The ADEC and ADEC White Paper

1. The ADEC and ADEC White Paper The HEASARC and The Virtual Observatory Tom McGlynn

2. Outline • What problem are we trying to solve? • What do we need from the HUG? • The ADCCC and ADEC • Current VO Activities • The ADEC White paper • Draft Concepts • Capabilities • Approach • Organization

3. What is the problem we are trying to solve? • Astrophysics science goals cannot be attained without coordinated use of data from multiple sources. • Decadal review VO recommendation • Virtual observatory activities are underway in the US and abroad. • What is NASA’s role? • Individual institutions are involved, but there is no systematic response.

4. HUG contributions • Advice • What is the best approach? • What are the key components? • Endorsement and advocacy • As representatives of the community indicate that this is important to do. • As individual astronomers make it known that this is something you want.

5. Background of the ADEC • ADCCC created in mid 90’s • Ad hoc organization of NASA archives with some outside representation • Keep each other informed of issues • Minimize duplication of effort • Address ‘boundary’ issues • EUVE archive

6. Creation of ADEC ADCCC formally recognized by NASA and reorganized as Astronomy Data Centers Executive Committee (Jan 2001). • Chair rotates each year • One representative from each data center. • CDS representative and potentially others from outside NASA.

7. Membership of the ADEC • NED – Barry Madore (chair) • ADS – Gunther Eichhorn • CXC – Pepi Fabbiano • IPAC - Andy Boden • IRSA – Bruce Berriman • GLAST – David Band • HEASARC – Tom McGlynn (acting) • LAMBDA – Gary Hinshaw • MAST – Marc Postman • NSSDC - Joe King • SIRTF – Lisa Storrie-Lombardi • HST - Paolo Padovani • CDS - Francoise Genova

8. ADEC Activities • Interface with journals • Standards for publishing data sets used in research • FITS technical working group • Build upon FITS standards • Interoperability technical working group • Establish interoperable systems within NASA centers.

9. ITWG Charter • Provide seamless (one stop shopping) access to all the NASA astrophysics catalog and data services regardless of where the information is located. • All services will be accessible via standard protocols • Access will be via the existing user interfaces • Results will appear consistent with the interface that initiated the request. • Affiliation of the data to the original site will be clearly stated.

10. Existing ADEC Links

11. Current Links • Mostly ad hoc bilateral agreements between institutions (or reverse engineering of existing links) • Easily broken by updates from either side. • Rarely provide systematic access to remote resources.

12. ITWG results Mixed… • Able to develop prototype interfaces, protocols and user services • Bibcode delivery to ADS • What services are available at a given region • Data set verifier services • Limited success in implementing these services over all centers or using them in operational user interfaces. • Hard to do real work for free….

13. SAWG Presentation • Results of ADEC and ITWG activities discussed at Science Archive Working Group (SAWG) meeting in October 2002. • SAWG requested White Paper describing the resources and approach needed to build a NASA interoperable archive. • SAWG will review and recommend action by NASA HQ. • Next SAWG meeting April 22-23 • ADEC meeting on March 12

14. Status of White Paper • Two different approaches suggested: • Build single unifying interface to integrate all archive systems • Master Object Directory • Agree on protocols and build systems on top of them • Continuation of ITWG approach but with actual resources. • Substantial overlap in content, but major differences in emphasis.

15. Master Object Directory. • All archives will process data received and provide a list of objects detected and datasets involved in a standardized way. • Lists of objects will be combined into a Master Directory of objects. • Users can query against master directory to find data in any NASA archive.

16. Archive Archive Archive Archive Object extractor Object extractor Object extractor Object extractor Catalog/Arch. I/F Catalog/Arch. I/F Catalog/Arch. I/F Catalog/Arch. I/F Master directory schematic Object Info Updates Master Directory Requests for data associated with target Object query Requested data MD Interface User

17. Comments • Clearly defined deliverables and new capabilities for user. • Complex queries on objects possible as local queries on Master Directory. • Technical concerns: • Handling non-object oriented datasets • Hierarchical and extended objects • ‘Political’ concerns: • Is this something within the purview of NASA centers alone? • Do we want to concentrate on a single ‘master’ interface?

18. Interoperability Layer Approach • Build thin layer of agreed interfaces to access data. • Modify existing resources to access remote data using new layer. • Data models describe resources in common framework. • Use layer as foundation for new capabilities (perhaps including object directory) • Essentially implementing a three-tier architecture in NASA archive systems.

19. Interoperability Layer Schematic Browse Starview OASIS New Interfaces Interoperability Layer Protocols Registry Correlator Archive Archive Archive Archive

20. Comments • Builds upon existing systems and provides multiple portals to data. • Less explicit coupling of data centers and services • Deliverables less well defined and more diffuse. • Provides more incremental changes to systems rather than dramatic new capabilities.

21. Commonalities • Common interface layer • Catalog and archive access • Regions covered by observations • Data models • Need to agree on some common semantic concepts, e.g., object, image, spectra, … independent of how these are stored. • Cross-correlation

22. What does the community need? • Common access to data and catalogs • Can’t require users to know all of the different interfaces. • Ability to combine data from different sources. • Data model descriptions of data

23. Management • Distributed management • Who does central oversight

24. Implications for HEASARC • Substantially enhanced capabilities for joining data in Browse, SkyView, Astrobrowse and other services. • Access to HEASARC data resources through other data portals. • Better coordination of NSF-funded and NASA sponsored NVO activities. • Need to ensure that this does not incur long term liabilities.