Persberichten 1999

2 juli 1999: Astronomers at ESO have recently been "Seeing the Light Through the Dark!" Some months ago, the ESO Very Large Telescope (VLT) observed a classical dark globule, Barnard 68 (B68) , in front of a dense star field in the Milky Way band. CCD images were obtained in various visual wavebands with the FORS1 multi-mode instrument at the 8.2-m VLT ANTU (UT1). They were combined into a colour photo.

29 juni 1999: One of the most famous comets is Hale-Bopp that passed near the Earth just over two years ago. It now moves out through the solar system, getting fainter with increasing distance. The estimated magnitude is now about 12.5 (visual), i.e. about 400 times fainter than what can be perceived with the unaided eye.

29 juni 1999: The launch in early 2003 of the Rosetta spacecraft of the European Space Agency (ESA), the 3rd "Cornerstone" mission of this organisation, will mark the beginning of an exciting scientific endeavour. Following two close passages by the Earth and another by Mars to gain speed, the complex 1.3-tonnes spacecraft will continue towards a rendez-vous with the icy nucleus of Comet Wirtanen [2], passing two asteroids on the way. Beginning in late 2011, at a time when the comet is close to its aphelion - the most distant point in its elongated orbit, about 770 million km from the Sun - the Rosetta "orbiter" will literally chase Comet Wirtanen for two years, sending back valuable data about the nucleus and its immediate environment. A "lander" will attach itself to this lump of frozen ice and dust, which is travelling through space at over 46,000 kilometres per hour, and analyse samples. A joint team from ESO and ESA's Space Science Department has proposed a short series of ground-based exploratory observations in support of this European space mission. Responding to the challenge, the second 8.2-m VLT telescope (KUEYEN), while undergoing commissioning at Paranal, has just performed a remarkable feat by observing the nucleus of Comet Wirtanen, now near its aphelion, i.e. at the location of the future Rosetta encounter. This is equivalent to viewing a pitch-black golfball, over 20,000 kilometres away!

22 juni 1999: The Wide Field Imager (WFI) , a 67-million pixel digital camera at the MPG/ESO 2.2-m telescope at the La Silla Observatory continues to produce remarkable images for astronomical research. At the same time, many of these are of great aesthetic value and provide impressive views into sky regions with unsual objects. Earlier this year, the WFI recorded a number of fields in the direction of the Large Magellanic Cloud (LMC), a satellite galaxy to our own Milky Way Galaxy, deep down in the southern sky. It is located at a distance of about 170,000 light-years and contains many nebulae and stellar clusters.Two colour composite photos of "H II regions" in the LMC are shown here, centred near N44 and N119 [1]. They are nebulae in which (some of) the gas is ionized, i.e. the atoms have lost one or more electrons by the action of energetic ultraviolet radiation emitted by very hot and luminous stars in this area. Both of these nebulae are seen in front of rich star fields in this galaxy in which there are also several stellar clusters.

21 juni 1999: The site at Cerro Paranal in the dry Atacama desert in Northern Chile is one of the best locations for astronomical observations from the surface of the Earth. Each of the four 8.2-m telescopes is a technological marvel with self-adjusting optics placed in a gigantic mechanical structure of the utmost precision, continuously controlled by advanced soft- and hardware. A multitude of extremely complex instruments with sensitive detectors capture the faint light from distant objects in the Universe and record the digital data fast and efficiently as images and spectra, with a minimum of induced noise. And now the next crucial link in this chain is in place. A few nights ago, following an extended test period, the VLT Data Flow System began providing the astronomers with a steady stream of high-quality, calibrated image and spectral data, ready to be interpreted. The VLT project has entered into a new phase with a larger degree of automation. Indeed, the first 8.2-m Unit Telescope, ANTU, with the FORS1 and ISAAC instruments, has now become a true astronomy machine.

