Communiqués de presse

20 décembre 2001: Through imaging at infrared wavelengths, evidence has been found for recent star formation in the so-called "Pillars of Creation" in the Eagle Nebula (also known as Messier 16), made famous when the NASA/ESA Hubble Space Telescope (HST) obtained spectacular visible-wavelength images of this object in 1995. Those huge pillars of gas and dust are being sculpted and illuminated by bright and powerful high-mass stars in the nearby NGC 6611 young stellar cluster. The Hubble astronomers suggested that perhaps even younger stars were forming inside. Using the ISAAC instrument on the VLT 8.2-metre ANTU telescope at the ESO Paranal Observatory, European astronomers have now made a wide-field infrared image of the Messier 16 region with excellent spatial resolution, enabling them to penetrate the obscuring dust and search for light from newly born stars.

14 décembre 2001: The European Southern Observatory (ESO) has been involved in many Europe-wide educational projects during the past years, in particular within European Science Weeks sponsored by the European Commission (EC). In order to further enhance the significant educational potential inherent in the numerous scientific endeavours now carried out by Europe's astronomers with ESO front-line telescope facilities, it has been decided to set up an Educational Office within the ESO EPR Department. It will from now on work closely with astronomy-oriented teachers, in particular at the high-school level , providing support, inspiration and new materials. Much of this interaction will happen via the European Association for Astronomy Education (EAAE).

5 décembre 2001: An international team of astronomers [2] has observed a Dark Matter object directly for the first time. Images and spectra of a MACHO microlens - a nearby dwarf star that gravitationally focuses light from a star in another galaxy - were taken by the NASA/ESA Hubble Space Telescope (HST) and the European Southern Observatory's Very Large Telescope (VLT). The result is a strong confirmation of the theory that a large fraction of Dark Matter exists as small, faint stars in galaxies such as our Milky Way.

5 décembre 2001: The Councils of the European Southern Observatory (ESO) and the UK Particle Physics and Astronomy Research Council (PPARC), at their respective meetings on December 3 and 5, 2001, have endorsed the terms for UK membership of ESO, as recently agreed by their Negotiating Teams. All members of the Councils - the governing bodies of the two organisations - welcomed the positive spirit in which the extensive negotiations had been conducted and expressed great satisfaction at the successful outcome of a complex process. The formal procedure of accession will now commence in the UK and is expected to be achieved in good time to allow accession from July 2002.

5 décembre 2001: A new European initiative called the Astrophysical Virtual Observatory (AVO) is being launched to provide astronomers with a breathtaking potential for new discoveries. It will enable them to seamlessly combine the data from both ground- and space-based telescopes which are making observations of the Universe across the whole range of wavelengths - from high-energy gamma rays through the ultraviolet and visible to the infrared and radio.

3 décembre 2001: A team of astronomers and engineers from French and German research institutes and ESO at the Paranal Observatory is celebrating the successful accomplishment of "First Light" for the NAOS-CONICA Adaptive Optics facility. With this event, another important milestone for the Very Large Telescope (VLT) project has been passed.

29 novembre 2001: Messier 83 (M83) is a relatively nearby spiral galaxy with a pronounced bar-like structure. It is located in the southern constellation Hydra (The Water-Snake) and is also known as NGC 5236; the distance is approximately 12 million light-years. Images of M83 obtained in visible light - like the VLT photo published exactly two years ago - show clumpy, well-defined spiral arms that are rich in young stars while the disk reveals a complex system of intricate dust lanes. This galaxy is known to be a site of vigorous star formation and no less than six supernovae (exploding stars) have been observed in M83 during the past century. It is a fairly symmetrical object and possesses no nearby companions.

28 novembre 2001: One of the most enigmatic stellar systems in our Milky Way Galaxy has been shown to harbour a very massive black hole. With 14 times more mass than the Sun [1], this is the heaviest known stellar black hole in the Galaxy. Using the ISAAC instrument on the Very Large Telescope (VLT) 8.2-metre ANTU telescope at the ESO Paranal Observatory, an international team of astronomers [2] peered into a remote area of the Milky Way to probe the binary system GRS 1915+105, located almost 40,000 light-years away. They were able to identify the low-mass star that feeds the black hole by means of a steady flow of stellar material. A detailed follow-up study revealed how this star revolves around its hungry companion. The analysis of the orbital motion then made it possible to estimate the mass of the black hole. The observation of the heavy black hole in GRS 1915+105 is opening up fundamental questions about how massive stellar black holes form, and whether or not such objects rotate around their own axes.

5 novembre 2001: It started as a preparatory technical experiment and it soon developed into a spectacular success. Those astronomers and engineers who were present in the control room that night now think of it as the scientific dawn of the Very Large Telescope Interferometer (VLTI). On October 29, 2001, ANTU and MELIPAL, two of the four VLT 8.2-metre Unit Telescopes at the ESO Paranal Observatory, were linked for the first time. Light from the southern star Achernar (Alpha Eridani) was captured by the two telescopes and sent to a common focus in the observatory's Interferometric Laboratory.

8 octobre 2001: A series of very detailed images of a binary system of two young stars have been combined into a movie. In merely 3 days, the stars swing around each other. As seen from the earth, they pass in front of each other twice during a full revolution, producing eclipses during which their combined brightness diminishes. A careful analysis of the orbital motions has now made it possible to deduce the masses of the two dancing stars. Both turn out to be about as heavy as our Sun. But while the Sun is about 4500 million years old, these two stars are still in their infancy.

8 octobre 2001: Is there life elsewhere in the Universe? Are we alone? These questions have always fascinated humanity and for more than 50 years, physicists, biologists, chemists, cosmologists, astronomers and other scientists have worked tirelessly to answer these fundamental questions. And now this November via webcast, all the world will have the opportunity to see and hear the latest news on extraterrestrial life from the most prestigious research centers and how for the past three months, European students have had the chance to jump into the scientists' shoes and explore these questions for themselves.

