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  • richardmitnick 7:55 am on March 17, 2017 Permalink | Reply
    Tags: ALMA, ALMA Confirms ability to see a “Cosmic Hole, , , , , , , Sunyaev-Zel'dovich effect (SZ effect)   

    From ALMA: “ALMA Confirms ability to see a “Cosmic Hole” 

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

    17 March 2017
    Nicolás Lira T.
    Press 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
    The image shows the measurement of the SZ effect in the galaxy cluster RX J1347.5-1145 taken with ALMA (blue). The background image was taken by the Hubble Space Telescope. A “hole” caused by the SZ effect is seen in the ALMA observations. Credit: ALMA (ESO/NAOJ/NRAO), Kitayama et al., NASA/ESA Hubble Space Telescope.

    Researchers using the Atacama Large Millimeter/submillimeter Array (ALMA) successfully imaged a radio “hole” around a galaxy cluster 4.8 billion light-years away from the Earth. This is the highest resolution image ever taken of such a hole caused by the Sunyaev-Zel’dovich effect (SZ effect). The image proves ALMA’s high capability to investigate the distribution and temperature of gas around galaxy clusters through the SZ effect.

    A research team led by Tetsu Kitayama, a professor at Toho University, Japan, used ALMA to investigate the hot gas in a galaxy cluster. The hot gas is an essential component to understand the nature and evolution of galaxy clusters. Even though the hot gas does not emit radio waves detectable with ALMA, the gas scatters the radio waves of the Cosmic Microwave Background and makes a “hole” around the galaxy cluster. This is the Sunyaev-Zel’dovich effect[1].

    The team observed the galaxy cluster RX J1347.5-1145 known among astronomers for its strong SZ effect and which has been observed many times with radio telescopes.

    2
    ROSAT Lensing Cluster RX J1347-1145. Max-Planck-Institut für extraterrestrische Physik

    For example, the Nobeyama 45-m Radio Telescope, operated by the National Astronomical Observatory of Japan, has revealed an uneven distribution of the hot gas in this galaxy cluster, which was not seen in X-ray observations.

    .
    Nobeyama Radio Telescope, located in the Nobeyama highlands in Nagano, Japan

    To better understand the unevenness, astronomers need higher resolution observations. But relatively smooth and widely-distributed objects, such as the hot gas in galaxy clusters, are difficult to image with high-resolution radio interferometers.

    To overcome this difficulty, ALMA utilized the Atacama Compact Array, also known as the Morita Array, the major Japanese contribution to the project.


    Atacama Compact Array alma.mtk.nao.ac.jp

    The Morita Array’s smaller diameter antennas and the close-packed antenna configuration provide a wider field of view. By using the data from the Morita Array, astronomers can precisely measure the radio waves from objects subtending a large angle on the sky.

    3
    This cluster of galaxies, RX J1347.5–1145, was observed by the NASA/ESA Hubble Space Telescope as part of the Cluster Lensing and Supernova survey with Hubble (CLASH). The cluster is one of most massive known galaxy clusters in the Universe. Credit: ESA/Hubble, NASA.


    NASA/ESA Hubble Telescope

    With ALMA, the team obtained an SZ effect image of RX J1347.5-1145, with twice the resolution and ten times better sensitivity than previous observations. This is the first image of the SZ effect with ALMA. The ALMA SZ image is consistent with the previous observations and better illustrates the pressure distribution of hot gas. It proves that ALMA is highly capable of observing the SZ effect and clearly shows that a gigantic collision is ongoing in this galaxy cluster.

    “It was nearly 50 years ago that the SZ effect was proposed for the first time,” explains Kitayama. “The effect is pretty weak, and it has been tough to image the effect with high resolution. Thanks to ALMA, this time we made a long-awaited breakthrough to pave a new path to probe the cosmic evolution.”

    Notes

    “Cosmic Microwave Background (CMB)” radio waves come from every direction. When CMB radio waves pass through the hot gas in a galaxy cluster, the radio waves interact with high-energy electrons in the hot gas and gain energy. As a result, the CMB radio waves shift to higher energy. Observing from the Earth, the CMB in the original energy range has less intensity near the galaxy cluster. This is called the “Sunyaev-Zel’dovich effect,” first proposed by Rashid Sunyaev and Yakov Zel’dovich in 1970.

    Additional information

    These observation results were published as Kitayama et al. The Sunyaev-Zel’dovich effect at 5″: RX J1347.5-1145 imaged by ALMA in the Publications of the Astronomical Society of Japan in October 2016.

    The research team members are: Tetsu Kitayama (Toho University), Shutaro Ueda (Japan Aerospace Exploration Agency), Shigehisa Takakuwa (Kagoshima University / Academia Sinica Institute of Astronomy and Astrophysics), Takahiro Tsutsumi (U. S. National Radio Astronomy Observatory), Eiichiro Komatsu (Max-Planck Institute for Astrophysics / Kavli Institute for the Physics and Mathematics of the Universe, The University of Tokyo), Takuya Akahori (Kagoshima University), Daisuke Iono (National Astronomical Observatory of Japan / SOKENDAI), Takuma Izumi (The University of Tokyo), Ryohei Kawabe (National Astronomical Observatory of Japan / SOKENDAI / The University of Tokyo), Kotaro Kohno (The University of Tokyo), Hiroshi Matsuo (National Astronomical Observatory of Japan / SOKENDAI), Naomi Ota (Nara Women’s University), Yasushi Suto (The University of Tokyo), Motokazu Takizawa (Yamagata University), and Kohji Yoshikawa (University of Tsukuba).

