist in Mexico and Europe.

  11. Interop., Kyoto, May 2005 PGos3 in the VO framework •  PGos3 is a very valuable tool in the VO context: • 'Star Formation Histories in Galaxies' was the extragalactic Science Case chosen for the AVO-Demo 2005. This involves retrieving multiwavelength datasets that are then compared against stellar spectral evolution codes, to enable information to be derived on galaxy star formation histories.  The Spanish Virtual Observatory is adapting PGos3 to the VO standards and requirements.

  12. Interop., Kyoto, May 2005 The evolutionary synthesis models  Definition: a model of the expected emission of a stellar population defined as the sum of the emission of the individual stars. •  The building blocks: • Initial Mass Function (IMF): the number of stars with different masses to include in the population at t=0. • The IMF is often approximated either by a power-law or by a sum of power-laws over different subranges. (e.g. α: 2.35, Salpeter, (1955):

  13. Interop., Kyoto, May 2005 Evolutionary synthesis models (II) • The IMF must be translated into spectral information to obtain the population spectrum at t=0.  Stellar Model Atmospheres

  14. Interop., Kyoto, May 2005 TSAP in PGos3: an example

  15. Interop., Kyoto, May 2005 Next step: implementation of the protocol for evolutionary synthesis models

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