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  • richardmitnick 3:02 pm on August 28, 2016 Permalink | Reply
    Tags: ALMA, , , , , ,   

    From SEEKER: “The Race to See Our Supermassive Black Hole” 

    Seeker bloc

    SEEKER

    May 26, 2016 [Article brought forward by ESO]
    No writer credit found

    Using the power of interferometry, two astronomical projects are, for the first time, close to directly observing the black hole in the center of the Milky Way.

    Sag A*  NASA Chandra X-Ray Observatory 23 July 2014, the supermassive black hole at the center of the Milky Way
    Sag A* NASA Chandra X-Ray Observatory 23 July 2014, the supermassive black hole at the center of the Milky Way

    There’s a monster living in the center of the galaxy.

    We know the supermassive black hole is there by tracking the motions of stars and gas clouds that orbit an invisible point. That point exerts an overwhelming tidal influence on all objects that get trapped in its gravitational domain and this force can be measured through stellar orbits to calculate its mass.

    It certainly isn’t the biggest black hole in the universe, but it isn’t the smallest either, it “weighs in” at an incredible 4 million times the mass of our sun.

    But this black hole behemoth, called Sagittarius A*, is over 20,000 light-years from Earth making direct observations, before now, nigh-on impossible. Despite its huge mass, the black hole is minuscule when seen from Earth; a telescope with an unprecedented angular resolution is needed.

    Though we already know a lot about Sagittarius A* from indirect observations, seeing is believing and there’s an international race, using the world’s most powerful observatories and sophisticated astronomical techniques, to zoom-in on the Milky Way’s black hole. This won’t only prove it’s really there, but it will reveal a region where space-time is so warped that we will be able to make direct tests of general relativity in the strongest gravity environment known to exist in the universe.

    The Event Horizon Telescope and GRAVITY

    A huge global effort is currently under way to link a network of global radio telescopes to create a virtual telescope that will span the width of our planet. Using the incredible power of interferometry, astronomers can combine the light from many distant radio antennae and collect it at one point, to mimic one large radio antenna spanning the globe.

    Event Horizon Telescope Array

    Event Horizon Telescope map
    Event Horizon Telescope map

    Arizona Radio Observatory
    Arizona Radio Observatory/Submillimeter-wave Astronomy (ARO/SMT)

    ESO/APEX
    Atacama Pathfinder EXperiment (APEX)

    CARMA Array no longer in service
    Combined Array for Research in Millimeter-wave Astronomy (CARMA)

    Atacama Submillimeter Telescope Experiment (ASTE)
    Atacama Submillimeter Telescope Experiment (ASTE)

    Caltech Submillimeter Observatory
    Caltech Submillimeter Observatory (CSO)

    IRAM NOEMA interferometer
    Institut de Radioastronomie Millimetrique (IRAM) 30m

    James Clerk Maxwell Telescope interior, Mauna Kea, Hawaii, USA
    James Clerk Maxwell Telescope interior, Mauna Kea, Hawaii, USA

    Large Millimeter Telescope Alfonso Serrano
    Large Millimeter Telescope Alfonso Serrano

    CfA Submillimeter Array Hawaii SAO
    Submillimeter Array Hawaii SAO

    Future Array/Telescopes

    ESO/NRAO/NAOJ ALMA Array
    ESO/NRAO/NAOJ ALMA Array, Chile

    Plateau de Bure interferometer
    Plateau de Bure interferometer

    South Pole Telescope SPTPOL
    South Pole Telescope SPTPOL

    This effort is known as the Event Horizon Telescope (EHT) and it is hoped the project will be able to attain the angular resolution and spatial definition required to soon produce its first radio observations of the bright ring just beyond Sagittarius A*’s event horizon — the point surrounding a black hole where nothing, not even light, can escape.

    However, another project has the same goal in mind, but it’s not going to observe in radio wavelengths, it’s going to stare deep into the galactic core to seek out optical and infrared light coming from Sagittarius A* and it just needs one observatory to make this goal a reality.

    1
    The ESO Very Large Telescope located atop Cerro Paranal in Chile. Ian O’Neill

    The GRAVITY instrument is currently undergoing commissioning at the ESO’s Very Large Telescope at Paranal Observatory high in the Atacama Desert in Chile (at an altitude of over 2,600 meters or 8,300 ft) and it will also use the power of interferometry to resolve our supermassive black hole. But rather than connecting global observatories like the EHT, GRAVITY will combine the light of the four 8 meter telescopes of the VLT Interferometer (collectively known as the VLTI) to create a “virtual” telescope measuring the distance between each individual telescope.

    ESO GRAVITY insrument
    ESO GRAVITY insrument

    “By doing this you can reach the same resolution and precision that you would get from a telescope that has a size, in this case, of roughly a hundred meters, simply because these eight meter-class telescopes are separated by roughly one hundred meters,” astronomer Oliver Pfuhl, of Max Planck Institute for Extraterrestrial Physics, Germany, told DNews. “If you combine the light from those you reach the same resolution as a virtual telescope of a hundred meters would have.”

    Strong Gravity Environment

    When GRAVITY is online it will be used to track features just outside Sagittarius A*’s event horizon.

    “For about ten years, we’ve known that this black hole is actually not black. Once in awhile it flares, so we see it brightening and darkening,” he said. This flaring is matter falling into the event horizon, generating a powerful flash of energy. The nature of these flares are poorly understood, but the instrument should be able to track this flaring material as it rapidly orbits the event horizon and fades away. These flares will also act as tracers, helping us see the structure of space-time immediately surrounding a black hole for the first time.

    2
    One of the four Very Large Telescope domes fires its new four-laser adaptive optics system. GRAVITY will make use of adaptive optics to improve observations of Sagittarius A* by compensating for the effects of atmospheric turbulence. ESO

    “Our goal is to measure these motions. We think that what we see as this flaring is actually gas which spirals into the black hole. This brightening and darkening is essentially the gas, when it comes too close to the black hole, the strong tidal forces make it heat up,” said Pfuhl.

    “If we can study these motions which happen so close to the black hole, we have a direct probe of the space time close to the black hole. In this way we have a direct test of general relativity in one of the most extreme environments which you can find in the universe.”

    While GRAVITY will be able to track these flaring events very close to the black hole, the Event Horizon Telescope will see the shadow, or silhouette, of the dark event horizon surrounded by radio wave emissions. Both projects will be able to measure different components of the region directly surrounding the event horizon, so combined observations in optical and radio wavelengths will complement one other.

    It just so happens that the Atacama Large Millimeter/submillimeter Array (ALMA), the largest radio observatory on the planet — also located in the Atacama Desert — will also be added to the EHT.

    “The Event Horizon Telescope will combine ALMA with telescopes around the world like Hawaii and other locations, and with that power you can look at really fine details especially in the black hole in the center of our galaxy and perhaps in some really nearby other galaxies that also have black holes in their centers,” ESO astronomer Linda Watson told DNews.

    3
    The ALMA antenna in a clustered formation on Chajnantor plateau during the #MeetESO event on May 11, 2016. The extreme location of the observatory can produce unpredictable weather and, as depicted here, a blizzard descended on the plateau cutting the visit short.
    Ian O’Neill

    ALMA itself is an interferometer combining the collecting power of 66 radio antennae located atop Chajnantor plateau some 5,000 meters (16,400 ft) in altitude. Watson uses ALMA data to study the cold dust in interstellar space, but when added to the EHT, its radio-collecting power will help us understand the dynamics of the environment surrounding Sagittarius A*.

    “ALMA’s an interferometer with 66 antennas, (the EHT) will treat ALMA as just one telescope and will combine it with other telescopes around the world to be another interferometer,” she added.

    Black Hole Mysteries

    Many black holes are thought to possess an accretion disk of swirling gas and dust. ALMA, when combined with the EHT, will be able to measure this disk’s structure, speed and direction of motion. Lacking direct observations, many of these characteristics have only been modeled by computer simulations or inferred from indirect observations. We’re about to enter an era when we can truly get to answer some of the biggest mysteries surrounding black hole dynamics.

    “The first thing we want to see is we want to understand how accretion works close to the black hole,” said Pfuhl. “This is also true for the Event Horizon Telescope. Another thing we want to learn is does our black hole have spin? That means, does it rotate?”

    Though the EHT and GRAVITY are working at different wavelengths, observing phenomena around Sagittarius A* will reveal different things about the closest supermassive black hole to Earth. By extension it is hoped that we may observe smaller black holes in our galaxy and other supermassive black holes in neighboring galaxies.