    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 10:34 am on March 15, 2017 Permalink | Reply
    Tags: ALMA, , , Cat's Paw Nebula (also known as NGC 6334), , , Protostar Blazes Bright, , Reshaping Its Stellar Nursery   

    From ALMA: “Protostar Blazes Bright, Reshaping Its Stellar Nursery” 

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

    15 March 2017
    Nicolás Lira T.
    Press 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
    ALMA image of the glowing dust inside NGC 6334I, a protocluster containing an infant star that is undergoing an intense growth spurt, likely triggered by an avalanche of gas falling onto its surface. ALMA (ESO/NAOJ/NRAO); C. Brogan, B. Saxton (NRAO/AUI/NSF).

    A massive protostar, deeply nestled in its dust-filled stellar nursery, recently roared to life, shining nearly 100 times brighter than before. This outburst, apparently triggered by an avalanche of star-forming gas crashing onto the surface of the star, supports the theory that young stars can undergo intense growth spurts that reshape their surroundings.

    Astronomers made this discovery by comparing new observations from the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile with earlier observations from the Submillimeter Array (SMA) in Hawaii.


    CfA Submillimeter Array Mauna Kea, Hawaii, USA

    “We were amazingly fortunate to detect this spectacular transformation of a young, massive star,” said Todd Hunter, an astronomer at the National Radio Astronomy Observatory (NRAO) in Charlottesville, Virginia, USA, and lead author on a paper published in the Astrophysical Journal Letters. “By studying a dense star-forming cloud with both ALMA and the SMA, we could see that something dramatic had taken place, completely changing a stellar nursery over a surprisingly short period of time.”

    In 2008, before the era of ALMA, Hunter and his colleagues used the SMA to observe a small but active portion of the Cat’s Paw Nebula (also known as NGC 6334), a star-forming complex located about 5,500 light-years from Earth in the direction of the southern constellation Scorpius. This nebula is similar in many respects to its northern cousin, the Orion Nebula, which is also brimming with young stars, star clusters, and dense cores of gas that are on the verge of becoming stars. The Cat’s Paw Nebula, however, is forming stars at a faster rate.

    2
    Inside the Cats’s Paw Nebula as seen in an infrared image from NASA’s Spitzer Space Telescope (left), ALMA discovered that an infant star is undergoing an intense growth spurt, shining nearly 100 brighter than before and reshaping its stellar nursery (right). Credit: ALMA (ESO/NAOJ/NRAO), T. Hunter; C. Brogan, B. Saxton (NRAO/AUI/NSF); NASA Spitzer.


    NASA/Spitzer

    The initial SMA observations of this portion of the nebula, dubbed NGC 6334I, revealed what appeared to be a typical protocluster: a dense cloud of dust and gas harboring several still-growing stars.

    Young stars form in these tightly packed regions when pockets of gas become so dense that they begin to collapse under their own gravity. Over time, disks of dust and gas form around these nascent stars and funnel material onto their surfaces helping them grow.

    This process, however, may not be entirely slow and steady. Astronomers now believe that young stars can also experience spectacular growth spurts, periods when they rapidly acquire mass by gorging on star-forming gas.

    The new ALMA observations of this region, taken in 2015 and 2016, reveal that dramatic changes occurred toward a portion of the protocluster called NGC 6334I-MM1 in the years since the original SMA observations. This region is now about four times brighter at millimeter wavelengths, meaning that the central protostar is nearly 100 times more luminous than before.

    The astronomers speculate that leading up to this outburst, an uncommonly large clump of material was drawn into the star’s accretion disk, creating a logjam of dust and gas. Once enough material accumulated, the logjam burst, releasing an avalanche of gas onto the growing star.

    4
    Comparing observations by two different millimeter-wavelength telescopes, ALMA and the SMA, astronomers noted a massive outburst in a star-forming cloud. Because the ALMA images are more sensitive and show finer detail, it was possible to use them to simulate what the SMA could have seen in 2015 and 2016. By subtracting the earlier SMA images from the simulated images, astronomers could see that a significant change had taken place in MM1 while the other three millimeter sources (MM2, MM3, and MM4) are unchanged. ALMA (ESO/NAOJ/NRAO); SMA, Harvard/Smithsonian CfA

    This extreme accretion event greatly increased the star’s luminosity, heating its surrounding dust. It’s this hot, glowing dust that the astronomers observed with ALMA. Though similar events have been observed in infrared light, this is the first time that such an event has been identified at millimeter wavelengths.

    To ensure that the observed changes were not the result of differences in the telescopes or simply a data-processing error, Hunter and his colleagues used the ALMA data as a model to accurately simulate what the SMA — with its more modest capabilities — would have seen if it conducted similar operations in 2015 and 2016. By digitally subtracting the actual 2008 SMA images from the simulated images, the astronomers confirmed that there was indeed a significant and consistent change to one member of the protocluster.

    “Once we made sure we were comparing the two sets of observations on an even playing field, we knew that we were witnessing a very special time in the growth of a star,” said Crystal Brogan, also with the NRAO and co-author on the paper.

    Further confirmation of this event came from complementary data taken by the Hartebeesthoek Radio Astronomy Observatory in South Africa.


    Hartebeesthoek Radio Astronomy Observatory, located west of Johannesburg South Africa

    This single-dish observatory was monitoring the radio signals from masers in the same region. Masers are the naturally occurring cosmic radio equivalent of lasers. They are powered by a variety of energetic processes throughout the universe, including outbursts from rapidly growing stars.

    The data from the Hartebeesthoek observatory reveal an abrupt and dramatic spike in maser emission from this region in early 2015, only a few months before the first ALMA observation. Such a spike is precisely what astronomers would expect to see if there were a protostar undergoing a major growth spurt.

    “These observations add evidence to the theory that star formation is punctuated by a sequence of dynamic events that build up a star, rather than a smooth continuous growth,” concluded Hunter. “It also tells us that it is important to monitor young stars at radio and millimeter wavelengths, because these wavelengths allow us to peer into the youngest, most deeply embedded star-forming regions. Catching such events at the earliest stage may reveal new phenomena of the star-formation process.”