30 août 2001: A new instrument, SIMBA ("SEST IMaging Bolometer Array"), has been installed at the Swedish-ESO Submillimetre Telescope (SEST) at the ESO La Silla Observatory in July 2001. It records astronomical images at a wavelength of 1.2 mm and is able to quickly map large sky areas. In order to achieve the best possible sensitivity, SIMBA is cooled to only 0.3 deg above the absolute zero on the temperature scale.

23 août 2001: Ceres, the first asteroid (minor planet) to be discovered in the Solar System, has held the record as the largest known object of its kind for two centuries. However, recent observations at the European Southern Observatory with the world's first operational virtual telescope 'Astrovirtel' have determined that the newly discovered distant asteroid "2001 KX76" is significantly larger, with a diameter of 1200 km, possibly even 1400 km.

22 août 2001: Very high abundances of the heavy element Lead have been discovered in three distant stars in the Milky Way Galaxy. This finding strongly supports the long-held view that roughly half of the stable elements heavier than Iron are produced in common stars during a phase towards the end of their life when they burn their Helium - the other half results from supernova explosions. All the Lead contained in each of the three stars weighs about as much as our Moon. The observations show that these "Lead stars" - all members of binary stellar systems - have been more enriched with Lead than with any other chemical element heavier than Iron. This new result is in excellent agreement with predictions by current stellar models about the build-up of heavy elements in stellar interiors. The new observations are reported by a team of Belgian and French astronomers [1] who used the Coude Echelle Spectrometer on the ESO 3.6-metre telescope at the La Silla Observatory (Chile).

14 août 2001: Supermassive Black Holes are present at the centres of many galaxies, some weighing hundreds of millions times more than the Sun. These extremely dense objects cannot be observed directly, but violently moving gas clouds and stars in their strong gravitational fields are responsible for the emission of energetic radiation from such "active galaxy nuclei" (AGN). A heavy Black Hole feeds agressively on its surroundings. When the neighbouring gas and stars finally spiral into the Black Hole, a substantial fraction of the infalling mass is transformed into pure energy. However, it is not yet well understood how, long before this dramatic event takes place, all that material is moved from the outer regions of the galaxy towards the central region. So how is the food for the central Black Hole delivered to the table in the first place? To cast more light on this central question, a team of French and Swiss astronomers [1] has carried out a series of trailblazing observations with the VLT Infrared Spectrometer And Array Camera (ISAAC) on the VLT 8.2-metre ANTU telescope at the ESO Paranal Observatory.

1 août 2001: The solar corona is a beautiful sight during total solar eclipses. It is the uppermost region of the extended solar atmosphere and consists of a very hot (over 1 million degrees), tenuous plasma of highly ionised elements that emit strong X-ray radiation. There is also a much weaker coronal emission in the optical part of the spectrum. The Sun is a normal star and X-ray observations from rockets and orbiting X-ray telescopes have shown that many other stars also possess coronae. But due to observational limits of the telescopes available so far, the much fainter optical emission from stellar coronae had never been detected. Now, however, an optical coronal line from iron ions that have lost 12 electrons (Fe XIII) has for the first time been observed in a star other than the Sun. The object, a cool star named CN Leonis, is located at a distance of 8 light-years. This impressive observational feat was performed with the UV-Visual Echelle Spectrograph (UVES) on the VLT 8.2-metre KUEYEN telescope at the ESO Paranal Observatory, within a programme by German astronomer Jürgen Schmitt and his collaborators at the University of Hamburg Observatory.

2 juillet 2001: The Universe is indescribably huge. Can it be possible that Humanity is the only form of intelligent life which exists in all this immensity? Are we really alone? Throughout history there have been sightings of creatures from elsewhere. Science fiction novels and films with flying saucers and bizarre looking aliens are part of our general culture. Perhaps the Earth is really only an experiment designed by mice and soon we will all be destroyed to make way for a new interstellar highway! The possibility that there is life in the Universe has always excited the general public and scientists are equally enthusiastic. Physicists, biologists, chemists, cosmologists, astronomers are researching all over Europe to try to answer this age-old question: Is there life in the Universe?

28 juin 2001: Sound waves running through a star can help astronomers reveal its inner properties. This particular branch of modern astrophysics is known as "asteroseismology". In the case of our Sun, the brightest star in the sky, such waves have been observed since some time, and have greatly improved our knowledge about what is going on inside. However, because they are much fainter, it has turned out to be very difficult to detect similar waves in other stars. Nevertheless, tiny oscillations in a solar-twin star have now been unambiguously detected by Swiss astronomers François Bouchy and Fabien Carrier from the Geneva Observatory, using the CORALIE spectrometer on the Swiss 1.2-metre Leonard Euler telescope at the ESO La Silla Observatory. This telescope is mostly used for discovering exoplanets. The star Alpha Centauri A is the nearest star visible to the naked eye, at a distance of a little more than 4 light-years. The new measurements show that it pulsates with a 7-minute cycle, very similar to what is observed in the Sun.

7 juin 2001: An international team of astronomers [2] is announcing today the discovery of dusty disks surrounding numerous very faint objects that are believed to be recently formed Brown Dwarfs in the Orion Nebula [3]. This finding is based on detailed observations with SOFI, a specialised infrared-sensitive instrument at the ESO 3.5-m New Technology Telescope at the La Silla Observatory. It is of special interest because it sheds light on the origin and nature of substellar objects, known as "Brown Dwarfs". In particular, these results suggest that Brown Dwarfs share a common origin with stars and that Brown Dwarfs are more similar in nature to stars than to planets and, like stars, have the potential to form with accompanying systems of planets. Moreover, the presence of dusty protoplanetary disks around the faintest objects in the Orion Nebula cluster confirms both the membership of these faint stars in the cluster and their nature as bona-fide substellar objects, making this the largest population of Brown Dwarf objects yet known.

7 juin 2001: Impressive thermal-infrared images have been obtained of the giant planet Jupiter during tests of a new detector in the ISAAC instrument on the ESO Very Large Telescope (VLT) at the Paranal Observatory (Chile). They show in particular the full extent of the northern auroral ring and part of the southern aurora. A volcanic eruption was also imaged on Io, the very active inner Jovian moon. Although these observations are of an experimental nature, they demonstrate a great potential for regular monitoring of the Jovian magnetosphere by ground-based telescopes together with space-based facilities. They also provide the added benefit of direct comparison with the terrestrial magnetosphere.

