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  • richardmitnick 9:53 am on May 16, 2019 Permalink | Reply
    Tags: "ALMA Discovers Aluminum around a Young Star", , , , , , , Radio Astronomy   

    From ALMA: “ALMA Discovers Aluminum around a Young Star” 

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

    From ALMA

    16 May, 2019

    Nicolás Lira
    Education and Public Outreach Coordinator
    Joint ALMA Observatory, Santiago – Chile
    Phone: +56 2 2467 6519
    Cell phone: +56 9 9445 7726
    Email: nicolas.lira@alma.cl

    Masaaki Hiramatsu
    Education and Public Outreach Officer, NAOJ Chile
, Tokyo – Japan
    Phone: +81 422 34 3630
    Email: hiramatsu.masaaki@nao.ac.jp

    Calum Turner
    ESO Assistant Public Information Officer
    Garching bei München, Germany
    Phone: +49 89 3200 6670
    Email: calum.turner@eso.org

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


    ALMA image of the distributions of AlO molecules (color) and warm dust particles (contours). The molecular outflow (not shown in this image) extends from the center to the top-left and bottom-right. Credit: ALMA (ESO/NAOJ/NRAO), Tachibana et al.

    Researchers using ALMA data discovered an aluminum-bearing molecule for the first time around a young star. Aluminum-rich inclusions found in meteorites are some of the oldest solid objects formed in the Solar System, but their formation process and stage is still poorly linked to star and planet formation. The discovery of aluminum oxide around a young star provides a crucial chance to study the initial formation process of meteorites and planets like the Earth.

    Disks of gas surround young stars. Some of the gas condenses into dust grains which then stick together to form more substantial objects, building up to form meteors, planetesimals, and eventually planets. Understanding the formation of these first solid objects is essential for understanding everything which follows.

    Shogo Tachibana, a professor at the University of Tokyo/Japan Aerospace Exploration Agency (JAXA), and his team analyzed the ALMA (Atacama Large Millimeter/submillimeter Array) data for Orion KL Source I, a massive young protostar, and found distinctive radio emissions from aluminum oxide (AlO) molecules. This is the first unambiguous detection of AlO around a young star.

    “Aluminum oxide played a significant role in the formation of the oldest material in the Solar System,” says Tachibana “Our discovery will contribute to the understanding of material evolution in the early Solar System.”

    Interestingly, the radio emissions from the AlO molecules are concentrated in the launching points of the outflows from the rotating disk around the protostar. In contrast, other molecules such as silicon monoxide (SiO) have been detected in a broader area in the outflow. Typically, the temperature is higher at the base of the outflows and lower in the downstream gas. “Non-detection of gas-phase AlO downstream indicates that the molecules have condensed into solid dust particles in the colder regions,” explains Tachibana. “Molecules can emit their distinctive radio signals in gas-phase, but not in solid-phase.”

    ALMA’s detection of AlO in the hot base of the outflow suggests that the molecules are formed in hot regions close to the protostar. Once moved to colder areas, AlO would be captured in dust particles which can become aluminum-rich dust, like the oldest solid in the Solar System, and further the building blocks for planets.

    The team will now observe other protostars looking for AlO. Combining the new results with data from meteorites and sample return missions like JAXA’s Hayabusa2 will provide essential insights into the formation and evolution of our Solar System and other planetary systems.
    Additional Information

    These observation results were published as Tachibana et al. “Spatial distribution of AlO in a high mass protostar candidate Orion Source I” in The Astrophysical Journal Letters on April 24, 2019.

    The research team members are: Shogo Tachibana (The University of Tokyo), Takafumi Kamizuka (The University of Tokyo), Tomoya Hirota (National Astronomical Observatory of Japan / SOKENDAI), Nami Sakai (RIKEN), Yoko Oya (The University of Tokyo), Aki Takigawa (Kyoto University), and Satoshi Yamamoto (The University of Tokyo)

    This research was supported by MEXT/JSPS KAKENHI (Nos. 25108002, 25108005, and 17K05398).

    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 Large

  • richardmitnick 2:11 pm on May 9, 2019 Permalink | Reply
    Tags: "Joining the Square Kilometre Array", , , , , MPG-Max Planck Gesellschaft, Radio Astronomy,   

    From Max Planck Gesellschaft: “Joining the Square Kilometre Array” 

    From Max Planck Gesellschaft

    May 08, 2019

    Max Planck Society becomes newest member of SKA Organization.

    The Max Planck Society has become the 13th member of the SKA Organisation, following an unanimous vote by the SKA Board of Directors. The decision to accept the application for membership was taken at the 29th Board meeting at SKA Organisation Global Headquarters in the UK.

    The Max Planck Society joins the final phase of the SKA Organisation, which is overseeing the telescope design phase, until the process of transitioning into the SKA Observatory, an intergovernmental organisation (IGO) established by treaty to manage the construction and operation of the SKA, is completed. Any further German engagement with a joining of the SKA Observatory remains to be decided and will be subject to future discussions.

    “I am delighted to welcome the Max Planck Society to the SKA Organisation as our 13th member, a deserved recognition of the significant contributions Germany has made to the SKA project over the years, and particularly in this crucial pre-construction phase”, said Chairperson of the SKA Board of Directors Dr. Catherine Cesarsky.