    3
    Computer simulation of what theoretical physiicists expect to see with the EHT — a round, dark disk surrounded by radio emissions.
    Avery E. Broderick/Univ. of Waterloo/Perimeter Institute (screenshot from the Convergence meeting)

    But as we patiently wait for the first direct observations of the black hole monster lurking in the center of our galaxy, an event that some scientists say will be as historic as the “Pale Blue Dot” photo of Earth as captured by Voyager 1 in 1990, it’s hard not to wonder which project will get there first.

    “I think it’s a very tight race,” said Pfuhl. “Let’s see.”

    See the full article here .

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  • richardmitnick 1:19 pm on August 25, 2016 Permalink | Reply
    Tags: ALMA, ALMA Finds Unexpected Trove of Gas Around Larger Stars, , , ,   

    From ALMA: “ALMA Finds Unexpected Trove of Gas Around Larger Stars” 

    ESO/NRAO/NAOJ ALMA Array
    ESO/NRAO/NAOJ ALMA Array in Chile in the Atacama at Chajnantor plateau, at 5,000 metres
    ALMA

    25 August 2016
    Contacts

    Nicolás Lira T.
    Education and Public Outreach Coordinator
    Joint ALMA Observatory
    Santiago, Chile
    Tel: +56 2 24 67 65 19
    Cell: +56 9 94 45 77 26
    Email: nicolas.lira@alma.cl

    Charles E. Blue
    Public Information Officer
    National Radio Astronomy Observatory
    Charlottesville, Virginia, USA
    Tel: +1 434 296 0314
    Cell: +1 202 236 6324
    E-mail: cblue@nrao.edu

    Masaaki Hiramatsu

    Education and Public Outreach Officer, NAOJ Chile
    Observatory
Tokyo, Japan

    Tel: +81 422 34 3630

    E-mail: hiramatsu.masaaki@nao.ac.jp

    Richard Hook
    Public Information Officer, ESO

    Garching bei München, Germany

    Tel: +49 89 3200 6655

    Cell: +49 151 1537 3591
    Email: rhook@eso.org

    1
    Artist impression of a debris disk surrounding a star in the Scorpius-Centaurus Association. ALMA discovered that — contrary to expectations — the more massive stars in this region retain considerable stores of carbon monoxide gas. This finding could offer new insights into the timeline for giant planet formation around young stars. Credit: NRAO/AUI/NSF; D. Berry / SkyWorks

    Astronomers using the Atacama Large Millimeter/submillimeter Array (ALMA) surveyed dozens of young stars – some Sun-like and others nearly double that size – and discovered that the larger variety have surprisingly rich reservoirs of carbon monoxide gas in their debris disks. In contrast, the lower-mass, Sun-like stars have debris disks that are virtually gas-free.

    This finding runs counter to astronomer’s expectations, which hold that stronger radiation from larger stars should strip away gas from their debris disks faster than the comparatively mild radiation from smaller stars. It may also offer new insights into the timeline for giant planet formation around young stars.

    Debris disks are found around stars that have shed their dusty, gas-filled protoplanetary disks and gone on to form planets, asteroids, comets, and other planetesimals. Around younger stars, however, many of these newly formed objects have yet to settle into stately orbits and routinely collide, producing enough rubble to spawn a “second-generation” disk of debris.

    “Previous spectroscopic measurements of debris disks revealed that certain ones had an unexpected chemical signature suggesting they had an overabundance of carbon monoxide gas,” said Jesse Lieman-Sifry, lead author on a paper published in Astrophysical Journal. At the time of the observations, Lieman-Sifry was an undergraduate astronomy major at Wesleyan University in Middletown, Connecticut. “This discovery was puzzling since astronomers believe that this gas should be long gone by the time we see evidence of a debris disk,” he said.

    In search of clues as to why certain stars harbor gas-rich disks, Lieman-Sifry and his team surveyed 24 star systems in the Scorpius-Centaurus Association. This loose stellar agglomeration, which lies a few hundred light-years from Earth, contains hundreds of low- and intermediate-mass stars. For reference, astronomers consider our Sun to be a low-mass star.

    The astronomers narrowed their search to stars between five and ten million years old — old enough to host full-fledged planetary systems and debris disks — and used ALMA to examine the millimeter-wavelength “glow” from the carbon monoxide in the star’s debris disks.

    The team carried out their survey over a total of six nights between December 2013 and December 2014, observing for a mere ten minutes each night. At the time it was conducted, this study constituted the most extensive millimeter-wavelength interferometric survey of stellar debris disks ever achieved.

    2
    ALMA image of the debris disk surrounding a star in the Scorpius-Centaurus Association known as HIP 73145. The green region maps the carbon monoxide gas that suffuses the debris disk. The red is the millimeter-wavelength light emitted by the dust surrounding the central star. The star HIP 73145 is estimated to be approximately twice the mass of the Sun. The disk in this system extends well past what would be the orbit of Neptune in our solar system, drawn in for scale. The location of the central star is also highlighted for reference. Credit: J. Lieman-Sifry, et al., ALMA (ESO/NAOJ/NRAO); B. Saxton (NRAO/AIU/NSF)

    Armed with an incredibly rich set of observations, the astronomers found the most gas-rich disks ever recorded in a single study. Among their sample of two dozen disks, the researchers spotted three that exhibited strong carbon monoxide emission. Much to their surprise, all three gas-rich disks surrounded stars about twice as massive as the Sun. None of the 16 smaller, Sun-like stars in the sample appeared to have disks with large stores of carbon monoxide. These observations suggest that larger stars are more likely to sport disks with significant gas reservoirs than Sun-like stars.

    This finding is counterintuitive, because higher-mass stars flood their planetary systems with energetic ultraviolet radiation that should destroy the carbon monoxide gas lingering in their debris disks. This new research reveals, however, that the larger stars are somehow able to either preserve or replenish their carbon monoxide stockpiles.

    “We’re not sure whether these stars are holding onto reservoirs of gas much longer than expected, or whether there’s a sort of ‘last gasp’ of second-generation gas produced by collisions of comets or evaporation from the icy mantles of dust grains,” said Meredith Hughes, an astronomer at Wesleyan University and coauthor of the study.

    The existence of this gas may have important implications for planet formation, says Hughes. Carbon monoxide is a major constituent of the atmospheres of giant planets. Its presence in debris disks could mean that other gases, including hydrogen, are present, but perhaps in much lower concentrations. If certain debris disks are able to hold onto appreciable amounts of gas, it might push back the expected deadline for giant planet formation around young stars, the astronomers speculate.

    3
    ALMA image of the debris disk surrounding a star in the Scorpius-Centaurus Association known as HIP 73145. The green region maps the carbon monoxide gas that suffuses the debris disk. The red is the millimeter-wavelength light emitted by the dust surrounding the central star. The star HIP 73145 is estimated to be approximately twice the mass of the Sun. The disk in this system extends well past what would be the orbit of Neptune in our solar system. Credit: J. Lieman-Sifry, et al., ALMA (ESO/NAOJ/NRAO); B. Saxton (NRAO/AIU/NSF)

    “Future high-resolution observations of these gas-rich systems may allow astronomers to infer the location of the gas within the disk, which may shed light on the origin of the gas,” says Antonio Hales, an astronomer with the Joint ALMA Observatory in Santiago, Chile, and the National Radio Astronomy Observatory in Charlottesville, Virginia, and coauthor on the study. “For instance, if the gas was produced by planetesimal collisions, it should be more highly concentrated in regions of the disk where those impacts occurred. ALMA is the only instrument capable of making these kind of high-resolution images.”

    According to Lieman-Sifry, these dusty disks are just as diverse as the planetary systems they accompany. The discovery that the debris disks around some larger stars retain carbon monoxide longer than their Sun-like counterparts may provide insights into the role this gas plays in the development of planetary systems.

    4
    Four out of 24 debris disks observed by ALMA in the Scorpius-Centaurus Association. Researchers were surprised to discover that the larger, more energetic stars retained much more gas in their debris disks than smaller, Sun-like stars. Credit: Lieman-Sifry et al. ALMA (ESO/NAOJ/NRAO); B. Saxton, NRAO/AUI/NSF

    Additional information

    This research is presented in the paper titled “Debris disks in the Scorpius-Centaurus OB association resolved by ALMA,” by J. Lieman-Sifry et al., published in Astrophysical Journal on 23 August 2016. [Preprint: http://arxiv.org/abs/1606.07068.

