Orion’s Secret Fire Dance

The Great Orion Nebula has captivated observers for at least four hundred years, but the ancient Mayans may have known about its secrets long before then. According to legend, the nebula might have been the smoke situated between the “Three Hearthstones” and the light of the emerging stars seen as the very embers of creation itself. Now the ESO-operated Atacama Pathfinder Experiment (APEX) in Chile has revealed what we cannot see. At wavelengths too long for human vision, this new image shows us an ancient fire dance painted in colors of cold interstellar dust.

As we know, deposits of gas and interstellar dust are virtual star factories. However, the very material which creates stars also masks them. So how do we peer behind the veil? The answer is to observe at alternative wavelengths of light. In this case, the submillimetre wavelength reveals what our eyes cannot see… dust grains igniting the view, even though they are just a few tens of degrees above absolute zero. This makes 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, the perfect instrument to play the tune for this cold fire dance.

Take a look around the picture. It’s just a small portion of a vast complex known as the Orion Molecular Cloud. Wafting across hundreds of light years space some 1350 light years away, this rich arena of hot young stars, cold dust clouds and bright nebula is the epitome of stellar creation. The image reveals the submillimetre-wavelength glow in shades of orange and it is combined with visible light for a total visual experience. Note deep ribbons, sheets and bubbles… These are the product of gravitational collapse and the effects of stellar winds. Powerful stellar processes are at work here. The atmospheres of the stars are crafting the clouds much the same way a gentle breeze swirls the smoke from a fire.

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Credit: ESO/Nick Risinger (skysurvey.org), Digitized Sky Survey 2. Music: movetwo

As beautiful as it is, there is still science behind the imagery. Astronomers have employed the data taken with ESA’s Herschel Space Observatory, along with the APEX information, to aid them in their search for early star formation. At this point in time, the researchers have been able to verify more than a dozen candidate protostars – objects which appear far brighter at longer wavelengths rather than short. It’s a triumph for the researchers. These new observations could well be the youngest protostars so far observed and it brings astronomers just one step closer to witnessing the moment when a star ignites.

Original Story Source: ESO News Release.

‘Dark Markings of the Sky’ are Hiding Star Formation

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This stunning new image shows a sinuous filament of cosmic dust more than ten light-years long. The makeup of filamentary cloud structures like this used to be a mystery, and in the early 20th century, Edward Emerson Barnard compiled a photographic atlas of these features, calling them “dark markings of the sky,” as these regions appeared as dark lanes, with no stars visible. Barnard correctly argued that this appearance was due to “obscuring matter in space.” Today we call segments in this particular cloud Barnard 211 and Barnard 213, or the Taurus Molecular Cloud. And we now know that these are clouds of interstellar gas and dust grains. But also, within these clouds, newborn stars are hidden, and dense clouds of gas are on the verge of collapsing to form yet more stars.

The Taurus Molecular Cloud is one of the closest regions of star formation to us. It is located in the constellation of Taurus about 450 light-years from Earth. The cosmic dust grains are so cold that observations at wavelengths of around one millimeter, such as these made with the LABOCA camera on APEX (Atacama Pathfinder Experiment) telescope in Chile, are needed to detect their faint glow.

This image shows two parts of a long filament. The dust grains — tiny particles similar to very fine soot and sand — absorb visible light, blocking our view of the rich star field behind the clouds. The Taurus Molecular Cloud is particularly dark at visible wavelengths, as it lacks the massive stars that illuminate the nebulae in other star-formation regions such as Orion.

But active star formation is taking place. This is why observations at longer wavelengths, such as the millimeter range, are essential for understanding the early stages of star formation.

Read more about this particular region at the ESO website.

Emerging Supermassive Black Holes Choke Star Formation

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Located on the Chajnantor plateau in the foothills of the Chilean Andes, ESO’s APEX telescope has been busy looking into deep, deep space. Recently a group of astronomers released their findings regarding massive galaxies in connection with extreme times of star formation in the early Universe. What they found was a sharp cut-off point in stellar creation, leaving “massive – but passive – galaxies” filled with mature stars. What could cause such a scenario? Try the materialization of a supermassive black hole…

By integrating data taken with 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 other facilities, astronomers were able to observe the relationship of bright, distant galaxies where they form into clusters. They found that the density of the population plays a major role – the tighter the grouping, the more massive the dark matter halo. These findings are the considered the most accurate made so far for this galaxy type.

Located about 10 billion light years away, these submillimetre galaxies were once home to starburst events – a time of intense formation. By obtaining estimations of dark matter halos and combining that information with computer modeling, scientists are able to hypothesize how the halos expanding with time. Eventually these once active galaxies settled down to form giant ellipticals – the most massive type known.

“This is the first time that we’ve been able to show this clear link between the most energetic starbursting galaxies in the early Universe, and the most massive galaxies in the present day,” says team leader Ryan Hickox of Dartmouth College, USA and Durham University, UK.

However, that’s not all the new observations have uncovered. Right now there’s speculation the starburst activity may have only lasted around 100 million years. While this is a very short period of cosmological time, this massive galactic function was once capable of producing double the amount of stars. Why it should end so suddenly is a puzzle that astronomers are eager to understand.

“We know that massive elliptical galaxies stopped producing stars rather suddenly a long time ago, and are now passive. And scientists are wondering what could possibly be powerful enough to shut down an entire galaxy’s starburst,” says team member Julie Wardlow of the University of California at Irvine, USA and Durham University, UK.

Right now the team’s findings are offering up a new solution. Perhaps at one point in cosmic history, starburst galaxies may have clustered together similar to quasars… locating themselves in the same dark matter halos. As one of the most kinetic forces in our Universe, quasars release intense radiation which is reasoned to be fostered by central black holes. This new evidence suggests intense starburst activity also empowers the quasar by supplying copious amounts of material to the black hole. In response, the quasar then releases a surge of energy which could eradicate the galaxy’s leftover gases. Without this elemental fuel, stars can no longer form and the galaxy growth comes to a halt.

“In short, the galaxies’ glory days of intense star formation also doom them by feeding the giant black hole at their centre, which then rapidly blows away or destroys the star-forming clouds,” explains team member David Alexander from Durham University, UK.

Original Story Source: European Southern Observatory News. For Further Reading: Research Paper Link.