Interoperability of astronomy data bases Fran

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Interoperability of astronomy data
basesFrançoise Genova, CDS
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Astronomy

• A small discipline
• Few commercial constraints
• A long term partnership to define exchange
  standards and links
• FITS early data exchange format
• on-line information in astronomy
• from observations to results

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Object name gtgt position
An early example of interoprerability Name
resolver
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Evolving world - Web Services - Very Large
Surveys
Simbad Name Resolver gtgt Sesame Web Service
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Web Services as building blocks
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The astronomy bibliographic network

• Links between
• electronic journals
• the ADS bibliographic database
• on-line services (SIMBAD, NED)
• archival data/published results
• bibcode e.g. 1999AA...351.1003G

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• References in an
• on-line article
• links to ADS
• quality check

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ADS - Abstracts - Scanned articles - Links to
original on-line paper - Links to other,
distributed information e.g. original
observations - Also-read articles
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ADS From bibliography To the original observation
s
Search an authors publications
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HST archive From observation To publication
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AA on line From publication to SIMBAD and more
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Simbad Information About the object
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Links To high energy observations in HEASARC, To
Catalogues
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Links from object names in journals an early
example IBVS
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Links to images and data
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GCVS
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Lessons learnt

• De facto standard
• SIMBAD/NED, ADS, journals, archives
• Cooperation between all the actors
• snowball effect
• Journals, ADS, data centres, archive centres
• The community is trained (everyday tools)
• Easy-to-build link
• but contents / validation are fundamental
• the role of experts remains fundamental for
  building value-added services

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Data federationTabular data in astronomy

• A common description for tabular data
• Reference catalogues
• Published tables
• Surveys
• Catalogues of observations in archives
• ReadMe
• physical organization ? contents

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ReadMe
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Tables published in articles are usable data!
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Links to observational data (images, spectra,
time series), often distributed in observatory
archives
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An homogenized view of heterogeneous
information With links to data
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Towards data integration

• XML
• VOTable gt Roys talk

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HEARSARC Browse
Astrores in action!
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With a touch of GLU

• Générateur de Liens Uniformes
• Resource dictionary (shared, distributed,
  hierarchical name space, clone management),
  knows the query syntax
• Resolver symbolic name gt URL
• An early registry prototype with many of the
  required functionalities (conversions, failure
  tests, )

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Observations from European archives Inclusive
NASA missions HST, Chandra, surveys,
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Glu Tag Resolver Symbolic name gtgt URL
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Data mining the Uniform Content Descriptors

• A set of UCDs has been first developed in the
  frame of the ESO/CDS Data Mining project to
  describe VizieR catalogue columns (100.000
  columns, 1.300 UCDs)
• Name for concept
• Assigned semi-automatically using column label,
  description and unit
• Used e.g. to check the coherence of information
  in tables

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UCD browser
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UCDunits conversion, selection
Select catalogues target
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Colour excess characterizes carbon stars
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http//cdsweb.u-strasbg.fr/UCD/
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Extension of UCDs

• SDSS 1.500 columns
• Manual verification needed
• Very few additional UCDs
• On-going
• UCDs for VOX
• UCDs for IDHA data model
• Add Metadata branch
• FITS keywords are often not accurate

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Validation, maintenance

• A new structure
• Prune the existing UCD tree
• UCD steering group
• Proposal in October 2003
• UCD V1.0
• Evolution mechanism

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The future

• Other knowledge basis
• List of object names
• Journal keywords
• Thesaurus (built by librarians)
• Astronomy described with different points of view
• Converging towards an ontology of astronomy??