    The team is composed of Jesse Lieman-Sifry (Wesleyan Univ., Middletown, Connecticut), A. Meredith Hughes (Wesleyan Univ., Middletown, Connecticut), John M. Carpenter (California Institute of Technology, Pasadena), Uma Gorti (SETI Institute, Mountain View, California), Antonio Hales (Joint ALMA Observatory, Santiago, Chile, and National Radio Astronomy Observatory, Charlottesville, Virginia), and Kevin M. Flaherty (Wesleyan Univ., Middletown, Connecticut).

    See the full article here .

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    The Atacama Large Millimeter/submillimeter Array (ALMA), an international astronomy facility, is a partnership of Europe, North America and East Asia in cooperation with the Republic of Chile. ALMA is funded in Europe by the European Organization for Astronomical Research in the Southern Hemisphere (ESO), in North America by the U.S. National Science Foundation (NSF) in cooperation with the National Research Council of Canada (NRC) and the National Science Council of Taiwan (NSC) and in East Asia by the National Institutes of Natural Sciences (NINS) of Japan in cooperation with the Academia Sinica (AS) in Taiwan.

    ALMA construction and operations are led on behalf of Europe by ESO, on behalf of North America by the National Radio Astronomy Observatory (NRAO), which is managed by Associated Universities, Inc. (AUI) and on behalf of East Asia by the National Astronomical Observatory of Japan (NAOJ). The Joint ALMA Observatory (JAO) provides the unified leadership and management of the construction, commissioning and operation of ALMA.

    NRAO Small

    ESO 50

    NAOJ

     
  • richardmitnick 9:38 am on August 15, 2016 Permalink | Reply
    Tags: ALMA, ALMA Achieved Highest Polarimetric Sensitivity, , , ,   

    From ALMA: “ALMA Achieved Highest Polarimetric Sensitivity” 

    ESO/NRAO/NAOJ ALMA Array
    ESO/NRAO/NAOJ ALMA Array in Chile in the Atacama at Chajnantor plateau, at 5,000 metres
    ALMA

    Monday, 18 July 2016 [Just found this at ALMA’s website. Never saw it in social media.]
    Nicolás Lira T.
    Education and Public Outreach Coordinator
    Joint ALMA Observatory
    Santiago, Chile
    Tel: +56 2 24 67 65 19
    Cell: +56 9 94 45 77 26
    Email: nicolas.lira@alma.cl

    Masaaki Hiramatsu

    Education and Public Outreach Officer, NAOJ Chile
    Observatory
Tokyo, Japan

    Tel: +81 422 34 3630

    E-mail: hiramatsu.masaaki@nao.ac.jp

    Richard Hook
    Public Information Officer, ESO

    Garching bei München, Germany

    Tel: +49 89 3200 6655

    Cell: +49 151 1537 3591
    Email: rhook@eso.org

    Charles E. Blue
    Public Information Officer
    National Radio Astronomy Observatory
    Charlottesville, Virginia, USA
    Tel: +1 (434) 296 0314
    Cell: +1 202 236 6324
    E-mail: cblue@nrao.edu

    1
    3C 286 observed with ALMA. Contours shows the intensity of radio waves and purple bars shows the polarization direction. The central part of the quasar is located in the center of the image, and a part of the jet ejected by the quasar is seen on the right. Credit: ALMA (ESO/NAOJ/NRAO), Nagai et al.

    Researchers have confirmed ALMA’s unprecedented capability for polarimetry in millimeter/submillimeter wavebands. Polarimetry is an important method to investigate magnetic fields in the Universe and astronomers are eager to use ALMA for unveiling magnetic mysteries, such as the launching mechanism of high energy jets from supermassive black holes.

    The magnetic field is ubiquitous and plays considerable roles in the Universe. We can find the directions by using a compass thanks to Earth’s magnetic field. Sunspots and solar flares are driven by magnetic fields in the Sun. Magnetic fields are also important in various occasions including formation of stars and planets, and exotic events around black holes. In spite of its significance, measurement of magnetic fields is difficult. Polarimetry is one of the handful methods to investigate magnetic fields in the Universe.

    ALMA is designed to perform sensitive polarimetry observations. To verify its capability, astronomers observe well-known objects and compare the results with those of existing telescopes. ALMA started science observations in 2011, but in parallel, science verification activities for advanced observation methods have been carried out.

    ALMA observed the bright source 3C 286 for the verifications of polarimetry observations. The source, located 7.3 billion light years away from us, is a quasar, emitting very strong radio waves. Many researchers assume that a supermassive black hole is located in the center of a quasar and intense magnetic fields are responsible for ejecting powerful jets. ALMA pointed to the root of the jet from 3C 286 to measure the intensity and the direction of the polarized wave. The result reveal details not seen before and clearly show that the magnetic field is stronger and more ordered towards the inner region of the jet that emerges from the quasar. This helps researchers to understand the magnetic field structure in the very heart of the quasar, furnishing vital clues about the physical processes that give rise to the radio emission.

    “This observation has certainly verified the high capability of the polarimetry observation with ALMA,” said Hiroshi Nagai at the National Astronomical Observatory of Japan and the leader of the verification team. “This is an important milestone for the ALMA project.”

    In general, the polarized component is as weak as a few percent of the total radio flux from an object. High sensitivity is essential for the precise polarimetry, and ALMA is suitable for it. The science verification activity includes the establishment of the proper calibration and many test observations have been performed to ensure the high precision. Such behind-the-scenes efforts provide a firm platform for advanced observations with ALMA.

    Additional information

    These observation results were published by Nagai et al. as “ALMA Science Verification Data: Millimeter Continuum Polarimetry of the Bright Radio Quasar 3C 286” in the Astrophysical Journal issued on 20 June 2016.

    The science verification activities for polarimetry is introduced in an article Polarization observations with ALMA in the serial column “¡Bienvenido a ALMA!”.

    The first scientific results containing ALMA full polarization data were published by the Astrophysical Journal Letters on June 30, 2016, as Interferometric Mapping Of Magnetic Fields: The Alma View Of The Massive Star-Forming Clump W43-MM1 by Cortés et al.

    See the full article here .

    Please help promote STEM in your local schools.
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    The Atacama Large Millimeter/submillimeter Array (ALMA), an international astronomy facility, is a partnership of Europe, North America and East Asia in cooperation with the Republic of Chile. ALMA is funded in Europe by the European Organization for Astronomical Research in the Southern Hemisphere (ESO), in North America by the U.S. National Science Foundation (NSF) in cooperation with the National Research Council of Canada (NRC) and the National Science Council of Taiwan (NSC) and in East Asia by the National Institutes of Natural Sciences (NINS) of Japan in cooperation with the Academia Sinica (AS) in Taiwan.

    ALMA construction and operations are led on behalf of Europe by ESO, on behalf of North America by the National Radio Astronomy Observatory (NRAO), which is managed by Associated Universities, Inc. (AUI) and on behalf of East Asia by the National Astronomical Observatory of Japan (NAOJ). The Joint ALMA Observatory (JAO) provides the unified leadership and management of the construction, commissioning and operation of ALMA.

    NRAO Small

    ESO 50

    NAOJ

     
  • richardmitnick 1:11 pm on July 29, 2016 Permalink | Reply
    Tags: ALMA, , , , NGC 4945, , U Manchester   

    From U Manchester: “Astronomers Uncover Hidden Stellar Birthplace” 

    U Manchester bloc

    University of Manchester

    26 July, 2016
    Joe Paxton

    1
    No image caption. No image credit.

    A team of astronomers from the University of Manchester, the Max Planck Institute for Radio Astronomy and the University of Bonn have uncovered a hidden stellar birthplace in a nearby spiral galaxy, using a telescope in Chile. The results show that the speed of star formation in the centre of the galaxy – and other galaxies like it – may be much higher than previously thought.

    The team penetrated the thick dust around the centre of galaxy NGC 4945 using the Atacama Large Millimeter Array (ALMA), a single telescope made up of 66 high precision antennas located 5000 metres above sea level in northern Chile.