    This research is presented in a paper titled “An extraordinary outburst in the massive protostellar system NGC6334I-MM1: Quadrupling of the millimeter continuum,” by T.R. Hunter et al., published in the Astrophysical Journal Letters [https://arxiv.org/abs/1701.08637].

    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.

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  • richardmitnick 12:18 pm on March 14, 2017 Permalink | Reply
    Tags: ALMA, ALMA peers into the hearts of stellar nurseries, , , ,   

    From ALMA: “ALMA peers into the hearts of stellar nurseries” 

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

    13 March 2017
    No writer credit

    1

    With their spectacular glowing arms, grand spiral galaxies seem to get all the attention — but NGC 6822, a barred irregular dwarf galaxy, proves that regular spirals do not have a monopoly on galactic beauty. Also called Barnard’s galaxy, NGC 6822 is located in the constellation of Sagittarius just 1.6 million light-years away and is brimming with rich star formation regions.

    This new image is a composite of older observations made with the Wide Field Imager attached to the 2.2-metre MPG/ESO telescope at ESO’s La Silla Observatory and new data collected by the Atacama Large Millimeter/submillimeter Array (ALMA). The areas observed with ALMA are highlighted in the image and can be seen here in detail.


    MPG/ESO 2.2 meter telescope at Cerro La Silla, Chile


    ESO WFI LaSilla 2.2-m MPG/ESO telescope at La Silla

    The observations by ALMA reveal the structure of star-forming gas clouds in unprecedented resolution. Observations in our own galaxy have shown that stars form in the dense cores of giant clouds of molecular hydrogen gas, the only places where gas can become cold enough to collapse under its own gravity. These conditions also foster the formation of other molecules, such as carbon monoxide, which are an indispensable tool in helping astronomers to detect galactic molecular hydrogen gas.

    Until recently, astronomers have only been able to resolve star formation regions within the Milky Way — but now ALMA’s sharp sight provides a window into star formation in other galaxies. The analysis of the data revealed that, unlike in our own galaxy, the observed molecules are concentrated into small, dense cores of gas. This explains why it has been so hard to observe extragalactic star formation regions so far, especially in low mass, low metallicity galaxies. ALMA also found that the cores in NGC 6822 behave remarkably similarly to stellar nurseries in the Milky Way, indicating that the physics of star formation in these low-mass galaxies resemble that which we see in our own galaxy.

    Research paper by Schruba et al.

    See the full article here .

    Please help promote STEM in your local schools.
    STEM Icon
    Stem Education Coalition

    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 12:06 pm on March 14, 2017 Permalink | Reply
    Tags: ALMA, , , , , NGC 6822   

    From ALMA: “ALMA observes clouds in NGC 6822” 

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

    1
    This montage shows four star-forming gas clouds in NGC 6822, a barred irregular dwarf galaxy, about 1.6 million light-years away. The observations were made with the Wide Field Imager [WFI] attached to the 2.2-metre MPG/ESO telescope at ESO’s La Silla Observatory, the Very Large Array and by the Atacama Large Millimeter/submillimeter Array (ALMA).


    MPG/ESO 2.2 meter telescope at Cerro La Silla, Chile


    ESO WFI LaSilla 2.2-m MPG/ESO telescope at La Silla


    NRAO/VLA, on the Plains of San Agustin fifty miles west of Socorro, NM, USA

    See the full article here .

    Please help promote STEM in your local schools.
    STEM Icon
    Stem Education Coalition

    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 Large
    NAOJ

     
  • richardmitnick 8:08 am on March 8, 2017 Permalink | Reply
    Tags: A2744_YD4, ALMA, Ancient Stardust Sheds Light on the First Stars, , ,   

    From ALMA: “Ancient Stardust Sheds Light on the First Stars” 

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

    3.8.17

    Nicolas Laporte
    University College London
    United Kingdom
    Tel: +44 2 035 495 802
    Cell: +44 7452 807 591
    Email: n.laporte@ucl.ac.uk

    Richard Ellis
    ESO Garching bei München, Germany
    Tel: +44 7885 403334
    Cell: +49 151 629 56829
    Email: rellis@eso.org

    Nicolás Lira T.
    Press 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

    Masaaki Hiramatsu

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

    Tel: +81 422 34 3630

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

    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
    Astronomers have used ALMA to detect a huge mass of glowing stardust in a galaxy seen when the Universe was only four percent of its present age. This galaxy was observed shortly after its formation and is the most distant galaxy in which dust has been detected. This observation is also the most distant detection of oxygen in the Universe. These new results provide brand-new insights into the birth and explosive deaths of the very first stars.

    3
    ALMA and Hubble Space Telescope views of the distant dusty galaxy A2744_YD4. This image is dominated by a spectacular view of the rich galaxy cluster Abell 2744 from the NASA/ESA Hubble Space Telescope. But, far beyond this cluster, and seen when the Universe was only about 600 million years old, is a very faint galaxy called A2744_YD4. New observations of this galaxy with ALMA, shown in red, have demonstrated that it is rich in dust. Credit: ALMA (ESO/NAOJ/NRAO), NASA, ESA, ESO and D. Coe (STScI)/J. Merten (Heidelberg/Bologna)

    An international team of astronomers, led by Nicolas Laporte of University College London, have used the Atacama Large Millimeter/submillimeter Array (ALMA) to observe A2744_YD4, the youngest and most remote galaxy ever seen by ALMA. They were surprised to find that this youthful galaxy contained an abundance of interstellar dust — dust formed by the deaths of an earlier generation of stars.

