potw1108a-credit-ESO-José-Francisco-Salgado
Four antennas of the Atacama Large Millimeter/submillimeter Array (ALMA) gaze up at the star-filled night sky, in anticipation of the work that lies ahead. The Moon lights the scene on the right, while the band of the Milky Way stretches across the upper left. ALMA is being constructed at an altitude of 5000 m on the Chajnantor plateau in the Atacama Desert in Chile. This is one of the driest places on Earth and this dryness, combined with the thin atmosphere at high altitude, offers superb conditions for observing the Universe at millimetre and submillimetre wavelengths. At these long wavelengths, astronomers can probe, for example, molecular clouds, which are dense regions of gas and dust where new stars are born when a cloud collapses under its own gravity. Currently, the Universe remains relatively unexplored at submillimetre wavelengths, so astronomers expect to uncover many new secrets about star formation, as well as the origins of galaxies and planets, when ALMA is operational. The ALMA project is a partnership of Europe, North America and East Asia in cooperation with the Republic of Chile. This panorama was taken by ESO Photo Ambassador José Francisco Salgado.
ALMA and a Starry Night
ALMA is the world'€™s most powerful telescope for studying the Universe at submillimetre and millimetre wavelengths. Construction work for ALMA will be completed in 2013, and a total of 66 of these high-precision antennas will be operating on the site. At the moment, the telescope is in its initial phase of Early Science Observations. Even though it is not fully constructed, the telescope is already producing outstanding results, outperforming all other submillimetre arrays. In the sky above the antennas, countless stars shine like distant jewels. Two other familiar celestial objects also stand out. First, the image is crowned by the Moon. Second, outshone by the glow of the Moon, it is possible to distinguish the Milky Way as a hazy stripe across the sky. Dark regions within the band are areas where the light from background stars is blocked by interstellar dust. This photograph was taken by ESO Photo Ambassador, Babak Tafreshi.
Asymmetric Ashes (artist's impression)
Artist's impression of how Type Ia supernovae may look like as revealed by spectro-polarimetry observations. The outer regions of the blast cloud is asymmetric, with different materials found in 'clumps', while the inner regions are smooth. Using observations of 17 supernovae made over more than 10 years with ESO's Very Large Telescope and the McDonald Observatory's Otto Struve Telescope, astronomers inferred the shape and structure of the debris cloud thrown out from Type Ia supernovae. Such supernovae are thought to be the result of the explosion of a small and dense star — a white dwarf — inside a binary system. As its companion continuously spills matter onto the white dwarf, the white dwarf reaches a critical mass, leading to a fatal instability and the supernova. But what sparks the initial explosion, and how the blast travels through the star have long been thorny issues. The study shows that the outer regions of the blast cloud is asymmetric, with different materials found in 'clumps', while the inner regions are smooth.
  • Created: November 30, 2006 - 00:00
  • Credit: ESO
eso1024b-credit-ESO-L. Calçada
This artist’s impression shows how the planet inside the disc of Beta Pictoris may look. Only 12 million years old, or less than three-thousandths of the age of the Sun, Beta Pictoris is 75% more massive than our parent star. It is located about 60 light-years away towards the constellation of Pictor (the Painter) and is one of the best-known examples of a star surrounded by a dusty debris disc. Earlier observations showed a warp of the disc, a secondary inclined disc and comets falling onto the star, all indirect, but tell-tale signs that strongly suggested the presence of a massive planet. Observations done with the NACO instrument on ESO'€™s Very Large Telescope in 2003, 2008 and 2009, have proven the presence of a planet around Beta Pictoris. It is located at a distance between 8 and 15 times the Earth-Sun separation (or Astronomical Units) which is about the distance Saturn is from the Sun. The planet has a mass of about nine Jupiter masses and is right mass and location to explain the observed warp in the inner parts of the disc.
eso1229a-credit-ESO-M_Kornmesser
This is an artist'€™s impression of the quasar 3C 279. Astronomers connected the Atacama Pathfinder Experiment (APEX), in Chile, to the Submillimeter Array (SMA) in Hawaii, USA, and the Submillimeter Telescope (SMT) in Arizona, USA for the first time, to make the sharpest observations ever, of the centre of a distant galaxy, the bright quasar 3C 279. Quasars are the very bright centres of distant galaxies that are powered by supermassive black holes. This quasar contains a black hole with a mass about one billion times that of the Sun, and is so far from Earth that its light has taken more than 5 billion years to reach us. The team were able to probe scales of less than a light-year across the quasar, a remarkable achievement for a target that is billions of light-years away.
eso1004a.-credit-ESO-L.Calçada-M.Kornmesser
This artist'€™s impression depicts the newly discovered stellar-mass black hole in the spiral galaxy NGC 300. The black hole has a mass of about twenty times the mass of the Sun and is associated with a Wolf-€“Rayet star : a star that will become a black hole itself. Thanks to the observations performed with the FORS2 instrument mounted on ESO'€™s Very Large Telescope, astronomers have confirmed an earlier hunch that the black hole and the Wolf-€“Rayet star dance around each other in a diabolic waltz, with a period of about 32 hours. The astronomers also found that the black hole is stripping matter away from the star as they orbit each other. How such a tightly bound system has survived the tumultuous phases that preceded the formation of the black hole is still a mystery.
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Arjan Dasselaar

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European Southern Observatory
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