The ADEC and ADEC White Paper

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The ADEC and ADEC White Paper

• The HEASARC and The Virtual Observatory

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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

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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 NASAs role?
• Individual institutions are involved, but there
  is no systematic response.

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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.

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Background of the ADEC

• ADCCC created in mid 90s
• 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

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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.

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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

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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.

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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.

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Existing ADEC Links
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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.

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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.

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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

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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.

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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.

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Master directory schematic
Object Info Updates
Master Directory
Requests for data associated with target
Object query
Requested data
MD Interface
User
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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?

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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.

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

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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

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What does the community need?

• Common access to data and catalogs
• Cant require users to know all of the different
  interfaces.
• Ability to combine data from different sources.
• Data model descriptions of data

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Management

• Distributed management
• Who does central oversight

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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.