Leicester University X-ray and Observational Astronomy Group

Julian Osborne : Data Analysis & Data Archives

In the last few years I have been leading a team of astronomers and engineers at Leicester to fulfil our obligations to the Swift project. Before that, my main role was to provide direction for the XMM-Newton Science Analysis Software provided by the Survey Science Centre. In addition I am the LEDAS data archive manager.


Swift: Catching Gamma-Ray Bursts on the Fly

Swift post-launch support

Swift is a US/UK/Italian satellite designed to study gamma-ray bursts. Launched on November 20, 2004, it includes a wide area Burst Alert Telescope and narrow field X-ray and UV/optical telescopes. The Swift satellite is unique in that it can autonomously detect gamma ray bursts and re-point within a few seconds, so catching them when they are still bright. Swift has been making detailed observations of around 100 GRBs a year, getting lightcurves and spectra from the time of the burst to up to a hundred days after. A gamma-ray burst signals the creation of a black hole, and GRB research has been at the forefront of high energy astrophysics since this was realised in the late 1990's.

Swift is partly a 'spare parts' satellite, having been made cheaply from left-over bits from earlier projects. Examples of this include two major parts of the X-ray telescope: the X-ray CCD in the Leicester-supplied X-ray camera (which is a duplicate of an XMM EPIC MOS CCD), and the X-ray mirrors, which are from the Italian Jet-X project (see these pictures); and the UV/optical telescope, which is also a near XMM duplicate. Leicester has also supplied the optical XRT telescope alignment monitor, designed to ensure that the GRB X-ray positions promptly distributed have the best possible positional accuracy.

Leicester has naturally played a significant role in calibrating the XRT, and this continues in orbit; Leicester scientists continue to enhance the so-called 'response matrix', which describes the spectral response of the CCD to the incoming X-rays. Leicester also hosts the UK Swift Science Data Centre, providing fast and easy access for UK astronomers to the rapidly evolving data, as well as Swift data analysis training for anyone who wants it, and software services to the Swift project.


The XMM-Newton Survey Science Centre

XMM-Newton is the European Space Agency's X-ray observatory. It has X-ray cameras built by us in Leicester. Our group also leads the Survey Science Centre of which I am a member. The XMM-Newton observatory has the largest set of X-ray telescopes ever, providing good quality images over a large area with high spectral resolution; it also has co-aligned X-ray grating spectrometers and and optical/UV telescope. It is complementary to NASA's Chandra X-ray observatory, which provides higher resolution images but with smaller telescopes.

The SSC is a consortium of 9 European institutes which have the following jobs:


Leicester Database and Archive Service LEDAS

The Leicester Data Archive Service: LEDAS

LEDAS provides an on-line astronomical database and archive access service for data from high energy astrophysics missions. LEDAS gives instant access to almost 1 Terabyte of data through its comprehensive web-based database query interface. The four main high energy data holdings are: In addition to these, the LEDAS also provides access to hundreds of other astronomical catalogues from ground-based observations and other space missions. All catalogue and bulk data databases can be accessed via the web using the ARchive Network InterfacE (ARNIE). One of the most important of these catalogues is the 2XMMp catalogue, which provides X-ray measurements on around 123,000 different X-ray sources and products on the brightest of these.

Since May 1998 the LEDAS has offered an optical sky image creation service, the Digitized Sky Survey (DSS) Image Browser. The DSS is a digitised version of Schmidt survey plates covering the entire sky at 1.7 arcsec resolution. The LEDAS DSS service offers access to the full sky, and users are able to request images up to 1 degree square in FITS, HDS and GIF formats (images larger than 1 degree square are also available on request).

LEDAS provides software for the analysis of Ginga data, and mirrors the Chandra, HEAsoft (ftools, fitsio, xanadu and xstar) and PIMMS distribution packages. It also provides and on-line service to WebPIMMS


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Julian Osborne: 21-Nov-2006