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Revolutionary ALMA Image Reveals Planetary Genesis

This is the sharpest image ever taken by ALMA — sharper than is routinely achieved in visible light with the NASA/ESA Hubble Space Telescope. It shows the protoplanetary disc surrounding the young star HL Tauri. The observations reveal substructures within the disc that have never been seen before and even show the possible positions of planets forming in the dark patches within the system.In this picture the features seen in the HL Tauri system are labelled.  Credit: ALMA (ESO/NAOJ/NRAO)

This is the sharpest image ever taken by ALMA — sharper than is routinely achieved in visible light with the NASA/ESA Hubble Space Telescope. It shows the protoplanetary disc surrounding the young star HL Tauri. The observations reveal substructures within the disc that have never been seen before and even show the possible positions of planets forming in the dark patches within the system.In this picture the features seen in the HL Tauri system are labelled.
Credit: ALMA (ESO/NAOJ/NRAO)

This new image from ALMA, the Atacama Large Millimeter/submillimeter Array, reveals extraordinarily fine detail that has never been seen before in the planet-forming disc around a young star. These are the first observations that have used ALMA in its near-final configuration and the sharpest pictures ever made at submillimetre wavelengths. The new results are an enormous step forward in the observation of how protoplanetary discs develop and how planets form….
…read more at http://www.eso.org/public/news/eso1436/

ALMA Probes Mysteries of Jets from Giant Black Holes

eso1344aTwo international teams of astronomers have used the power of the Atacama Large Millimeter/submillimeter Array (ALMA) to focus on jets from the huge black holes at the centres of galaxies and observe how they affect their surroundings. They have respectively obtained the best view yet of the molecular gas around a nearby, quiet black hole and caught an unexpected glimpse of the base of a powerful jet close to a distant black hole.

There are supermassive black holes — with masses up to several billion solar masses — at the hearts of almost all galaxies in the Universe, including our own galaxy, the Milky Way. In the remote past, these bizarre objects were very active, swallowing enormous quantities of matter from their surroundings, shining with dazzling brilliance, and expelling tiny fractions of this matter through extremely powerful jets. In the current Universe, most supermassive black holes are much less active than they were in their youth, but the interplay between jets and their surroundings is still shaping galaxy evolution.

Two new studies, both published today in the journal Astronomy & Astrophysics, used ALMA to probe black hole jets at very different scales: a nearby and relatively quiet black hole in the galaxy NGC 1433 and a very distant and active object called PKS 1830-211.

“ALMA has revealed a surprising spiral structure in the molecular gas close to the centre of NGC 1433,” says Françoise Combes (Observatoire de Paris, France), who is the lead author of the first paper. “This explains how the material is flowing in to fuel the black hole. With the sharp new observations from ALMA, we have discovered a jet of material flowing away from the black hole, extending for only 150 light-years. This is the smallest such molecular outflow ever observed in an external galaxy.”

The discovery of this outflow, which is being dragged along by the jet from the central black hole, shows how such jets can stop star formation and regulate the growth of the central bulges of galaxies [1].

In PKS 1830-211, Ivan Martí-Vidal (Chalmers University of Technology, Onsala Space Observatory, Onsala, Sweden) and his team also observed a supermassive black hole with a jet, but a much brighter and more active one in the early Universe [2]. It is unusual because its brilliant light passes a massive intervening galaxy on its way to Earth, and is split into two images by gravitational lensing [3].

From time to time, supermassive black holes suddenly swallow a huge amount of mass [4], which increases the power of the jet and boosts the radiation up to the very highest energies. And now ALMA has, by chance, caught one of these events as it happens in PKS 1830-211.

“The ALMA observation of this case of black hole indigestion has been completely serendipitous. We were observing PKS 1830-211 for another purpose, and then we spotted subtle changes of colour and intensity among the images of the gravitational lens. A very careful look at this unexpected behaviour led us to the conclusion that we were observing, just by a very lucky chance, right at the time when fresh new matter entered into the jet base of the black hole,” says Sebastien Muller, a co-author of the second paper.

The team also looked to see whether this violent event had been picked up with other telescopes and were surprised to find a very clear signal in gamma rays, thanks to monitoring observations with NASA’s Fermi Gamma-ray Space Telescope. The process that caused the increase of radiation at ALMA’s long wavelengths was also responsible of boosting the light in the jet dramatically, up to the highest energies in the Universe [5].

