F. Genova, Berlin 7, Paris, 2 December 2009

The astronomical information network

F. Genova, Berlin 7, Paris, 2 December 2009

Sharing astronomical data : why (1)• Major scientific objectives

– Long term observations of variable natural phenomena– A large number of objects, complex interactions, many

scales• Observations with different techniques, at different

scales (ground- and space-based observatories, large surveys)Multi-wavelength observations makea significant and increasing fraction of publications

F. Genova, Berlin 7, Paris, 2 December 2009

Very Large Telescope

Planck

SPITZER

Also: small and mediumsize ground-based telescope

Cosmic background+ objects

F. Genova, Berlin 7, Paris, 2 December 2009

Sharing astronomical data: why (2)

• Re-using data for scientific objectives different from the original ones, i.e. optimize the science return of large ground- and space-based instruments and of large surveys

IUE (1978-1996): five times more publications from data retrieved in the archive than from the selected observing teams (Wamsteker, Griffin, 1995) – a major precursor

• More than 300,000 queries/day on the CDS services (which are only a part of the global information system)

F. Genova, Berlin 7, Paris, 2 December 2009

‘Data’ in astronomy• A huge amount of heterogeneous, distributed ‘data’

(continuum): observations, added-value databases (e.g. CDS’ SIMBAD, VizieR), tools, bibliographic data (academic journals, ADS) – also, theory data

• International partnership to define common standards to share data – e.g. FITS – and links

• A network of on-line information, which begun soon after the advent of the internet, and has revolutionized the way astronomers work

• Early, excellent collaboration between academic journals, data centres and archives to build a ‘bibliographic network’

F. Genova, Berlin 7, Paris, 2 December 2009

The astronomical data network• Data policy

– Observational data is available after a proprietary period (1 year)

– Academic journals (a few ‘large’ journals)• Table of contents and abstracts freely available• Full content in general available after 3 years – some in open access• Some data tables immediately available through data centres

• It seems easy – it is so easy to do a web page! BUT lots of work behind the scene: Using and re-using data requires– it is properly described– users are confident in its QUALITY

F. Genova, Berlin 7, Paris, 2 December 2009

From bibliography to data

The NASA ADS bibliographic database

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Access to the data in archives (ESA, ESO, NASA…)

Added-value work at the archives to create the links

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A single view of the tables published in academic journals; Collab. journals + data centres

Catalogues and published tables

A single standard

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An homogeneous view of very heterogeneous information in a single service

• A new paradigm: published tables = data (1993)• Additional quality checks in addition to referee• Data discovery (Unified Content Descriptors)

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Courtesy ofM.G. Allen

One among many available tools: tha Aladin portal to imagesUnified access to distributed data bases

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European strategic exercisefor astronomy:

Astronet Roadmap (2008)

The data/serviceinfrastructure isan important partof the disciplinary infrastructure

F. Genova, Berlin 7, Paris, 2 December 2009

The astronomy knowledge infrastructure• Science driven information network widely used by the

scientific community• A model based on open access to data and services

(pragmatic open access strategy)• A fully distributed model with no central point

– Agencies responsible for large infrastructures provide data archives – Established data centres provide value-added services and tools– Now smaller, motivated actors are appearing

• Links, portals, access tools• International interoperability standards: a complex task• Mid-term sustainability

– Support to archive/data centres– Support to national projects which work on interoperability (VObs)