    ESO/NRAO/NAOJ ALMA Array in Chile in the Atacama at  Chajnantor plateau, at 5,000 metres
    ESO/NRAO/NAOJ ALMA Array in Chile in the Atacama at Chajnantor plateau, at 5,000 metres

    Astronomers typically look for ultraviolet light or infrared emissions from the brightest, hottest, and bluest stars. The places where stars form are often surrounded by interstellar dust that absorbs the ultraviolet and visible light from the hot blue stars, making it difficult to see where stars are forming. However, the interstellar dust gets warmer when it absorbs light and produces infrared radiation.

    NGC 4945 is unusual because the interstellar dust is so dense that it even absorbs the infrared light that it produces, meaning that astronomers find it hard to know what is happening in the centre of the galaxy. However, ALMA is able to see through even the thickest interstellar dust.

    “When we looked at the galaxy with ALMA, its centre was ten times brighter than we would have anticipated based on the mid-infrared image. It was so bright that I asked one of my collaborators to check my calculations just to make sure that I hadn’t made an error.”
    Dr. George J. Bendo

    “While it looks very dusty and very bright in the infrared compared to the Milky Way or other nearby spiral galaxies, it is very similar to other infrared-bright starburst galaxies that are more common in the more distant universe. If other astronomers are trying to look at star formation using infrared light, they might be missing a lot of what’s happening if the star forming regions are as obscured as in NGC 4945.”

    Fellow collaborator Professor Gary Fuller, also from the University of Manchester, added: “These results demonstrate the remarkable power of ALMA to study star formation which would otherwise be hidden.”

    See the full article here .

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    U Manchester campus

    The University of Manchester (UoM) is a public research university in the city of Manchester, England, formed in 2004 by the merger of the University of Manchester Institute of Science and Technology (renamed in 1966, est. 1956 as Manchester College of Science and Technology) which had its ultimate origins in the Mechanics’ Institute established in the city in 1824 and the Victoria University of Manchester founded by charter in 1904 after the dissolution of the federal Victoria University (which also had members in Leeds and Liverpool), but originating in Owens College, founded in Manchester in 1851. The University of Manchester is regarded as a red brick university, and was a product of the civic university movement of the late 19th century. It formed a constituent part of the federal Victoria University between 1880, when it received its royal charter, and 1903–1904, when it was dissolved.

    The University of Manchester is ranked 33rd in the world by QS World University Rankings 2015-16. In the 2015 Academic Ranking of World Universities, Manchester is ranked 41st in the world and 5th in the UK. In an employability ranking published by Emerging in 2015, where CEOs and chairmen were asked to select the top universities which they recruited from, Manchester placed 24th in the world and 5th nationally. The Global Employability University Ranking conducted by THE places Manchester at 27th world-wide and 10th in Europe, ahead of academic powerhouses such as Cornell, UPenn and LSE. It is ranked joint 56th in the world and 18th in Europe in the 2015-16 Times Higher Education World University Rankings. In the 2014 Research Excellence Framework, Manchester came fifth in terms of research power and seventeenth for grade point average quality when including specialist institutions. More students try to gain entry to the University of Manchester than to any other university in the country, with more than 55,000 applications for undergraduate courses in 2014 resulting in 6.5 applicants for every place available. According to the 2015 High Fliers Report, Manchester is the most targeted university by the largest number of leading graduate employers in the UK.

    The university owns and operates major cultural assets such as the Manchester Museum, Whitworth Art Gallery, John Rylands Library and Jodrell Bank Observatory which includes the Grade I listed Lovell Telescope.

     
  • richardmitnick 8:12 am on July 29, 2016 Permalink | Reply
    Tags: ALMA, , , , , The Role of Magnetic Fields in Star-Formation   

    From CfA: “The Role of Magnetic Fields in Star-Formation” 

    Smithsonian Astrophysical Observatory
    Smithsonian Astrophysical Observatory

    July 1, 2016
    No writer credit

    1
    A false-color far-infrared image of the star forming region W43; the contours are for molecular gas density. The subregion MM1 located just left of center in not conspicuous in the image but is the site of massive star formation and fragmentation. A new study has mapped the magnetic fields in this region, and found they are not strong enough to prevent further gravitational collapse. ESA/Herschel and L.Q. Nguyen et al.

    The star forming molecular clump W43-MM1 is very massive and dense, containing about 2100 solar-masses of material in a region only one-third of a light-year across (for comparison, the nearest star to the Sun is a bit over four light-years away). Previous observations of this clump found evidence for infalling motions (signaling that material is still accumulating onto a new star) and weak magnetic fields. These fields are detected by looking for polarized light, which is produced when radiation scatters off of elongated dust grains aligned by magnetic fields. The Submillimeter Array recently probed this source with high spatial resolutions and found evidence for even stronger magnetic fields in places. One of the outstanding issues in star formation is the extent to which magnetic fields inhibit the collapse of material onto stars, and this source seems to offer a particularly useful example.

    CfA astronomers Josep Girart and TK Sridharan and their colleagues have used the ALMA submillimeter facility to obtain images with spatial scales as small as 0.03 light-years. Their detailed polarization maps show that the magnetic field is well ordered all across the clump, which itself is actually fifteen smaller fragments, one of which (at 312 solar-masses) appears to be the most massive fragment known.

    The scientists analyze the magnetic field strengths and show that, even in the least massive fragment the field is not strong enough to inhibit gravitational collapse. In fact, they find indications that gravity, as it pulls material inward, drags the magnetic field lines along. They are, however, unable to rule out possible further fragmentation. The research is the most precise study of magnetic fields in star forming massive clumps yet undertaken, and provides a new reference point for theoretical models.

    Reference(s):

    Interferometric Mapping of Magnetic Fields: The ALMA View of the Massive Star-forming Clump W43-MM1, Paulo C. Cortes, Josep M. Girart, Charles L. H. Hull, Tirupati K. Sridharan, Fabien Louvet, Richard Plambeck, Zhi-Yun Li, Richard M. Crutcher, and Shih-Ping Lai, ApJ 825, L15, 2016.

    See the full article here .

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    About CfA

    The Center for Astrophysics combines the resources and research facilities of the Harvard College Observatory and the Smithsonian Astrophysical Observatory under a single director to pursue studies of those basic physical processes that determine the nature and evolution of the universe. The Smithsonian Astrophysical Observatory (SAO) is a bureau of the Smithsonian Institution, founded in 1890. The Harvard College Observatory (HCO), founded in 1839, is a research institution of the Faculty of Arts and Sciences, Harvard University, and provides facilities and substantial other support for teaching activities of the Department of Astronomy. The long relationship between the two organizations, which began when the SAO moved its headquarters to Cambridge in 1955, was formalized by the establishment of a joint center in 1973. The CfA’s history of accomplishments in astronomy and astrophysics is reflected in a wide range of awards and prizes received by individual CfA scientists.

    Today, some 300 Smithsonian and Harvard scientists cooperate in broad programs of astrophysical research supported by Federal appropriations and University funds as well as contracts and grants from government agencies. These scientific investigations, touching on almost all major topics in astronomy, are organized into the following divisions, scientific departments and service groups.

     
  • richardmitnick 2:12 pm on July 13, 2016 Permalink | Reply
    Tags: ALMA, ALMA Observes First Protoplanetary Water Snow Line Thanks to Stellar Outburst, , , ,   

    From ALMA: “ALMA Observes First Protoplanetary Water Snow Line Thanks to Stellar Outburst” 

    ESO/NRAO/NAOJ ALMA Array
    ESO/NRAO/NAOJ ALMA Array in Chile in the Atacama at Chajnantor plateau, at 5,000 metres
    ALMA

    13 July 2016
    Lucas Cieza
    Universidad Diego Portales
    Santiago, Chile
    Tel: +56 22 676 8154
    Cell: +56 95 000 6541
    Email: lucas.cieza@mail.udp.cl

    Nicolás Lira T.
    Education and Public Outreach Coordinator
    Joint ALMA Observatory
    Santiago, Chile
    Tel: +56 2 24 67 65 19
    Cell: +56 9 94 45 77 26
    Email: nicolas.lira@alma.cl

    Richard Hook
    Public Information Officer, ESO

    Garching bei München, Germany

    Tel: +49 89 3200 6655

    Cell: +49 151 1537 3591
    Email: rhook@eso.org

    Charles E. Blue
    Public Information Officer
    National Radio Astronomy Observatory
    Charlottesville, Virginia, USA
    Tel: +1 434 296 0314
    Cell: +1 202 236 6324
    E-mail: cblue@nrao.edu

    Masaaki Hiramatsu

    Education and Public Outreach Officer, NAOJ Chile
    Observatory
Tokyo, Japan

    Tel: +81 422 34 3630

    E-mail: hiramatsu.masaaki@nao.ac.jp

    1
    Artist impression of the water snowline around the young star V883 Orionis, as detected with ALMA. Credit: A. Angelich (NRAO/AUI/NSF)/ALMA (ESO/NAOJ/NRAO).

