Virtual Observatory Developments in Europe and in the US

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• Virtual Observatory Developments in Europe and in
  the US
• Rudolf Albrecht
• Space Telescope European Coordinating Facility
• European Space Agency
• Robert J. Hanisch
• Space Telescope Science Institute/NVO
• Paolo Padovani
• Space Telescope European Coordinating Facility
• European Southern observatory/AVO

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Virtual Observatory motivation

• State-of-the-art observing facilities in space
  and on the ground produce an ever-increasing
  amount of high-quality data
• Due to the high cost of the facilities and due to
  the limited observing time these data are very
  valuable
• All facilities collect the data in digital
  archives and make them available for further
  scientific exploitation. This includes
  investigations not envisaged by the original
  observer, combining data from different programs,
  or examining the data for changes over time.
• The Virtual Observatory is the logical next step
  it allows to combine data from several such
  archives to perform multi-wavelength, synoptic
  investigations.

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Decadal Survey Recommendation

• National Academy of Sciences Decadal Survey
  recommended NVO as highest priority small
  (lt100M) project
• Several small initiatives recommended by the
  committee span both ground and space. The first
  among themthe National Virtual Observatory
  (NVO)is the committees top priority among the
  small initiatives. The NVO will provide a
  virtual sky based on the enormous data sets
  being created now and the even larger ones
  proposed for the future. It will enable a new
  mode of research for professional astronomers and
  will provide to the public an unparalleled
  opportunity for education and discovery.
• Astronomy and Astrophysics in the New
  Millennium, p. 14

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1 microSky (DPOSS)
Astronomy is Facing a Data Avalanche
Multi-Terabyte (soon multi-Petabyte) sky surveys
and archives over a broad range of wavelengths
Billions of detected sources, hundreds of
measured attributes per source
1 nanoSky (HDF-S)
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A PanchromaticApproach to the Universe
reveals a more complete physical picture The
resulting complexity of data translates into
increased demands for data analysis, visualization
, and understanding
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NVO History

• 1990s NASA establishes wavelength-oriented
  science archive centers multiple large
  ground-based digital sky survey projects
  initiated
• April 1999, Decadal Survey Panel on Theory,
  Computation, and Data Discovery met in Los Alamos
• Szalay, Prince, and Alcock coin the name
  National Virtual Observatory
• November 1999, NVO organizational workshop at JHU
• February 2000, 2nd NVO workshop at NOAO-Tucson
• June 2000, conference held at Caltech, Towards a
  Virtual Observatory
• June 2000, ad hoc steering committee formed
• February 2001, AASC/NAS report Astronomy and
  Astrophysics in the New Millennium released
• April 2001, proposal submitted to NSF ITR
  program, 17 collaborating organizations, led by
  A. Szalay (JHU)
• September 2001, NSF announces proposal selection
• January 2003, first NVO science prototypes shown
  at Seattle AAS

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Virtual Observatory in Europe

• AVO Project started November 2001
• Three-year, 5 M, Phase A project, funded by the
  European Commission (Fifth Framework Programme
  FP5) and six organizations ESO, ESA,
  AstroGrid, CNRS (CDS, TERAPIX), University Louis
  Pasteur, JBO
• Manpower 17 FTEs/yr total, 50/50 EC and
  partners, 1 FTE/yr ECF
• Next step EURO-VO, implementation phase (subject
  to EC funding)

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AVO (Phase A) Goals

• Definition of Science Reference Mission
• Definition of scientific requirements
• Implementation of selected science cases through
  demonstrations
• Science Working Group established two years ago
  to provide scientific advice to AVO Project

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What the Virtual Observatory is

• A suite of international standards for the
  discovery, exchange, intercomparison, and
  analysis of network-accessible astronomical data
• A data access and analysis environment that
  exploits the emerging computation/software/data
  Grid
• A framework for data processing that enables and
  encourages the re-use of algorithms
• A tool for science planning Identify gaps in
  coverage of parameter space. Which new missions,
  instruments, experiments will have largest
  impact?
• A catalyst for world-wide access to astronomical
  archives
• A routinely used tool of the research astronomer
• A vehicle for education and public outreach

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What the Virtual Observatory is not

• A replacement for building new telescopes and
  instruments
• A centralized repository for data
• A data quality enforcement organization

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VO Architecture
Data Models, UCDs, Metadata
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VOTable

• Reached international agreement on VOTable V1.0
  specification in April 2002
• XML-based standard with in-line data or links to
  external data
• Utilized for basic catalog and image access
  protocols
• Merges AstroRes heritage with XML flexibility
• Complements FITS
• Multiple I/O libraries available (Java, Perl,
  C, C)

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Data Models

• Data modeling effort aimed at defining basic data
  types and relationships among them
• High-level entities image, spectrum, time
  series, catalog
• Low-level entries quantity, resolution, time of
  observation
• Interfaces and protocols for other VO services
  derived from DM relationships

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Data Access Layer

• Data Access Layer is mediator between NVO data
  requests and data delivery
• Defined Cone Search protocol and have 100
  implementations
• Defined Simple Image Access Protocol (SIAP) and
  have 20 implementations
• Specification for Simple Spectral Access Protocol
  in development

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Resource Metadata and Registry

• Resource Metadata describes NVO data collections,
  services this metadata is collected into a
  Registry
• Resource Identifiers are component of resource
  metadata have agreed on syntax
• Using Open Archive Initiative protocols for
  metadata harvesting
• Now focusing on query mechanisms and general
  updating/synching options
• Prototype registry utilized in science
  demonstration, Data Inventory Service

