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/