    New observations with the Atacama Large Millimeter/submillimeter Array (ALMA) have produced the first image of a water snow line within a protoplanetary disk. This line marks where the temperature in the disk surrounding a young star drops sufficiently low for snow to form. A dramatic increase in the brightness of the young star V883 Orionis flash heated the inner portion of the disk, pushing the water snow line out to a far greater distance than is normal for a protostar, and making it possible to observe it for the first time. The results will be published in the journal Nature on July 14, 2016.

    2
    Image of the planet-forming disc around the young star V883 Orionis was obtained by ALMA in long-baseline mode. This star is currently in outburst, which has pushed the water snow line further from the star and allowed it to be detected for the first time. The dark ring midway through the disc is the water snowline, the point from the star where the temperature and pressure dip low enough for water ice to form. Credit: ALMA (ESO/NAOJ/NRAO)/L. Cieza.

    Young stars are often surrounded by dense, rotating disks of gas and dust, known as protoplanetary disks, from which planets are born. Snow lines are the regions in those disks where the temperature reaches the sublimation point for most of the volatile molecules. In the inner disk regions, inside water snow lines, water is vaporized, while outside these lines, in the outer disk, water is found frozen in the form of snow. These lines are so important that they define the basic architecture of planetary systems like our own [1] and are usually located for a typical solar-type star at around 3 au from the star [2].

    However, the recent ALMA observations, to be published in Nature, show that the water snow line in V883 Orionis is currently at more than 40 au of the central star (corresponding to Neptune’s orbit in our system), greatly facilitating its detection [3]. This star is only thirty percent more massive than the Sun, but its luminosity is 400 times brighter as it’s currently experiencing what is known as a FU Ori outburst, a sudden increase in temperature and luminosity due to large amounts of material being transferred from the disk to the star [4]. This explains the displaced location of its water snow line: the disk has been flash-heated by the stellar outburst.

    Lead author Lucas Cieza explains: “The ALMA observations came as a surprise to us. Our observations were designed to look for disk fragmentation leading to planet formation. We saw none of that; instead, we found what looks like a ring at 40 au. This illustrates well the transformational power of ALMA, which delivers exciting results even if they are not the ones we were looking for.”

    The discovery that these outbursts may blast the water snow line to about 10 times its typical radius is very significant for the development of good planetary formation models. Such outbursts are believed to be a stage in the evolution of most planetary systems, so this may be the first observation of a common occurrence. In that case, this observation from ALMA could contribute significantly to a better understanding of how planets form and evolve throughout the Universe.

    3
    This illustration shows how the outburst of the young star V883 Orionis has displaced the water snowline much further out from the star, and rendered it detectable with ALMA. Credit: ALMA (ESO/NAOJ/NRAO)/L. Cieza.

    4
    This image of the planet-forming disc around the young star V883 Orionis was obtained by ALMA in long-baseline mode. This star is currently in outburst, which has pushed the water snow line further from the star and allowed it to be detected for the first time. The dark ring midway through the disc is the water snowline, the point from the star where the temperature and pressure dip low enough for water ice to form. Credit: ALMA (ESO/NAOJ/NRAO)/L. Cieza.

    Notes

    [1] In the solar nebula – which gave birth to our Solar System – this line was between the orbits of Mars and Jupiter during the formation of the Solar System, hence the rocky planets Mercury, Venus, Earth and Mars formed within the line, and the gaseous planets Jupiter, Saturn, Uranus and Neptune formed outside.

    [2] 1 au, or one astronomical unit, is the mean distance between the Earth and the Sun, around 149.6 million kilometers. This unit is typically used to describe distances measured within the Solar System and planetary systems around other stars.

    [3] Resolution is the ability to discern that objects are separate. To the human eye, several bright torches at a distance would seem like a single glowing spot, and only at closer quarters would each torch be distinguishable. The same principle applies to telescopes, and these new observations have exploited the exquisite resolution of ALMA in its long baseline modes. The resolution of ALMA at the distance of V883 Orionis is about 12 au — enough to resolve the water snow line at 40 au in this outbursting system, but not for a typical young star.

    [4] Stars are believed to acquire most of their mass during these short but intense accretion events.

    Additional information

    These observation results were published in a paper entitled “Imaging the water snow-line during a protostellar outburst” to appear in the journal Nature on 14 July, 2016.

    The research team is composed of Lucas A. Cieza [1,2], Simón Casassus [2,3], John Tobin [4], Steven Bos [4], Jonathan P. Williams [5], Sebastián Pérez [2,3], Zhaohuan Zhu [6], Claudio Cáceres [2,7], Héctor Cánovas [2,7], Michael M. Dunham [8], Antonio Hales [9], José L. Prieto [1], David A. Príncipe [1,2], Matthias R. Schreiber [2,7], Dary Ruiz-Rodríguez [10] and Alice Zurlo [1,2,3].

    [1] Núcleo de Astronomía, Facultad de Ingeniería, Universidad Diego Portales, Santiago, Chile.

    [2] Millenium Nucleus “Protoplanetary Disks in ALMA Early Science”, Santiago, Chile.

    [3] Departamento de Astronomía, Universidad de Chile, Santiago, Chile.

    [4] Leiden Observatory, Leiden University, Leiden, The Netherlands.

    [5] Institute for Astronomy, University of Hawaii at Manoa, Honolulu, USA.

    [6] Department of Astrophysical Sciences, Princeton University, Princeton, USA.

    [7] Departamento de Física y Astronomía, Universidad de Valparaíso, Valparaíso, Chile.

    [8] Harvard-Smithsonian Center for Astrophysics, Cambridge, USA.


    [9] Joint ALMA Observatory, Santiago, Chile.

    [10] Australian National University, Mount Stromlo Observatory, Canberra, Australia.

    See the full article here .

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    The Atacama Large Millimeter/submillimeter Array (ALMA), an international astronomy facility, is a partnership of Europe, North America and East Asia in cooperation with the Republic of Chile. ALMA is funded in Europe by the European Organization for Astronomical Research in the Southern Hemisphere (ESO), in North America by the U.S. National Science Foundation (NSF) in cooperation with the National Research Council of Canada (NRC) and the National Science Council of Taiwan (NSC) and in East Asia by the National Institutes of Natural Sciences (NINS) of Japan in cooperation with the Academia Sinica (AS) in Taiwan.

    ALMA construction and operations are led on behalf of Europe by ESO, on behalf of North America by the National Radio Astronomy Observatory (NRAO), which is managed by Associated Universities, Inc. (AUI) and on behalf of East Asia by the National Astronomical Observatory of Japan (NAOJ). The Joint ALMA Observatory (JAO) provides the unified leadership and management of the construction, commissioning and operation of ALMA.

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  • richardmitnick 10:00 am on July 9, 2016 Permalink | Reply
    Tags: ALMA, ALMA finds a swirling cool jet that reveals a growing supermassive black hole, , , ONSALA,   

    From ONSALA: “ALMA finds a swirling cool jet that reveals a growing supermassive black hole” 

    1

    ONSALA

    7.4.16
    No writer credit found

    1
    1.Alma’s close-up view of the centre of galaxy NGC 1377 (upper left) reveals a swirling jet. In this colour-coded image, reddish gas clouds are moving away from us, bluish clouds towards us, relative to the galaxy’s centre. The Alma image shows light with wavelength around one millimetre from molecules of carbon monoxide (CO). A cartoon view (lower right) shows how these clouds are moving, this time seen from the side. ​CTIO/H. Roussel et al./ESO (left panel); Alma/ESO/NRAO/S. Aalto (top right panel); S. Aalto (lower right panel)

    A Chalmers-led team of astronomers have used the Alma telescope to make the surprising discovery of a jet of cool, dense gas in the centre of a galaxy located 70 million light years from Earth. The jet, with its unusual, swirling structure, gives new clues to a long-standing astronomical mystery – how supermassive black holes grow.

    A team of astronomers led by Susanne Aalto, professor of radio astronomy at Chalmers, has used the Alma telescope (Atacama Large Millimeter/submillimeter Array) to observe a remarkable structure in the centre of the galaxy NGC 1377, located 70 million light years from Earth in the constellation Eridanus (the River).

