Monday (April 7th 2003) sees the release of one of the largest catalogues of
celestial X-ray sources ever made. The result of over a year’s observations
by the European Space Agency’s XMM-Newton space telescope, the new
Serendipitous Source Catalogue locates tens of thousands of previously
unknown X-ray emitting stars and galaxies. This vast catalogue will be a
major resource for future research in high-energy astrophysics, for example
allowing astronomers to study large numbers of galaxies with huge black
holes in their centres.

Dr Mike Watson, XMM-Newton Survey Scientist, said: “XMM-Newton’s X-ray
mirrors have the largest collecting area ever flown, giving it impressive
sensitivity to find the faintest objects in the X-ray Universe. XMM-Newton’s
advanced optics and instrumentation also make it possible to discover X-ray
sources buried in interstellar gas and dust, which earlier satellites were
not able to detect, so this new catalogue reveals many new obscured objects
such as galaxies with hidden central black holes.”

The data in the catalogue was collected using the EPIC X-ray cameras on the
XMM-Newton observatory. These 3 cameras, all pointing in the same direction,
image an area of the sky the size of the full moon. When XMM-Newton is
targeted at selected astronomical objects, it also collects information on
other X-ray sources, which happen to be in its field of view, providing a
rich ‘serendipitous’ by-product of the planned observations. Each image from
these cameras contains many tens of previously unknown X-ray sources.

Dr John Pye, who leads the catalogue team at Leicester, said: “This
catalogue is the result of the hard work of a dedicated team, both here at
the University of Leicester, at the other UK institutes involved (Mullard
Space Science Laboratory – University College London, and Institute of
Astronomy – Cambridge University) and at institutes in Germany, France,
Spain and Italy. The catalogue already contains over 33,000 X-ray sources,
but our work continues and the next version will be the largest X-ray
astronomical catalogue ever made. By the end of the expected 10-year
XMM-Newton mission we can expect the final catalogue to reach half a million
objects.”

The catalogue was made by the XMM-Newton Survey Science Centre (SSC), a
European collaboration led by Dr Mike Watson at Leicester, on behalf of the
European Space Agency (ESA). All XMM-Newton data is sent from the ESA
Science Operations Centre near Madrid to be processed by the SSC at
Leicester using computer programs developed by the SSC and ESA teams. As
well as the XMM-Newton data, the catalogue incorporates the results of
matching the X-ray objects with entries in a wide range of existing
astronomical catalogues, using the impressive data collections provided at
the Centre de Donnees astronomiques de Strasbourg. This feature of the
catalogue provides a unique multi-wavelength view and a foretaste of the
power of the Virtual Observatory (see below) concept. The SSC is also making
observations with other, ground-based, telescopes in order to clarify the
nature of some of the new X-ray sources.

The ESA Project Scientist for XMM-Newton, Dr Fred Jansen, said: “I am very
pleased to see this first release of the XMM-Newton catalogue, it will be a
standard reference for decades to come. The catalogue contains rich
information on vast numbers of newly discovered sources of X-ray emission.”

Notes for Editors

Dr Watson will announce the release of the catalogue to the astronomy
community in a short presentation at the UK National Astronomy Meeting being
held in Dublin on 7 – 11 April 2003.

XMM-Newton
XMM-Newton was launched by the European Space Agency on the 10th of December
1999 by an Ariane V rocket from French Guiana. It is in a 48-hour orbit
around the earth, faultlessly performing astronomical observations for the
world’s astrophysical community. XMM-Newton is the most sensitive X-ray
telescope ever built. The EPIC X-ray cameras were built by a team led by Dr
Martin Turner of the University of Leicester, continuing a long series of
successful space X-ray instrumentation built by this group.

X-ray Astronomy
X-rays are a form of electromagnetic radiation and in space they are
generated by extremely hot materials (with temperatures over 1 million
degrees Celsius). These sorts of temperatures occur, for example, in
supernovae, stellar flares and near black holes, where the strong pull of
gravity accelerates objects to very high speeds. X-rays from space are
readily absorbed by the Earth’s atmosphere, which means they can only be
studied by launching satellites into orbit.

Resources

XMM-Newton catalogue:

http://xmmssc-www.star.le.ac.uk/newpages/xcat_public.html

XMM-Newton Survey Science Centre:

http://xmmssc-www.star.le.ac.uk/

ESA XMM-Newton sites:

http://xmm.vilspa.esa.es/ or http://sci.esa.int/xmm/

International Virtual Observatory Alliance http://www.ivoa.net/
A virtual observatory is a collection of inter-operating data archives and
software tools, which utilise the internet to form a scientific research
environment in which astronomical research can be conducted. This allows
comparisons of data from different instruments, telescopes and wavelengths
to be done with ease.

Pictures:

XMM-Newton in orbit-
http://xmm.vilspa.esa.es/external/xmm_user_support/documentation/technical/Spacecraft/xmm_earth.shtml

EPIC Camera

http://www.src.le.ac.uk/projects/xmm/gallery/epicdev/fullsize.phtml?start=2

Contacts:

Dr Mike Watson
University of Leicester
Tel: +44 (0) 116 2523553
Fax: +44 (0) 116 252 3311
Email: mgw@star.le.ac.uk
Dr Watson will be available for press contact at the National Astronomy
Meeting on Tuesday April 8th and Wednesday April 9th.

Dr John Pye
University of Leicester
Tel: +44 (0) 116 2523552
Fax: +44 (0) 116 2522464
Email: pye@star.le.ac.uk

Dr Fred Jansen
ESA XMM-Newton Project Scientist
Tel: +31 (0) 71 565 4426
E-mail: fjansen@astro.estec.esa.nl

Julia Maddock
PPARC Press Office
Tel: +44 (0) 1793 442094
Email: julia.maddock@pparc.ac.uk

UK involvement in XMM-Newton is funded by the Particle Physics and Astronomy
Research Council at a total of about 25.5 million to date, in addition to
paying subscription to the European Space Agency.

The Particle Physics and Astronomy Research Council (PPARC) is the UK’s
strategic science investment agency. It funds research, education and public
understanding in four areas of science – particle physics, astronomy,
cosmology and space science.

PPARC is government funded and provides research grants and studentships to
scientists in British universities, gives researchers access to world-class
facilities and funds the UK membership of international bodies such as the
European Laboratory for Particle Physics (CERN), and the European Space
Agency. It also contributes money for the UK telescopes overseas on La
Palma, Hawaii, Australia and in Chile, the UK Astronomy Technology Centre at
the Royal Observatory, Edinburgh and the MERLIN/VLBI National Facility,
which includes the Lovell Telescope at Jodrell Bank observatory.

PPARC’s Public Understanding of Science and Technology Awards Scheme funds
both small local projects and national initiatives aimed at improving public
understanding of its areas of science.