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Posts Tagged ‘ALMA’

Astronomers ‘Unscramble’ Einstein Ring To Reveal Most Detailed View Ever Of Star Formation In The Distant Universe


Credit: ALMA (NRAO/ESO/NAOJ)/Y. Tamura (The University of Tokyo)/Mark Swinbank (Durham University)

Credit: ALMA (NRAO/ESO/NAOJ)/Y. Tamura (The University of Tokyo)/Mark Swinbank (Durham University)

ALMA’s Long Baseline Campaign produced spectacular images of the distant, gravitationally lensed galaxy called HATLAS J090311.6+003906, otherwise known as SDP.81. New analyses of these images reveal details never before seen in a galaxy so remote, including phenomenally massive yet concentrated clumps of star-forming material.

The ALMA observations of SDP.81, made at the end of 2014, were enabled by a cosmic effect known as gravitational lensing. A large galaxy nestled between SDP.81 and ALMA is acting as a lens, magnifying the more distant galaxy’s light and warping it into a near-perfect example of a phenomenon known as an Einstein Ring.

In the months following these observations, at least seven groups of scientists have independently analyzed the ALMA data on SDP.81. This flurry of research papers has divulged unprecedented information about the galaxy, including details about its structure, contents, motion, and other physical characteristics.

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Sharp-Eyed Alma Spots A Flare On Famous Red Giant Star


Artist’s impression of a giant flare on the surface of red giant Mira A. Credit: Katja Lindblom, CC BY-NC-ND 4.0

Artist’s impression of a giant flare on the surface of red giant Mira A. Credit: Katja Lindblom, CC BY-NC-ND 4.0

Super-sharp observations with the telescope Alma have revealed what seems to be a gigantic flare on the surface of Mira, one of the closest and most famous red giant stars in the sky. Activity like this in red giants – similar to what we see in the Sun – comes as a surprise to astronomers. The discovery could help explain how winds from giant stars make their contribution to our galaxy’s ecosystem.

New observations with Alma have given astronomers their sharpest ever view of the famous double star Mira. The images clearly show the two stars in the system, Mira A and Mira B, but that’s not all. For the first time ever at millimetre wavelengths, they reveal details on the surface of Mira A.

“Alma’s vision is so sharp that we can begin to see details on the surface of the star. Part of the stellar surface is not just extremely bright, it also varies in brightness. This must be a giant flare, and we think it’s related to a flare which X-ray telescopes observed some years ago”, says Wouter Vlemmings, astronomer at Chalmers, who led the team.

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Giant Spiraling Molecular Gas Arms As Cradles Of Dense Massive Molecular Cores


Credit: ALMA(ESO/NAOJ/NRAO), H. B. Liu, J. Dale

Credit: ALMA(ESO/NAOJ/NRAO), H. B. Liu, J. Dale

A research team led by Dr. Hauyu Liu at the Institute of Astronomy and Astrophysics, Academia Sinica (ASIAA) observed the luminous OB cluster-forming massive molecular clump G33.92+0.11 with the Atacama Large Millimeter/submillimeter Array (ALMA), and unveiled the fine molecular gas structures deeply embedded at the center of the parent molecular cloud. This finding provides a greatly simplified picture of overall cloud geometry and kinematics, which represents a crucial step forward in the understanding of the upper end of the stellar and molecular core mass functions. The research was published in the April 28 issue of The Astrophysical Journal.

Via ALMA observations, this research for the first time resolved an embedded giant coherent dense gas structure on a several light-year scale. Surprisingly, this dense gas structure presents several spiral arms, which appear like a version of the previously observed spiral arms surrounding the low-mass protobinary, scaled-up by a factor of ~103. These giant spiral arms, and the massive molecular gas cores located at their convergence, are cradles to form the highest mass stars in this stellar cluster.

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ALMA Discovers Proto Super Star Cluster — A Cosmic ‘Dinosaur Egg’ About To Hatch


Credit: K. Johnson, U.Va.; ALMA (NRAO/ESO/NAOJ)

Credit: K. Johnson, U.Va.; ALMA (NRAO/ESO/NAOJ)

Globular clusters – dazzling agglomerations of up to a million ancient stars – are among the oldest objects in the universe. Though plentiful in and around many galaxies, newborn examples are vanishingly rare and the conditions necessary to create new ones have never been detected, until now.