    German research institutions and industry have been an intrinsic part of SKA-related projects since its earliest days, and have significant involvement in ongoing SKA design activities. In particular, the Max Planck Society provides instrumentation in the form of detectors, data acquisition and analysis systems for South Africa’s world-class MeerKAT telescope, an SKA precursor facility which will become part of SKA-Mid.

    SKA Meerkat telescope, South African design

    “I am extremely pleased to see our German colleagues consolidating their long-lasting involvement in SKA-related activities both at a scientific and industrial level”, added Prof. Philip Diamond, SKA Director-General. “Germany’s great wealth of expertise in radio astronomy, both in science and engineering, will continue to be invaluable as we move ever closer to SKA construction and operations.”

    The Max Planck Society is a non-profit organisation with 84 institutes and research facilities. In collaboration with other German institutions and industry, it has been involved across many areas of SKA design work, including within the Mid Frequency Dish Array, Low Frequency Aperture Array, Central Signal Processor, Science Data Processor, Telescope Manager, Signal and Data Transport consortia, and research and development work within the Phased Array Feeds and Wideband Single Pixel Feeds consortia.

    Among the Max Planck Society’s institutes is the Max Planck Institute for Radio Astronomy (MPIfR) a key player in the SKA’s Dish engineering consortium.

    Max Planck Institute for Radio Astronomy Bonn Germany

    Together with German industry partners, such as the telescope antenna specialists MT Mechatronics (MTM), and international partners, the Dish consortium is responsible for designing the SKA’s mid-frequency array (SKA-Mid), to be deployed in South Africa, The Dish consortium has already delivered two prototype SKA dishes: SKA-P, which is currently being tested in China, and SKA-MPI, funded by the Max Planck Society, which is under construction on the SKA site in South Africa’s Karoo region.

    “The SKA is a great opportunity for astronomers, engineers, physicists and data scientists. Besides becoming an amazing discovery machine, SKA pushes the boundaries of what is technically possible, especially in the handling and analysis of huge amounts of data. The Max Planck Society is in the middle of all these exciting science and technology developments, and we are pleased to now be able to contribute officially to the SKAO efforts”, says Prof Michael Kramer, director at the MPIfR.

    See the full article here .


    Please help promote STEM in your local schools.

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    The Max Planck Society is Germany’s most successful research organization. Since its establishment in 1948, no fewer than 18 Nobel laureates have emerged from the ranks of its scientists, putting it on a par with the best and most prestigious research institutions worldwide. The more than 15,000 publications each year in internationally renowned scientific journals are proof of the outstanding research work conducted at Max Planck Institutes – and many of those articles are among the most-cited publications in the relevant field.

    What is the basis of this success? The scientific attractiveness of the Max Planck Society is based on its understanding of research: Max Planck Institutes are built up solely around the world’s leading researchers. They themselves define their research subjects and are given the best working conditions, as well as free reign in selecting their staff. This is the core of the Harnack principle, which dates back to Adolph von Harnack, the first president of the Kaiser Wilhelm Society, which was established in 1911. This principle has been successfully applied for nearly one hundred years. The Max Planck Society continues the tradition of its predecessor institution with this structural principle of the person-centered research organization.

    The currently 83 Max Planck Institutes and facilities conduct basic research in the service of the general public in the natural sciences, life sciences, social sciences, and the humanities. Max Planck Institutes focus on research fields that are particularly innovative, or that are especially demanding in terms of funding or time requirements. And their research spectrum is continually evolving: new institutes are established to find answers to seminal, forward-looking scientific questions, while others are closed when, for example, their research field has been widely established at universities. This continuous renewal preserves the scope the Max Planck Society needs to react quickly to pioneering scientific developments.

  • richardmitnick 8:46 am on April 29, 2019 Permalink | Reply
    Tags: , , , , , , Radio Astronomy   

    From NASA Spitzer: “The Giant Galaxy Around the Giant Black Hole” 

    NASA/Spitzer Telescope

    From NASA Spitzer


    Calla Cofield
    Jet Propulsion Laboratory, Pasadena, Calif.

    A composite image showing the galaxy Messier 87 and, in inset, the particle jets emerging from the black hole at its heart. NASA/JPL-Caltech/IPAC/Event Horizon Telescope Collaboration Armstrong Roberts/ClassicStock/Getty Images.

    On April 10, 2019, the Event Horizon Telescope (EHT) unveiled the first-ever image of a black hole’s event horizon, the area beyond which light cannot escape the immense gravity of the black hole. That giant black hole, with a mass of 6.5 billion Suns, is located in the elliptical galaxy Messier 87 (M87). EHT is an international collaboration whose support in the U.S. includes the National Science Foundation.

    This image from NASA’s Spitzer Space Telescope shows the entire Messier 87 galaxy in infrared light. The EHT image, by contrast, relied on light in radio wavelengths and showed the black hole’s shadow against the backdrop of high-energy material around it.

    EHT map

    Located about 55 million light-years from Earth, M87 has been a subject of astronomical study for more than 100 years and has been imaged by many NASA observatories, including the Hubble Space Telescope, the Chandra X-ray Observatory and NuSTAR.

