The EuroVO-DCA Enrique Solano INTA-LAEFF INTA-LAEFFSpanish-VO The Virtual Observatory: the role of Science, present status The Virtual Observatory: the

The EuroVO-DCAThe EuroVO-DCAEnrique Solano Enrique Solano

INTA-LAEFFINTA-LAEFF

Spanish-VOSpanish-VO

• The Virtual Observatory: the role of Science, present The Virtual Observatory: the role of Science, present statusstatus

• The Euro-VO Data Centre AllianceThe Euro-VO Data Centre Alliance

• VALD and the VOVALD and the VO

VALD Workshop, Vienna, Feb 2007

Astronomy in the XXI century• Advances in technology

– Telescope design and fabrication

– Large-scale detector arrays

– Highly automated pipeline and reduction software

– Permit to explore the Universe in a multi-parameter space over a wide range in the spatial and temporal domain.

• Advances in computational capabilities

– Allow, for the first time, direct comparisons between complex theoretical calculations and large, statistically significant observational databases.

BUT…BUT…


• All this should lead to a more complete and less biased understanding of complex astrophysical phenomena.

Astronomy in the XXI century (cont’d)

– The progress in the scientific exploitation is

not keeping pace with the exponential

growth of the information.

– This new scenario is demanding changes in

the “classical” methodology.


The classical way of doing Astronomy

I. Get the data

I. Reduce and analyze the data locally.

New data Archive data


VO: a complementary approach

• The classical method has demonstrated

to be quite inefficient when dealing with

problems that require either:

Interoperability among data services and/or

Management of large volumes of data.


An interoperability problem: Building of SEDs

ISO

IUE

Radio

• Wavelength: mm Flux: mJy

UBVRIJHK

• Wavelength: Å + Magnitudes!!!

Researches must search multiple sites (assuming they even know about all the useful sites).


The solutions provided by VO to solve the interoperability problem

• Agree and build standards.

• Standard semantic: UCDs

• Standard access protocols

• Standard output formats

• Standard data models

• Automated discovery tools (registries)

• Uptake of standards by the data services.

• Development of a federation of astronomical data centres (“data grid”).


“large” really means LARGE Archive data are dramatically increasing.

ESO/ST-ECF ESO/ST-ECF Science Archive Science Archive Facility holdingsFacility holdings

(x100 increase in the next 7 years)

LSSTLSST• It will scan the visible sky

every few nights.• Few TB/night. A factor of

1000 larger than current surveys.


The solution provided by VO to solve the problem of the data avalanche

• Move from download to service paradigm

• Leave the data where it is.

• Remote operations on data (search, analysis,

etc).

• Ship the results not the data.


The role of Science in the VO projects VO is driven by science and it will become a science driver.

Although technology enabled, the Virtual Observatory must not be seen as a technological project only. Its final goal is to produce better, new and more efficient science.

Showing the science community the potential benefits of VO was a major and early task in the VO projects (NVO, AstroGrid, AVO,…).

Creation of Scientific WGs to provide advice to the project.

Elaboration of lists of VO-use cases with a clear definition of the science requirements.


Real VO Science? Is it possible? YES!!. The tools are already available


VO Tools

VO Tools (II)

VO-Science papers

• Extragalactic case: Discovery of 30 type 2 QSOs.

First refereed astronomical paper enabled via end-to-

end use of VO tools and systems:


Discovering type 2 quasars

• Seyfert 2’s high-power counterparts. Characterized by narrow lines and hard X-ray emission ( Lx > 1e44 erg/s).

• Data: X-ray catalogue for the two GOODS fields (Alexander et al.

2003)

• Filtering: HR ≥ -0.2 for absorbed sources 294 found

HR=(H+S) / (H-S); H = (2.0 - 8.0 keV), S = (0.5 – 2.0 keV)

• Cross-matching with the GOODS ACS catalogues to get the optical

counterparts 168 matches.

• Data manipulation: X-ray power for unidentified sources derived from:

Log L (2-10) = log f(2 – 10 keV) / f(R) + 43.05 (Fiore 2003). • Results: 31 new QSOs 2 (only 9 sources previously known).