31 mai 2001: A new image of a distant quasar (the luminous core of an "active" galaxy) shows that it is engaged in a gravitational battle with its neighbouring galaxies. It also provides information on how supermassive black holes present in the center of quasars are fed. Using the FORS2 multi-mode instrument at the ESO 8.2-metre VLT KUEYEN telescope on Paranal (Chile), a team of German astronomers [1] obtained a spectacular image of the close and complex environment of the distant quasar "HE 1013-2136", located some 10 billion light-years away [2]. The remarkable structures revealed in this photo lend support to the hypothesis that quasar activity is connected to gravitational interaction between galaxies, already at this early epoch of the Universe (about 5 billion years after the Big Bang).

21 mai 2001: Since the early 1950s, a number of powerful research infrastructures and laboratories which are used by an extensive network of scientists have been developed and deployed within Europe by European Intergovernmental Research Organisations (EIRO). Together, they represent European spearheads in some of the most crucial basic and applied research fields. Seven of these organisations have set up a co-ordination and collaboration group (EIROFORUM) with their top executives (Directors General or equivalent) as members. They include CERN (particle physics), EMBL (molecular biology), ESA (space activities), ESO (astronomy and astrophysics), ESRF (synchrotron radiation), ILL (neutron source) and EFDA (fusion).

18 mai 2001: New, trailblazing observations with the ESO Very Large Telescope (VLT) at Paranal lend strong support to current computer models of the early universe: It is "spongy", with galaxies forming along filaments, like droplets along the strands of a spiders web. A group of astronomers at ESO and in Denmark [1] determined the distances to some very faint galaxies in the neighbourhood of a distant quasar. Plotting their positions in a three-dimensional map, they found that these objects are located within a narrow "filament", exactly as predicted by the present theories for the development of the first structures in the young universe. The objects are most likely "building blocks" from which galaxies and clusters of galaxies assemble.

18 mai 2001: New images from the VLT show that one of the two nuclei of Comet LINEAR (C/2001 A2), now about 100 million km from the Earth, has just split into at least two pieces. The three fragments are now moving through space in nearly parallel orbits while they slowly drift apart. This comet will pass through its perihelion (nearest point to the Sun) on May 25, 2001, at a distance of about 116 million kilometres. It has brightened considerably due to the splitting of its "dirty snowball" nucleus and can now be seen with the unaided eye by observers in the southern hemisphere as a faint object in the southern constellation of Lepus (The Hare).

9 mai 2001: Did the star HD 82943 swallow one of its planets? What may at a first glance look like the recipe for a dramatic science-fiction story is in fact the well-considered conclusion of a serious scientific study, to be published by a group of astronomers in Switzerland and Spain [1] in tomorrow's issue of the international research journal "Nature".

25 avril 2001: Using the FORS1 multi-mode instrument at the 8.2-metre VLT ANTU telescope on Paranal during a microlensing event, the team was able to obtain detailed spectra of the different parts of the remote star. In doing so, they managed to probe its gaseous atmosphere at different depths. This is the first time that it has been possible to obtain detailed, spatially resolved spectra across the full face of a normal star other than the Sun [4].

10 avril 2001: The Osservatorio Astronomico Capodimonte Deep Field (OACDF) is a multi-colour imaging survey project that is opening a new window towards the distant universe. It is conducted with the ESO Wide Field Imager (WFI) , a 67-million pixel advanced camera attached to the MPG/ESO 2.2-metre telescope at the La Silla Observatory (Chile). As a pilot project at the Osservatorio Astronomico di Capodimonte (OAC) [1], the OACDF aims at providing a large photometric database for deep extragalactic studies, with important by-products for galactic and planetary research. Moreover, it also serves to gather experience in the proper and efficient handling of very large data sets, preparing for the arrival of the VLT Survey Telescope (VST) with the 1 x 1 degree 2 OmegaCam facility.

6 avril 2001: Representatives from Europe, Japan, and North America met in Tokyo today and signed a Resolution affirming their mutual intent to construct and operate a giant radio telescope in co-operation with the Republic of Chile, where the telescope will be located.

4 avril 2001: The intensive and exciting hunt for planets around other stars ("exoplanets") is continuing with great success in both hemispheres. Today, an international team of astronomers from the Geneva Observatory and other research institutes [1] is announcing the discovery of no less than eleven new, planetary companions to solar-type stars, HD 8574, HD 28185, HD 50554, HD 74156, HD 80606, HD 82943, HD 106252, HD 141937, HD 178911B, HD 141937, among which two new multi-planet systems. The masses of these new objects range from slightly less than to about 10 times the mass of the planet Jupiter [2]. The new detections are based on measured velocity changes of the stars [3], performed with the CORALIE spectrometer on the Swiss 1.2-metre Leonard Euler telescope at the ESO La Silla Observatory, as well as with instruments on telescopes at the Haute-Provence Observatory and on the Keck telescopes on Mauna Kea (Hawaii, USA).

30 mars 2001: A new astronomical instrument, TIMMI2, has just been installed on the ESO 3.6-metre telescope at La Silla. The first images have just been obtained and hold great promise for future research programmes with this facility. The Thermal Infrared MultiMode Instrument was built in a collaboration between ESO and a consortium headed by the Jena University Observatory (Germany). It detects infrared radiation in the 5-24 µm mid-IR spectral region. It is particularly well suited for observations of the complex processes that take place in the innermost regions of star-forming clouds. It is also a forerunner of a similar, but even more powerful instrument to be installed at the 8.2-metre VLT telescopes on Paranal during the next years. Among the first images are some of the most penetrating, mid-infrared views ever obtained of the central region of the Orion Nebula.

23 mars 2001: For hundreds of years, probably even longer, astronomers have sought the solitude, far from the disturbing influence of other human activities. Not without reason, their remote observatories have sometimes been likened with monasteries, sacred sites where man is closer to the skies and himself.

18 mars 2001: Following the "First Light" for the fourth of the 8.2-metre telescopes of the VLT Observatory on Paranal in September 2000, ESO scientists and engineers have just successfully accomplished the next major step of this large project.