10 juni 1999: Representatives from the U.S. and Europe signed an agreement today in Washington to continue collaboration on the first phase of a giant new telescope project. The telescope will image the Universe with unprecedented sensitivity and sharpness at millimeter wavelengths (between the radio and infrared spectral regions). It will be a major step for astronomy, making it possible to study the origins of galaxies, stars and planets. A Joint Press Release by the US National Science Foundation (NSF) and the European Southern Observatory (ESO)

10 juni 1999: The Atacama Large Millimeter Array (ALMA) is the new name [2] for a giant millimeter-wavelength telescope project. As described in the accompanying joint press release by ESO and the U.S. National Science Foundation , the present design and development phase is now a Europe-U.S. collaboration, and may soon include Japan. ALMA may become the largest ground-based astronomy project of the next decade after VLT/VLTI, and one of the major new facilities for world astronomy. ALMA will make it possible to study the origins of galaxies, stars and planets.

27 mei 1999: An important event took place at the ESO Paranal Observatory last week. Following intense work over several months, the big pieces of the mechanical structure of the fourth 8.2-m VLT Unit Telescope have been assembled! On May 19, at 10:00 in the morning, the VLT UT4 (YEPUN) top ring with the spider that carries the M2 Unit on which the 1.1-m secondary mirror will later be placed, was installed on the top of the telescope. This is the last big mechanical piece of the last UT telescope on Paranal. Two photos (PR 23a/99 and 23b/99) illustrate this. There are now two operating 8.2-m telescopes (ANTU/UT1 and KUEYEN/UT2) and two telescope structures (MELIPAL/UT3 and YEPUN/UT4). The latter telescopes will see First Light within the next year. The large 300 tonnes crane with which the heavy telescope pieces were lifted into place and which has dominated the skyline of the Paranal mountaintop for nearly 3 years, will now be dismantled and shipped elsewhere.

18 mei 1999: International teams of astronomers are now busy working on new and exciting data obtained during the last week with telescopes at the European Southern Observatory (ESO). Their object of study is the remnant of a mysterious cosmic explosion far out in space, first detected as a gigantic outburst of gamma rays on May 10. Gamma-Ray Bursters (GRBs) are brief flashes of very energetic radiation - they represent by far the most powerful type of explosion known in the Universe and their afterglow in optical light can be 10 million times brighter than the brightest supernovae [1]. The May 10 event ranks among the brightest one hundred of the over 2500 GRB's detected in the last decade.

30 april 1999: The new Wide-Field Imager (WFI) at the MPG/ESO 2.2-m telescope at the La Silla observatory continues to obtain impressive images of the southern sky. Recently, a series of images were obtained of areas in the Milky Way band, including some in which interstellar nebulae of gas and dust are seen. Each frame records 8184 x 8196, or over 67 million, pixels in a sky field of 32 x 32 arcmin 2. The present photos show the RCW 108 complex of bright and dark nebulae in the southern association Ara OB1, a star-forming region in the constellation Ara (The Altar), deep in the southern sky.

30 april 1999: During the continued tests of the two astronomical instruments (FORS1 and ISAAC) at the first VLT 8.2-m Unit Telescope, ANTU (formerly UT1), impressive images have been obtained of a variety of celestial objects. These observations were made through different optical filtres. In some cases, CCD frames could be combined into colour renderings of the objects. We show here some of the new images, obtained with the multi-mode FORS1 instrument shortly before the arrival of the first "visiting astronomers" at Paranal in early April 1999. The first (20a/99) is of a small and nearby, dark cloud, a type of object that has not been imaged before by the VLT, and among the galaxies, the warped dust band in a "Sombrero"-like galaxy is of particular scientific interest. In most cases, the image quality is of the order of 0.6 arcsec.

7 april 1999: The VLT Control Room at the Paranal Observatory is becoming a busy place indeed. From here, two specialist teams of ESO astronomers and engineers now operate two VLT 8.2-m Unit Telescopes in parallel, ANTU and KUEYEN (formerly UT1 and UT2). Regular science observations have just started with the first of these giant telescopes, while impressive astronomical images are being obtained with the second.