    NASA/ESA Hubble Telescope

    NASA/Chandra X-ray Telescope

    NASA/DTU/ASI NuSTAR X-ray telescope

    In 1918, astronomer Heber Curtis first noticed “a curious straight ray” extending from the galaxy’s center. This bright jet of high-energy material, produced by a disk of material spinning rapidly around the black hole, is visible in multiple wavelengths of light, from radio waves through X-rays. When the particles in the jet impact the interstellar medium (the sparse material filling the space between stars in M87), they create a shockwave that radiates in infrared and radio wavelengths of light but not visible light. In the Spitzer image, the shockwave is more prominent than the jet itself.

    The brighter jet, located to the right of the galaxy’s center, is traveling almost directly toward Earth. Its brightness is amplified due to its high speed in our direction, but even more so because of what scientists call “relativistic effects,” which arise because the material in the jet is traveling near the speed of light. The jet’s trajectory is just slightly offset from our line of sight with respect to the galaxy, so we can still see some of the length of the jet. The shockwave begins around the point where the jet appears to curve down, highlighting the regions where the fast-moving particles are colliding with gas in the galaxy and slowing down.

    The second jet, by contrast, is moving so rapidly away from us that the relativistic effects render it invisible at all wavelengths. But the shockwave it creates in the interstellar medium can still be seen here.

    Located on the left side of the galaxy’s center, the shockwave looks like an inverted letter “C.” While not visible in optical images, the lobe can also be seen in radio waves, as in this image from the National Radio Astronomy Observatory’s Very Large Array.

    NRAO/Karl V Jansky Expanded Very Large Array, on the Plains of San Agustin fifty miles west of Socorro, NM, USA, at an elevation of 6970 ft (2124 m)

    By combining observations in the infrared, radio waves, visible light, X-rays and extremely energetic gamma rays, scientists can study the physics of these powerful jets. Scientists are still striving for a solid theoretical understanding of how gas being pulled into black holes creates outflowing jets.

    Infrared light at wavelengths of 3.6 and 4.5 microns are rendered in blue and green, showing the distribution of stars, while dust features that glow brightly at 8.0 microns are shown in red. The image was taken during Spitzer’s initial “cold” mission.

    See the full article here .


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    Stem Education Coalition

    The Spitzer Space Telescope is a NASA mission managed by the Jet Propulsion Laboratory located on the campus of the California Institute of Technology and part of NASA’s Infrared Processing and Analysis Center.

    NASA image

    NASA JPL Icon

    Caltech Logo

  • richardmitnick 12:02 pm on April 26, 2019 Permalink | Reply
    Tags: , ALMA- Atacama Large Millimeter/submillimeter Array, , , Automated Imaging Routine for Compact Arrays for the Radio Sun (AIRCARS), , , , Radio Astronomy, SKA - Murchison Widefield Array (MWA), SKA- Pathfinder (ASKAP) is a radio telescope array located at Murchison Radio-astronomy Observatory (MRO) in the Australian Mid West   

    From AAS NOVA: “Prepping for Even Bigger Data in the Era of Interferometry” 


    From AAS NOVA

    26 April 2019
    Kerry Hensley

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

    The Atacama Large Millimeter/submillimeter Array (ALMA), with its collection of 66 radio dishes, is one of several telescope arrays capable of capturing images of the Sun at radio wavelengths. [Y. Beletsky (LCO)/ESO]

    Interferometric arrays collect massive amounts of information, leaving astronomers with a happy problem: too much data! How can we handle mountains of data in an efficient way?

    SKA Murchison Widefield Array, Boolardy station in outback Western Australia, at the Murchison Radio-astronomy Observatory (MRO)

    One of many tiles comprising the Murchison Widefield Array (MWA). Radio interferometric arrays like MWA generate vast amounts of data. [Dr. John Goldsmith/Celestial Visions]

    Too Much of a Good Thing?

    Astronomers have come a long way from the early days of manually cataloging stars and sketching sunspots by hand. Even though today’s data sets are larger and more complex, many astronomers still manually calibrate and process their data.

    This hands-on data processing won’t always be feasible, though; interferometry — the process of linking together tens to thousands of telescopes or antennae to produce images with ever-finer angular resolution — generates far more data than humans could hope to handle manually. Just one minute’s worth of data from the Murchison Widefield Array (MWA), a radio interferometer made up of 4,096 antennae, yields roughly 10,000 images!

    With the number of interferometers increasing, we’ll need to be smart about how we process all that data to minimize computing hours while maximizing the quality of the output. Among the many detectors requiring novel data-processing techniques is the planned Square Kilometer Array (SKA), which will comprise a million antennae and 2,000 radio telescopes. How can we get a handle on all this data without getting too hands-on?

    Australian Square Kilometre Array Pathfinder (ASKAP) is a radio telescope array located at Murchison Radio-astronomy Observatory (MRO) in the Australian Mid West. ASKAP consists of 36 identical parabolic antennas, each 12 metres in diameter, working together as a single instrument with a total collecting area of approximately 4,000 square metres.

    SKA Hera at SKA South Africa

    SKA Meerkat telescope(s), 90 km outside the small Northern Cape town of Carnarvon, SA

    An illustration of how increasing numbers of detectors are included in the model of the target for self-calibration. The first step includes only the blue detectors near the center, and subsequent steps add the red, teal, black, and yellow detectors to increase the complexity of the model. [Mondal et al. 2019]

    Dealing with Data Pileup

    To tackle this problem, a team led by Surajit Mondal (Tata Institute of Fundamental Research, India) developed an automated processing pipeline for interferometric data — the Automated Imaging Routine for Compact Arrays for the Radio Sun (AIRCARS). They focused on processing solar radio images, which need to capture a huge dynamic range — from extremely bright active regions to faint, wispy filaments.

