Photo de la semaine

13 septembre 2010: Spiralling around, 61 million light-years away in the constellation Fornax (the Furnace), NGC 1365 is enormous. At 200000 light-years across, it is one of the largest galaxies known to astronomers. This, plus the sharply defined bar of old stars across its structure is why it is also known as the Great Barred Spiral Galaxy. Astronomers think that the Milky Way may look very similar to this galaxy, but at half the size. The bright centre of the galaxy is thought to be due to huge amounts of superhot gas ejected from the ring of material circling a central black hole. Young luminous hot stars, born out of the interstellar clouds, give the arms a prominent appearance and a blue colour. The bar and spiral pattern rotates, with one full turn taking about 350 million years. This image combines observations performed through three different filters (B, V, R) with the 1.5-metre ...

6 septembre 2010: Au milieu d'Août 2010 l'ambassadeur photo de l'ESO Yuri Beletsky a pris cette étonnante photo à l'observatoire ESO de Paranal. Un groupe d'astronomes observait le centre de la Voie Lactée en utilisant l'installation d'étoile laser guide à Yepun, l'un des quatres Unit Telescope du Very Large Telescope (VLT). Le laser de Yepun traverse le majestueux ciel austral et créé une étoile artificielle à une altitude de 90km, haut dans la mésosphère terrestre. Le Laser Guide Star (LGS) fait parti du système d'optique adaptative du VLT et est utilisé comme une référence pour corriger les effets flous de l'atmosphère sur les images. La couleur du laser est choisie précisément pour exciter une couche de sodium se trouvant dans les couches supérieurs de l'atmosphère, on peut reconnaitre la couleur familière des lampes à sodium des éclairages de rue. Cette couche d'atomes de sodium est probablement un reste des météorites entrant l'atmosphère terrestre. ...

30 août 2010: NGC 5426 and NGC 5427 are two spiral galaxies of similar sizes engaged in a dramatic dance. It is not certain that this interaction will end in a collision and ultimately a merging of the two galaxies, although the galaxies have already been affected. Together known as Arp 271, this dance will last for tens of millions of years, creating new stars as a result of the mutual gravitational attraction between the galaxies, a pull seen in the bridge of stars already connecting the two. Located 90 million light-years away towards the constellation of Virgo (the Virgin), the Arp 271 pair is about 130 000 light-years across. It was originally discovered in 1785 by William Herschel. Quite possibly, our own Milky Way will undergo a similar collision in about five billion years with the neighbouring Andromeda galaxy, which is now located about 2.6 million light-years away from the Milky Way. ...

23 août 2010: During a night at ESO’s Very Large Telescope (VLT), the stars seem to rotate around the southern celestial pole. The skies over Paranal provide splendid observing opportunities for the astronomers below. At the observatory on Cerro Paranal in the dry Atacama Desert of Chile, one of the observatory’s four 8.2-metre telescopes can be seen on the right performing its nightly task of looking at the heavens. Two of the four 1.8-metre Auxiliary Telescopes are also seen in the picture. The dry, high environment at 2600 metres above sea level, and the extraordinarily advanced equipment makes observing time at the VLT highly sought after by astronomers around the world.

16 août 2010: Every year in mid-August the Perseid meteor shower has its peak. Meteors, colloquially known as “shooting stars”, are caused by pieces of cosmic debris entering Earth’s atmosphere at high velocity, leaving a trail of glowing gases. Most of the particles that cause meteors are smaller than a grain of sand and usually disintegrate in the atmosphere, only rarely reaching the Earth’s surface as a meteorite. The Perseid shower takes place as the Earth moves through the stream of debris left behind by Comet Swift-Tuttle. In 2010 the peak was predicted to take place between 12–13 August 2010. Despite the Perseids being best visible in the northern hemisphere, due to the path of Comet Swift-Tuttle's orbit, the shower was also spotted from the exceptionally dark skies over ESO’s Paranal Observatory in Chile. In order not to miss any meteors in the display, ESO Photo Ambassador Stéphane Guisard set up 3 cameras ...