    ESO/NRAO/NAOJ ALMA Array in Chile in the Atacama at  Chajnantor plateau, at 5,000 metres
    ESO/NRAO/NAOJ ALMA Array in Chile in the Atacama at Chajnantor plateau, at 5,000 metres

    The results are presented in a paper published in the June 2016 issue of the journal Astronomy and Astrophysics.

    “We were curious about this galaxy because of its bright, dust-enshrouded centre. What we weren’t expecting was this: a long, narrow jet streaming out from the galaxy nucleus”, says Susanne Aalto.

    2
    2. Alma’s close-up view of the centre of galaxy NGC 1377 reveals a swirling jet. In this colour-coded image, reddish gas clouds are moving away from us, bluish clouds towards us, relative to the galaxy’s centre. The image shows light with wavelength around one millimetre from molecules of carbon monoxide (CO).
    Image credit: ALMA/ESO/NRAO/S. Aalto & F. Costagliola

    The observations with Alma reveal a jet which is 500 light years long and less than 60 light years across, travelling at speeds of at least 800 000 kilometres per hour (500 000 miles per hour).

    Most galaxies have a supermassive black hole in their centres; these black holes can have masses of between a few million to a billion solar masses. How they grew to be so massive is a long-standing mystery for scientists.

    A black hole’s presence can be seen indirectly by telescopes when matter is falling into it – a process which astronomers call “accretion”. Jets of fast-moving material are typical signatures that a black hole is growing by accreting matter. The jet in NGC 1377 reveals the presence of a supermassive black hole. But it has even more to tell us, explains Francesco Costagliola (Chalmers and ORA-INAF, Italy), co-author on the paper.

    3
    3. This cartoon view shows how the clouds of material that make up the jet are moving outward from the central black hole, this time seen from the side. Red colours show clouds that are moving away from us, and blue colours show clouds that are moving towards us, relative to the black hole in the galaxy’s centre.
    Image credit: S. Aalto

    “The jets we usually see emerging from galaxy nuclei are very narrow tubes of hot plasma. This jet is very different. Instead it’s extremely cool, and its light comes from dense gas composed of molecules”, he says.

    The jet has ejected molecular gas equivalent to two million times the mass of the Sun over a period of only around half a million years – a very short time in the life of a galaxy. During this short and dramatic phase in the galaxy’s evolution, its central, supermassive black hole must have grown fast.

    “Black holes that cause powerful narrow jets can grow slowly by accreting hot plasma. The black hole in NGC1377, on the other hand, is on a diet of cold gas and dust, and can therefore grow – at least for now – at a much faster rate”, explains team member Jay Gallagher (University of Wisconsin-Madison).

    The motion of the gas in the jet also surprised the astronomers. The measurements with Alma are consistent with a jet that is precessing – swirling outwards like water from a garden sprinkler.

    “The jet’s unusual swirling could be due to an uneven flow of gas towards the central black hole. Another possibility is that the galaxy’s centre contains two supermassive black holes in orbit around each other”, says Sebastien Muller, Chalmers, also a member of the team.

    The discovery of the remarkable cool, swirling jet from the centre of this galaxy would have been impossible without Alma, concludes Susanne Aalto.

    “Alma’s unique ability to detect and measure cold gas is revolutionising our understanding of galaxies and their central black holes. In NGC 1377 we’re witnessing a transient stage in a galaxy’s evolution which will help us understand the most rapid and important growth phases of supermassive black holes, and the life cycle of galaxies in the universe”, she says.

    More about the research

    This research is presented in the article A precessing molecular jet signaling an obscured, growing supermassive black hole in NGC 1377?, published in the June 2016 issue of Astronomy and Astrophysics (http://dx.doi.org/10.1051/0004-6361/201527664).

    The team is composed of Susanne Aalto (Chalmers), Francesco Costagliola (Chalmers and ORA-INAF, Italy), Sebastien Muller (Chalmers), K, Sakamoto (Institute of Astronomy and Astrophysics, Academia Sinica, Taipei, Taiwan), Jay S. Gallagher (Department of Astronomy, University of Wisconsin-Madison), K. Dasyra (National and Kapodistrian​ University of Athens, Greece), K. Wada (Kagoshima University, Japan), F. Combes (Paris Observatory, France), S. Garcia-Burillo (Observatorio Astronomico Nacional (OAN)-Observatorio de Madrid, Spain), L. E. Kristensen (Harvard-Smithsonian Center for Astrophysics, USA), S. Martin (European Southern Observatory, Joint Alma Observatory and IRAM, France), P. van der Werf (Leiden Observatory, Netherlands), A. S. Evans (University of Virginia and Virginia and National Radio Astronomy Observatory, USA) and J. Kotilainen (Finnish Centre for Astronomy with ESO (FINCA), University of Turku, Finland).

    See the full article here .

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    Onsala 20 meter telescope exterior Sweden
    Onsala 20 meter telescope Sweden

    Onsala Space Observatory (OSO), the Swedish National Facility for Radio Astronomy, provides scientists with equipment to study the Earth and the rest of the Universe. We operate several radio telescopes in Onsala, 45 km south of Göteborg, and take part in international projects. The observatory is a geodetic fundamental station. Examples of facilities and activities:

    The 20 and 25 m telescopes in Onsala: Studies of the birth and death of stars, and of molecules in the Milky Way and other galaxies.
    The LOFAR station in Onsala: One part of an international network of antennas for studies of, e.g., the early history of the Universe.
    VLBI: Telescopes in different countries are linked together for better resolution (“sharper images”) and for measurements of the Earth.
    SKA: Developing technology for the world’s largest radio telescope.
    APEX: Radio telescope in Chile for sub-millimetre waves. Research about everything from planets to the structure of the Universe.
    ALMA: Using and developing the Atacama Large Millimeter/submillimeter Array in Chile.
    Space geodesy: Radio telescopes (VLBI), satellites (e.g., GPS), gravimeters and tide gauges are used to measure, e.g., Earth’s rotation, movements in Earth’s crust, sea level, and water vapour in the atmosphere.
    Time keeping: Two hydrogen maser clocks and one cesium clock contribute to establishing the official Swedish time and international time.
    SALSA: Small radio telescopes in Onsala for educational purposes.
    Receiver development: Laboratories for development of sensitive radio receivers.

    Onsala Space Observatory is hosted by Department of Earth and Space Sciences at Chalmers University of Technology, and is operated on behalf of the Swedish Research Council. There are particularly strong links to the Department’s research groups in Advanced receiver development, Radio astronomy and astrophysics, Space geodesy and geodynamics, and Global environmental measurements and modelling.

    The observatory was founded in 1949 by professor Olof Rydbeck.

     
  • richardmitnick 5:38 am on July 2, 2016 Permalink | Reply
    Tags: ALMA, ALMA discovers dew drops surrounding dusty spider’s web, , , ,   

    From RAS: “ALMA discovers dew drops surrounding dusty spider’s web” 

    Royal Astronomical Society

    Royal Astronomical Society

    01 July 2016
    Media contacts

    Dr Robert Massey
    Royal Astronomical Society
    Mob: +44 (0)7802 877 699
    rm@ras.org.uk

    Ms Anita Heward
    Royal Astronomical Society
    Mob: +44 (0)7756 034 243
    anitaheward@btinternet.com

    Science contacts

    Dr Bitten Gullberg
    Centre for Extragalactic Astronomy
    Durham University
    bitten.gullberg@durham.ac.uk

    1`
    The Spiderweb Galaxy as seen by the Hubble Space Telescope (optical) in red, the Very Large Array (radio) in green and the Atacama Large Millimeter/submillimeter Array (sub-millimetre) in blue. The red colour shows where the stars are located within this system of galaxies. The radio jet is shown in green, and the position of the dust and water are seen in blue. The water is located to the left and right of the central galaxy. The water to the right is at the position where the radio jet bends down wards. The dust is also seen in blue. The dust is located at the central galaxy and in smaller companion galaxies in its surroundings. Credit: NASA/ESA/HST/STScI/NRAO/ESO/

    Astronomers have spotted glowing droplets of condensed water in the distant Spiderweb Galaxy – but not where they expected to find them. Detections with the Atacama Large Millimeter/submillimeter Array (ALMA) show that the water is located far out in the galaxy and therefore cannot be associated with central, dusty, star-forming regions, as previously thought.