13 mars 2001: Important scientific advances often happen when complementary investigational techniques are brought together. In the present case, X-ray and optical/infrared observations with some of the world's foremost telescopes have provided the crucial information needed to solve a 40-year old cosmological riddle.

8 mars 2001: The nearby galaxy Centaurus A harbours a supermassive black hole at its centre. Using the ISAAC instrument at the ESO Very Large Telescope (VLT), an international team of astronomers [1] has peered right through the spectacular dust lane of the peculiar galaxy Centaurus A, located approximately 11 million light-years away. They were able to probe the thin disk of gas that surrounds the very center of this galaxy. The new measurements show that the compact nucleus in the middle weighs more than 200 million solar masses! This is too much just to be due to normal stars. The astronomers thus conclude the existence of a supermassive black hole lurking at the centre of Centaurus A.

6 mars 2001: ESO has released a new image of the famous comet Hale-Bopp, where the large nucleus of ice and dust is still seen glowing. This is very unusual since the comet is currently in a very cold place, between the orbits of Saturn and Uranus, almost 2000 million kilometres away from the Sun.

2 mars 2001: Globular clusters are very massive assemblies of stars. More than 100 are known in the Milky Way galaxy and most of them harbour several million stars. They are very dense - at their centers, the typical distance between individual stars is comparable to the size of the Solar System, or 100 to 1000 times closer than the corresponding distances between stars in the solar neighborhood. Globular clusters are among the oldest objects known , with estimated ages of 11 to 15 billion years [1]. All stars in a globular cluster were formed at nearly the same moment, and from the same parent cloud of gas and dust. The original chemical composition of all stars is therefore the same. But now, an international group of astronomers [2], working with the UVES Spectrograph at the ESO Very Large Telescope (VLT), have obtained some unexpected results during a detailed analysis of dwarf stars in some globular clusters . Such stars have about the same mass as our Sun and like it, they evolve very slowly. Thus they still ought to have about the same abundances of most chemical elements.

7 février 2001: Most astronomers would agree that the age of the Universe - the time elapsed since the "Big Bang" - is one of the "holy grails of cosmology". Despite great efforts during recent years, the various estimates of this basic number have resulted in rather diverse values. When derived from current cosmological models, it depends on a number of theoretical assumptions that are not very well constrained by the incomplete available observational data. At present, a value in the range of 10-16 billion years [1] is considered most likely. But now, an international team of astronomers [2] has used the powerful ESO Very Large Telescope (VLT) and its very efficient spectrograph UVES to perform a unique measurement that paves the way for a new and more accurate determination of the age of the Universe. They measured for the first time the amount of the radioactive isotope Uranium-238 in a star that was born when the Milky Way, the galaxy in which we live, was still forming. It is the first measurement ever of uranium outside the Solar System.

26 janvier 2001: Last year saw very good progress at ESO's Paranal Observatory, the site of the Very Large Telescope (VLT). The third and fourth 8.2-metre Unit Telescopes, MELIPAL and YEPUN had "First Light," while the first two, ANTU and KUEYEN, were busy collecting first-class data for hundreds of astronomers. Meanwhile, work continued towards the next phase of the VLT project, the combination of the telescopes into the VLT Interferometer. The test instrument, VINCI is now being installed in the VLTI Laboratory at the centre of the observing platform on the top of Paranal.

17 janvier 2001: Orion the Hunter is perhaps the best known constellation in the sky, well placed in the evening at this time of the year for observers in both the northern and southern hemispheres, and instantly recognisable. And for astronomers, Orion is surely one of the most important constellations, as it contains one of the nearest and most active stellar nurseries in the Milky Way, the galaxy in which we live.

11 janvier 2001: This Video Clip is issued on the web in conjunction with the release of an 18-min documentary video from the Science Festival of the "Physics On Stage" programme. This unique event took place during November 6-11, 2000, on the CERN premises at the French-Swiss border near Geneva, and formed part of the European Science and Technology Week 2000, an initiative by the European Commission to raise the public awareness of science in Europe.

10 janvier 2001: How do stars like our Sun come into being? Which fundamental processes are responsible for transforming a dark and diffuse interstellar cloud of gas and dust into a much denser, shining object? Astronomers have just taken an important step towards answering this fundamental question. Based on the most detailed study ever made of the internal structure of a small interstellar cloud, three scientists from ESO and the USA [1] have found that it is apparently on the verge of becoming unstable - and thus in the stage immediately preceding a dramatic collapse into a dense and hot, low-mass star.

4 janvier 2001: At the beginning of the new millennium, ESO and its staff are facing the future with confidence. The four 8.2-metre Unit Telescopes of the Very Large Telescope (VLT) are in great shape and the VLT Interferometer (VLTI) will soon have "first fringes". The intercontinental ALMA project is progressing well and concepts for extremely large optical/infrared telescopes are being studied.

22 décembre 2000: Merry Christmas and a Happy New Year!

20 décembre 2000: Some years ago, the Paranal mountain was still a remote and inhospitable site, some 12 km from the Pacific Coast in the dry Atacama desert in northern Chile. Few aircraft passengers flying along that coast would notice anything particular about this peak, except perhaps that it was one of the tallest in the steep coastal mountain range. Already in the early 1960's, pioneer astronomers crossed this desolate region in search of suitable sites for future observatories. One of them, Jürgen Stock, did notice the Paranal peak as a possible candidate. However, without any water in this extremely dry area, how could any people, even hardy scientists, ever live up there? He then went on to discover La Silla, where ESO decided to build its first observatory in 1964.

20 décembre 2000: A fundamental prediction of the Big Bang theory has finally been verified. For the first time, an actual measurement has been made of the temperature of the cosmic microwave background radiation, at a time when the Universe was only about 2.5 billion years old. This fundamental and very difficult observation was achieved by a team of astronomers from India, France and ESO [1]. They obtained a detailed spectrum of a quasar in the distant Universe, using the UV-Visual Echelle Spectrograph (UVES) instrument at the ESO 8.2-m VLT KUEYEN telescope at the Paranal Observatory.