9 août 2010: Haro 11 appears to shine gently amid clouds of gas and dust, but this placid facade belies the monumental rate of star formation occurring in this “starburst” galaxy. By combining data from ESO’s Very Large Telescope and the NASA/ESA Hubble Space Telescope, astronomers have created a new image of this incredibly bright and distant galaxy. The team of astronomers from Stockholm University, Sweden, and the Geneva Observatory, Switzerland, have identified 200 separate clusters of very young, massive stars. Most of these are less than 10 million years old. Many of the clusters are so bright in infrared light that astronomers suspect that the stars are still emerging from the cloudy cocoons where they were born. The observations have led the astronomers to conclude that Haro 11 is most likely the result of a merger between a galaxy rich in stars and a younger, gas-rich galaxy. Haro 11 is found to ...

2 août 2010: Dans la recherche pour de nombreux mondes, peu de télescopes ont eu autant de succès que le télescope de 3.6 mètres de l'ESO et le télescope Suisse Leonhard Euler de 3.6 mètres, tous les deux représentés dans cette image. Le télescope de 3.6 mètres est la demeure de HARPS (High Accuracy Radial Velocity Planet Searcher), un spectrographe avec une précision sans précèdent et détenteur de nombreux records dans le domaine de la recherche d'exoplanètes, y compris la découverte de la plus légère et la plus petite exoplanète jamais mesurée. Avec HARPS, le télescope Leonhard Euler a permis aux astronomes de trouver que six exoplanètes d'un groupe de 27 était en orbite dans la direction opposée à la rotation de leur étoile hôte, donnant un sérieux et inattendu défi au théories actuelles sur la formation de planète. À 2400 mètres d'altitude dans la partie sud du désert chilien d'Atacama, La Silla ...

26 juillet 2010: NGC 4027, also known as Arp 22, stretches its single extended spiral arm in this face-on image. Located about 75 million light-years away in the constellation of Corvus (the Crow), this barred spiral galaxy is identified as a peculiar galaxy by this extended arm, thought to be the result of a collision with another galaxy millions of years ago — most likely a small galaxy known as NGC 4027A. NGC 4027 is part of the NGC 4038 Group, a group of galaxies that also contains the famous distorted couple known as the Antennae Galaxies (see eso0209 and heic0615). This image is based on data collected with the ESO Faint Object Spectrograph and Camera (EFOSC) attached to the 3.58-metre New Technology Telescope (NTT) at the ESO La Silla Observatory in Chile. The data were collected through three broadband filters (B, V and R) and two narrowband filters (Hα and doubly ionised ...

19 juillet 2010: A European Atacama Large Millimeter/submillimeter Array (ALMA) antenna takes a ride on Lore, one of the ALMA Transporters, at the 2900-metre altitude Operations Support Facility in the Chilean Andes. This took place on 23 June 2010, and was the first time that European antennas have been lifted with the transporters, a procedure that was fully successful, with both moves completed in a single day. The first two European antennas for ALMA have been moved to two new outdoor foundation pads in order to perform tests of their dish surface accuracy. In this process, known as holography, the antennas observe the signals from a special transmitter located on a nearby tower. In order to allow parallel assembly of several antennas, two new foundations have recently been built. As the newly built foundations lie between the original positions of the two antennas and the holography tower, the antennas were moved to the ...

12 juillet 2010: Yesterday 11 July 2010, between 20:15 and 22:51 CEST, the path of a total solar eclipse streaked across the Pacific Ocean touching several small islands including Tuamotu in French Polynesia, Mangaia in the Cook Islands and Chile's Easter Island. The total eclipse brushed the southern mainland of Chile, and was seen as a partial eclipse in the rest of the country. At ESO's Paranal Observatory ESO Photo Ambassador Yuri Beletsky snapped this photo near the mid-point of the eclipse. On the mainland of Chile, outside the zone of complete darkness, the partial eclipse was visible from ESO's Paranal Observatory. With the naked eye, eclipses are difficult — and dangerous — to watch until they reach totality, as the Sun is so bright. But a filter reduces the glare and here reveals the advancing disk of the Moon as it moves across the face of the Sun. In this photograph, the ...

