Leicester Database

1
Leicester Database Archive Service
J. D. Law-Green, J. P. Osborne, R. S.
WarwickX-Ray Observational Astronomy Group,
University of Leicester
What is LEDAS?
LEDAS and AstroGrid
AstroGrid is a 3.7M eScience project funded by
PPARC to create a protoype Virtual Observatory
for UK astronomers. We are working extensively
with AstroGrid developers to enable VO access to
LEDAS datasets, providing a Web Services (SOAP)
interface to query LEDAS remotely. LEDAS is the
first data-centre outside the AG consortium to
undertake this work. This will be followed by
further AstroGrid components, such as an
interactive web portal and MySpace server
(allowing users to cache search results on a
storage server at LEDAS for further analysis).
The Leicester Database Archive System (LEDAS)
is an online astronomical database service
providing access to catalogues and data product
archives with an emphasis towards high-energy
astrophysics. LEDAS provides UK access to the
1XMM archive, Chandra Science Archive, the ASCA
Public Data Archive and the Ginga Products
Archive. LEDAS has been a public facility since
1992. The LEDAS cluster now stores 1.6TB of
catalogue and archive data (see Figure 1) and the
data volume continues to grow rapidly. The
service is very popular, receiving c.25,000 web
hits per month, and providing data downloads of
2 GB per month. LEDAS has a full-time developer
/ support scientist who can be contacted at
ledas-help_at_star.le.ac.uk. Comments and questions
about the archive databases and requests for new
datasets/services are welcomed.
Fig. 3 New archive web interface (ARNIE v5)
showing results of search on 1XMM catalogue.
Other LEDAS work
LEDAS is involved in other eScience
projects- Swift Leicester will host the UK
Data Centre for the Swift Gamma-Ray Burst
Explorer mission. The UKDC will archive Swift
observations and provide public access to the
data. LEDAS is currently providing systems
support to the UKDC. The UKDC will build on LEDAS
infrastructure and software. WASP The Wide
Area Sky Patrol is a collaboration to build a
system of robotic survey telescopes. Objectives
include discovery of extrasolar planets by
transit method, and detection of transient or
moving objects such as gamma-ray bursts or NEOs.
The WASP dataset will be an invaluable resource
for time-domain astrophysics. LEDAS is assisting
with an experimental WASP data archive, to
develop techniques in handling very large
(TB-sized) databases. A public archive interface
at Leicester is foreseen once WASP enters routine
service.
New LEDAS Services
A number of LEDAS services have recently been
expanded or enhanced- ARNIE a web search
interface to over 300 astronomical catalogues.
The new version (v5) can now search multiple
catalogues simultaneously, output several formats
including VOTable, and provide interactive
graphical displays of results using VOPlot and
Aladin. DSS Web access to images from the
Digitised Sky Survey. The latest update provides
access to the new higher resolution DSS-II
images, with optional coordinate grid
overlays. XMM LEDAS now provides access to the
public data holdings of the XMM Serendipitous
Source Survey (1XMM), the first wide-area
detection catalogue by the XMM-Newton mission.
Catalogues, calibrated images and observing logs
can be accessed online using the simple search
interface (see Fig. 3). Chandra LEDAS hosts the
only mirror outside the United States of the
Chandra Data Archive. We provide fast, local
access for UK users to download raw and processed
public-domain data. The Archive currently stores
360GB of data, an amount growing by approx.
4GB/week. The LEDAS archive now has a
fully-featured Java-based search interface, see
http//chandra.ledas.ac.uk/
LEDAS Data Holdings
Fig. 1 Current LEDAS Data Holdings
DSS Digitised Sky Survey Chandra Chandra
Public ArchiveXMM XMM Serendipitous Source
Catalogue (1XMM) archiveASCA ASCA Science
ArchiveROSAT ROSAT Public ArchiveBLASTA Large
catalogues (including GSC, 2MASS)Other Other
mission archives, including Ginga, Einstein
Fig. 2 New archive hardware installed at LEDAS.
The new servers have a total storage capacity of
6TB.
Fig. 4 SuperWASP cameras (image courtesy
www.superwasp.org).
http//www.ledas.ac.uk/