Press Release

Eye-openers from XMM-Newton

By SpaceRef Editor

February 9, 2000

Filed under European Space Agency

The first pictures from ESA’s new X-ray space observatory fully demonstrate the capabilities of the spacecraft’s telescopes and its science
instruments. The images were officially presented on 9 February at the XMM-Newton Science Operations Centre in Villafranca, Spain.

The images were obtained between 19-25 January at the very start of the science payload commissioning process. The spacecraft viewed three regions
of the sky: part of the Large Magellanic Cloud (LMC), the Hickson Cluster Group 16 (HCG-16), and the star HR 1099. These targets were chosen
because they all present a variety of X-ray extended and point sources and are very interesting regions.

The expanding cauldon in the Large Magellanic Cloud

The Large Magellanic Cloud also known as the Nebula Major is about 20 thousand light years in diameter. Situated 160 thousand light years from
Earth, it is one of two irregularly shaped galaxies that are easily seen with the naked eye in the southern hemisphere. These galaxies are satellites of
the Milky Way and appear to be slowly spiralling into our own Galaxy.

The first image obtained by the EPIC-PN X-ray cameras viewed the 30 Doradus region of the Large Magellanic Cloud. Also called the Tarantula
Nebula, 30 Doradus is a cauldron of creation where exploding stars are releasing vast amounts of matter and where new stars are being born.

The image presents the million degree temperatures of the emitting medium, with blue indicating the hottest regions; green intermediate temperatures
and red the coldest regions. The white and blue arc-like formation just off the centre is a new object, only part of which was known in the past. It has
the appearance of a supernova remnant with its expanding glowing-hot gas producing X-ray emission as it collides with the interstellar medium.

On the lower right of the picture is the remains of a star that exploded as Supernova 1987A on 24 February 1987. It was the first supernova to reach
naked-eye brightness since 1604 (Kepler’s star) and remained visible to the naked eye for nearly nine months. The brightest source in the view, upper
left, is another supernova remnant (N157D).

Martin Turner, Principal Investigator for the EPIC cameras… “These first pictures are tremendously exciting after so many years of
work. They are all that we hoped they would be. In the LMC we can see the elements, which go to make up new stars
and planets, being released in giant stellar explosions. We can even see the creation of new stars going on, using
elements scattered through space by previous stellar explosions. This is what we built the EPIC cameras for and they are
really fulfilling their promise”

Multiwavelength views of Hickson Group 16

The HCG-16 viewed by EPIC and by the Optical Monitor in the visible and ultraviolet wavelengths is one of approximately a hundred compact
galaxy clusters listed by Canadian astronomer Paul Hickson in the 1980s. The criteria for the Hickson cluster groups included their compactness,
their isolation from other galaxies and a limited magnitude range between their members. Most Hicksons are very faint, but a few can be observed
with modest aperture telescopes.

Galaxies in Hickson groups have a high probability of interacting. Their study has shed light on the question of galactic evolution and the effects of
interaction. Investigation into their gravitational behaviour has also significantly contributed to our understanding of “dark matter”, the mysterious
matter that most astronomers feel comprises well over 90% of our universe.

Observation of celestial objects from space over a range of X-ray, ultraviolet and visible wavelengths, is a unique feature of the XMM-Newton
mission. The EPIC-PN view of the Hickson 16 group shows a handful of bright X-sources and in the background more than a hundred faint X-ray
sources that XMM-Newton is revealing for the first time.

Juxtaposing the X-ray view of HCG 16 with that of the Optical Monitor reveals one of the great strengths of XMM-Newton in being able to routinely
compare the optical, ultraviolet and X-ray properties of objects.

Many of the X-ray sources are revealed as elongated “fuzzy blobs” coincident with some of the optical galaxies. Routine access to ultraviolet images
is a first for the mission, allowing astronomers to learn much more about individual objects. Obtaining a ratio of the brightness of individual sources
seen with different filters (‘filter spectroscopy’) gives indications on their temperature and composition. Using XMM-Newton to search for variability
from sources such as these will enable astronomers to hunt for those elusive black holes thought to lurk at the centres of many galaxies.

“The performance of our instrument is very much as we expected” says Keith Mason, Principal Investigator for the Optical Monitor.
“We have worked for over a decade on this mission and it is very exciting having the first data. And the pictures really
show all the value of the multi-wavelength approach of the XMM design.”

HR1099 in an infernal waltz

HR 1099 is a sixth magnitude star located about a 100 light years from the Sun only just visible to the naked eye. Its formidable brightness in the
EPIC-MOS image conceals in fact a binary pair. Whereas our Sun rotates in 30 days, these two stars are whizzing around each other in only 3 days.

The rapid motion causes a kind of infernal dynamo, twisting the stars’ magnetic fields into contorted shapes. If one star resembles our own Sun, its
partner is infinitely more active than our Sun. It is the scene of intense stellar flares and storms which astronomers believe are due to the release of
magnetic energy as the fields untwist. Measuring the phenomena that are present greatly helps us understand the way our own Sun functions and its
effects upon us. Again this X-ray image reveals many serendipitous sources, hitherto unknown.