    One of the challenges in radio interferometry is removing the effects of instrumental artifacts and the plasma in Earth’s atmosphere. Most radio interferometry data are corrected with a self-calibration process that treats the instrumental artifacts and the brightness of the target as free parameters and iteratively minimizes the difference between the observations and a model of the target.

    AIRCARS works especially well when applied to a compact array — one with many detectors clustered in the center and fewer near the outskirts. This configuration allows the pipeline to start with relatively little information about the target from just a few central detectors and gradually build a complex model of the target to be used in its self-calibration routine.

    An example of the improvement of the dynamic range of MWA images through the self-calibration process. The number of iterations increases from top to bottom and left to right. The dashed circle indicates the location of the Sun’s disk. [Mondal et al. 2019]

    AIRCARS in Our Future

    In their tests on MWA data, the authors find that AIRCARS is capable of capturing a dynamic range up to 100,000:1 — a huge improvement over previous processing methods.

    Mondal and collaborators note that AIRCARS can be configured to attain the maximum possible dynamic range without constraints on computing time, or to accept user-imposed time limits to rapidly process large amounts of data, depending on the user’s computational requirements.

    Because the pipeline needs no human supervision, astronomers can take a step back from processing the vast amount of incoming data and focus instead on the exciting science we can do with interferometry.


    “Unsupervised Generation of High Dynamic Range Solar Images: A Novel Algorithm for Self-calibration of Interferometry Data,” Surajit Mondal et al 2019 ApJ 875 97.

    See the full article here .


    Please help promote STEM in your local schools.

    Stem Education Coalition


    AAS Mission and Vision Statement

    The mission of the American Astronomical Society is to enhance and share humanity’s scientific understanding of the Universe.

    The Society, through its publications, disseminates and archives the results of astronomical research. The Society also communicates and explains our understanding of the universe to the public.
    The Society facilitates and strengthens the interactions among members through professional meetings and other means. The Society supports member divisions representing specialized research and astronomical interests.
    The Society represents the goals of its community of members to the nation and the world. The Society also works with other scientific and educational societies to promote the advancement of science.
    The Society, through its members, trains, mentors and supports the next generation of astronomers. The Society supports and promotes increased participation of historically underrepresented groups in astronomy.
    The Society assists its members to develop their skills in the fields of education and public outreach at all levels. The Society promotes broad interest in astronomy, which enhances science literacy and leads many to careers in science and engineering.

    Adopted June 7, 2009

  • richardmitnick 12:15 pm on April 24, 2019 Permalink | Reply
    Tags: "Scientists Use Asteroid to Measure Smallest Star Size to Date", , , , , , Radio Astronomy,   

    From Harvard-Smithsonian Center for Astrophysics: “Scientists Use Asteroid to Measure Smallest Star Size to Date” 

    Harvard Smithsonian Center for Astrophysics

    From Harvard-Smithsonian Center for Astrophysics

    April 16, 2019

    Amy Oliver
    Public Affairs
    Center for Astrophysics | Harvard & Smithsonian
    Fred Lawrence Whipple Observatory
    +1 617-495-7462

    Tyler Jump
    Public Affairs
    Center for Astrophysics | Harvard & Smithsonian
    +1 617-495-7462


    Scientists in the VERITAS (Very Energetic Radiation Imaging Telescope Array System) Collaboration have published a paper in Nature Astronomy journal detailing the results of their work with the VERITAS array—located at the Center for Astrophysics’ Fred Lawrence Whipple Observatory in Amado, Arizona—to measure the smallest apparent size of stars in the night sky known to date.

    CfA/VERITAS, a major ground-based gamma-ray observatory with an array of four 12m optical reflectors for gamma-ray astronomy in the GeV – TeV energy range. Located at Fred Lawrence Whipple Observatory,Mount Hopkins, Arizona, US in AZ, USA, Altitude 2,606 m (8,550 ft)

    Measurements taken using the VERITAS telescopes revealed the diameter of a giant star located 2,674 light years from Earth. Taken on February 22, 2018, at the Whipple Observatory, data revealed the star to be 11 times the diameter of Earth’s Sun. Using the four 12-m gamma-ray telescopes of VERITAS, the team collected 300 images per second to detect the diffraction pattern in the shadow sweeping past the telescopes as the star TYC 5517-227-1 was occulted by the 60-km asteroid Imprinetta. “From these data, the brightness profile of the diffraction pattern of the star was reconstructed with high accuracy,” said Dr. Michael Daniel, Operations Manager, VERITAS. “This allowed us to determine the actual diameter of the star, and determine it to be a red giant, although it could previously be classified as ambiguous.”

    Three months later, on May 22, 2018, the team repeated the experiment when asteroid Penelope—diameter 88-km—occulted star TYC 278-748-1 located 700 light years from Earth. “Using the same formula for data collection and calculations, we determined this star to be 2.17 times the diameter Earth’s Sun,” said Daniel. “This direct measurement allowed us to correct an earlier estimation that placed the star’s diameter at 1.415 times that of our sun.”

