Theory in the Theory in the Virtual ObservatoryVirtual Observatory

Gerard Lemson, GAVOGerard Lemson, GAVO

2005-06-302005-06-30 RingbergRingberg, Gerard Lemson, Gerard Lemson

The VOThe VO Broad goalBroad goal

Make results of astronomical research, data Make results of astronomical research, data and and applications, more readily applications, more readily available to larger community, and create value-adding services. available to larger community, and create value-adding services.

Facilitate:Facilitate: communication of resultscommunication of results checking of resultschecking of results use of resultsuse of results comparison of different resultscomparison of different results combination of different results to create new onescombination of different results to create new ones

ThroughThrough online availability of datasets and applicationsonline availability of datasets and applications standardized publication and discovery mechanismsstandardized publication and discovery mechanisms standardized description (meta-data, FITS++)standardized description (meta-data, FITS++) standardized selection mechanismsstandardized selection mechanisms standardized form(at)s of standardized form(at)s of transmittedtransmitted data data value added servicesvalue added services

Why ?Why ?

2005-06-302005-06-30 RingbergRingberg, Gerard Lemson, Gerard Lemson

SDSS

ROSAT

2MASS

FIRST GAIA

2005-06-302005-06-30 RingbergRingberg, Gerard Lemson, Gerard Lemson

ROSATFIRST GAIA

SDSS2MASS

2005-06-302005-06-30 RingbergRingberg, Gerard Lemson, Gerard Lemson

RegistryRegistry publicationpublication discoverydiscovery

Data modelsData models description (UCD)description (UCD)

Query protocolsQuery protocols selection (selection (cone searchcone search, ADQL), ADQL) combination (XMatch)combination (XMatch)

Data access protocolsData access protocols retrieval (VOTable)retrieval (VOTable)

ApplicationsApplications user interfaces (Aladin)user interfaces (Aladin) visualisation (VOPlot)visualisation (VOPlot) analysis (…)analysis (…)

2005-06-302005-06-30 RingbergRingberg, Gerard Lemson, Gerard Lemson

TheoryTheory Existing protocols not applicableExisting protocols not applicable

Position based queriesPosition based queries Combination of different archives less obviousCombination of different archives less obvious

Data models insufficientData models insufficient New “observables”New “observables” Different “provenance”Different “provenance” Different characterizationDifferent characterization More complex data structuresMore complex data structures

Less well developed history of archivingLess well developed history of archiving No FITS for simulationsNo FITS for simulations

New use casesNew use cases Theorists : data mining simulation resultsTheorists : data mining simulation results Observers : virtual telescopeObservers : virtual telescope

2005-06-302005-06-30 RingbergRingberg, Gerard Lemson, Gerard Lemson

Archiving of simulationsArchiving of simulations

Use relational databaseUse relational database GalICS GalICS SDSSSDSS

Halo merger trees from milli-MillenniumHalo merger trees from milli-Millennium data model for treesdata model for trees

SAM galaxy cataloguesSAM galaxy catalogues links to haloslinks to halos add merger treesadd merger trees

SQL query interface SQL query interface http://www.g-vo.org/mpasims (Springel, Croton, Blaizot)http://www.g-vo.org/mpasims (Springel, Croton, Blaizot)

Soon: add dynamic SAM to interfaceSoon: add dynamic SAM to interface

2005-06-302005-06-30 RingbergRingberg, Gerard Lemson, Gerard Lemson

Observed

Simulated

Thanks to Alexis Finoguenov, Ulrich Briel, Peter Schuecker, MPE)

Thanks to Volker Springel

Virtual TelescopeVirtual Telescope

2005-06-302005-06-30 RingbergRingberg, Gerard Lemson, Gerard Lemson

Virtual TelescopeVirtual Telescope

Use simulations for help in interpreting Use simulations for help in interpreting observations (e.g. Peter Schneider for this observations (e.g. Peter Schneider for this morning)morning)

Bring simulations into “observational plane”Bring simulations into “observational plane” Create results similar to observationsCreate results similar to observations Can be analysed with same techniques as Can be analysed with same techniques as

observationsobservations Can be compared “directly” to obs-s\Can be compared “directly” to obs-s\

Use cases:Use cases: Check observational biases using realistic modelsCheck observational biases using realistic models Survey/observation planningSurvey/observation planning Check models to observationsCheck models to observations

2005-06-302005-06-30 RingbergRingberg, Gerard Lemson, Gerard Lemson

PrototypesPrototypes

VisualisationVisualisation SmacSmac (Dolag) (Dolag) MoMaFMoMaF (Blaizot) (Blaizot)

Virtual telescopeVirtual telescope http://www.g-vo.org/planckhttp://www.g-vo.org/planck

2005-06-302005-06-30 RingbergRingberg, Gerard Lemson, Gerard Lemson

Interoperability: Interoperability: Virtual telescope configurationVirtual telescope configuration

ComponentsComponents simulationssimulations telescope modelstelescope models foregrounds (incl. lensing)foregrounds (incl. lensing)

SpecificationSpecification ““pre-observation image”pre-observation image” interfacesinterfaces workflowworkflow

Implementations …Implementations …

Virtual telescope Virtual telescope data flowdata flow

Virtual telescope

Simulation archive

Theory/observational

interface

Find possibly relevanthydro simulations(registry, dm, voql)

Observe selectedsimulations virtually

(application, services)

X-RayObservation

“Find similarsimulations”

Retrieve data (dal)

Feature Extractor

Registry service

ComparatorRetrieve data (dal) Analysis softawreAnalyse

Compare

Extract queriablefeatures (dm, ucd)

Retrieve telescopeconfiguration (dm)

2005-06-302005-06-30 RingbergRingberg, Gerard Lemson, Gerard Lemson

Quotes:Quotes:

"I think the global virtual observatory is a "I think the global virtual observatory is a fantastic idea" fantastic idea" - Martin Rees, Physics Today, Feb 2002- Martin Rees, Physics Today, Feb 2002

... too much money will be sunk into software; ... ... too much money will be sunk into software; ... archives at ground-based observatories should archives at ground-based observatories should be brought up to snuff before thinking about be brought up to snuff before thinking about linking them; and ... users won't be able to trust linking them; and ... users won't be able to trust the processed data they call up.“the processed data they call up.“ - Physics Today, Feb 2002 - Physics Today, Feb 2002

“… “… that VO nonsense …” that VO nonsense …” - anon, Ringberg 2005- anon, Ringberg 2005

2005-06-302005-06-30 RingbergRingberg, Gerard Lemson, Gerard Lemson

DiscussionDiscussion

What do you want from the VO ?What do you want from the VO ? What should VO projects focus on ?What should VO projects focus on ?

What could/do you contribute to the VO ?What could/do you contribute to the VO ? Why is the VO a waste of resources ?Why is the VO a waste of resources ?

Should spend money on more postdocs.Should spend money on more postdocs. What are the dangers of the VO?What are the dangers of the VO?

Too easy to do to bad science.Too easy to do to bad science. What are the possible advantages of the VO?What are the possible advantages of the VO?

Easier to do good, new science.Easier to do good, new science. Easy to check bad science.Easy to check bad science.