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Unified Content Descriptors

• UCDs provide common data dictionary for
  describing contents of catalogs
• CDS initiative, now broadened to international VO
  discussion
• Current discussion focusing on structure and
  extensibility

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VO Query Language

• Working on minimal extensions to SQL to support
  astronomical queries (e.g., spatial proximity) ?
  Astronomical Data Query Language
• Defining standard query service based on SDSS
  SkyQuery OpenSkyNode and OpenSkyQuery
• Investigating higher-level query languages
  natural language
• Xquery

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Grid and Web Services

• Increasing number of web services (cone search
  and SIAP wrappers, for example)
• Registry services will be implemented as web
  services
• Prototyped use of Grid in galaxy morphology
  science demonstration
• ROME (Remote Object Management Environment)
  project provides stateful user interface to
  Grid-based or other compute-intensive
  applications
• Working closely with Grid community to understand
  progress on Grid services, e.g., OGSA, and to
  determine best time to adopt

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The AVO Prototype

• Evolved from Aladin (CDS)
• Downloadable Java application
• Extensible toolset with plug-ins Astronomy
  Catalogue Extractor (ACE), SpecView, VOPlot, SED
  and cross-match utilities
• New standards Simple Image Access (SIA) and
  Simple Spectral Access (SSA first time ever)
• Prototype but also research tool

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NVO Science Prototypes

• Science prototypes guide and validate technical
  initiatives
• NVO Year 1
• Brown dwarf candidate search
• Gamma-ray burst follow-up
• Galaxy morphology measurement (utilizing
  computational grid)
• Year 1.5
• Data Inventory Service
• Year 2
• Data Inventory Service with registry-based
  resource selection
• Access to theoretical simulation (globular
  cluster) and virtual observations

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Brown Dwarf Candidate Search
Scientific Motivation The search for brown
dwarfs has been revolutionized by the latest deep
sky surveys. A key attribute to discovering brown
dwarfs is the federation of many surveys over
different wavelengths. Such matching of catalogs
is currently laborious and time consuming. This
matching problem is generic to many areas of
astrophysics. Data Resources Sloan Digital Sky
Survey (SDSS) Early Data Release (15 million
objects) 2-Micron All Sky Survey (2MASS) 2nd
Incremental Point Source Catalog (162 million
objects)
What the VO Brings Today, doing datasets is
user-intensive and is replicated by many
different users. Also, the correlation of these
two datasets can take years of CPU time if not
done correctly. The NVO brings two key aspects
to this problem. First, it removes the need for
the user to download large data to their machine,
making direct use of distributed data. Second,
the matching algorithm used here is
computa-tionally efficient and designed to give
answers in minutes rather than hours results can
be returned to the user in real-time.
Sloan z magnitudes vs. 2MASS J magnitudes, with
brown dwarf candidates in red.  Data are from the
SDSS Early Data Release and 2MASS 2nd Incremental
Release.
Future Prospects Catalog matching of large
datasets is a generic problem in astrophysics.
Therefore, making the matching facility available
to any user for use on any dataset will greatly
enhance the productivity of scientists. Standard
I/O formats allow developers to create tols to
use the matched data and easily integrate with
existing visualization and analysis tools
(anomaly detector). Bringing these data together
on remote machines with enough CPU to perform
analysis (Grid technology) will allow
cross-comparisons of unprecedented scale.
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• As a T dwarf becomes cooler (i.e., methane and
  water absorptions increase) or more distant
• SDSS detects it only at z band
• 2MASS detects it only at J band

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Demo Leads to Discovery!

• New brown dwarf candidate confirmed
  spectroscopically with Keck Observatory

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January 2004 AVO Demo Overview

• Two scenarios
• Extragalactic Obscured (Type 2) Quasars
• Galactic Classification of Young Stellar Objects
  (YSO)
• Multiwavelength, heterogeneous, and complex data
  VLA, CGPS, ISO, 2MASS, USNO, 2.2m/WFI, VLT/FORS,
  HST/ACS, XMM, and Chandra (images, spectra, and
  catalogues)
• Access to any VO-compliant data seamless and
  transparent access to ESA ISO XMM archives and
  ESO data products
• AVO from First Light to First Science!

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January 2004 AVO First Science
redshift 3.046
Ly?
C IV
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January 2004 AVO First Science
30 new obscured QSOs in GOODS CDFSHDFN x 5
increase
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The Future
GridNet
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2005
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International VO Alliance
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International VO Alliance

• The IVOA brings together the astronomers,
  developers, and managers of the VO initiatives
  world-wide
• Agreements on standards for data access (VOTable,
  catalog queries, image retrieval, resource
  descriptions, etc.)
• Coordination of development activities
• Sharing of software
• Sharing of experience
• 14 participating organizations Astrogrid, AVO,
  US-NVO, VO-Australia, VO-Canada, VO-China,
  VO-France, VO-Germany (GAVO), VO-Hungary,
  VO-India, VO-Italy (DRACO), VO-Japan, VO-Korea,
  VO-Russia
• httpwww.ivoa.net

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The VO Vision

• The VO is the semantic web for astronomy (Tim
  Berners-Lee)
• The VO democratizes astronomical research
• The VO brings the universe to your desktop
• The professional astronomer
• Graduate students
• Undergraduates
• K-12
• Amateurs
• The public (the taxpayers)
• http//us-vo.org http//www.euro-vo.org/