    With almost any star on the night sky too distant from Earth to be directly measured using even the best of optical telescopes, scientists overcame these limitations using diffraction, which occurs when an object, like an asteroid, passes in front of a star, making a shadow called an occultation. “The incredibly faint shadows of asteroids pass over us every day,” explained Dr. Tarek Hassan, DESY. “But the rim of the shadow isn’t perfectly sharp. Instead, wrinkles of light surround the central shadow, like water ripples.”

    For VERITAS scientists, however, the task was not as easy as turning telescopes to the sky. “Asteroid occultations are difficult to predict,” said Daniel. “The only chance to catch the diffraction pattern is to make very fast snapshots when the shadow of the occultation sweeps across the telescope.”

    Astronomers have similarly used this method— which measures to an angular diameter of roughly one milliarcsecond—to measure angular sizes of stars occulted by Earth’s moon. “The trouble is that not many telescopes are large enough for the occultation method to measure the diffraction pattern with confirmed accuracy over the turbulence in the Earth’s atmosphere,” said Daniel. “VERITAS telescopes are uniquely sensitive as we use them primarily for observing faint light from very-high-energy gamma rays and cosmic rays. While they do not produce images as elegant as those from traditional optical telescopes, they see and capture fast variations of light, and we estimate that they can analyze stars up to ten times farther away with extreme accuracy than optical telescopes using the lunar occultation method can.”

    At its conclusion, the pilot study resulted in the direct measurement of the size of a star at the smallest angular scale in the night sky to date, and established a new method to determine the angular diameter of stars.

    About VERITAS

    VERITAS (Very Energetic Radiation Imaging Telescope Array System) is a ground-based array of four, 12-m optical reflectors for gamma-ray astronomy located at the Center for Astrophysics | Harvard & Smithsonian, Fred Lawrence Whipple Observatory in Amado, Arizona. VERITAS is the world’s most sensitive very-high-energy gamma-ray observatory, and it detects gamma rays via the extremely brief flashes of blue “Cherenkov” light they create when they are absorbed in the Earth’s atmosphere.

    VERITAS is supported by grants from the U.S. Department of Energy Office of Science, the U.S. National Science Foundation, and the Smithsonian Institution, and by NSERC in Canada.

    The VERITAS Collaboration consists of about 80 scientists from 20 institutions in the United States, Canada, Germany and Ireland.

    For more information about VERITAS visit http://veritas.sao.arizona.edu

    About DESY

    DESY is one of the world’s leading particle accelerator centers. Researchers use the large‐scale facilities at DESY to explore the microcosm in all its variety – ranging from the interaction of tiny elementary particles to the behavior of innovative nanomaterials and the vital processes that take place between biomolecules to the great mysteries of the universe. The accelerators and detectors that DESY develops and builds at its locations in Hamburg and Zeuthen are unique research tools. DESY is a member of the Helmholtz Association, and receives its funding from the German Federal Ministry of Education and Research (BMBF) (90 per cent) and the German federal states of Hamburg and Brandenburg (10 per cent).

    See the full article here .

    Please help promote STEM in your local schools.

    Stem Education Coalition

    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.

  • richardmitnick 12:37 pm on April 16, 2019 Permalink | Reply
    Tags: An HII region CTB 102 has been difficult to study, , , , , , , Radio Astronomy, Taeduk Radio Astronomy Observatory in South Korea   

    From Iowa State University via Futurity: “Maps reveal massive clouds in star-forming region” 

    From Iowa State University



    April 16th, 2019
    Mike Krapfl-Iowa State

    (Credit: Filip Bunkens/Unsplash)

    Astronomers have made the first high-resolution, radio telescope observations of the molecular clouds within a huge star-forming region of the outer Milky Way.

    This image from a radio telescope shows a huge star-forming region of the outer Milky Way galaxy. The ovals identify the main subdivisions of the region’s molecular cloud, including the smaller 1a, which is very efficient at producing stars. (Credit: Charles Kerton)

    “This region is behind a nearby cloud of dust and gas,” says Charles Kerton, an associate professor of physics and astronomy at Iowa State University and a member of the study team.

    “The cloud blocks the light and so we have to use infrared or radio observations to study it.”

    The Milky Way region, called CTB 102, is about 14,000 light years from Earth. It’s classified as an HII region, meaning it contains clouds of ionized—charged—hydrogen atoms. And, because of its distance from Earth and the dust and gas in between, it has been difficult to study.

    And so, “this region has been very poorly mapped out,” Kerton says.

    The astronomers used a newly commissioned radio telescope at the Taeduk Radio Astronomy Observatory in South Korea to take high resolution, carbon monoxide observations of the galactic region’s molecular clouds, Kerton says.

    Taeduk Radio Astronomy Observatory owned and operated by Korea Astronomy and Space Science Institute. It is located in the science town of Taeduk, part of Daejeon, South Korea. in South Korea

    “That tells us the mass and structure of the material in the interstellar medium there.”

    The astronomers also compared their radio observations with existing infrared data from the Wide-field Infrared Survey Explorer and the Two Micron All Sky Survey. The infrared data allowed them to classify young stars forming within the region’s molecular clouds.

    NASA Wise Telescope

    Caltech 2MASS Telescopes, a joint project of the University of Massachusetts and the Infrared Processing and Analysis Center (IPAC) at Caltech, at the Whipple Observatory on Mt. Hopkins south of Tucson, AZ, Altitude 2,606 m (8,550 ft) and at the Cerro Tololo Inter-American Observatory at an altitude of 2200 meters near La Serena, Chile.