    Follow-up observations using the X-shooter instrument on ESO’s Very Large Telescope confirmed the enormous distance to A2744_YD4. The galaxy appears to us as it was when the Universe was only 600 million years old, during the period when the first stars and galaxies were forming [1].

    ESO X-shooter on VLT at Cerro Paranal, Chile
    ESO X-shooter on VLT at Cerro Paranal, Chile

    ESO/VLT at Cerro Paranal, with an elevation of 2,635 metres (8,645 ft) above sea level
    ESO/VLT at Cerro Paranal, with an elevation of 2,635 metres (8,645 ft) above sea level

    “Not only is A2744_YD4 the most distant galaxy yet observed by ALMA,” comments Nicolas Laporte, “but the detection of so much dust indicates early supernovae must have already polluted this galaxy.”

    Cosmic dust is mainly composed of silicon, carbon and aluminium, in grains as small as a millionth of a centimetre across. The chemical elements in these grains are forged inside stars and are scattered across the cosmos when the stars die, most spectacularly in supernova explosions, the final fate of short-lived, massive stars. Today, this dust is plentiful and is a key building block in the formation of stars, planets and complex molecules; but in the early Universe — before the first generations of stars died out — it was scarce.

    The observations of the dusty galaxy A2744_YD4 were made possible because this galaxy lies behind a massive galaxy cluster called Abell 2744 [2].

    1
    Abell 2744, nicknamed Pandora’s Cluster. The galaxies in the cluster make up less than five percent of its mass. The gas (around 20 percent) is so hot that it shines only in X-rays (coloured red in this image). The distribution of invisible dark matter (making up around 75 percent of the cluster’s mass) is coloured here in blue.
    Date 22 June 2011
    Source HubbleSite
    Author NASA, ESA, J. Merten (Institute for Theoretical Astrophysics, Heidelberg/Astronomical Observatory of Bologna), and D. Coe (STScI)

    Because of a phenomenon called gravitational lensing, the cluster acted like a giant cosmic “telescope” to magnify the more distant A2744_YD4 by about 1.8 times, allowing the team to peer far back into the early Universe.

    Gravitational Lensing NASA/ESA
    Gravitational Lensing NASA/ESA

    Gravitational microlensing, S. Liebes, Physical Review B, 133 (1964): 835
    Gravitational microlensing, S. Liebes, Physical Review B, 133 (1964)

    The ALMA observations also detected the glowing emission of ionised oxygen from A2744_YD4. This is the most distant, and hence earliest, detection of oxygen in the Universe, surpassing another ALMA result from 2016.

    The detection of dust in the early Universe provides new information on when the first supernovae exploded and hence the time when the first hot stars bathed the Universe in light. Determining the timing of this “cosmic dawn” is one of the holy grails of modern astronomy, and it can be indirectly probed through the study of early interstellar dust.

    The team estimates that A2744_YD4 contained an amount of dust equivalent to 6 million times the mass of our Sun, while the galaxy’s total stellar mass — the mass of all its stars — was 2 billion times the mass of our Sun. The team also measured the rate of star formation in A2744_YD4 and found that stars are forming at a rate of 20 solar masses per year — compared to just one solar mass per year in the Milky Way [3].

    “This rate is not unusual for such a distant galaxy, but it does shed light on how quickly the dust in A2744_YD4 formed,” explains Richard Ellis (ESO and University College London), a co-author of the study. “Remarkably, the required time is only about 200 million years — so we are witnessing this galaxy shortly after its formation.”

    This means that significant star formation began approximately 200 million years before the epoch at which the galaxy is being observed. This provides a great opportunity for ALMA to help study the era when the first stars and galaxies “switched on” — the earliest epoch yet probed. Our Sun, our planet and our existence are the products — 13 billion years later — of this first generation of stars. By studying their formation, lives and deaths, we are exploring our origins.

    “With ALMA, the prospects for performing deeper and more extensive observations of similar galaxies at these early times are very promising,” says Ellis.

    And Laporte concludes: “Further measurements of this kind offer the exciting prospect of tracing early star formation and the creation of the heavier chemical elements even further back into the early Universe.”
    Notes

    [1] This time corresponds to a redshift of z=8.38, during the epoch of reionisation.

    [2] Abell 2744 is a massive object, lying 3.5 billion light-years away (redshift 0.308), that is thought to be the result of four smaller galaxy clusters colliding. It has been nicknamed Pandora’s Cluster because of the many strange and different phenomena that were unleashed by the huge collision that occurred over a period of about 350 million years. The galaxies only make up five percent of the cluster’s mass, while dark matter makes up seventy-five percent, providing the massive gravitational influence necessary to bend and magnify the light of background galaxies. The remaining twenty percent of the total mass is thought to be in the form of hot gas.

    [3] This rate means that the total mass of the stars formed every year is equivalent to 20 times the mass of the Sun.
    More information

    This research was presented in a paper entitled Dust in the Reionization Era: ALMA Observations of a z =8.38 Gravitationally-Lensed Galaxy by Laporte et al., to appear in The Astrophysical Journal Letters.

    The team is composed of N. Laporte (University College London, UK), R. S. Ellis (University College London, UK; ESO, Garching, Germany), F. Boone (Institut de Recherche en Astrophysique et Planétologie (IRAP), Toulouse, France), F. E. Bauer (Pontificia Universidad Católica de Chile, Instituto de Astrofísica, Santiago, Chile), D. Quénard (Queen Mary University of London, London, UK), G. Roberts-Borsani (University College London, UK), R. Pelló (Institut de Recherche en Astrophysique et Planétologie (IRAP), Toulouse, France), I. Pérez-Fournon (Instituto de Astrofísica de Canarias, Tenerife, Spain; Universidad de La Laguna, Tenerife, Spain), and A. Streblyanska (Instituto de Astrofísica de Canarias, Tenerife, Spain; Universidad de La Laguna, Tenerife, Spain).