26 maart 1999: The portrait of NGC 4945 above adorns the centrefold of the most recent issue of the ESO Messenger (no. 95; March 1999). It provides another impressive demonstration of the observational capabilities of the new WFI Camera at the MPG/ESO 2.2-m telescope at La Silla.

6 maart 1999: This has been a busy, but also a very successful and rewarding week for the European Southern Observatory and its staff. While "First Light" was achieved at the second 8.2-m VLT Unit Telescope (UT2) ahead of schedule, UT1 produced its sharpest image so far. This happened at a moment of exceptional observing conditions in the night between March 4 and 5, 1999. During a 6-min exposure of the majestic spiral galaxy, NGC 2997, stellar images of only 0.25 arcsec FWHM (full-width half-maximum) were recorded. This and two other frames of nearly the same quality have provided the base for the beautiful colour-composite shown above. At this excellent angular resolution, individual star forming regions are well visible along the spiral arms. Of particular interest is the peculiar, twisted shape of the long spiral arm to the right.

27 februari 1999: To mark the beginning of the VLT era, the European Southern Observatory is organizing a VLT Opening Symposium which will take place in Antofagasta (Chile) on 1-4 March 1999, just before the start of regular observations with the ESO Very Large Telescope on 1 April, 1999. The Symposium occupies four full days and is held on the campus of the Universidad Catolica del Norte. It consists of plenary sessions on "Science in the VLT Era and Beyond" and three parallel Workshops on "Clusters of Galaxies at High Redshift" , "Star-way to the Universe" and "From Extrasolar Planets to Brown Dwarfs".

27 februari 1999: The galaxy cluster 1ES 0657-55 is located in the southern constellation Carina (The Keel), south of the Milky Way band. Its redshift has been measured as z = 0.29. It is a source of strong and very hot X-ray emission and has an asymmetric galaxy distribution, indicating a large mass and recent formation. Images obtained with the ESO 3.6-m New Technology Telescope (NTT) at La Silla have revealed the presence of an arc , i.e. presumably a background galaxy at larger distance, whose image is strongly distorted by the gravitational field of this cluster.

27 februari 1999: NGC 1850 is a double cluster in the Large Magellanic Cloud, a satellite galaxy to the Milky Way Galaxy, deep in the southern sky. This cluster is representative of a class of objects, young, globular-like stellar associations, that has no counterpart in our own Galaxy.

27 februari 1999: The FORS1 multi-mode instrument is able to record images as well as spectra of even very distant objects. During the past months, data have been obtained that show the properties of some of the remotest known objects in the Universe.

27 februari 1999: NGC 1232 is a prominent southern Sc spiral galaxy in the constellation Eridanus (The River). With a diameter of nearly 200,000 lightyears, it is about twice the size of the Milky Way galaxy. The distance is about 100 million light-years, but the excellent optical quality of the VLT and FORS allows us to see an incredible wealth of details.

27 februari 1999: Continuing progress in astronomical technology is opening new possibilities for the study of the distant universe. One of the most exciting, recent additions to this branch of astrophysics, known as cosmology, has been the discovery of a large population of galaxies in the primordial Universe in which intensive star-formation is going on. They are so distant (their redshifts are larger than 3 [1]) that the corresponding look-back time is over 90% of the age of the Universe, now estimated at about 14 - 15 billion years (1 billion = 1,000 million). We observe these objects as they were, when the Universe was between 1 and 2 billion years old. The investigation of the early Universe is one of the primary scientific goals that have motivated the construction of the ESO Very Large Telescope and its very diverse complement of instrumentation. The aim of these studies is to extend the observations of basic properties of galaxies to objects at the largest possible distances and hence the earliest possible epochs. We would like to learn as much as possible about these very faint galaxies, including their numbers and hence their space density, as well as their brightness, colours, sizes and shapes. What are the rates with which stars are formed in different galaxies at different epochs, what is their chemical composition and mass? How do they move in space and how do they cluster?