Transcript talk
Science with the Virtual Observatory Brian R. Kent NRAO 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 collections from multiple web sites, a need arises for standards, protocols, and fundamental tools and data access layer to provide cross communication. Enter: A Virtual Observatory! “A distributed, scalable education and research environment for searching, integrating, and analyzing observational, experimental, and model databases.” - P. Fox, NCAR; VSTO Without VO astronomer archive 1 service 3 archive 2 service 2 archive 3 survey 1 n services, n interfaces service 1 survey 2 survey 3 With VO astronomer archive 1 archive 2 service 3 VO archive 3 survey 1 n services, “1” interface (don’t have to change yours!) service 2 service 1 survey 2 survey 3 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 Graham, 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 higherlevel 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 Paradigm and 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...) Example client applications and pipeline FITS to IDL Bandpass Calibration RFI flagging 2D signal extraction Data cube gridding ALFALFA Data Processing Pipeline Baseline Flatfield 3D signal extraction Data Cube Visualization Flux Measurement 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/