    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.

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  • richardmitnick 10:59 pm on March 2, 2017 Permalink | Reply
    Tags: ALMA, ALMA adds a new dimension to a Hubble Space Telescope result, , , , , LL Pegasi,   

    From ALMA: “ALMA adds a new dimension to a Hubble Space Telescope result” 

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

    02 March 2017
    Dr. Hyosun Kim
    ASIAA
    Tel: +886-2-2366-5418
    Email: hkim@asiaa.sinica.edu.tw

    Dr. Sheng-Yuan Liu
    ASIAA
    Tel: +886-2-2366-5440
    Email: syliu@asiaa.sinica.edu.tw

    Nicolás Lira T.
    Press 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
    An international team of astronomers using the Atacama Large Millimeter/submillimeter Array (ALMA) have unraveled the elliptical nature of the binary orbit of the old star LL Pegasi and its companion. The figure shows the composite image of molecular gas around LL Pegasi. By comparing this gas distribution depicted in exquisite detail by ALMA with theoretical simulations, the team concluded that the bifurcation of the spiral-shell pattern is resulted from a highly elliptical binary system. Credit: ALMA (ESO/NAOJ/NRAO) / Hyosun Kim et al.

    An international team of astronomers, led by Hyosun Kim in Academia Sinica Institute of Astronomy and Astrophysics (ASIAA, Taiwan), has found a way of deriving the orbital shape of binary stars that have orbital periods too long to be directly measured. This new technique was possible thanks to an observation toward the old star LL Pegasi (also known as AFGL 3068) using the state-of-the-art telescope, the Atacama Large Millimeter/submillimeter Array (ALMA).

    9
    This remarkable picture from the Advanced Camera for Surveys [ACS] on the NASA/ESA Hubble Space Telescope shows one of the most perfect geometrical forms created in space. It captures the formation of an unusual pre-planetary nebula, known as IRAS 23166+1655, around the star LL Pegasi (also known as AFGL 3068) in the constellation of Pegasus (the Winged Horse).

    NASA/ESA Hubble Telescope
    NASA/ESA Hubble Telescope

    NASA Hubble ACS
    “NASA Hubble/ACS

    “It is exciting to see such a beautiful spiral-shell pattern in the sky. Our observations have revealed the exquisitely ordered three-dimensional geometry of this spiral-shell pattern, and we have produced a very satisfying theory to account for its details,” says Hyosun Kim.

    The new ALMA images reveal the detailed features of spiral-shell pattern imprinted in the gas material continuously ejected from LL Pegasi. A comparison of this observation with computer simulations led the team, for the first time, to the conclusion that a binary system with a highly elliptical orbit is responsible for its morphology of gas distribution. In particular, the bifurcation of the spiral-shell pattern, which is clearly visible in the ALMA images, is a unique characteristic of elliptical binaries. This quintessential object opens a new window on the nature of central binaries through the repetitive patterns that reside far from the star at distances of a few thousand the stellar radii.

    “The exquisite sensitivity and ability of ALMA to image with high precision such complex spiral patterns were essential for this study. We are delighted to see the crisp images translated into rich results and their implications in binary research,” says Alfonso Trejo (ASIAA, Taiwan), a co-author of the study.

    Binaries in elliptical orbits for stars in late stellar evolutionary phases may be ubiquitous over an extensive period range. Many planetary nebulae (stars that are in the next stage of stellar evolution) consist of nearly spherical structures in the outer part and highly-asymmetric structures in the inner part. Near-spherical patterns include those appearing like spirals, shells, and arcs, while highly non-spherical features are bipolar- or multipolar-like. The coexistence of such geometrically distinct structures is enigmatic because it hints at the simultaneous presence of both wide and close binary interactions.

    3
    An international team of astronomers using the Atacama Large Millimeter/submillimeter Array (ALMA) have unraveled the elliptical nature of the binary orbit of the old star LL Pegasi and its companion. The figure shows the composite image of molecular gas around LL Pegasi. By comparing this gas distribution depicted in exquisite detail by ALMA with theoretical simulations, the team concluded that the bifurcation of the spiral-shell pattern (indicated by a white box) is resulted from a highly elliptical binary system. Credit: ALMA (ESO/NAOJ/NRAO) / Hyosun Kim et al.

    This phenomenon has been attributed to the binary stars with elliptical orbits. As indicated by the current research, the orbital parameters of central binaries can be obtained by a careful inspection of the outer recurrent patterns, which hint at the origin of the transition from the near-spherical to asymmetric structures.

    4
    (Left) HST image of LL Pegasi publicized in 2010. Credit: ESA/NASA & R. Sahai. (Right) ALMA image of LL Pegasi. Credit: ALMA (ESO/NAOJ/NRAO) / Hyosun Kim et al.

    LL Pegasi is a mass-losing giant star with a size of 200 times or more that of the Sun. Among the stellar evolutionary phases, it is currently on the asymptotic giant branch, which reflects the future of the Sun a few billion years from now. This star was spotlighted about ten years ago due to a picture of an almost-perfect spiral taken with the NASA/ESA Hubble Space Telescope (HST) [1]. The presence of a spiral surrounding an old star had never been reported before the discovery of this object.

    6
    Visualizing the ALMA image cube of LL Pegasi. Each frame of the video shows the molecular gas material surrounding LL Pegasi for a different line-of-sight velocity. This velocity, advancing 1 km/s per frame, is given at the top-right corner. The field size is 20,000 times the distance between the Sun and the Earth. Credit: ALMA (ESO/NAOJ/NRAO) / Hyosun Kim et al.

    “This unusually ordered system opens the door to understanding how the orbits of such systems evolve with time, since each winding of the spiral samples a different orbit in a different period,” says Mark Morris (UCLA, USA), a co-author of the study.