28 juin 2010: NGC 3628 is a spiral galaxy and a member of a small, but conspicuous group of galaxies located about 35 million light-years away, toward the constellation of Leo (the Lion). The other distinguished members of this family, known collectively as the Leo Triplet, are two well-known prominent spiral galaxies, Messier 65 and Messier 66 (not seen on the image), which were both discovered in 1780 by famous French comet hunter Charles Messier. NGC 3628 is the faintest of the trio and escaped Messier’s observations with his rather small telescope. It was discovered and catalogued by William Herschel only four years later. NGC 3628 hides its spiral structure because it is seen perfectly edge-on, exactly as we observe the Milky Way on a clear night. Its most distinctive feature is a dark band of dust that lies across the plane of the disc and which is visibly distorted outwards, as a ...

21 juin 2010: One morning, in March 2008, a rare and beautiful sight greeted Yuri Beletsky, astronomer at ESO’s Very Large Telescope (VLT) observatory at Paranal in northern Chile. In the sky above the observing deck, the planets Mercury and Venus were in alignment above the Moon, in a celestial event known as a conjunction. Mercury, the smallest of the planets and shining highest in the sky in this image, orbits closest to the Sun of all the eight planets in our Solar System. Venus comes next, followed by Earth and its Moon. So this image captures the full stock of major astronomical bodies that pass between Earth and its host star. To the bottom left, seen as an impressive silhouette, and accompanying this cosmic chance encounter, is one of the four 1.8-metre Auxiliary Telescopes (ATs) deployed at Paranal. These mobile telescopes are used for interferometry, an astronomical technique that essentially combines the ...

14 juin 2010: On the Chajnantor plateau, the Atacama Large Millimeter/submillimeter Array (ALMA) is growing. On 31 May 2010, the number of ALMA’s state-of-the-art antennas on the 5000-metre-altitude plateau in the Chilean Andes increased to five. This photograph shows the five 12-metre diameter antennas at the Array Operations Site, clustered on the closely spaced foundation pads of what will be ALMA’s “Atacama Compact Array”. When complete, ALMA will have fifty-four 12-metre and twelve 7-metre diameter antennas, operating together as an interferometer: the signals from the individual antennas are combined in a specialised supercomputer — the ALMA correlator — so that the array of antennas acts as a single, giant telescope. The team of astronomers and engineers have now achieved a successful test linking all of these first five antennas together as an interferometer. This result follows the successful first measurements with a pair of antennas in October 2009 (see ESO Announcement) and the ...

7 juin 2010: As the full Moon sets, the Sun is about to rise on the opposite horizon. The Very Large Telescope (VLT) has already closed its eyes after a long night of observations, and telescope operators and astronomers sleep while technicians, engineers and day astronomers wake up for a new day of work. Operations never stop at the most productive astronomical ground-based observatory in the world. ESO staff member Gordon Gillet welcomed the new day by capturing this stunning image from 14 km away, on the road to the nearby Cerro Armazones, the peak recently chosen by the ESO Council as the preferred location for the planned 40-metre-class European Extremely Large Telescope (E-ELT). Contrary to what one may think, this picture is no montage. The Moon appears large because it is seen close to the horizon and our perception is deceived by the proximity of references on the ground. In order to ...

31 mai 2010: NGC 6118, a grand-design spiral galaxy, shines bright in this image, displaying its central bar and tight spiral arms from its home in the constellation of Serpens (The Snake). The galaxy is sometimes known to amateur astronomers as the “Blinking Galaxy” because this relatively faint, fuzzy object would appear to flick into existence when viewed through their telescopes in a certain orientation, and then suddenly disappear again as the eye position shifted. The brilliant blue star-forming regions of the galaxy, where hot young stars are born, are beautifully illuminated, even from over 80 million light-years away. In 2004, regular observers of this galaxy saw a “new star” appear near the edge of the galaxy (above the centre of the image). Far from being a new star, this object, supernova 2004dk, is in fact the final, powerful burst of light emitted by the explosion of a star. Though shy to lesser ...

