Robert Hanisch

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THE US NATIONAL VIRTUAL OBSERVATORY
NVO Science Applications

• Robert Hanisch
• US NVO Project Manager
• Space Telescope Science Institute

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Astronomy is facing a data avalanche
1 microSky (DPOSS)
Multi-Terabyte (soon multi-Petabyte) sky surveys
and archives over a broad range of wavelengths
Billions of sources, hundreds of attributes per
source
1 nanoSky (HDF-S)
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The changing face of observational astronomy

• Large digital sky surveys are becoming dominant
  source of data in astronomy gt 100 TB, growing
  rapidly
• SDSS, 2MASS, DPOSS, GSC, FIRST, NVSS, RASS, IRAS,
  QUEST, GALEX, SST CMBR experiments Microlensing
  experiments NEAT, LONEOS, and other searches for
  Solar system objects
• Digital libraries ADS, astro-ph, NED, CDS, NSSDC
• Observatory archives HST, CXO, space and
  ground-based
• Future PanSTARRS, LSST, and other synoptic
  surveys astrometric missions, GW detectors
• Data sets orders of magnitude larger, more
  complex, more homogeneous than in the past
• Roughly 1 TB/Sky/band/epoch
• Human Genome is lt 1 GB, Library of Congress 20
  TB

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Toward a new astronomy

• Past Observations of small, carefully selected
  samples (often with a priori prejudices) of
  objects in one or a few wavelength bands

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Toward a new astronomy

• Future Multi-wavelength data for millions of
  objects, allowing us to
• Discover significant patterns from the analysis
  of statistically rich and unbiased image/catalog
  databases
• Understand complex astrophysical systems via
  confrontation between data and sophisticated
  numerical simulation

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Toward a new astronomy

• Discovering new phenomena and patterns in these
  datasets will require simultaneous access to
  multi-wavelength archives, advanced visualization
  and statistical analysis tools

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The Virtual Observatory is

• A set of international standards to share complex
  data
• A modular set of tools to work with distributed
  data
• A simple environment to publish data to
• An essential part of the research astronomers
  toolkit
• A catalyst for world-wide access to astronomical
  archives
• A vehicle for education and public outreach

?

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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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Science prototypes

• Science demonstrations show capabilities of new
  infrastructure, motivate and guide technical
  developments. For example
• Data discovery, multi-? comparisons
• Search for brown dwarfs
• Galaxy morphologies in clusters
• Globular cluster simulations

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Science results

• Padovani et al. (2004)) demonstrates that VO
  tools are mature enough to produce cutting-edge
  science results by exploiting astronomical data
  beyond classical identification limits (R
  ? 25)

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Science results

• McGlynn et al. (2004) classified all unidentified
  ROSAT WGACAT objects using VO data access methods
  to cross-correlate multi-wavelength catalogs
• Technique applied to find candidate X-ray
  binaries and now to SDSS photometric catalog
• More than 400 papers related to virtual
  observatory in ADS

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Science results

• AAS Special Session papers
• de Mello, D. Sosey, M. Environments of
  Starburst Galaxies Diagnosed with the NVO
• Van Duyne, J. Lucas, R. Tamura, T. Rohde, D.
  Searching for Distant Galaxy Clusters Utilizing
  the Virtual Observatory for Multiwavelength
  Images and Survey Cross-correlation
• Miller, C. J. Krughoff, K. S. Ho, T. K. A Dust
  Extinction Web Service in the VO Framework

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NVO Registry Portal
Find source catalogs, image archives, and other
astronomical resources registered with the NVO
A Registry is a distributed database of Virtual
Observatory resources primarily access services
for catalog, image, and spectral data, but also
descriptions of organizations and data
collections. There are several coordinated
registry implementations that share information
by harvesting each other's resources. This
registry is at STScI in Baltimore, MD.
Searches for resources can be done by keyword, or
advanced queries can be expressed in the SQL
language. The registry is open for humans through
web forms, or machines through SOAP web services.
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DataScope
Discover and explore data in the Virtual
Observatory
Using the NVO DataScope scientists can discover
and explore hundreds of data resources available
in the Virtual Observatory. DataScope uses the
VO registry and VO access protocols to link to
archives and catalogs around the world. Users can
immediately discover what is known about a given
region of the sky they can view survey images
from the radio through the X-ray, explore
archived observations from multiple archives,
find recent articles describing analysis of data
in the region,
A summary page provides a quick précis of all of
the available data. Users can download images and
tables for further analysis on their local
machines, or they can go directly to a growing
set of VO enabled analysis tools, including
Aladin, OASIS, VOPlot and VOStat.
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OpenSkyQuery
Cross-match your data with numerous catalogs
OpenSkyQuery allows you to cross-match
astronomical catalogs and select subsets of
catalogs with a general and powerful query
language. You can also import a personal catalog
of objects and cross-match it against selected
databases.
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Spectrum Services
Search, plot, and retrieve SDSS, 2dF, and other
spectra
The Spectrum Services web site is dedicated to
spectrum related VO services. On this site you
will find tools and tutorials on how to access
close to 500,000 spectra from the Sloan Digital
Sky Survey (SDSS DR1) and the 2 degree Field
redshift survey (2dFGRS). The services are open
to everyone to publish their own spectra in the
same framework. Reading the tutorials on XML Web
Services, you can learn how to integrate the 45
GB spectrum and passband database with your
programs with few lines of code.
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Web Enabled Source Identification with
Cross-Matching (WESIX)
Upload images to SExtractor and cross-correlate
the objects found with selected survey catalogs.
This NVO service does source extraction and
cross-matching for any astrometric FITS image.
The user uploads a FITS image, and the remote
service runs the SExtractor software for source
extraction. The resulting catalog can be
cross-matched with any of several major surveys,
and the results returned as a VOTable. The web
page also allows use of Aladin or VOPlot to
visualize results.
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How to Publish to the NVO
Make your data collection available to others
The NVO is a powerful environment for locating
and integrating a wide variety of data
originating from many different instruments and
exploring many different research questions in
astronomy. But how does data get into that
environment in the first place? Data is exposed
to the NVO environment through a process called
publishing. This
"how-to" document is aimed anyone who has data
and would like to share it with the astronomy
community through the NVO. Remember, though, data
is not the only thing you can publishyou can
also publish services. That is, if you have a
piece of software that might be useful to others
and would like to make it accessible over the
network, publishing it as a service makes it
possible for other NVO applications to make use
of it.
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Future VO-enabled applications

• NVO applications for 2005-2006 TBD in
  consultation with Science Steering Committee
• Fast data inventory service
• Sky coverage footprint services
• WCS fixer
• Integration of DataScope with VOEvent
  notifications
• Forms-based interfaces for database queries and
  cross-correlations

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Frequently used tools

• Aladin (CDS, Strasbourg) http//aladin.u-strasbg.
  fr/aladin.gml
• VOPlot (VO India) http//vo.iucaa.ernet.in/voi/v
  oplot.htm
• Mirage (Lucent) http//cm.bell-labs.com/who/tkh/m
  irage/index.html
• TOPCAT (Starlink) http//www.star.bris.ac.uk/mbt
  /topcat/
• Specview (STScI) http//www.stsci.edu/resources/s
  oftware_hardware/specview
• VOSpec (ESAC) http//esavo.esa.int/vospec/