Discovering the elements

The final two examples of the initial data collected by XMM-Newton take the form of spectra. They are provided by one of the two Reflection Grating
Spectrometers (RGS). Just as in optical spectroscopy, different elements absorb and emit light at specific and unique points of the radiation spectrum.
The RGS spread these out in the form of two “bananas”, the two so-called ‘spectral orders’ of the instrument. Emission lines appear as distinct
features in the rainbow of X-ray colours, acting as signatures that reveal a great deal of information to astronomers.

The RGS spectra of HR 1099 are examples. The graphs display peaks or lines that correspond to the various elements present in the source. One can
distinguish for instance the presence of different types of iron, oxygen carbon and neon. From the analysis of this data one can deduce the
temperatures, densities, abundances and velocities of the different materials.

“Firstly, the nice separation of the two spectral order bands shows the resolution of the RGS CCDs is well up to
expectations” comments Bert Brinkman, RGS Principal Investigator. “For the spectrometers as a whole, the resolution which is of
prime importance, is exactly or marginally better than what we expected after the ground calibrations. The instruments
promise a lot for the future.”

All the images reveal hitherto unknown X-ray sources. Faint point sources barely perceptible with previous X-ray space telescopes appear in all their
splendour. Understanding everything they show is somewhat premature since the XMM-Newton instruments have yet to be calibrated.

XMM Project Scientist Fred Jansen says: “As these are the very first astronomical data and we are already observing lots of
new science, XMM-Newton holds a very clear promise for an exciting and scientific future.”

ESA’s Director of Science Prof. Roger Bonnet is equally impressed. “I am amazed by the quality of the pictures as compared to
previous X-ray missions. We see on them a lot of new sources, especially in the parts of the spectrum which correspond
to the hottest temperatures and we see that the Universe is hotter than we thought and that many new sources are
appearing. We are very hopeful that many more objects will be discovered and that by extending the temperature
measurements of the Universe to many objects, we will have a much better picture of the history and the hectic behaviour
of stars at the end of their life”.

The Calibration and Performance Verification phase for XMM-Newton’s science instruments is to begin on 3 March, with routine science operations
starting in June.

(*)Pictures available on the ESA website at http://www.esa.int, then Image Gallery, then News and at http://sci.esa.int/xmm/firstimages

Following in Newton’s footsteps

The European Space Agency has decided to honour one of the world’s most illustrious scientists by giving the name of Isaac Newton to the XMM
mission. The X-ray space telescope is henceforth called the XMM-Newton observatory.

The work of Sir Isaac Newton (1642-1727) in the field of mathematics, optics and physics laid the foundations for modern science. He made a major
impact on theoretical and practical astronomy and today one cannot evoke an apple, a reflecting telescope, a light-splitting prism and or a sextant
without recalling Newton’s contributions to science.

“We have chosen this name because Sir Isaac Newton was the man who invented spectroscopy and XMM is a
spectroscopy mission” explains Prof. Roger Bonnet ESA Director of Science. “The name of Newton is associated with the falling
apple, which is the symbol of gravity and with XMM I hope that we will find a large number of black hole candidates
which are of course associated with the theory of gravity. There was no better choice of name than XMM-Newton for this
mission”.

Stargazing with XMM-Newton

On the occasion of the presentation of the X-ray observatory’s first images, the European Space Agency is launching “Stargazing”, the third
XMM-Newton competition. European youngsters, 16 to 18 years old at the end of secondary school, will be able to win observing time using the
X-ray telescope.

“We are extending the concept of backyard astronomy” says Prof. Bonnet. “Through this telescope’s ability to be operated from
the ground in a friendly way, young people will be offered a unique opportunity to learn how to operate and manage an
observatory as complex as XMM-Newton. I would be very surprised if this contest does not trigger some new vocations.”

This competition follows the “What’s new Mr Galileo” essay contest which allowed over 400 lucky winners to visit French Guiana, and the “Draw me
a telescope” competition in which young children designed the XMM launch logo.

Stargazing will allow school classes throughout Europe to make proposals for observation in conjunction with scientists working on the
XMM-Newton mission. The deadline for proposals is 12 May 2000.

As from June, two schools per country will be selected. In July-August 2000 two students from each class will be visiting the XMM-Newton Science
Operations Centre in Villafranca, Spain in order to finalise their proposals.

The best four observation proposals will be selected and will be carried out by the XMM-Newton science team at the end of the year and early 2001.
The results will be presented at the following Le Bourget Air Show in mid-June 2001.

Further information about the competition and its rules can be found at: http://sci.esa.int/xmm/competition

For more information please contact:

ESA – Communication Department

Media Relations Office

Tel: +33(0)1.53.69.7155

Fax: +33(0)1.53.69.7690

Dr. Fred Jansen, XMM Project Scientist

ESA – Estec (Noordwijk, The Netherlands)

Tel: +31 71 565 4426

Email: fjansen@astro.estec.esa.nl

Dr. Martin Turner, EPIC Principal Inverstigator

Department of Physics and Astronomy, University of Leicester