National Astronomy Meeting 5th April 2006
The X-Ray Synoptic Viewer:
X-Ray Data Access and Reductionin the Virtual Observatory
Duncan Law-Green (LEDAS: Leicester Database & Archive Service)
LEDAS homepagewww.ledas.ac.uk
What is LEDAS?
UK’s high-energy astrophysics data centre, located at Leicester
In continuous operation since 1989 (EXOSAT database).
Current data holdings >1.6TB processed and calibrated bulk data from several major X-ray astronomy satellites (Einstein, EXOSAT, ROSAT, Ginga, ASCA, XMM-Newton, Chandra).
Access to >420 astronomical catalogues and science reference data (e.g. spectral line lists)
Database search and display facilities developed in-house (ARNIE5)
DBMS: HEASARC Browse (legacy), TDB binary, Sybase (Chandra mirror), MySQL, Postgres.
Successful, attracting >250,000 hits/month in 2005, c.f. 2 million hits/month for SDSS SkyServer.
AstroGrid Deployment @ LEDAS : 1
Mar 04: New server “Galahad” (AG/LEDAS)(Dual Xeon 2.6, 2GB RAM, 1TB RAID)
Jul 04: AG Itn 05: Local MySQL server on galahad. Successful test PAL deployment(HEASARC Master Optical, ~4 million rows)
Feb 05: Leicester AG staff begin using Galahad for v1.0 release work. v1.0 components installed on Galahad: Registry, XrayDSA, FileStore, JES.
Registry: fully operational, core AG systemXrayDSA: Deployment of 1XMM catalogue via MySQL
Dec 05: Disk failure on galahad, loss of XrayDSA, partial loss of FileStore. Rebuild in progress.
Jan 06: New server “Camelot” (LEDAS)(Dual Opteron, 2GB RAM, 1.2TB RAID)
Mar 06: Deployment of DSA v1.1, local Registry on camelot.Work in progress.
AstroGrid Deployment @ LEDAS : 2
Future Developments: • DSA for all 420+ catalogues at LEDAS
• Bulk data: SIAP (images), SSAP (spectra), “STAP” (time series?) Complex, heterogeneous datasets X-ray Data Model
• Local LEDAS Registry (already running)
• MySpace server
• Community for high-energy researchers
• High-energy science workflows
External Resources:• VO support for Swift UKDC (catalogues already in LEDAS)
• VO support for WASP archive @ Leicester?
Synoptic: “Of or constituting a synopsis; presenting a summary of the principal parts or a general view of the whole.” (dictionary.com)
X-Ray Synoptic Viewer (XSV):An integrated graphical VO tool for:
● viewing X-ray images from multiple missions ● selecting X-ray datasets for further inspection● extracting calibrated flux information● further processing of archive data fluxes/limits● Historical X-ray light curves● ...more
X-Ray Synoptic Viewer - 2
ALADIN image here
Raw & processed archive data
FITS HDS JPG
X-Ray Synoptic Viewer - 2
ALADIN image here
Raw & processed archive data
Catalogue Fluxes
FITS HDS JPG
X-Ray Synoptic Viewer - 2
ALADIN image here
Raw & processed archive data
Catalogue Fluxes
Generated Fluxes
FITS HDS JPG
X-Ray Synoptic Viewer - 2
ALADIN image here
Raw & processed archive data
Catalogue Fluxes
Generated Fluxes
Flux limits
FITS HDS JPG
X-Ray Synoptic Viewer - 2
ALADIN image here
Raw & processed archive data
Catalogue Fluxes
Generated Fluxes
Flux limits
Automation (workflow)
Generated spectra/time series
FITS HDS JPG
Mission archives for Synoptic Viewer
Instrument Operational datesEinstein IPC/HRI 1978-1981EXOSAT CMA 1983-1986ROSAT PSPC/HRI 1990-1999ASCA SIS/GIS 1993-2001SAX LECS/MECS 1996-2002Chandra ACIS/HRC 1999-Chandra LEG/MEG 1999-XMM-Newton EPIC 1999-XMM-Newton RGS (grating) 1999-Swift XRT 2004-Suzaku XIS 2005-
X-Ray Correlator (XCO)
Cross-correlation tool, integrated with Synoptic Viewer.
Cross-match X-ray source positions (from LEDAS images or source catalogues) with external databases.
More challenging at X-rays because of positional uncertainties: 10”-30” for earlier missions, to 1”-5” for XMM-Newton, results in multiple counterparts.
User-selectable figure-of-merit, match algorithm
Apply matching constraints by e.g. fx / fopt
or optical colours. Account for X-ray pointing
Rank by figure-of-merit, give statistical confidence.
S1 S2
S3
S4
Science Cases...
Synoptic Viewer
Multi-mission historical X-ray light curves.Long-term variability of all sources in a nearby galaxy. Search formost variable sources in entire sky, e.g. Stellar capture events in nuclei of nearby galaxies, many orders of magnitude flux variation on t ~ months-years. Applicability at other wavebands (e.g. WASP).
X-Ray Correlator
GRB identifications: integrated, efficient identification of counterparts, quantitative basis for ID. Need confidence in ID for rapid followup observations.
XMM identifications: federation of large X-ray catalogues (e.g. 2XMM, >105 sources) with optical, IR. Figure-of-merit provides large, “clean” samples of sources.
Project status:
PPARC 2005 data curation review: expressed support for UK data centres
Bid submitted Dec 2005, awaiting response.
...watch this space!
http://www.ledas.ac.uk/
Leicester Database & Archive Service