    The regularity of the pattern was quite surprising, leading to being considered as a binary system in a circular orbit. It is now equally striking that this best-characterized, unambiguous, and complete spiral is influenced by an elliptical-orbit binary.

    “While the HST image shows us the beautiful spiral structure, it is a 2D projection of a 3D shape, which becomes fully revealed in the ALMA data,” says Raghvendra Sahai (JPL, USA), a co-author of the study. The new ALMA images reveal the spatiokinematic information of dense molecular gas in the spiral-shell pattern, unveiling the dynamics of the mass loss from the giant star modulated by its orbital motion.

    7
    Zooming into the old star LL Pegasi in the constellation of Pegasus. Credit: Hyosun Kim (ASIAA)

    “The exquisite sensitivity and ability of ALMA to image with high precision such complex spiral patterns were essential for this study. We are delighted to see the crisp images translated into rich results and their implications in binary research,” says Alfonso Trejo (ASIAA, Taiwan), a co-author of the study.

    “The interval of spiral arms yields the orbital period of LL Pegasi to be about 800 years, at which the binary motion can be barely detected even with continuous observations over several human lifetimes. Decoding the spiral-shell pattern is a clever way to trace back the history of orbital motion,” adds Sheng-Yuan Liu (ASIAA, Taiwan), a co-author of the study.

    “By putting this striking spiral-shell on display, nature has left us some clear messages. Deciphering those messages to determine the dynamics of the central stars is the challenge that astronomers are facing,” remarks Hyosun Kim.

    Notes

    [1] The HST results are reported in Morris et al. 2006 (Proceeding of the International Astronomical Union Symposium 234, pp. 469-470) and Mauron & Huggins 2006 (Astronomy and Astrophysics 452, pp. 257-268).

    This research was presented in a paper “The Large-Scale Nebular Pattern of a Superwind Binary in an Eccentric Orbit,” by Kim et al. to appear in the journal Nature Astronomy.

    The team is composed of Hyosun Kim (ASIAA, Taiwan; East Asian Core Observatories Association Fellow), Alfonso Trejo (ASIAA, Taiwan), Sheng-Yuan Liu (ASIAA, Taiwan), Raghvendra Sahai (Jet Propulsion Laboratory, USA), Ronald E. Taam (ASIAA, Taiwan; Northwestern University, USA), Mark R. Morris (University of California, Los Angeles, USA), Naomi Hirano (ASIAA, Taiwan), and I-Ta Hsieh (ASIAA, Taiwan).

    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.

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  • richardmitnick 12:44 pm on February 20, 2017 Permalink | Reply
    Tags: ALMA, , ,   

    From ALMA via ESO: “ALMA’s Hole in the Universe” 

    ALMA Array

    ALMA

    20 February 2017
    No writer credit

    1
    Credit: ALMA (ESO/NAOJ/NRAO)/T. Kitayama (Toho University, Japan)/ESA/Hubble & NASA

    The events surrounding the Big Bang were so cataclysmic that they left an indelible imprint on the fabric of the cosmos. We can detect these scars today by observing the oldest light in the Universe. As it was created nearly 14 billion years ago, this light — which exists now as weak microwave radiation and is thus named the cosmic microwave background (CMB) — has now expanded to permeate the entire cosmos, filling it with detectable photons.

    CMB per ESA/Planck
    CMB per ESA/Planck

    The CMB can be used to probe the cosmos via something known as the Sunyaev-Zel’dovich (SZ) effect, which was first observed over 30 years ago. We detect the CMB here on Earth when its constituent microwave photons travel to us through space. On their journey to us, they can pass through galaxy clusters that contain high-energy electrons. These electrons give the photons a tiny boost of energy. Detecting these boosted photons through our telescopes is challenging but important — they can help astronomers to understand some of the fundamental properties of the Universe, such as the location and distribution of dense galaxy clusters.

    This image shows the first measurements of the thermal Sunyaev-Zel’dovich effect from the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile (in blue). Astronomers combined data from ALMA’s 7- and 12-metre antennas to produce the sharpest possible image. The target was one of the most massive known galaxy clusters, RX J1347.5–1145, the centre of which shows up here in the dark “hole” in the ALMA observations. The energy distribution of the CMB photons shifts and appears as a temperature decrease at the wavelength observed by ALMA, hence a dark patch is observed in this image at the location of the cluster.

    See the full article here .

    Please help promote STEM in your local schools.
    STEM Icon
    Stem Education Coalition

    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 11:16 am on February 15, 2017 Permalink | Reply
    Tags: ALMA, , , , , O-type stars, Rotating circumstellar discs, , Supermassive stars   

    From SRON: “Supermassive stars also formed from circumstellar discs” 

    sron-bloc
    SRON

    13 February 2017
    No writer credit found

    1
    Artist’s impression of a disk around an O-type protostar. No image credit.

    Supermassive stars also appear to be formed in a process that involves rotating circumstellar discs of dust, just like their smaller siblings with a ‘normal’ mass. This was revealed in new research by 24 scientists, among whom was Floris van der Tak (SRON), who wanted to know why stars do not all evolve to be the same.

    When a sun-like star is born from a cloud of gas and dust, the dust and gas do not fall directly onto the growing baby star. Dust that comes near the star first rotates in a disc around this protostar and is then added to the star via the disc. However, besides the very frequently occurring stars like our sun, there are also stars from far more massive categories, the biggest of which is the O-type. Such stars are at least ten times heavier than our sun.

    The researchers wondered whether they could also observe the birth of these heavy types of stars somewhere in the universe, and whether discs of dust revolved around these as well. If such discs were present, then they wanted to know how the properties of the discs of baby suns differed from those of their heavier family members.