    ESO/NRAO/NAOJ ALMA Array in Chile in the Atacama at  Chajnantor plateau, at 5,000 metres
    ESO/NRAO/NAOJ ALMA Array in Chile in the Atacama at Chajnantor plateau

    The results will be presented at the National Astronomy Meeting 2016 in Nottingham by Dr Bitten Gullberg on Friday 1st July.

    “Observations of light emitted by water and by dust often go hand-in-hand. We usually interpret them as an insight into star-forming regions, with the illumination from young stars warming dust particles and water molecules until they start to glow. Now, thanks to the power of ALMA, we can — for the first time — separate out the emissions from the dust and water populations, and pinpoint their exact origins in the galaxy. The results are quite unexpected in that we’ve found that the water is located nowhere near the dusty stellar nurseries,” explained Dr Gullberg, of the Centre for Extragalactic Astronomy, Durham University, UK.

    The Spiderweb Galaxy is one of the most massive galaxies known. It lies 10 billion light-years away and is made up of dozens of star-forming galaxies in the process of merging together. The ALMA observations show that the light from the dust originates in the Spiderweb Galaxy itself. However, the light from the water is concentrated in two regions far to the east and west of the galaxy core.

    Gullberg and her colleagues believe that the explanation lies with powerful jets of radio waves that are ejected from a supermassive black hole at the centre of the Spiderweb Galaxy. The radio jets compress clouds of gas along their path and heat up water molecules contained within the clouds until they emit radiation.

    “Our results show how important it is to pinpoint the exact locations and origins for light in galaxies. We may also have new clues to the processes that trigger star formation in interstellar clouds,” said Gullberg. “Stars are born out of cold, dense molecular gas. The regions in the Spiderweb where we’ve detected water are currently too hot for stars to form. But the interaction with the radio jets changes the composition of the gas clouds. When the molecules have cooled down again, it will be possible for the seeds of new stars to form. These “dew drop” regions could become the next stellar nurseries in this massive, complex galaxy.”

    Further information

    ALMA Finds Dew Drops in the Dusty Spider’s Web, Bitten Gullberg et al, February 2016, Astronomy & Astrophysics: http://arxiv.org/pdf/1602.04823v1.pdf

    See the full article here .

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    The Royal Astronomical Society (RAS), founded in 1820, encourages and promotes the study of astronomy, solar-system science, geophysics and closely related branches of science.

     
  • richardmitnick 1:28 pm on July 1, 2016 Permalink | Reply
    Tags: ALMA, ALMA Uses ‘Double Vision’ to Study Galaxy’s Gaseous Ingredients, , ,   

    From ALMA: “ALMA Uses ‘Double Vision’ to Study Galaxy’s Gaseous Ingredients” 

    ALMA Array

    ALMA

    01 July 2016
    Nicolás Lira T.
    Education and Public Outreach Coordinator
    Joint ALMA Observatory
    Santiago, Chile
    Tel: +56 2 24 67 65 19
    Cell: +56 9 94 45 77 26
    Email: nicolas.lira@alma.cl

    Charles E. Blue
    Public Information Officer
    National Radio Astronomy Observatory
    Charlottesville, Virginia, USA
    Tel: +1 434 296 0314
    Cell: +1 202 236 6324
    E-mail: cblue@nrao.edu

    Richard Hook
    Public Information Officer, ESO

    Garching bei München, Germany

    Tel: +49 89 3200 6655

    Cell: +49 151 1537 3591
    Email: rhook@eso.org

    Masaaki Hiramatsu

    Education and Public Outreach Officer, NAOJ Chile
    Observatory
Tokyo, Japan

    Tel: +81 422 34 3630

    E-mail: hiramatsu.masaaki@nao.ac.jp

    1
    Composite ALMA and optical image showing glowing emission from carbon monoxide (red) in galaxy PKS0439_008_04. The more distant quasar, PKS0439-433 (central blue feature), revealed through absorption in the visible spectrum the presence of an extended, diffuse halo of molecular gas surrounding the galaxy. The optical data are from the Irénée du Pont Telescope at the Las Campanas Observatory. Credit: Neeleman et al.; ALMA (ESO/NAOJ/NRAO); B. Saxton (NRAO/AUI/NSF); H.-W. Chen, Carnegie Observatories.

    Las Campanas Dupont telescope exterior,Atacama Desert, Chile
    Las Campanas Dupont telescope interior
    Carnegie Las Campanas Dupont telescope, Atacama Desert, Chile

    Researchers using the Atacama Large Millimeter/submillimeter Array (ALMA) combined two techniques for the first time to achieve the most comprehensive study to date of molecular gas in a galaxy. They observed the emission of the very nearby galaxy PKS0439_008_04 and, at the same time, the absorption of a far quasar on a direct line of sight with the galaxy.

    Astronomers usually study molecular gas —the fuel for star formation— using one of two methods: either by investigating a galaxy’s “emission” or its “absorption.” The former technique involves looking at the natural radio emission from the gas that permeates the galaxy and its expansive halo. The latter method examines the light from more distant objects, like a bright quasar, that gets absorbed as it passes through the galaxy.

    This work constitutes the most comprehensive study of molecular gas in a galaxy to date. “Previously, quasar absorption studies ‘blinded’ telescopes to the less intense and much more diffuse emission signal from the galaxy,” said Marcel Neeleman, with the University of California’s Lick Observatory and lead author on a paper published in Astrophysical Journal Letters. In this study, astronomers were able to directly detect the faint emission signal from carbon monoxide in the galaxy.

    By comparing this emission to the absorption signal from the quasar, the researchers found that the strongest absorption did not occur in the disk of the galaxy. Instead, most of the quasar’s light was absorbed by the diffuse gas surrounding the galaxy—gas that would be nearly impossible to detect through other means.

    The astronomers’ results suggest that far from the galaxy, there is a significant amount of molecular gas that is not actually part of the galaxy, but bound to it. “We may be witnessing the recycling of material that, in a few billion years, will again trigger a burst of star formation,” concluded Neeleman.

    The nearby galaxy, known as PKS0439_008_04, is approximately 1.4 billion light-years from Earth. The more distant quasar, PKS0439-433, is approximately 7.3 billion light-years from Earth. Both are in the direction of the constellation Caelum.

    Additional information

    These observation results were published as Neeleman et al. First Connection between Cold Gas in Emission and Absorption: CO Emission from a Galaxy-Quasar Pair, in the Astrophysical Journal of Letters, April 2016. (Preprint: https://arxiv.org/abs/1604.05720).
    The team is composed of Marcel Neeleman [1], J. Xavier Prochaska [1], Martin A. Zwaan [2], Nissim Kanekar [3], Lise Christensen [4], Miroslava Dessauges-Zavadsky [5], Johan P.U. Fynbo [4], Eelco van Kampen [2], Palle Møller [2] and Tayyaba Zafar [6].

    [1] Department of Astronomy & Astrophysics, UCO/Lick Ob- servatory, University of California, Santa Cruz, USA.

    [2] European Southern Observatory, Garching bei München, Germany.

    [3] Swarnajayanti Fellow; National Centre for Radio Astrophysics, Tata Institute of Fundamental Research, Pune, India.

    [4] Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Copenhagen, Denmark.

    [5] Observatoire de Genève, Université de Genève, Sauverny, Switzerland.

    [6] Australian Astronomical Observatory, North Ryde, Australia.

    See the full article here .

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    The Atacama Large Millimeter/submillimeter Array (ALMA), an international astronomy facility, is a partnership of Europe, North America and East Asia in cooperation with the Republic of Chile. ALMA is funded in Europe by the European Organization for Astronomical Research in the Southern Hemisphere (ESO), in North America by the U.S. National Science Foundation (NSF) in cooperation with the National Research Council of Canada (NRC) and the National Science Council of Taiwan (NSC) and in East Asia by the National Institutes of Natural Sciences (NINS) of Japan in cooperation with the Academia Sinica (AS) in Taiwan.

    ALMA construction and operations are led on behalf of Europe by ESO, on behalf of North America by the National Radio Astronomy Observatory (NRAO), which is managed by Associated Universities, Inc. (AUI) and on behalf of East Asia by the National Astronomical Observatory of Japan (NAOJ). The Joint ALMA Observatory (JAO) provides the unified leadership and management of the construction, commissioning and operation of ALMA.

