Posts Tagged ‘APEX’

Hidden Nurseries In The Milky Way

APEX, the Atacama Pathfinder Experiment, is a telescope of 12 m diameter at an exceptional site on Earth: the Chajnantor plateau is located 5100 m above sea level in the Atacama desert in Chile. It was used to map the whole inner part of the plane of our Milky Way, ranging from the Southern constellations of Vela and Carina all the way to the Northern constellations of Aquila and the great Cygnus rift. The APEX Telescope Large Area Survey of the Galaxy (ATLASGAL) mapped the Galactic Plane at a wavelength of 0.87 mm. Cold interstellar dust emits strongly in this part of the electromagnetic spectrum, called the sub-millimeter range, while it is blocking visible and infrared wavelengths. The survey has revealed an unprecedented number of cold dense clumps of gas and dust as the cradles of massive stars, thus providing a complete view of their birthplaces in the Milky Way. Based on this census, an international team of scientists led by Timea Csengeri from the Max Planck Institute for Radio Astronomy in Bonn has estimated the time scale for these nurseries to grow stars. This has been found to be a very fast process: with only 75,000 years on average it is much shorter than the corresponding time scales typically found for nurseries of lower mass stars.

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Orion’s Hidden Fiery Ribbon

Credit: ESO/Digitized Sky Survey 2

Credit: ESO/Digitized Sky Survey 2

Clouds of gas and interstellar dust are the raw materials from which stars are made. But these tiny dust grains block our view of what lies within and behind the clouds — at least at visible wavelengths — making it difficult to observe the processes of star formation.

This is why astronomers need to use instruments that are able to see at other wavelengths of light. At submillimetre wavelengths, rather than blocking light, the dust grains shine due to their temperatures of a few tens of degrees above absolute zero. The APEX telescope with its submillimetre-wavelength camera LABOCA, located at an altitude of 5000 metres above sea level on the Chajnantor Plateau in the Chilean Andes, is the ideal tool for this kind of observation.

This spectacular new picture shows just a part of a bigger complex called the Orion Molecular Cloud, in the constellation of Orion (The Hunter). A rich melting pot of bright nebulae, hot young stars and cold dust clouds, this region is hundreds of light-years across and located about 1350 light-years from us. The submillimetre-wavelength glow arising from the cold dust clouds is seen in orange in this image and is overlaid on a view of the region taken in the more familiar visible light.

The dust clouds form beautiful filaments, sheets, and bubbles as a result of processes including gravitational collapse and the effects of stellar winds. These winds are streams of gas ejected from the atmospheres of stars, which are powerful enough to shape the surrounding clouds into the convoluted forms seen here.

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APEX Turns Eye to Dark Clouds in Taurus

February 15, 2012 Leave a comment

Image Credit: ESO/APEX (MPIfR/ESO/OSO)/A. Hacar et al./Digitized Sky Survey 2. Acknowledgment: Davide De Martin.

Image Credit: ESO/APEX (MPIfR/ESO/OSO)/A. Hacar et al./Digitized Sky Survey 2. Acknowledgment: Davide De Martin.

A new image from the APEX (Atacama Pathfinder Experiment) telescope in Chile shows a sinuous filament of cosmic dust more than ten light-years long. In it, newborn stars are hidden, and dense clouds of gas are on the verge of collapsing to form yet more stars. It is one of the regions of star formation closest to us. The cosmic dust grains are so cold that observations at wavelengths of around one millimetre, such as these made with the LABOCA camera on APEX, are needed to detect their faint glow.

The Taurus Molecular Cloud, in the constellation of Taurus (The Bull), lies about 450 light-years from Earth. This image shows two parts of a long, filamentary structure in this cloud, which are known as Barnard 211 and Barnard 213. Their names come from Edward Emerson Barnard’s photographic atlas of the “dark markings of the sky”, compiled in the early 20th century. In visible light, these regions appear as dark lanes, lacking in stars. Barnard correctly argued that this appearance was due to “obscuring matter in space”.

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Wild Early Lives of Today’s Most Massive Galaxies

January 25, 2012 Leave a comment

Credit: ESO, APEX (MPIfR/ESO/OSO), A. Weiss et al., NASA Spitzer Science Center

Credit: ESO, APEX (MPIfR/ESO/OSO), A. Weiss et al., NASA Spitzer Science Center

Using the APEX telescope, a team of astronomers has found the strongest link so far between the most powerful bursts of star formation in the early Universe, and the most massive galaxies found today. The galaxies, flowering with dramatic starbursts in the early Universe, saw the birth of new stars abruptly cut short, leaving them as massive — but passive — galaxies of aging stars in the present day. The astronomers also have a likely culprit for the sudden end to the starbursts: the emergence of supermassive black holes.

Astronomers have combined observations from the LABOCA camera on the ESO-operated 12-metre Atacama Pathfinder Experiment (APEX) telescope with measurements made with ESO’s Very Large Telescope, NASA’s Spitzer Space Telescope, and others, to look at the way that bright, distant galaxies are gathered together in groups or clusters.

The more closely the galaxies are clustered, the more massive are their halos of dark matter — the invisible material that makes up the vast majority of a galaxy’s mass. The new results are the most accurate clustering measurements ever made for this type of galaxy.

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