“This is the first time that such a clear connection between gamma rays and submillimetre radio waves has been established as coming from the real base of a black hole’s jet,” adds Sebastien Muller.

The two new observations are just the start of ALMA’s investigations into the workings of jets from supermassive black holes, near and far. Combes’s team is already studying other nearby active galaxies with ALMA and the unique object PKS 1830-211 is expected to be the focus of much future research with ALMA and other telescopes.

“There is still a lot to be learned about how black holes can create these huge energetic jets of matter and radiation,” concludes Ivan Martí-Vidal. “But the new results, obtained even before ALMA was completed, show that it is a uniquely powerful tool for probing these jets — and the discoveries are just beginning!”

Notes
[1] This process, called feedback, may explain the mysterious relationship between the mass of a black hole at the centre of a galaxy and the mass of the surrounding bulge. The black hole accretes gas and grows more active, but then produces jets that clear out gas from the surrounding regions and stop star formation.

[2] PKS 1830-211 has a redshift of 2.5, meaning that its light had to travel for about 11 billion years before reaching us. The light we see was emitted when the Universe was just 20% of its current age. By comparison the light from NGC 1433 takes only about 30 million years to reach the Earth, a very short time in galactic terms.

[3] Einstein’s theory of general relativity predicts that light rays will be deflected as they pass a massive object such as a galaxy. This effect is called gravitational lensing and, since the first find in 1979, numerous such gravitational lenses have been discovered. The lensing can create multiple images as well as distort and magnify the background light sources.

[4] The infalling material could be a star or a molecular cloud. Such an infalling cloud has been observed at the centre of the Milky Way (eso1151, eso1332).

[5] This energy is emitted as gamma rays, the shortest wavelength and highest energy form of electromagnetic radiation.

Read more at http://www.eso.org/public/news/eso1344/

ALMA Takes Close Look at Drama of Starbirth

Astronomers using the Atacama Large Millimeter/submillimeter Array (ALMA) have obtained a vivid close-up view of material streaming away from a newborn star. By looking at the glow coming from carbon monoxide molecules in an object called Herbig-Haro 46/47 they have discovered that its jets are even more energetic than previously thought. The very detailed new images have also revealed a previously unknown jet pointing in a totally different direction.

Young stars are violent objects that eject material at speeds as high as one million kilometres per hour. When this material crashes into the surrounding gas it glows, creating a Herbig-Haro object [1]. A spectacular example is named Herbig-Haro 46/47 and is situated about 1400 light-years from Earth in the southern constellation of Vela (The Sails). This object was the target of a study using ALMA during the Early Science phase, whilst the telescope was still under construction and well before the array was completed.

The new images reveal fine detail in two jets, one coming towards Earth and one moving away. The receding jet was almost invisible in earlier pictures made in visible light, due to obscuration by the dust clouds surrounding the new-born star. ALMA has not only provided much sharper images than earlier facilities but also allowed astronomers to measure how fast the glowing material is moving through space.

These new observations of Herbig-Haro 46/47 revealed that some of the ejected material had velocities much higher than had been measured before. This means the outflowing gas carries much more energy and momentum than previously thought.

The team leader and first author of the new study, Héctor Arce (Yale University, USA) explains that “ALMA’s exquisite sensitivity allows the detection of previously unseen features in this source, like this very fast outflow. It also seems to be a textbook example of a simple model where the molecular outflow is generated by a wide-angle wind from the young star.”

eso1336aThe observations were obtained in just five hours of ALMA observation time – even though ALMA was still under construction at the time – similar quality observations with other telescopes would have taken ten times longer.

“The detail in the Herbig-Haro 46/47 images is stunning. Perhaps more stunning is the fact that, for these types of observations, we really are still in the early days. In the future ALMA will provide even better images than this in a fraction of the time,” adds Stuartt Corder (Joint ALMA Observatory, Chile), a co-author on the new paper.

Diego Mardones (Universidad de Chile), another co-author, emphasises that “this system is similar to most isolated low mass stars during their formation and birth. But it is also unusual because the outflow impacts the cloud directly on one side of the young star and escapes out of the cloud on the other. This makes it an excellent system for studying the impact of the stellar winds on the parent cloud from which the young star is formed.”