24 mai 2010: Alongside the B-710 road, between the Paranal airstrip and the turn-off to Cerro Armazones in the Chilean Atacama Desert, a crew is hard at work laying a fibre data cable. The cable will connect the observatories at Paranal (ESO) and Armazones (OCA) with the main scientific data backbone in South America, bridging the gap between these remote outposts and the scientific community thirsty for their data. This new cable, laid down by ESO, is part of the EVALSO (Enabling Virtual Access to Latin-American Southern Observatories) project that aims to create an entire high-speed data infrastructure between these two astronomical sites in Chile and the rest of the scientific and academic community. Once completed, the high-speed interconnectivity will be from the Santiago area, via the main Chilean backbone along the Panamerican Highway, to the ESO site on Cerro Paranal, which houses the Very Large Telescope (VLT) and to Cerro Armazones, currently ...

17 mai 2010: The Santiago Central Office building, the soon-to-be headquarters of the Atacama Large Millimeter/submillimeter Array (ALMA) project in the Vitacura district of the Chilean capital. The new building is rapidly approaching completion and is adjacent to ESO’s Santiago offices. It was built by ESO as part of its responsibilities as the European ALMA partner. The ALMA Santiago Central Office building covers nearly 7000 square metres, stands two storeys tall, and includes an underground parking area for 130 cars. ALMA, the largest astronomical project in existence, is a revolutionary astronomical telescope, comprising an array of 66 giant 12-metre and 7-metre diameter antennas observing at millimetre and submillimetre wavelengths. The facility is currently under construction on the 5000-metre high Chajnantor plateau in the Chilean Andes. ALMA is a partnership of Europe, North America and East Asia in cooperation with the Republic of Chile.

10 mai 2010: High in the Chilean Andes, at 5000 metres above sea level, one of the giant Atacama Large Millimeter/submillimeter Array (ALMA) antenna transporters contemplates an unexpected sight — a delicate dusting of snow whitens the breathtaking landscape of the Chajnantor plateau, home of the ALMA project. Snow is a very rare event at this extremely arid site and is a consequence of the Altiplanic winter, caused when the jet stream reverses and comes from the chill east. Chajnantor is one of the driest sites in the world, making it excellent for astronomical observations. The hill in the background is Toco, a 5600-metre mountain toward the north. This image was taken on 30 April 2010. The ALMA transporters, two giant custom-built vehicles, can move the antennas across the Chajnantor plateau, allowing different configurations of the array. Since late 2009, there have been three antennas at 5000 metres. Eventually ALMA will have a ...

3 mai 2010: This picture looks like a scene from a science fiction movie, with strange, distant structures rising over a desolate alien valley. In fact, this is the barren Atacama Desert in northern Chile, and the oddly shaped buildings silhouetted against the sky are part of ESO’s Very Large Telescope (VLT) observatory, the world’s most advanced ground-based observatory. The four 8.2-metre Unit Telescopes stand out to the right on the summit of Mount Paranal. To the left looms the new 4.1-metre Visible and Infrared Survey Telescope for Astronomy (VISTA), the largest survey telescope in operation. The extremely arid conditions and high altitude of the Paranal region make it an optimum site to locate an astronomical observatory. The otherworldliness and remoteness of the area add to the adventure of conducting cutting-edge astronomy.

26 avril 2010: NGC 253, also known as the Sculptor Galaxy, is the brightest of the Sculptor Group of galaxies, found in the constellation of the same name, and lying approximately 13 million light-years from Earth. The Sculptor Galaxy is known as a starburst galaxy for its current high rate of star formation, one result of which is its superwind, a stream energetic material spewing out from the centre of the galaxy out into space. The purple light comes from that frenzy of star formation, which originally began 30 million years ago, while the yellowish colour is created by dust lit up by young, massive stars. This image combines observations performed through three different filters (B, V, R) with the 1.5-metre Danish telescope at the ESO La Silla Observatory in Chile.