13 décembre 2000: Due to a happy coincidence, the ESO/ST-ECF Science Archive Facility is celebrating three different milestones at the same time: 1) its 10th anniversary since the establishment in 1991, 2) the 10,000th request for data, and 3) the signing-up of active user number 2000. This Archive contains over 8 Terabytes (1 Terabyte = 1 million million bytes) of valuable observational data from the NASA/ESA Hubble Space Telescope (HST), the ESO Very Large Telescope (VLT) and other ESO telescopes. Its success paves the way for the establishment of "Virtual Observatories" from which first-class data can be obtained by astronomers all over the world. This greatly enhances the opportunities for more (young) scientists to participate in front-line research.

8 décembre 2000: The most massive spiral galaxy known so far in the Universe has been discovered by a team of astronomers from Garching, Padova, Leiden, ESO and London [1]. They base their conclusion on recent observations with ISAAC, an infrared-sensitive, multi-mode instrument on ESO's Very Large Telescope at the Paranal Observatory. This galaxy has been designated ISOHDFS 27 and is located at a distance of approx. 6 billion light-years (the redshift is 0.58). Its measured mass is more than 1000 billion times that of the Sun [2]. It is thus about four times more massive than our own galaxy, the Milky Way, and twice as heavy as the heaviest spiral galaxy known so far.

1 décembre 2000: An international team of astronomers [1] has succeeded in mapping the "dark" (invisible) matter in the Universe, as seen in 50 different directions from the Earth. They find that, within the uncertainty, it is unlikely that mass alone would stop the current expansion of the Universe. This fundamental result is based on the powerful, but challenging method of "cosmic shear". It depends on very accurate measurements of the apparent, weak distortion and preferential orientation of images of distant galaxies. This effect is caused by deflection of the light from those galaxies by the large mass concentrations in the Universe it encounters on its way to us. The larger these masses are, the larger are the apparent image distortions and the more pronounced are the alignments of neigbouring galaxy images. The new analysis was made possible by means of unique observational data, obtained under excellent conditions with the the ESO 8.2-m VLT ANTU telescope and the multi-mode FORS1 instrument at the Paranal Observatory.

22 novembre 2000: The Particle Physics and Astronomy Research Council (PPARC), the UK's strategic science investment agency, today announced that the government of the United Kingdom is making funds available that provide a baseline for this country to join the European Southern Observatory (ESO).

13 novembre 2000: A few months from now, light from celestial objects will be directed for the first time towards ESO's Very Large Telescope Interferometer (VLTI) at the Paranal Observatory (Chile). During this "First Light" event and the subsequent test phase, the light will be recorded with a special test instrument, VINCI (VLT INterferometer Commissioning Instrument). The main components of this high-tech instrument are aptly named MONA (a system that combines the light beams from several telescopes by means of optical fibers) and LISA (the infrared camera). VINCI was designed and constructed within a fruitful collaboration between ESO and several research institutes and industrial companies in France and Germany. It is now being assembled at the ESO Headquarters in Garching (Germany) and will soon be ready for installation at the telescope on Paranal. With the VLTI and VINCI, Europe's astronomers are now entering the first, crucial phase of an exciting scientific and technology venture that will ultimately put the world's most powerful optical/IR interferometric facility in their hands.

27 octobre 2000: A remarkable, wide-field infrared image allows to see in unprecedented detail the inner regions of RCW 108, a large complex of stars and nebulae in the southern Milky Way. It is one of the widest, "deepest" and most spectacular infrared astronomical images ever obtained of a starforming region. It is based on approx. 600 individual exposures with the SOFI multi-mode instrument on the ESO 3.58-metre New Technology Telescope (NTT) at the ESO La Silla Observatory (Chile).

26 octobre 2000: Four new moons have been discovered orbiting Saturn, raising the number to twenty-two. This means that Saturn is now the planet in the Solar System with most known satellites. The previous record holder, Uranus, has twenty-one known satellites. Two of the new objects were first seen with the Wide-Field Imager (WFI) camera at the ESO La Silla Observatory (Chile). They have diameters of 10 to 50 km, and calculations have shown that they are almost certainly small satellites (moons) that accompany Saturn on irregular orbits.

18 octobre 2000: Can you imagine how much physics is in a simple match of ping-pong, in throwing a boomerang, or in a musical concert? Physics is all around us and governs our lives. The World-Wide Web and mobile communication are only two examples of technologies that have rapidly found their way from science into the everyday life. But who is going to maintain these technologies and develop new ones in the future? Probably not young Europeans, as recent surveys show a frightening decline of interest in physics and technology among Europe's citizens, especially schoolchildren. Fewer and fewer young people enrol in physics courses at university. The project "Physics on Stage" tackles this problem head on.

17 octobre 2000: Observations with telescopes at the ESO La Silla and Paranal observatories (Chile) have enabled an international team of astronomers [1] to measure the distance of a "gamma-ray burst", an extremely violent, cosmic explosion of still unknown physical origin. It turns out to be the most remote gamma-ray burst ever observed. The exceedingly powerful flash of light from this event was emitted when the Universe was very young, less than about 1,500 million years old, or only 10% of its present age. Travelling with the speed of light (300,000 km/sec) during 11,000 million years or more, the signal finally reached the Earth on January 31, 2000. The brightness of the exploding object was enormous, at least 1,000,000,000,000 times that of our Sun, or thousands of times that of the explosion of a single, heavy star (a "supernova"). The ESO Very Large Telescope (VLT) was also involved in trail-blazing observations of another gamma-ray burst in May 1999, c.f. ESO PR 08/99.

13 octobre 2000: The following Press Release, now retracted, is kept on the web for information and historical reference.

11 octobre 2000: Less than one month after "First Light" for the fourth 8.2-m YEPUN telescope (ESO PR 18/00), another special moment occurred at ESO's Paranal Observatory. This time, it was the first truly "underground" event, in the 168-metre long Interferometric Tunnel that has been dug beneath the platform at the top of the mountain. As one staff member remarked on this occasion, it was something like "the first scheduled trip of the Paranal metro"!