VO-Science papers (cnt’d)

• Identification of very luminous AGB stars in LMC, SMC, M31 and M33 using 2MASS color criteria.


• Supervised classification of ROSAT sources into six categories: stars, white dwarfs, X-ray binaries, galaxies, AGNs and clusters of galaxies.


VO-Science papers (cnt’d)

• McGlynn et al. (2004, ApJ,616,1284)

The VO-Science Workshop

• 80 contributions

(53 oral)


Science with VO


0

20

40

60

80

100

2000 2001 2002 2003 2004 2005 2006

VO in ADS: “Virtual Observatory” in title (2000-2006)

0

100

200

300

400

All Refer. VO-Science








How is VO structured?How is VO structured?

2001 – 2002: Four major international Phase-A projects (ASTROGRID, AVO, NVO, CVO).

2002: The number of VO projects continues to

increase. There is a need to create a common

framework.

IVOA was created in June 2002 with the

mission to facilitate the international

coordination and collaboration.


How is VO structured?How is VO structured?


AVO Project: 2002 - 2004 Manpower: ~ 17 FTEs/yr total, 50/50 EC and

partners

Euro-VOEuro-VO• Phase-B deployment of an operational VO in Europe.

• The three faces of EURO-VO:

DCA: Data Centre Alliance FC: Facility Centre

• Organisation of workshops, • Support of VO-enabled science projects.

TC: Technology Centre• Technology research and development projects.


EuroVO-DCAEuroVO-DCA

Third attempt succeeded (VO-NET I3 March 2004, EuroVO-DCA I3 March 2005)

EC framework: eInfrastructure / Communication

Network Development / Coordination Action

Same Unit as GEANT and GRIDs

28 months starting 1 Sept 2006.

EuroVO-DCAEuroVO-DCA

Third attempt succeeded (VO-NET I3 March 2004, EuroVO-DCA I3 March 2005)

EC framework: eInfrastructure / Communication

Network Development / Coordination Action

Same Unit as GEANT and GRIDs

28 months starting 1 Sept 2006.

What is a Data Centre for EuroVO-DCA?What is a Data Centre for EuroVO-DCA?


• “Classical” data centres, such as ground-and space-based observatory archives, and generalist data centres providing added-value services and tools.

• Assumptions– Willingness to provide a service to the community– Sustainability

• Critical mass• Financial support (e.g. from local authorities)

– Concern for quality

• EuroVO-DCA will help European data centres to integrate their data and services in the VO framework by sharing expertise and reusing experience.









Atomic and Molecular Databases in the VO

• Atomic and Molecular Databases are essential for the interpretation of astrophysical spectra.

• It is important, therefore, to make these data widely available.

• Data model: abstract model that describes how data is

represented and used.


SLAP: Simple Line Access Protocol

• Standard protocol for retrieving spectral lines from databases.

• Basic parameter is wavelength. http://xxx?WAVELENGTH

=5.1E-6/5.6E-6

• Other extra search parameters (chemical element, energy level range, temperature,…) could be implemented to restrict the search.

SLAP: Simple Line Access Protocol

• SLAP metadata may contain links to scientific publications related to the spectral line.



Output: VoTable

SLAP in action (courtesy of ESA-VO)

Conclusions VO Science is not science fiction. It already exists.

VO is not replacing the scientist (sorry, there are not plans to implement a “write paper” button ) but making them much more efficient. VO will help astronomers to do what they really want to do: ask scientific questions, interpret the data and publish the results rather than hunting and gathering data.

VO has crossed the non-return point: The biggest data providers (NASA, ESA, ESO, …) have understood the importance of this initiative and are already adapting their contents to VO requirements.

Many teams are willing to provide data and services in their domains of expertise. The VO development is a strong incentive to share data and knowledge.

DCA represents an excellent opportunity to adapt your archives / services to the VO.


Documents

The EuroVO-DCA Enrique Solano INTA-LAEFF INTA-LAEFFSpanish-VO The Virtual Observatory: the role of Science, present status The Virtual Observatory: the