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  • richardmitnick 9:23 am on June 28, 2016 Permalink | Reply
    Tags: ALMA, ALMA Discovers a Rotating Ring of Complex Organic Molecules, , ,   

    From ALMA: “ALMA Discover[s] a Rotating Ring of Complex Organic Molecules” 

    ESO/NRAO/NAOJ ALMA Array
    ESO/NRAO/NAOJ ALMA Array in Chile in the Atacama at Chajnantor plateau, at 5,000 metres

    ALMA

    28 June 2016
    Nicolás Lira T.
    Education and Public Outreach Coordinator
    Joint ALMA Observatory
    Santiago, Chile
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    Masaaki Hiramatsu

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    Observatory
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    Richard Hook
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    Charles E. Blue
    Public Information Officer
    National Radio Astronomy Observatory
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    E-mail: cblue@nrao.edu

    1
    Figure 1. (Upper panel) A schematic illustration of the infalling gas around the protostar. A disk structure with a radius of about 50 AU exists around the protostar. The disk in turn is surrounded by an envelope of gas extended over a 200 AU scale. OCS exists in the envelope gas, while methyl formate mainly exists in the boundary area between the envelope gas and the disk structure. (Lower left) Intensity distribution of methyl formate (HCOOCH3) observed with ALMA. A structure elongated along A-B can be seen centered on the position of the protostar. Methyl formate is located within 50 AU from the protostar. (Lower right) Intensity distribution of OCS (carbonyl sulfide) observed with ALMA. A structure elongated along A-B can be seen centered on the position of the protostar position, similar to the case of OCS. However the distribution of OCS (~200 AU) is more extended than that of methyl formate. Credit: ALMA (ESO/NAOJ/NRAO), Oya et al.

    Researchers using the Atacama Large Millimeter/submillimeter Array (ALMA) have discovered a rotating ring containing large organic molecules around a protostar. This observation definitively shows that organic materials formed in interstellar space are brought into the planet-forming region. Researchers also found that the molecular species brought into the planet-forming region vary from one protostar to another. Chemical composition is a new way to answer the long-standing question of whether or not the Solar System is a typical example of a planetary system.

    Astronomers have long known that organic molecules form in diffuse gas clouds floating between stars. It is thought that as the Solar System formed 4.6 billion years ago, some of these organic molecules were transported from interstellar space to the planet forming disk. Later, these molecules played important roles in the chemical evolution resulting in the emergence of life on the Earth. However, it is still unknown what kinds and quantities of organic molecules were actually supplied from interstellar space. Although radio astronomy observations during the last decade showed that saturated complex organic molecules, such as methanol (CH3OH) and methyl formate (HCOOCH3) [1], exist around Solar-type protostars, their distributions were too compact to be resolved with the radio telescopes available at the time.

    An international team led by Yoko Oya, a graduate student from the Department of Physics at the University of Tokyo, and Nami Sakai, an associate chief scientist of RIKEN, studied with ALMA the distribution of various organic molecules around a Solar-type protostar, IRAS 16293-2422A, at a high spatial resolution. They discovered a ring structure of complex organic molecules around the protostar. The radius of the ring is 50 times wider than the Earth’s orbit. This size is comparable to the size of the Solar System, and the ring structure most likely represents the boundary region between infalling gas and a rotating disk structure around the protostar.

    The observations clearly showed the distribution of large organic molecules methyl formate (HCOOCH3) and carbonyl sulfide (OCS). Apparently the distribution of methyl formate is confined in a more compact area around the protostar than the OCS distribution, which mainly traces the infalling gas. “When we measured the motion of the gas containing methyl formate by using the Doppler effect,” said Oya, “we found a clear rotation motion specific to the ring structure.” In this way, they identified the rotating ring structure of methyl formate, although it is not resolved spatially. A similar ring structure is also found for methanol.

    These saturated organic molecules are formed in interstellar space and are preserved on the surfaces of dust grains. Around the outer boundary of the disk structure, they evaporate due to shock generated by collisions of the disk and infalling material, and/or due to heating by the light from the baby star. This result is the first direct evidence that interstellar organic materials are indeed fed into the rotating disk structure that eventually forms a planetary system.

    2
    Figure 2. (Upper Left) Velocity structure of methyl formate observed along the A-B axis. The abscissa is the position along the A-B axis shown in Figure 1, while the ordinate is the line-of-sight velocity of methyl formate. Positive velocity means that the gas is going away from the observer, while negative velocity means that the gas is approaching the observer. The velocity on the A side is the opposite of that on the B side. (Lower Left) The above features can be interpreted as the rotating ring shown here schematically. Based on molecular velocity information, methyl formate is found to exist in the rotating ring. The size of the ring is about 50 AU, which corresponds to the boundary between the infalling gas and the disk structure. (Upper Right) Velocity structure of H2CS (thioformaldehyde) observed along the A-B axis shown in Figure 1. The H2CS emission is seen farther away from the protostar than the methyl formate emission, indicating its existence in the infalling gas. The velocity increases as it approaches the protostar. Furthermore, the emission is also visible within the ring boundary, and the velocity is higher than that observed for methyl formate. (Lower Right) A schematic illustration of the distribution of H2CS. Both the infalling gas and the disk structure can be seen. Credit: ALMA (ESO/NAOJ/NRAO), Oya et al.

    3
    Figure 3. Schematic illustration of the molecular distribution around the protostars. (Left) The case of IRAS 16293-2422A, in which saturated complex organic molecules are abundant. The boundary is highlighted by saturated complex organic molecules. (Right) The case of L1527, in which unsaturated complex organic molecules are abundant. The boundary is highlighted by SO (sulfur monoxide). Credit: ALMA (ESO/NAOJ/NRAO), Oya et al.

    In 2014, the team found a similar ring structure of SO (sulfur monoxide) around another Solar-type protostar, L1527. In this source, unsaturated complex organic molecules such as CCH and cyclic-C3H2 are very abundant in the infalling gas, while SO preferentially exists in the boundary between the infalling gas and the disk structure. Although the physical structure in L1527 is similar to that found in IRAS 16293-2422A, the chemical composition is much different. Saturated complex organic molecules are almost completely absent in L1527.

    The present result, taken together with previous results on L1527, clearly demonstrates for the first time that the materials delivered to a planetary system differ from star to star. A new perspective on chemical composition is thus indispensable for a thorough understanding of the origin of the Solar System and the origin of life on the Earth.

    Notes

    [1] Organic molecules without multiple bonds between atoms are collectively called saturated molecules. On the other hand, molecules with multiple bonds are called unsaturated molecules.

    Additional information

    These observation results were published as Oya et al. Infalling-Rotating Motion and Associated Chemical Change in the Envelope of IRAS 16293-2422 Source A Studied with ALMA in the Astrophysical Journal issued on 20 June 2016.

    The research team members are:

    Yoko Oya (The University of Tokyo), Nami Sakai (RIKEN), Ana López-Sepulcre (The University of Tokyo), Yoshimasa Watanabe (The University of Tokyo), Cecilia Ceccarelli (Universite Grenoble Alpes/CNRS), Bertrand Lefloch (Universite Grenoble Alpes/CNRS), Cécile Favre (Universite Grenoble Alpes/CNRS), Satoshi Yamamoto (The University of Tokyo)

    This study is supported by the Japan Society for Promotion of Science (JSPS), Grant-in-Aid from the Ministry of Education, Culture, Sports, Science, and Technologies of Japan (21224002, 25400223, 25108005, and 15J0161), JSPS-MAEE Japan-France Integrated Action Program (SAKURA: 25765VC), and CNRS France-Japan action program.

    See the full article here .

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    The Atacama Large Millimeter/submillimeter Array (ALMA), an international astronomy facility, is a partnership of Europe, North America and East Asia in cooperation with the Republic of Chile. ALMA is funded in Europe by the European Organization for Astronomical Research in the Southern Hemisphere (ESO), in North America by the U.S. National Science Foundation (NSF) in cooperation with the National Research Council of Canada (NRC) and the National Science Council of Taiwan (NSC) and in East Asia by the National Institutes of Natural Sciences (NINS) of Japan in cooperation with the Academia Sinica (AS) in Taiwan.

    ALMA construction and operations are led on behalf of Europe by ESO, on behalf of North America by the National Radio Astronomy Observatory (NRAO), which is managed by Associated Universities, Inc. (AUI) and on behalf of East Asia by the National Astronomical Observatory of Japan (NAOJ). The Joint ALMA Observatory (JAO) provides the unified leadership and management of the construction, commissioning and operation of ALMA.

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