6 octobre 2000: The R Coronae Australis complex of young stars and interstellar gas clouds is one of the nearest star-forming regions, at a distance of approx. 500 light-years from the Sun. It is seen in the southern constellation of that name (The "Southern Crown"). Images of this sky area were recently obtained with the Wide Field Imager (WFI), a 67-million pixel digital camera that is installed at the 2.2-metre MPG/ESO Telescope at ESO's La Silla Observatory.

14 septembre 2000: Beautiful images of astronomical objects often contain a lot of scientifically interesting information - PR Photo 24a/00, shown above, is a fine example of this old maxime. It provides a deep and unsually wide look into a giant star forming region in the Milky Way. It is known as Messier 17 (M 17), or the Omega, Swan, Horseshoe, or Lobster Nebula, because of its characteristic shape when photographed in visible light. It is located at a distance of approx. 5000 light-years (1.6 kpc), and is seen in the southern constellation of Sagittarius (The Archer), near the main plane of the Milky Way.

11 septembre 2000: Deep inside the Milky Way, an old and lonely neutron star plows its way through interstellar space. Known as RX J1856.5-3754, it measures only ~ 20 km across. Although it is unusually hot for its age, about 700,000 °C, earlier observations did not reveal any activity at all, contrary to all other neutron stars known so far. In order to better understand this extreme type of object, a detailed study of RX J1856.5-3754 was undertaken by Marten van Kerkwijk (Institute of Astronomy of the University of Utrecht, The Netherlands) and Shri Kulkarni (California Institute of Technology, Pasadena, California, USA). To the astronomers' delight and surprise, images and spectra obtained with the ESO Very Large Telescope (VLT) now show a small nearby cone-shaped ("bowshock") nebula. It shines in the light from hydrogen atoms and is obviously a product of some kind of interaction with this strange star.

4 septembre 2000: It was a historical moment last night (September 3 - 4, 2000) in the VLT Control Room at the Paranal Observatory , after nearly 15 years of hard work. Finally, four teams of astronomers and engineers were sitting at the terminals - and each team with access to an 8.2-m telescope! From now on, the powerful "Paranal Quartet" will be observing night after night, with a combined mirror surface of more than 210 m 2. And beginning next year, some of them will be linked to form part of the unique VLT Interferometer with unparalleled sensitivity and image sharpness.

28 août 2000: These days, the ESO staff at Paranal is having a strong feeling of "déja-vu". Only seven months after the third 8.2-metre VLT Unit Telescope, MELIPAL, achieved "First Light", this crucial moment is now rapidly approaching for YEPUN , the fourth and last of the giants at the ESO observatory.

8 août 2000: In a textbook example of useful collaboration between ground- and space-based astronomical telescopes, the ESO Very Large Telescope has imaged the "shower" of "mini-comets" in Comet LINEAR, first seen by the Hubble Space Telescope (HST) a few days ago [1].

4 août 2000: Two astronomers, both specialists in minor bodies in the solar system, have performed observations with ESO telescopes that provide important information about a small moon, recently discovered in orbit around the solar system's largest planet, Jupiter. Brett Gladman (of the Centre National de la Recherche Scientifique (CNRS) and working at Observatoire de la Cote d'Azur, France) and Hermann Boehnhardt (ESO-Paranal) obtained detailed data on the object S/1999 J 1, definitively confirming it as a natural satellite of Jupiter. Seventeen Jovian moons are now known.

28 juillet 2000: About 70 million years ago, when dinosaurs were still walking on the Earth, a series of violent thermo-nuclear explosions took place in a distant galaxy. After a very long travel across vast reaches of virtually empty space (70 million light-years, or ~ 7 x 10 20 km), dim light carrying the message about these events has finally reached us. It was recorded by the ESO Very Large Telescope (VLT) at the Paranal Observatory (Chile) during an observing programme by a group of Italian astronomers [1]. The subsequent analysis has shown that the observers witnessed the most distant nova outbursts ever seen. They were caused by "stellar cannibalism" in binary systems in which one relatively cool star loses matter to its smaller and hotter companion. An instability results that leads to the ignition of a "hydrogen bomb" on the surface of the receiving star.

21 juillet 2000: Astronomers are eager to better understand the formation of stars and planets - with an eye on the complex processes that lead to the emergence of our own solar system some 4600 million years ago. Brown Dwarfs (BDs) play a special role in this context. Within the cosmic zoo, they represent a class of "intermediate" objects. While they are smaller than normal stars, they shine by their own energy for a limited time, in contrast to planets. Recent observations with the ESO Very Large Telescope (VLT) of a "young" Brown Dwarf in a multiple stellar system are taking on a particular importance in this connection. An evaluation of the new data by an international team of astronomers [1] shows that it is by far the youngest of only four such objects found in a stellar system so far. The results are now providing new insights into the stellar formation process.

27 juin 2000: The Republic of Portugal will become the ninth member state of the European Southern Observatory (ESO) [1]. Today, during a ceremony at the ESO Headquarters in Garching (Germany), a corresponding Agreement was signed by the Portuguese Minister of Science and Technology, José Mariano Gago and the ESO Director General, Catherine Cesarsky, in the presence of other high officials from Portugal and the ESO member states (see the video eso0022a in this release). Following subsequent ratification by the Portuguese Parliament of the ESO Convention and the associated protocols [2], it is foreseen that Portugal will formally join this organisation on January 1, 2001.

16 juin 2000: The main construction phase at the ESO Paranal Observatory is now over and normal operations have begun with two of the four 8.2-metre Unit Telescopes, ANTU and KUEYEN. The next major event will be the installation of the first astronomical instrument, VIMOS (VIsible MultiObject Spectrograph), at the third telescope, MELIPAL. "First Light" for the fourth telescope, YEPUN will follow later this year. The present collection of 29 photos illustrates the current state of the VLT site. They have been divided by theme into five sections that may be accessed by clicking on the corresponding images above.

24 mai 2000: European science and technology will gain further strength when the new, front-line Nova-ESO VLTI Expertise Centre (NEVEC) opens in Leiden (The Netherlands) this week. It is a joint venture of the Netherlands Research School for Astronomy (NOVA) (itself a collaboration between the Universities of Amsterdam, Groningen, Leiden, and Utrecht) and the European Southern Observatory (ESO). It is concerned with the Very Large Telescope Interferometer (VLTI).