    The data yield three major observations, the astronomers report in their paper, which will appear in The Astrophysical Journal.

    First, the astronomers used radio data to describe the physical structure and characteristics of the region’s newly mapped molecular clouds—they’re fairly large, about 180 light years across with a mass equal to about 100,000 masses of our sun. Next, they used infrared data to determine the young stellar content within the clouds. And finally, they combined the two data streams to study the efficiency of star formation within the galactic region.

    The researchers report the star formation efficiency of the entire CTB 102 region is about 5 to 10 percent, similar to other giant molecular clouds within the galaxy. But, they found one subregion of the clouds with a star formation efficiency of 17 to 37 percent (depending on how they calculate the mass of the subregion). That’s much higher than astronomers would expect for a subregion of its size. The researchers speculate the subregion is the site of a massive cluster of young, developing stars embedded in the molecular cloud.

    Why all the star formation in that one subregion? Kerton says that’s a question for further study. Maybe, he says, there’s something special about the interstellar material in that subregion, which is next to the massive HII region.

    “This is our first look at all of this,” Kerton says. “The older data were just a few dots, a few pixels. We couldn’t isolate this relatively small region of the galaxy.”

    But now they can—with the help of the new South Korean radio observatory.

    The study’s high-resolution observations, Kerton says, “are also a demonstration that the telescope is ideal for studying similar regions in our galaxy—there are many other potential targets.”

    Additional researchers from Korea Astronomy and Space Science Institute and the University of Nebraska contributed to the work.

    See the full article here .


    Please help promote STEM in your local schools.

    Stem Education Coalition

    Iowa State University is a public, land-grant university, where students get a great academic start in learning communities and stay active in 800-plus student organizations, undergrad research, internships and study abroad. They learn from world-class scholars who are tackling some of the world’s biggest challenges — feeding the hungry, finding alternative fuels and advancing manufacturing.

    Iowa Agricultural College and Model Farm (now Iowa State University) was officially established on March 22, 1858, by the legislature of the State of Iowa. Story County was selected as a site on June 21, 1859, and the original farm of 648 acres was purchased for a cost of $5,379. The Farm House, the first building on the Iowa State campus, was completed in 1861, and in 1862, the Iowa legislature voted to accept the provision of the Morrill Act, which was awarded to the agricultural college in 1864.

    Iowa State University Knapp-Wilson Farm House. Photo between 1911-1926

    Iowa Agricultural College (Iowa State College of Agricultural and Mechanic Arts as of 1898), as a land grant institution, focused on the ideals that higher education should be accessible to all and that the university should teach liberal and practical subjects. These ideals are integral to the land-grant university.

    The first official class entered at Ames in 1869, and the first class (24 men and 2 women) graduated in 1872. Iowa State was and is a leader in agriculture, engineering, extension, home economics, and created the nation’s first state veterinary medicine school in 1879.

    In 1959, the college was officially renamed Iowa State University of Science and Technology. The focus on technology has led directly to many research patents and inventions including the first binary computer (the ABC), Maytag blue cheese, the round hay baler, and many more.

    Beginning with a small number of students and Old Main, Iowa State University now has approximately 27,000 students and over 100 buildings with world class programs in agriculture, technology, science, and art.

    Iowa State University is a very special place, full of history. But what truly makes it unique is a rare combination of campus beauty, the opportunity to be a part of the land-grant experiment, and to create a progressive and inventive spirit that we call the Cyclone experience. Appreciate what we have here, for it is indeed, one of a kind.

  • richardmitnick 8:52 am on April 12, 2019 Permalink | Reply
    Tags: , , , , Greenland Telescope will join the EHT by moving to the summit of the Greenland ice sheet summit of 3000 ft, , Radio Astronomy,   

    From Niels Bohr Institute at University of Copenhagen: “Greenland Telescope to image black holes by moving onto the Greenland ice sheet” 

    University of Copenhagen

    Niels Bohr Institute bloc

    From Niels Bohr Institute

    10 April 2019

    Marianne Vestergaard
    Associate Professor, DARK, Niels Bohr Institute, University of Copenhagen
    Phone: +45 35 32 59 09

    Scientists from the Niels Bohr Institute, University of Copenhagen, will soon be able to participate in the “Event Horizon Telescope” (EHT) with the Greenland Telescope (GLT). The GLT will become part of a global network of radio telescopes designed to get the first images of black holes.

    NRAO/CfA Greenland Telescope will be moved to the Summit of the ice sheet during the summer of 2021, reaching an altitude of approx. 3000 meters above sea level, where the clear, dry and cold climate will offer better observing conditions. Photo: Greenlandtelescope.dk

    How do you take a picture of something that emits no light?

    It’s hard to get an image of a black hole. They are the darkest objects in the universe because their gravity is so intense that no light can escape them, and their tremendous density makes them very small in spite of their enormous mass. To overcome these problems, the experiment is targeting much larger black holes than normal, namely so-called supermassive black holes, millions or billions of times more massive than the sun, as well as distributing the network of telescopes across the Globe to maximise the resolution of the image. It is possible to detect the black hole because the EHT can image the “shadow” of the black hole against a bright background of hot material near it.