Astronomers using the Atacama Large Millimeter/submillimeter Array (ALMA) have discovered what may be the first known example of a globular cluster about to be born: an incredibly massive, extremely dense, yet star-free cloud of molecular gas.

“We may be witnessing one of the most ancient and extreme modes of star formation in the universe,” said Kelsey Johnson, an astronomer at the University of Virginia in Charlottesville and lead author on a paper accepted for publication in the Astrophysical Journal. “This remarkable object looks like it was plucked straight out of the very early universe. To discover something that has all the characteristics of a globular cluster, yet has not begun making stars, is like finding a dinosaur egg that’s about to hatch.”

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‘Perfect Storm’ Quenching Star Formation Around A Supermassive Black Hole

December 17, 2014 Leave a comment

A combined Hubble Space Telescope / ALMA image of NGC 1266. Credit: NASA/ESA Hubble; ALMA (NRAO/ESO/NAOJ)

A combined Hubble Space Telescope / ALMA image of NGC 1266. Credit: NASA/ESA Hubble; ALMA (NRAO/ESO/NAOJ)

High-energy jets powered by supermassive black holes can blast away a galaxy’s star-forming fuel, resulting in so-called “red and dead” galaxies: those brimming with ancient red stars yet containing little or no hydrogen gas to create new ones.

Now astronomers using the Atacama Large Millimeter/submillimeter Array (ALMA) have discovered that black holes don’t have to be nearly so powerful to shut down star formation. By observing the dust and gas at the center of NGC 1266, a nearby lenticular galaxy with a relatively modest central black hole, the astronomers have detected a “perfect storm” of turbulence that is squelching star formation in a region that would otherwise be an ideal star factory.

This turbulence is stirred up by jets from the galaxy’s central black hole slamming into an incredibly dense envelope of gas. This dense region, which may be the result of a recent merger with another smaller galaxy, blocks nearly 98 percent of material propelled by the jets from escaping the galactic center.

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ALMA Confirms Comets Forge Organic Molecules In Their Dusty Atmospheres

August 12, 2014 Leave a comment

The emission from organic molecules in the atmosphere of comet ISON as observed with ALMA. Credit: B. Saxton (NRAO/AUI/NSF); M. Cordiner, NASA, et al.

The emission from organic molecules in the atmosphere of comet ISON as observed with ALMA. Credit: B. Saxton (NRAO/AUI/NSF); M. Cordiner, NASA, et al.

An international team of scientists using the Atacama Large Millimeter/submillimeter Array (ALMA) has made incredible 3D images of the ghostly atmospheres surrounding comets ISON and Lemmon. These new observations provided important insights into how and where comets forge new chemicals, including intriguing organic compounds.

Comets contain some of the oldest and most pristine materials in our Solar System. Understanding their unique chemistry could reveal much about the birth of our planet and the origin of organic compounds that are the building blocks of life. ALMA’s high-resolution observations provided a tantalizing 3D perspective of the distribution of the molecules within these two cometary atmospheres, or comas.

“We achieved truly first-of-a-kind mapping of important molecules that help us understand the nature of comets,” said team leader Martin Cordiner, a Catholic University of America astrochemist working at NASA’s Goddard Space Flight Center in Greenbelt, Maryland.

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‘Death Stars’ In Orion Blast Planets Before They Even Form


Artist's concept. Credit: NRAO/AUI/NSF; B. Saxton

Artist’s concept. Credit: NRAO/AUI/NSF; B. Saxton

The Orion Nebula is home to hundreds of young stars and even younger protostars known as proplyds. Many of these nascent systems will go on to develop planets, while others will have their planet-forming dust and gas blasted away by the fierce ultraviolet radiation emitted by massive O-type stars that lurk nearby.

A team of astronomers from Canada and the United States has used the Atacama Large Millimeter/submillimeter Array (ALMA) to study the often deadly relationship between highly luminous O-type stars and nearby protostars in the Orion Nebula. Their data reveal that protostars within 0.1 light-years (about 600 billion miles) of an O-type star are doomed to have their cocoons of dust and gas stripped away in just a few millions years, much faster than planets are able to form.