3 mai 2000: Dwarf galaxies may not be as impressive in appearance as their larger brethren, but they are at least as interesting from a scientific point of view. And sometimes they may have hidden properties that will only be found by means of careful observations, probing the signals of their stars at the faintest level. Such as the entirely unexpected, well developed spiral structure within an otherwise seemingly normal dwarf elliptical galaxy! This is the surprise result of a new study by a team of astronomers [1], headed by Helmut Jerjen from the Australian National University (Canberra) who obtained detailed observations with the ESO Very Large Telescope (VLT) of the dwarf galaxy IC 3328 in the Virgo Cluster of Galaxies, some 50 million light-years away.

2 mai 2000: This Video Clip is issued on the web in conjunction with the "Physics On Stage" programme that is part of the European Week for Science and Technology and will culminate in a Science Festival during November 6-11, 2000, on the CERN premises at the French-Swiss border near Geneva.

15 avril 2000: The intensive and exciting hunt for planets around other stars ("exoplanets") is continuing with great success in both hemispheres. Today, a team of astronomers of the Geneva Observatory [1] are announcing the discovery of no less than eight new, very-low mass companions to solar-type stars. The masses of these objects range from less than that of planet Saturn to about 15 times that of Jupiter.

13 avril 2000: A special Workshop "Portugal - ESO - VLT" will be held at the Lisbon University Museum of Science on April 17-18, 2000. It is primarily directed towards young Portuguese scientists and will inform them about the ESO Very Large Telescope (VLT) and the many exciting research possibilities with this new facility. The Workshop is accompanied by a public exhibition about ESO and its telescopes , as well as a Press Conference on April 17 with participation of the Portuguese Minister of Science and Technology and the ESO Director General. A public lecture will be given about ESO and the VLT on April 18.

13 avril 2000: Starting in the evening of April 1, 2000, Ghislain Golse and Francisco Castander from the Observatoire Midi-Pyrénées (Toulouse, France) [1] were the first "visiting astronomers" at Paranal to carry out science observations with the second 8.2-metre VLT Unit Telescope, KUEYEN. Using the FORS2 multi-mode instrument as a spectrograph, they measured the distances to a number of very remote galaxies, located far out in space behind two clusters of galaxies. Such observations may help to determine the values of cosmological parameters that define the geometry and fate of the Universe.

10 avril 2000: Astronomical data archives increasingly resemble virtual gold mines of information. A new project, known as ASTROVIRTEL aims to exploit these astronomical treasure troves by allowing scientists to use the archives as virtual telescopes.

6 avril 2000: Astronomers working with a major new instrument at the ESO Very Large Telescope (VLT) at the Paranal Observatory have had a first taste of what is bound to become a research bonanza. Recent test observations with the Ultraviolet-Visual Echelle Spectrograph (UVES) have demonstrated the exceptional science potential of this powerful facility.

16 mars 2000: Which are the latest astronomical discoveries made with the new 8-10 metre class astronomical telescopes? Will it be possible to construct even more powerful instruments on the ground and in space to explore the near and distant Universe at all wavelengths from gamma-rays to radio waves? Which research areas in this dynamical science are likely to achieve break-throughs with emerging new technologies?

14 mars 2000: The European and U.S. partners in the Atacama Large Millimeter Array (ALMA) project have awarded contracts to firms in Italy and the USA, respectively, for two prototype antennas. [1] ALMA is a planned telescope array, expected to consist of 64 millimeter-wave antennas with 12-meter diameter dishes. The array will be built at a high-altitude, extremely dry mountain site in Chile's Atacama desert, and is scheduled to be completed sometime in this decade.

14 mars 2000: Recent observations by an international team of astronomers [1] with the 15-metre Swedish-ESO Submillimetre Telescope at the La Silla observatory (Chile) have shown that the unusual, nearby galaxy Centaurus A is surrounded by shells in which carbon monoxide molecules are present. These new exciting results are the first of their kind. In addition to the intrinsic scientific value of this discovery, it also provides an instructive example of what will become possible for more distant galaxies with the projected Atacama Large Millimeter Array (ALMA), now in the planning phase.

1 mars 2000: Physics is everywhere . The laws of physics govern the Universe, the Sun, the Earth and even our own lives. In today's rapidly developing society, we are becoming increasingly dependent on high technology – computers, transport, and communication are just some of the key areas that are the result of discoveries by scientists working in physics. But how much do the citizens of Europe really know about physics? Here is a unique opportunity to learn more about this elusive subject!

23 février 2000: The Executive Board of the UK Visible and Infrared Survey Telescope (VISTA) project announced today [1] that it is aiming at the installation of a new and powerful astronomical telescope at the ESO Paranal Observatory (Chile).

23 février 2000: In addition to their scientific value, many of the exposures now being obtained by visiting astronomers to ESO's Very Large Telescope (VLT) are also very beautiful. This is certainly true for this new image of the famous early-type spiral galaxy Messier 104, widely known as the "Sombrero" (the Mexican hat) because of its particular shape.

17 février 2000: Working with the ESO Very Large Telescope (VLT) at the Paranal Observatory, a group of European astronomers [1] has just obtained one of the deepest looks into the distant Universe ever made by an optical telescope. These observations were carried out in the near-infrared spectral region and are part of an attempt to locate very distant galaxies that have so far escaped detection in the visual bands. The first results are very promising and some concentrations of galaxies at very large distances were uncovered.

8 février 2000: The commissioning of the FORS2 multi-mode astronomical instrument at KUEYEN , the second FOcal Reducer/low dispersion Spectrograph at the ESO Very Large Telescope, was successfully finished today. This important work – that may be likened with the test driving of a new car model – took place during two periods, from October 22 to November 21, 1999, and January 22 to February 8, 2000.