    While black holes have been theoretically expected for the best part of a century, the first conclusive evidence for the existence of black holes was only obtained in 2015, when gravitational waves from a merger of two (smaller) black holes were detected. However, so far, no one has ever managed to get an image of a black hole because they are so small and so dark. In the center of almost every galaxy in the Universe there is a compact and supermassive object that astronomers believe to be supermassive black holes, vastly more massive than the merging black holes detected in 2015. But the final evidence is still lacking that these concentrations of mass in the hearts of galaxies are actually black holes. By detecting and creating an image of the black hole, viewed in contrast against the powerful radiation from the gas being drawn into the hole, researchers can confirm that the compact object doesn’t have a surface to reflect any light, and that light behaves in the warped way that we expect from the theory of general relativity near a black hole and its strong gravitational field.

    [Supermassive black hole at Messier 87 was successfully imaged by the Event Horizon Telescope in 2107


    In April of 2017, all 8 of the telescopes/telescope arrays associated with the Event Horizon Telescope pointed at Messier 87. This is what a supermassive black hole looks like, where the event horizon is clearly visible. Event Horizon Telescope collaboration et al.]

    Danish access to the data EHT will be producing

    A press conference was held at DTU Space on Wednesday 10. April, where the first results from the EHT consortium were presented. With the addition of the Greenland Telescope, the precision and sensitivity of the images will substantially increase, and at the same time, Danish researchers will gain access to the EHT.

    “ It is fascinating to know that our generation is not only the first to learn, via detections of gravitational waves, that black holes really exist. We will also be the first to see what they look like!” says Marianne Vestergaard, associate professor at DARK, the Niels Bohr Institute and she continues: “We, the researchers, are thrilled. These excellent results from the Event Horizon Telescope show us the remarkable things that a dedicated, global collaboration can achieve, and it reveals the great potential there is for exploring the complex parts of our universe of which black holes are a manifest. It is particularly enjoyable that we, the Danish researchers, will be able to contribute to this new type of telescope on the front line.

    The Summit of the icecap will be the new home for the Greenland Telescope

    Greenland Telescope will be moved to the Summit of the ice sheet, reaching an altitude of approx. 3000 meters above sea level. The air is much drier, and the clear, dry and cold climate will offer better observing conditions compared to the humid air along the coast. The complicated task of moving the telescope across the ice is planned to take place during the summer of 2021. Researchers from the Niels Bohr Institute’s Physics of Ice, Climate and Earth section are assisting in that operation.

    See the full article here .


    Stem Education Coalition

    Niels Bohr Institute Campus

    Niels Bohr Institute (Danish: Niels Bohr Institutet) is a research institute of the University of Copenhagen. The research of the institute spans astronomy, geophysics, nanotechnology, particle physics, quantum mechanics and biophysics.

    The Institute was founded in 1921, as the Institute for Theoretical Physics of the University of Copenhagen, by the Danish theoretical physicist Niels Bohr, who had been on the staff of the University of Copenhagen since 1914, and who had been lobbying for its creation since his appointment as professor in 1916. On the 80th anniversary of Niels Bohr’s birth – October 7, 1965 – the Institute officially became The Niels Bohr Institute.[1] Much of its original funding came from the charitable foundation of the Carlsberg brewery, and later from the Rockefeller Foundation.[2]

    During the 1920s, and 1930s, the Institute was the center of the developing disciplines of atomic physics and quantum physics. Physicists from across Europe (and sometimes further abroad) often visited the Institute to confer with Bohr on new theories and discoveries. The Copenhagen interpretation of quantum mechanics is named after work done at the Institute during this time.

    On January 1, 1993 the institute was fused with the Astronomic Observatory, the Ørsted Laboratory and the Geophysical Institute. The new resulting institute retained the name Niels Bohr Institute.

    The University of Copenhagen (UCPH) (Danish: Københavns Universitet) is the oldest university and research institution in Denmark. Founded in 1479 as a studium generale, it is the second oldest institution for higher education in Scandinavia after Uppsala University (1477). The university has 23,473 undergraduate students, 17,398 postgraduate students, 2,968 doctoral students and over 9,000 employees. The university has four campuses located in and around Copenhagen, with the headquarters located in central Copenhagen. Most courses are taught in Danish; however, many courses are also offered in English and a few in German. The university has several thousands of foreign students, about half of whom come from Nordic countries.

    The university is a member of the International Alliance of Research Universities (IARU), along with University of Cambridge, Yale University, The Australian National University, and UC Berkeley, amongst others. The 2016 Academic Ranking of World Universities ranks the University of Copenhagen as the best university in Scandinavia and 30th in the world, the 2016-2017 Times Higher Education World University Rankings as 120th in the world, and the 2016-2017 QS World University Rankings as 68th in the world. The university has had 9 alumni become Nobel laureates and has produced one Turing Award recipient

  • richardmitnick 6:10 pm on April 11, 2019 Permalink | Reply
    Tags: , , , , , , , Radio Astronomy, , ,   

    From Nautilus: “First Black-Hole Image: It’s Not Looks That Count” 


    From Nautilus

    Apr 11, 2019
    Sabine Hossenfelder

    FIRST LOOK: The Event Horizon Telescope measures wavelength in the millimeter regime, too long to be seen by eye, but ideally suited to the task of imaging a black hole: The gas surrounding the black hole is almost transparent at this wavelength and the light travels to Earth almost undisturbed. Since we cannot see light of such wavelength by eye, the released telescope image shows the observed signal shifted into the visible range.Event Horizon Telescope Collaboration.

