# Presentation: 501069

## The ADEC and ADEC White Paper

- The HEASARC and The Virtual Observatory

## 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

## 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.

## 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.

## 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

## 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.

## 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*

## 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.

## 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.

## Existing ADEC Links

## 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.

## 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....

## 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

## 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.

## 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.

## Master directory schematic

- Master
- Directory

- Object Info Updates

- MD Interface

- Object query

- Requests for data associated with target

- User

- Requested data

## 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?

## 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.

## Interoperability Layer Schematic

- Archive

- Archive

- Archive

- Archive

- Interoperability Layer Protocols

- Correlator

- Registry

- Browse

- Starview

- OASIS

- New Interfaces

## 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.

## 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

## 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

## Management

- Distributed management
- Who does central oversight

## 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.