28 janvier 2000: This was a night to remember at the ESO Paranal Observatory! For the first time, three 8.2-metre Very Large Telescopes (VLTs) were observing in parallel, with a combined mirror surface of nearly 160 metres squared. In the evening of January 26, the third 8.2-metre Unit Telescope, MELIPAL ("The Southern Cross" in the Mapuche language), was pointed to the sky for the first time and successfully achieved "First Light". During this night, a number of astronomical exposures were made that served to evaluate provisionally the performance of the new telescope. The ESO staff expressed great satisfaction with MELIPAL and there were broad smiles all over the mountain.

21 janvier 2000: Happy expectations are again growing at ESO's Paranal Observatory. For the third time in less than two years, the special moment of "First Light" for an 8.2-metre VLT Unit Telescope is getting close -- now is the turn of MELIPAL.

12 janvier 2000: After the first two Unit Telescopes of ESO's Very Large Telescope started their operation in 1999, the year 2000 will witness the "first light" of the other two telescopes, starting with MELIPAL.

5 janvier 2000: Many different activities took place at ESO during the past year. They range from technological and scientific feats to official and astronomical events at the ESO sites in Europe and Chile.

21 décembre 1999: A main scientific application of wide-angle imaging in astronomy is the census and photometric and morphological classification (i.e. by colour and shape) of large quantities of celestial objects in order to identify sources of particular interest that warrant in-depth follow-up observations. This is normally done by means of spectroscopy, a basic observing technique that allows much more comprehensive physical diagnostics than does an image. However, detailed spectral observations requires the great light-collecting power of large telescopes such as the Very Large Telescope (VLT). In the past, many important classes of astronomical objects have been discovered by such survey work. Another central goal of wide-field imaging is the identification and characterisation of structures that extend over large sky areas, e.g., of the Milky Way in which we live, of comparatively nearby galaxies, and even of the Universe as a whole. The structure of astronomical objects reveals much about their history of formation which, because of the inherently very long ("astronomical") timescales, cannot be directly observed.

16 décembre 1999: Recent observations with the FORS1 instrument at the first 8.2-m VLT Unit Telescope (ANTU) by an international group of astronomers [1] have resulted in crucial new information about some small and faint stars within an old star cluster in the Milky Way.

14 décembre 1999: On December 14, 1999, REOSC , the Optical Department of the SAGEM Group , finished the polishing of the fourth 8.2-m main mirror for the Very Large Telescope (VLT) of the European Southern Observatory. The mirror was today delivered to ESO at a ceremony at the REOSC factory in Saint Pierre du Perray, just south of Paris.

8 décembre 1999: A series of photographs from the Paranal Observatory was obtained with large-format cameras in mid-November 1999 by the ESO EPR Team.

3 décembre 1999: In the course of the current installation of ESO's Very Large Telescope (VLT) , a delicate operation has just been successfully achieved at the Paranal Observatory. The coated 8.2-m Zerodur main mirror for the third VLT 8.2-m Unit Telescope, MELIPAL , is now in place!

29 novembre 1999: "First Light" was achieved in May 1998 for VLT ANTU, the first 8.2-m Unit Telescope at the Paranal Observatory. Since then, thousands of detailed images and spectra of a great variety of celestial objects have been recorded with this major new research facility. While some of these were obtained for scientific programmes and were therefore directed towards specific research needs, others were made during the "Commissioning Phases" in 1998/99 for the two major astronomical instruments, FORS1 (FOcal Reducer and Spectrograph) and ISAAC (Infrared Spectrometer And Array Camera). They were carried out in order to test thoroughly the performance of the telescope and its instruments before the new facility was handed over to the astronomers on April 1, 1999. The Commissioning data are accordingly of variable quality and, contrarily to the science data, normally not intensity calibrated. However, while some of these frames are short test exposures that mainly served to ascertain the image quality under various observing conditions, a substantial fraction still contains scientifically valuable data.

17 novembre 1999: The first, major astronomical instrument to be installed at the ESO Very Large Telescope (VLT) was FORS1 ( FO cal R educer and S pectrograph) in September 1998. Immediately after being attached to the Cassegrain focus of the first 8.2-m Unit Telescope, ANTU , it produced a series of spectacular images, cf. ESO PR 14/98. Many important observations have since been made with this outstanding facility. Now FORS2, its powerful twin, has been installed at the second VLT Unit Telescope, KUEYEN. It is the fourth major instrument at the VLT after FORS1 , ISAAC and UVES. The FORS2 Commissioning Team that is busy installing and testing this large and complex instrument reports that "First Light" was successfully achieved already on October 29, 1999, only two days after FORS2 was first mounted at the Cassegrain focus. Since then, various observation modes have been carefully tested, including normal and high-resolution imaging, echelle and multi-object spectroscopy, as well as fast photometry with millisecond time resolution. A number of fine images were obtained during this work, some of which are made available with the present Press Release.

26 octobre 1999: The La Silla Observatory is located in the Chilean Atacama Desert, one of the driest and loneliest areas of the world. The land around this isolated peak was acquired in 1964 and following some years of construction work, the inauguration of ESO's first observatory took place just over 30 years ago, in March 1969. The solitude of this remote desert site is well illustrated by the above panorama, obtained in 1996.

13 octobre 1999: An international group of astronomers [1] has used the ESO Very Large Telescope (VLT) at Paranal (Chile) to perform unique observations of an interstellar nebula in which stars are currently being born.

7 octobre 1999: The clip contains a full-scale computer animation of the Atacama Large Millimeter Array (ALMA) at the future site of this large astronomical facility.

5 octobre 1999: A major new astronomical instrument for the ESO Very Large Telescope at Paranal (Chile), the UVES high-resolution spectrograph, has just made its first observations of astronomical objects. The astronomers are delighted with the quality of the spectra obtained at this moment of "First Light". Although much fine-tuning still has to be done, this early success promises well for new and exciting science projects with this large European research facility.

17 septembre 1999: Work is progressing well at ESO's Very Large Telescope (VLT) project, both at the Paranal Observatory and in Europe. Here is a brief summary with recent news from this major project, illustrated with photos from the construction.

18 août 1999: A team of European astronomers [1] has found a cold and extremely faint object in interstellar space, high above the galactic plane. It is a Methane Brown Dwarf of which only a few are known. This is by far the most distant one identified to date.