    In 2015, the birth of such a heavy O-type star with a circumstellar disc had already been observed. The 24 researchers, led by Riccardo Cesaroni, have now described four more stars. They used the ALMA telescope in Chile to observe the stars in the infrared spectrum, which allowed them to observe the rotating discs as well.

    The heavy discs weigh about half of the protostar’s mass. That is a lot: in the case of sun-like protostar, the disc weighs about 1 to 10 percent of the protostar’s mass.

    “Furthermore, such weight makes the heavy discs unstable due to their own gravity. That might explain why this type of star can be far heavier than sun-like stars,” says Van der Tak.

    The researchers published their results in the renowned journal Astrophysics & Astronomy. A pre-print is already available at http://www.arcetri.astro.it/science/starform/preprints/cesa_29.pdf

    See the full article here .

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    sron-campus

    How did the Earth and life on it evolve? How do stars and planets evolve? How did the universe evolve? What is the position of the Earth and humankind in that immense universe? These are fundamental questions that have always intrigued humankind. Moreover, people have always possessed an urge to explore and push back the boundaries of science and technology.

    Science

    Since the launch of Sputnik in 1957, Dutch astronomers have seen the added value of space missions for science. Reaching beyond the Earth’s atmosphere would open up new windows on the universe and provide fantastic views of our home planet. It would at last be possible to pick up cosmic radiation that never normally reached the Earth’s surface, such as X-rays, ultraviolet and infrared radiation. A wealth of scientific information from every corner of the universe would then become available.

    The first Dutch scientific rocket experiments and contributions to European and American satellites in the early 1960s, formed the start of an activity in which a small country would develop an enviable reputation: scientific space research.

    Groundbreaking technology

    Nowadays we take for granted images of the Earth from space, beautiful photos from the Hubble Space Telescope or landings of space vehicles on nearby planets. Yet sometimes we all too easily forget that none of these scientific successes would have been possible without the people who developed groundbreaking technology. Technology that sooner or later will also prove useful to life on Earth.

     
  • richardmitnick 12:16 pm on February 14, 2017 Permalink | Reply
    Tags: ALMA, , , , Black-Hole Powered Jets Forge Fuel for Star Formation, ,   

    From ALMA: “Black-Hole Powered Jets Forge Fuel for Star Formation” 

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

    14 February 2017
    Nicolás Lira T.
    Press 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
    Composite image showing how powerful radio jets from the supermassive black hole at the center of a galaxy in the Phoenix Cluster inflated huge “bubbles” in the hot, ionized gas surrounding the galaxy (the cavities inside the blue region imaged by NASA’s Chandra X-ray observatory). Hugging the outside of these bubbles, ALMA discovered an unexpected trove of cold gas, the fuel for star formation (red). The background image is from the Hubble Space Telescope. Credit: ALMA (ESO/NAOJ/NRAO) H.Russell, et al.; NASA/ESA Hubble; NASA/CXC/MIT/M.McDonald et al.; B. Saxton (NRAO/AUI/NSF).

    5
    Phoenix cluster. http://masseffect.wikia.com/wiki/The_Phoenix_Massing

    Astronomers using the Atacama Large Millimeter/submillimeter Array (ALMA) have discovered a surprising connection between a supermassive black hole and the galaxy where it resides.

    Powerful radio jets from the black hole – which normally suppress star formation – are stimulating the production of cold gas in the galaxy’s extended halo of hot gas. This newly identified supply of cold, dense gas could eventually fuel future star birth as well as feed the black hole itself.

    The researchers used ALMA to study a galaxy at the heart of the Phoenix Cluster, an uncommonly crowded collection of galaxies about 5.7 billion light-years from Earth.

    The central galaxy in this cluster harbors a supermassive black hole that is in the process of devouring star-forming gas, which fuels a pair of powerful jets that erupt from the black hole in opposite directions into intergalactic space. Astronomers refer to this type of black-hole powered system as an active galactic nucleus (AGN).

    Earlier research with NASA’s Chandra X-ray observatory revealed that the jets from this AGN are carving out a pair of giant “radio bubbles,” huge cavities in the hot, diffuse plasma that surrounds the galaxy.

    NASA/Chandra Telescope
    NASA/Chandra Telescope

    These expanding bubbles should create conditions that are too inhospitable for the surrounding hot gas to cool and condense, which are essential steps for future star formation.

    3
    ALMA image of cold molecular gas at the heart of the Phoenix Cluster. The filaments extending from the center hug enormous radio bubbles created by jets from a supermassive black hole. This discovery sheds light on the complex relationship between a supermassive black hole and its host galaxy. Credit: ALMA (ESO/NAOJ/NRAO), H. Russell et al.; B. Saxton (NRAO/AUI/NSF).

    The latest ALMA observations, however, reveal long filaments of cold molecular gas condensing around the outer edges of the radio bubbles. These filaments extend up to 82,000 light-years from either side of the AGN. They collectively contain enough material to make about 10 billion suns.

    4
    Artist impression of galaxy at the center of the Phoenix Cluster. Powerful radio jets from the supermassive black hole at the center of the galaxy are creating giant radio bubbles (blue) in the ionized gas surrounding the galaxy. ALMA has detected cold molecular gas (red) hugging the outside of the bubbles. This material could eventually fall into the galaxy where it could fuel future star birth and feed the supermassive black hole. Credit: B. Saxton (NRAO/AUI/NSF)

    “With ALMA we can see that there’s a direct link between these radio bubbles inflated by the supermassive black hole and the future fuel for galaxy growth,” said Helen Russell, an astronomer with the University of Cambridge, UK, and lead author on a paper appearing in the Astrophysical Journal. “This gives us new insights into how a black hole can regulate future star birth and how a galaxy can acquire additional material to fuel an active black hole.”

