AstroGrid and the Virtual Observatory Nicholas Walton AstroGrid and Euro-VO Technology Centre Project Scientist (Institute of Astronomy, University of Cambridge) Anita Richards (Jodrell Bank Observatory, University of Manchester)
The Challenge of Data: Access and Analysis Astronomy is an observational science Progress is made via understanding gained from the study of the cosmos Powerful observatories exist producing observational data across the wavelength domain data comes in many formats levels of complexity Data is held globally: USA, Europe, Asia heterogeneous data archives Research partnerships are also global Connecting researchers with data and applications is the challenge for the Virtual Observatory p2
Traditional Observatories: e.g. ESO, HST Images from ESO NASA p3
The Evolving Scientific Process: 1 Astronomy is an observational science observe the sky & analyse the observations compare and contrast with models make analytic predictions, and look again p4
The Evolving Scientific Process: 2 Astronomy becomes a computational science observe all the sky in many colours generate large scale simulations compare and contrast with observations p5
Supernova Remnant Cassiopeia-A a 300 year old Supernova The Challenge and Opportunity of multiwavelength data: Shocks seen in the X-ray Chandra image Dust shows in the IR Mapping e s in the magnetic field as revealed by Radio data Heavy elements seen in the optical Images from Chandra Science Centre p6
The Need for Virtual Observatories: Managing Technological Change The massive Growth of Data Number + size of telescopes Increase in size and multiplex capabilities of instrumentation: Optical: ESO's 4x8m VLT, 2x8m Gemini X-ray: XMM-Newton sub-mm: ALMA Infra-Red: VISTA > 100 GB/nights Radio: e-merlin > data rates ~320 Gbps All sky at 0.1 arcsec 100 TB N A Walton: AstroGrid SAG : Meeting 1 : IoA : June 19, 2003 Printed: 08/11/04 p7
Multi-λ M31 & bitrate inflation WSRT HI (Braun & Thilker) Plate(Roberts) Big Ear Perki ns Hand drawn (Al Sufi) NVSS, IRAS, XMM, AVO p8 slide: Anita Richards
The need for a Virtual Observatory Hubble UDF Million second exposure 6000x6000 pix 11.5 sq. arcmin 10,000 galaxies p9
The need for a Virtual Observatory SWIRE ELAIS N1 9 sq. degrees (~3000 UDF) (moon ~0.2 sq. deg.) ~ 600,000 objects All Sky 40,000 sq. deg or 3 Billion objects! p10
Astronomy Data Most astronomical data now held in on-line archives Diversity images, spectra, 3-D, tables units, errors user interface varies from archive to archive Major astronomy archives include: Sloan Digital Sky Survey: http://www.sdss.org European Southern Observatory: http://archive.eso.org STScI (MAST: incl HST): http://archive.stsci.edu/ Chandra (X-Ray): http://cxc.harvard.edu/cda/ IPAC (IR-data including Spitzer): http://www.ipac.caltech.edu/ Cambridge (UK optical data): http://casu.ast.cam.ac.uk/casuadc User required to interact with many differing services time consuming and difficult + plus issues of data volumes p11
... towards single point access... Create a system that recognises: data comes from many sources: thus data interoperability applications are needed to work on data... so Requires a system built upon agreed interoperability standards... and this Exploits wider IT developments: Grid and WS technologies access to high speed networks power of XML/ SOAP/ REST etc but note: backbones ~10Tb/s, desktops ~100Mb/s reduced costs of h/w: all data now on spinning disks p12
IVOA: Stds Enabling Interoperability The International Virtual Observatory Alliance http://www.ivoa.net A global partnership Projects represent global astronomy data providers IVOA a forum for interoperability standards VO projects build on these standards p13
IVOA Standard Areas Standard vocabulary (semantics) Standard ontology describing how terms are related Standard data model (encoding format) for each type of measurement Standard query language for issuing spatial, temporal, and semantic queries across the catalogs. Standard access services for retrieving catalog records or image cutouts. Standard mechanisms for interacting with storage systems (VOSpace) Standard authentication/ authorisation mechanisms Standard event notification services. p14
AstroGrid: the UK's Virtual Observatory Improve the quality, ease, speed and cost effectiveness of on-line astronomy Make comparison and integration of data easier Remove barriers to multi-wavelength astronomy Enable access to very large data sets Software system built to IVOA standards p15
AstroGrid 2007.2 Release: Jul 2007 http://www.astrogird.org/launch p16
