Science with the Virtual Observatory Brian R. Kent NRAO.
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Transcript of Science with the Virtual Observatory Brian R. Kent NRAO.
Science Science with the with the Virtual Virtual ObservatoryObservatory
Brian R. KentBrian R. KentNRAONRAO
Virtual Observatory…
Let’s answer two questions:
In a nutshell, what is it?
What can I do with it?
Into the nutshell…Philosophy behind the VO
With the wealth of archive data and data With the wealth of archive data and data collections from multiple web sites, a need collections from multiple web sites, a need arises for standards, protocols, and arises for standards, protocols, and fundamental tools and data access layer to fundamental tools and data access layer to provide cross communication.provide cross communication.
Enter: A Virtual Observatory!Enter: A Virtual Observatory! ““A distributed, scalable education and research A distributed, scalable education and research
environment for searching, integrating, and environment for searching, integrating, and analyzing observational, experimental, and analyzing observational, experimental, and model databases.” model databases.”
- - P. Fox, NCAR; VSTOP. Fox, NCAR; VSTO
Without VO
astronomer
archive 1
survey 2survey 1
archive 2
service 1archive 3
service 2
survey 3
service 3
n services, n interfaces
astronomer
archive 1
survey 2survey 1
archive 2
service 1archive 3
service 2
survey 3
service 3
n services, “1” interface
(don’t have to change yours!)
VO
With VO
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
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
Threads of the VO Fabric
Multiwavelength Astrophysics
Threads of the VO Fabric
Multiwavelength Astrophysics Archival Research (astronomers buying drives)
Threads of the VO Fabric
Multiwavelength Astrophysics Archival Research Astronomy with Large Surveys Credit: DuPlain and Crossley
Threads of the VO Fabric Multiwavelength Astrophysics Archival Research Astronomy with Large Surveys Temporal Astronomy
CREDIT: Roy Williams, Rob Seaman, Alasdair Allan, Andrew Drake, Robert White, Matthew CREDIT: Roy Williams, Rob Seaman, Alasdair Allan, Andrew Drake, Robert White, Matthew Graham, Philip WarnerGraham, Philip Warner
Threads of the VO Fabric Multiwavelength Astrophysics Archival Research Astronomy with Large Surveys Temporal Astronomy Wide bandwidth –
large datasets, oodles of spectral lines…
Credit: A. Remijan
VO Elements
VO Registry and Inventory – phone book of the VO!
Protocols:
SimpleSearch, ConeSearch
SIAP, SSAP
VOEvent for transients
Data Access Layer
Higher Level Services
DataScope
VO Table Viewer
VIM services
Web based mosaicking!
Montage allows:
Online combination of imaging surveys,
limited online combination of user images
Unlimited combination offline with open source libraries
New Data Discovery Portal
Finding Resources, Services, and Catalogs: VO Directory
The “phone book” of the VO – lists entries for: Small data, images and spectra collections Centralized data archives Services and functions Most importantly – acts as a metadata repository for
all these archives, collections, and services.
Finding Catalogs in your “Area”
VO Inventory allows multi-source catalog searches, cross-matching, and table joins
Finding information: ConeSearch
Simple first protocol – easy to implement and useful.
Often found operating in the background of higher-level services.
Imaging and Spectral Line Catalogs SIAP/SSAP
(Simple Image/Spectral Access Protocol)
Allows for the searching of image and spectra metadata
Metadata links user queries and services with original imaging repositories – humongous imaging databases are not mirrored or copied.
Datascope and multi-catalog searches
Datascope and multi-catalog searches
New VO Visual Integrating and Mining
AJAX Paradigmand client-side dynamics web apps
Asynchronous Javascript And XML
Most common usage is in online Google Maps, Microsoft Live! Maps, or even your online shopping basket!
Allows for interactive interfaces to be built without Flash, Silverlight, or Java plugins
VOTable makes use of this incredibly useful programming paradigm (will see in demo...)
FITS to IDLFITS to IDL
Bandpass Bandpass CalibrationCalibration
RFI RFI flaggingflagging
2D signal 2D signal extractionextraction
Data cube Data cube griddinggridding
Baseline Baseline FlatfieldFlatfield
Data Cube Data Cube VisualizationVisualization
3D signal 3D signal extractionextraction
Flux Flux MeasurementMeasurement
ALFALFA ALFALFA Data Processing Data Processing PipelinePipeline
Example client applications and pipeline
Grab spectrum from a single pixel in the data cube.
Fetch data from NASA Extragalactic database
Sloan too!
Compare with previous spectra…
New VO Portal
Deployed February 2009 Demos of:
Registry and Inventory usage Datascope VO Table utilities Visual Integration and Mining
More information and Resources
NRAO VO Wiki information website (link to various introductory talks)
https://safe.nrao.edu/wiki/bin/view/Main/VoGuide http://www.cv.nrao.edu/~bkent/computing/ VO “Cookbook” Acknowledgement: Bob Hanisch Now, a short web demo… Watch the CfA colloquia webcast!
http://www.cfa.harvard.edu/events/colloquia/webcast/