    The AGN and Galaxy Growth Connection

    The new ALMA observations reveal previously unknown connections between an AGN and the abundance of cold molecular gas that fuels star birth.

    “To produce powerful jets, black holes must feed on the same material that the galaxy uses to make new stars,” said Michael McDonald, an astrophysicist at the Massachusetts Institute of Technology in Cambridge and coauthor on the paper. “This material powers the jets that disrupt the region and quenches star formation. This illustrates how black holes can slow the growth of their host galaxies.”

    Without a significant source of heat, the most massive galaxies in the universe would be forming stars at extreme rates that far exceed observations. Astronomers believe that the heat, in the form of radiation and jets, from an actively feeding supermassive black hole prevents overcooling of the cluster’s hot gas atmosphere, suppressing star formation.

    This story, however, now appears more complex. In the Phoenix Cluster, Russell and her team found an additional process that ties the galaxy and its black hole together. The radio jets that heat the core of the cluster’s hot atmosphere also appear to stimulate the production of the cold gas required to sustain the AGN.

    “That’s what makes this result so surprising,” said Brian McNamara, an astronomer at the University of Waterloo, Ontario, and co-author on the paper. “This supermassive black hole is regulating the growth of the galaxy by blowing bubbles and heating the gases around it. Remarkably, it also is cooling enough gas to feed itself.”

    This result helps astronomers understand the workings of the cosmic “thermostat” that controls the launching of radio jets from the supermassive black hole.

    “This could also explain how the most massive black holes were able to both suppress run-away starbursts and regulate the growth of their host galaxies over the past six billion years or so of cosmic history,” noted Russell.

    Additional information

    This research is presented in a paper titled ALMA observations of massive molecular gas filaments encasing radio bubbles in the Phoenix Cluster, by H.R. Russell et al., published in the Astrophysical Journal

    See the full article here .

    Please help promote STEM in your local schools.
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    Stem Education Coalition

    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 4:27 pm on January 25, 2017 Permalink | Reply
    Tags: ALMA, , , Milky-Way-Like Galaxies Seen in their Awkward Adolescent Years, , ,   

    From NRAO: “Milky-Way-Like Galaxies Seen in their Awkward Adolescent Years” 

    NRAO Icon
    National Radio Astronomy Observatory

    NRAO Banner

    December 20, 2016
    Charles Blue
    NRAO Public Information Officer
    +1 434.296.0314;
    cblue@nrao.edu

    1
    Four Milky-Way-like progenitor galaxies as seen as they would have appeared 9 billion years ago. ALMA observations of carbon monoxide (red) is superimposed on images taken with the Hubble Space Telescope. The carbon monoxide would most likely be suffused throughout the young galaxies. Credit. ALMA (ESO/NAOJ/NRAO) C. Papovich; A. Angelich (NRAO/AUI/NSF); NASA/ESA Hubble Space Telescope

    Spiral galaxies like our own Milky Way were not always the well-ordered, pinwheel-like structures we see in the universe today. Astronomers believe that about 8-10 billion years ago, progenitors of the Milky Way and similar spiral galaxies were smaller, less organized, but amazingly rich in star-forming material; so much so, that they would have been veritable star factories, churning out new stars faster than at any other point in their lifetimes. Now, astronomers using the Atacama Large Millimeter/submillimeter Array (ALMA) have found evidence to support this view. By studying four very young versions of galaxies like the Milky Way as they were seen approximately 9 billion years ago, the astronomers discovered that each galaxy was incredibly rich in carbon monoxide gas, a well-known tracer of star-forming gas. “We used ALMA to detect adolescent versions of the Milky Way and found that such galaxies do indeed have much higher amounts of molecular gas, which would fuel rapid star formation,” said Casey Papovich, an astronomer at Texas A&M University in College Station and lead author on a paper appearing in Nature Astronomy. “I liken these galaxies to an adolescent human who consumes prodigious amounts of food to fuel their own growth during their teenage years.” Though the relative abundance of star-forming gas is extreme in these galaxies, they are not yet fully formed and rather small compared to the Milky Way as we see it today. The new ALMA data indicate that the vast majority of the mass in these galaxies is in cold molecular gas rather than in stars. These observations, the astronomers note, are helping build a complete picture of how matter in Milky-Way-size galaxies evolved and how our own galaxy formed.

    See the full article here .

    Please help promote STEM in your local schools.

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    The NRAO operates a complementary, state-of-the-art suite of radio telescope facilities for use by the scientific community, regardless of institutional or national affiliation: the Very Large Array (VLA), the Robert C. Byrd Green Bank Telescope (GBT), and the Very Long Baseline Array (VLBA)*.

    ALMA Array

    NRAO ALMA

    GBO radio telescope, Green Bank, West Virginia, USA
    Green Bank Observatory radio telescope, Green Bank, West Virginia, USA, formerly supported by NSF, but now on its own
    NRAO VLA
    NRAO VLA

    The NRAO is building two new major research facilities in partnership with the international community that will soon open new scientific frontiers: the Atacama Large Millimeter/submillimeter Array (ALMA), and the Expanded Very Large Array (EVLA). Access to ALMA observing time by the North American astronomical community will be through the North American ALMA Science Center (NAASC).
    *The Very Long Baseline Array (VLBA) comprises ten radio telescopes spanning 5,351 miles. It’s the world’s largest, sharpest, dedicated telescope array. With an eye this sharp, you could be in Los Angeles and clearly read a street sign in New York City!

    Astronomers use the continent-sized VLBA to zoom in on objects that shine brightly in radio waves, long-wavelength light that’s well below infrared on the spectrum. They observe blazars, quasars, black holes, and stars in every stage of the stellar life cycle. They plot pulsars, exoplanets, and masers, and track asteroids and planets.

     
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