“O-type stars, which are really monsters compared to our Sun, emit tremendous amounts of ultraviolet radiation and this can play havoc during the development of young planetary systems,” remarked Rita Mann, an astronomer with the National Research Council of Canada in Victoria, and lead author on a paper in the Astrophysical Journal. “Using ALMA, we looked at dozens of embryonic stars with planet-forming potential and, for the first time, found clear indications where protoplanetary disks simply vanished under the intense glow of a neighboring massive star.”

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Nearby Star’s Icy Debris Suggests ‘Shepherd’ Planet


An international team of astronomers exploring the disk of gas and dust around a nearby star have uncovered a compact cloud of poisonous gas formed by ongoing rapid-fire collisions among a swarm of icy, comet-like bodies. The researchers suggest the comet swarm is either the remnant of a crash between two icy worlds the size of Mars or frozen debris trapped and concentrated by the gravity of an as-yet-unseen planet.

Using the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile, the researchers mapped millimeter-wavelength light from dust and carbon monoxide (CO) molecules in a disk surrounding the bright star Beta Pictoris. Located about 63 light-years away and only 20 million years old, the star hosts one of the closest, brightest and youngest debris disks known, making it an ideal laboratory for studying the early development of planetary systems.

“Although toxic to us, carbon monoxide is one of many gases found in comets and other icy bodies,” said team member Aki Roberge, an astrophysicist at NASA’s Goddard Space Flight Center in Greenbelt, Md. “In the rough-and-tumble environment around a young star, these objects frequently collide and generate fragments that release dust, icy grains and stored gases.”

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ALMA Discovers A Formation Site Of A Giant Planetary System

January 21, 2014 Leave a comment

Credit: ALMA (ESO/NAOJ/NRAO), Fukagawa et al.

Credit: ALMA (ESO/NAOJ/NRAO), Fukagawa et al.

A team of Japanese astronomers has obtained a firm evidence of formation of a giant planetary system around a young star by the observations with the Atacama Large Millimeter/submillimeter Array (ALMA). This result has a transformative impact on the theories of planet formation and gives us a clue to the origin of a wide variety of planetary systems.

The research team, led by astronomers at Osaka University and Ibaraki University, observed a young star named HD142527 in the constellation Lupus (the Wolf) with ALMA. The ALMA image shows that cosmic dust, which is component material of planets, is circling around the star in a form of asymmetric ring. By measuring the density of dust in the densest part of the ring, the astronomers found that it is highly possible that planets are now being formed in that region. This region is far from the central star, about 5 times larger than the distance between the Sun and the Neptune. This is the first firm evidence of planet formation found so far from the central star in a protoplanetary disk. The research team plans further observations of HD142527 with ALMA for closer investigation, as well as other protoplanetary disks to have a comprehensive understanding of the planet formation in general.

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Starless Cloud Cores Reveal Why Some Stars Are Bigger Than Others

December 20, 2013 Leave a comment

Credit: Bill Saxton & Alexandra Angelich (NRAO/AUI/NSF); ALMA (ESO/NAOJ/NRAO)

Credit: Bill Saxton & Alexandra Angelich (NRAO/AUI/NSF); ALMA (ESO/NAOJ/NRAO)

Massive stars – those at least 8 times the mass of our Sun – present an intriguing mystery: how do they grow so large when the vast majority of stars in the Milky Way are considerably smaller?

To find the answer, astronomers used the Atacama Large Millimeter/submillimeter Array (ALMA) telescope to survey the cores of some of the darkest, coldest, and densest clouds in our Galaxy to search for the telltale signs of star formation.

To find the answer, astronomers used the Atacama Large Millimeter/submillimeter Array (ALMA) telescope to survey the cores of some of the darkest, coldest, and densest clouds in our Galaxy to search for the telltale signs of star formation.

Since these cloud cores are so massive and dense, gravity should have already overwhelmed their supporting gas pressure, allowing them to collapse to form new, Sun-mass stars. If a star had not yet begun to shine, that would be a hint that something extra was supporting the cloud.

“A starless core would indicate that some force was balancing out the pull of gravity, regulating star formation, and allowing vast amounts of material to accumulate in a scaled-up version of the way our own Sun formed,” remarked Jonathan Tan, an astrophysicist at the University of Florida, Gainesville, and lead author of a paper published today in the Astrophysical Journal. “This suggests that massive stars and Sun-like stars follow a universal mechanism for star formation. The only difference is the size of their parent clouds.”

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