The sharpness and sensitivity achieved by these ALMA observations also allowed the team to discover an unsuspected outflow component that seems to be coming from a lower mass companion to the young star. This secondary outflow is seen almost at right angles to the principal object and is apparently carving its own hole out of the surrounding cloud.

Arce concludes that “ALMA has made it possible to detect features in the observed outflow much more clearly than previous studies. This shows that there will certainly be many surprises and fascinating discoveries to be made with the full array. ALMA will certainly revolutionise the field of star formation!”
Notes

[1] The astronomers George Herbig and Guillermo Haro were not the first to see one of the objects that now bear their names, but they were the first to study the spectra of these strange objects in detail. They realised that they were not just clumps of gas and dust that reflected light, or glowed under the influence of the ultraviolet light from young stars, but were a new class of objects associated with shocks created by material ejected at high speeds in star formation regions.

Read more: http://www.eso.org/public/news/eso1336/

ALMA turns its eyes to Centaurus A

This new image of Centaurus A combines ALMA and near-infrared observations of the massive elliptical radio galaxy. The new ALMA observations, shown in a range of green, yellow and orange colors, reveal the position and motion of the clouds of gas in the galaxy. They are the sharpest and most sensitive such observations ever made. ALMA was tuned to detect signals with a wavelength around 1.3 millimeters, emitted by molecules of carbon monoxide gas. The motion of the gas in the galaxy causes slight changes to this wavelength, due to the Doppler effect. The motion is shown in this image as changes in color. Greener features trace gas coming towards us while more orange features depict gas moving away. We can see that the gas to the left of the center is moving towards us, while the gas to the right of the center is moving away from us, indicating that the gas is orbiting around the galaxy. The ALMA observations are overlaid on a near-infrared image of Centaurus A obtained with the SOFI instrument attached to the ESO New Technology Telescope (NTT). Credit: ALMA (ESO/NAOJ/NRAO); ESO/Y. Beletsky
Read more:phys.org

At the End of the Earth, Seeking Clues to the Universe

Antennas of the Atacama Large Millimeter/submillimeter Array being installed, 16,597 feet above sea level

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Trucks stall on the road to this plateau 16,597 feet up in the Atacama Desert, where scientists are installing one of the world’s largest ground-based astronomical projects. Heads ache. Noses bleed. Dizziness overcomes the researchers toiling in the shadow of the Licancabur volcano.
“Then there’s what we call ‘jelly legs,’ ” said Diego García-Appadoo, a Spanish astronomer studying galaxy formation. “You feel shattered, as if you ran a marathon.”

Still, the same conditions that make the Atacama, Earth’s driest desert, so inhospitable make it beguiling for astronomy. In northern Chile, it is far from big cities, with little light pollution. Its arid climate prevents radio signals from being absorbed by water droplets. The altitude, as high as the Himalaya base camps for climbers preparing to scale Mount Everest, places astronomers closer to the heavens.

Opened last October, the Atacama Large Millimeter/submillimeter Array, known as ALMA, will have spread 66 radio antennas near the spine of the Andes by the time it is completed next year. Drawing more than $1 billion in funding mainly from the United States, European countries and Japan, ALMA will help the oxygen-deprived scientists flocking to this region to study the origins of the universe.

The project also strengthens Chile’s position in the vanguard of astronomy. Observatories are already scattered throughout the Atacama, including the Cerro Paranal Observatory, where scientists discovered in 2010 the largest star observed to date, and the Cerro Tololo Inter-American Observatory, which was founded in 1961 and endured Chile’s tumult of revolution and counterrevolution in the 1970s.

But ALMA opens a new stage for astronomy in Chile, which is favored by international research organizations for the stability of its economy and legal system. Like other radio telescopes, ALMA does not detect optical light but radio waves, allowing researchers to study parts of the universe that are dark, like the clouds of cold gas from which stars are formed.

With ALMA, astronomers hope to see where the first galaxies were formed, and perhaps even detect solar systems with the conditions to support life, like water-bearing planets. But the scientists here express caution about their chances of finding life elsewhere in the universe, explaining that such definitive proof is likely to remain elusive.