Astro-Run Time: VO accessibility N A Walton VOTC @ Euro-VO SAC: ESTEC, Noordwijk 18 Jun 2007 p17 Printed: 8/24/07
AstroGrid... in a nutshell Simple workbench access to VO services Concept of 'VOSpace': virtual user space for data, workflows, results ability to share with research teams, collaborators Powerful, yet simple tools to enable data discovery thus data and applications are easily available astroscope, helioscope System to support creation of user defined workflows find data, process data, interpret data save workflows Range of applications on remote servers for bulk processing on the client for visualisation, and final processing S2-147 a SNR Walton: AstroGrid and the VO 5o x Nicholas 5o Hα-r 24 Aug 2007 - STFC @ Durham p18
Workbench User Interface to VO services Delivery via Java Webstart technology Components Registry Find Data Work with Applications Build Workflows Look at the results... p19
VO Desktop: coming soon... Workbench frontend from spring 2008 Select a search-space Search for resources Filter these resources View selected resources Use the selection Invoke it Save it Export it Richer browsing of data and publications p20
Use p21
Plastic VO tools on the desktop http://plastic.sourceforge.net Enables applications to 'talk' to each other select sources in one application and these will show up in another application Communication protocol for client side VO tools Easy to adopt and extend Wide buy-in tools from UK, France, USA, etc Developed mainly by AstroGrid p22
AstroGrid Redshift Maker p23
The integrated VO workspace for astronomy data analysis p24
AstroGrid Workflows: automation... p25
... and Scripts access all the AstroGrid VO functionality from the command line connecting via AstroGrid's 'AstroRuntime' use python, perl, C++, etc p26
Coming Up... some live demos Single Object: investigating 3C295, an Active Galactic Nuclei demonstrates use of visual tools, including AstroScope radio, x-ray, optical data comparison Statistical Studies: investigating the Galactic Plane cross matching objects from the 2MASS infrared survey with those from the IPHAS optical survey aim to select the classes of stars for population studies, distances, etc selections based on object properties data held in the UK and the USA demonstrates use of command line scripts: see help at http://www2.astrogrid.org/science/scripting and follow 'python'... but first a couple of words about a typical survey data set... in this case IPHAS p27
Example Large Scale Survey: the IPHAS Survey of the Galactic Plane IPHAS: The Isaac Newton Telescope/ Wide Field Camera Photometric H-alpha Survey of the Norther Galactic Plane (PI: Janet Drew: Imperial, UK) Element of the wider IPHAS/VPHAS+/UVEX consortium: forming EGAPS (European Galactic Plane Surveys) see http://www.egaps.org large collaboration of scientists from ~10 countries Key Goals: Large scale Milky Way structure and study of early and late type populations (preferentially selected via H-alpha emission line properties) VO access work partly implemented through the May 2006 AG Tools Call programme - http://www.astrogrid.org/calls p28
IPHAS Survey 7635 Pointings ~2000 sq deg x 2 (overlap, 5'x5' offset) thus 15270 Pointing in total r, Ha, and i ~30 GB/night of data = > 1TB total p29
Survey Products Photometric catalogue ~200 million objects Detection of ~50000 Hαemitting objects p30
IPHAS: Images IC 5070 the pelican nebula: Credit Nick Wright (UCL) p31
Models for Galactic Structure Young populations good tracers of galactic structure e.g. Russeil (2003) study based on positions of star forming complexes (from HI, HII, CO observations) Vallee (2005) statistical study of recent work points also to 4 arm model Key point for IPHAS find the tracers which map the structure... Russeil 4-arm model - 1) Sagittarius-Carina, 2) Scutum-Crux, 1') Norma-Cygnus, 2') Perseus arms sun marked by X p32
Structure: use of the IPHAS survey Pickles 1998 stellar library IPHAS is deep enough to sample most of the plane r~20 = unreddened A0 dwarfs at 20kpc A stars are luminous to allow for the study of distant clusters A0V reddening line a population of easilymodelled standard candles Thus select early type (A, B stars) from their position in the colour-colour plane p33
Types of stars from their colours... e.g: Example OBA type Emission line stars (green) Probable dme stars (red) Carbon star two WDs Dispersion due to photometric calibration issues, stars in differing fields, this will be corrected in upcoming data release ~A0 stars (blue) p34
Links AstroGrid International Virtual Observatory Alliance http://www.astrogrid.org http://www.ivoa.net Euro-VO http://www.euro-vo.org p35