“We won’t be able to see life, but perhaps signatures of life,” said Thijs de Graauw, a Dutch astronomer who is ALMA’s director.

Still, scientists believe ALMA will make transformational leaps possible in the understanding of the universe, enabling a hunt for so-called cold gas tracers, the ashes of exploded stars from a time about a few hundred million years after the Big Bang that astronomers call “cosmic dawn.”……
Read more: www.nytimes.com

Alma, a super-sensitive radio telescope

…. 5,000m above sea level in Chile, will detect a new galaxy every three minutes

The Atacama Large Millimeter/submillimeter Array on the Chilean desert's Chajnantor plateau. It will eventually consist of 66 antennas operating together as a single giant telescope. Photograph: Babak Tafreshi/ESO

Alma telescope glimpses space’s mysteries from on top of the world

Spend a few days with astronomers at the world’s most sophisticated telescopes in the mountains of Chile, and your skin will begin to feel different. Cheeks become stretched a little tighter; hands and lips get chapped. It seems to make little difference how much water you drink. Spend a few weeks here and, the astronomers will tell you, the headaches and dizziness start. “You really feel it when you’ve been here a long time,” says Jonathan Smoker, an astronomer at the European Southern Observatory (ESO) at Mount Paranal in northern Chile. “Sometimes my hands start to bleed because it’s so dry here.”

The scientists and technicians who work here are not allowed to stay on the mountain for more than 14 days at a time. After that, they have to go down to sea level to recuperate. At 2,500m up in the northern Atacama desert, Paranal is no place for human beings to live for long periods: dry, dusty and devoid of much life. But it is perfect for watching the skies: at night, the bone dry air means the Very Large Telescope (VLT) can track and measure stars, black holes and planets with exquisite precision using its four individual observatories. At the heart of each observatory is an 8m-wide mirror made from a single piece of polished glass, the exact shape of which changes 100 times per second to counteract, in real time, the distorting effects of the air on the starlight that it is trying to detect.

The VLT, opened in 1998, was the first telescope to image an exoplanet and it has made significant contributions to our understanding of the giant black hole at the centre of the Milky Way. But it is not the most extreme of the telescopes ESO operates. The VLT has recently been joined in Chile by an even bigger, even more sensitive telescope: the Atacama Large Millimetre/Submillimetre Array (Alma). When complete in 2013, this collection of 66 carbon-fibre radio antennae, each 12m wide, will open astronomers’ eyes to the half of the universe that has, until now, been hidden to modern optical telescopes.

Alma will detect radiation similar to microwaves, around 1,000 times longer than the light we see with our eyes – but easily absorbed by water in the atmosphere. So astronomers picked the Chajnantor plateau, 5,000m up on the Andes, near the border with Bolivia, to build their new array. It is one of the driest places in the world, and the air contains half the oxygen of that at sea level. At this height, Alma will be able to produce pin-sharp images of the parts of the universe shrouded by dust…………

Read more: www.guardian.co.uk

ALMA Opens Its Eyes

The most powerful millimetre/submillimetre-wavelength telescope in the world opens for business and reveals its first image

Humanity’s most complex ground-based astronomy observatory, the Atacama Large Millimeter/submillimeter Array (ALMA), has officially opened for astronomers. The first released image, from a telescope still under construction, reveals a view of the Universe that cannot be seen at all by visible-light and infrared telescopes. Thousands of scientists from around the world have competed to be among the first few researchers to explore some of the darkest, coldest, furthest, and most hidden secrets of the cosmos with this new astronomical tool.

At present, around a third of ALMA’s eventual 66 radio antennas, with separations up to only 125 metres rather than the maximum 16 kilometres, make up the growing array on the Chajnantor plateau in northern Chile, at an elevation of 5000 metres. And yet, even under construction, ALMA has become the best telescope of its kind — as reflected by the extraordinary number of astronomers who requested time to observe with ALMA.

Even in this very early phase ALMA already outperforms all other submillimetre arrays. Reaching this milestone is a tribute to the impressive efforts of the many scientists and engineers in the ALMA partner regions around the world who made it possible,” said Tim de Zeeuw, Director General of ESO, the European partner in ALMA….. Continue reading ALMA Opens Its Eyes