    “The Day Feynman Worked Out Black-Hole Radiation on My Blackboard”
    After a few minutes, Richard Feynman had worked out the process of spontaneous emission, which is what Stephen Hawking became famous for a year later.Wikicommons.

    The Italian 14th-century painter, Giotto di Bondone, when asked by the Pope to prove his talent, is said to have swung his arm and drawn a perfect circle. But geometric perfection is limited by the medium. Inspect a canvas closely enough, and every circle will eventually appear grainy. If perfection is what you seek, don’t look at man-made art, look at the sky. More precisely, look at a black hole.

    Looking at a black hole is what the Event Horizon Telescope has done for the past 12 years. Yesterday, the collaboration released the long-awaited results from its first full run in April 2017. Contrary to expectation, their inaugural image is not, as many expected, Sagittarius A*, the black hole at the center of the Milky Way. Instead, it is the supermassive black hole in the elliptic galaxy Messier 87, about 55 million light-years from here. This black hole weighs in at 6.5 billion times the mass of our sun, and is considerably larger than the black hole in our own galaxy [1,000 times the size of SGR A*]. So, even though the Messier 87 black hole is a thousand times farther away than Sagittarius A*, it still appears half the size in the sky.

    The Event Horizon Telescope (EHT) is not less remarkable than the objects it observes. With a collaboration of 200 people, the EHT uses not a single telescope, but a global network of nine telescopes. Its sites, from Greenland to the South Pole and from Hawaii to the French Alps, act in concert as one. Together, the collaboration commands a telescope the size of planet Earth, staring at a tiny patch in the northern sky that contains the Messier-87 black hole.

    Event Horizon Telescope Array

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

    Atacama Pathfinder EXperiment

    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 30m Radio telescope, on Pico Veleta in the Spanish Sierra Nevada,, Altitude 2,850 m (9,350 ft)

    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 Mauna Kea, Hawaii, USA, Altitude 4,080 m (13,390 ft)

    Submillimeter Array Hawaii SAO

    ESO/NRAO/NAOJ ALMA Array, Chile [recently added]

    South Pole Telescope SPTPOL
    South Pole Telescope SPTPOL [recently added]

    Future Array/Telescopes

    NOEMA (NOrthern Extended Millimeter Array) will double the number of its 15 meter antennas of its predecessor from six to twelve, located in the French Alpes on the wide and isolated Plateau de Bure at an elevation of 2550 meters

    NSF CfA Greenland telescope

    Greenland Telescope

    ARO 12m Radio Telescope, Kitt Peak National Observatory, Arizona, USA, Altitude 1,914 m (6,280 ft)

    ARO 12m Radio Telescope

    In theory, black holes are regions of space where the gravitational pull is so large that everything, including light, becomes trapped for eternity. The surface of the trapping region is called the “event horizon.” It has no substance; it is a property of space itself. In the simplest case, the event horizon is a sphere—a perfect sphere, made of nothing.

    In reality, it’s complicated. Astrophysicists have had evidence for the existence of black holes since the 1990s, but so far all observations have been indirect—inferred from the motion of visible stars and gas, leaving doubt as to whether the dark object really possesses the defining event horizon. It turned out difficult to actually see a black hole. Trouble is, they’re black. They trap light. And while Stephen Hawking proved that black holes must emit radiation due to quantum effects, this quantum glow is far too feeble to observe.

    But much like the prisoners in Plato’s cave, we can see black holes by observing the shadows they cast. Black holes attract gas from their environment. This gas collects in a spinning disk, and heats up as it spirals into the event horizon, pushing around electric charges. This gives rise to strong magnetic fields that can create a “jet,” a narrow, directed stream of particles leaving the black hole at almost the speed of light. But whatever strays too close to the event horizon falls in and vanishes without a trace.

    At the same time black holes bend rays of light, bend them so strongly, indeed, that looking at the front of a black hole, we can see part of the disk behind it. The light that just about manages to escape reveals what happens nearby the horizon. It is an asymmetric image that the astrophysicists expect, brighter on the side of the black hole where the material surrounding it moves toward us, and darker where it moves away from us. The hot gas combined with the gravitational lensing creates the unique observable signature that the EHT looks out for.

    The experimental challenge is formidable. The network’s telescopes must synchronize their data-taking using atomic clocks. Weather conditions must be favorable at all locations simultaneously. Once recorded, the amount of data is so staggeringly large, it must be shipped on hard disks to central locations for processing.

    The theoretical challenges are not any lesser. Black holes bend light so much that it can wrap around the horizon multiple times. The resulting image is too complicated to capture in simple equations. Though the math had been known since the 1920s, it wasn’t until 1978 that physicists got a first glimpse of what a black hole would actually look like. In that year, the French astrophysicist Jean-Pierre Luminet programmed the calculation on an IBM 7040 using punchcards. He drew the image by hand.

    Today, astrophysicists use computers many times more powerful to predict the accretion of gas onto the black hole and how the light bends before reaching us. Still, the partly turbulent motion of the gas, the electric and magnetic fields created by it, and the intricacies of the particle’s interactions are not fully understood.

    The EHT’s observations agree with expectation. But this result is more than just another triumph of Einstein’s theory of general relativity. It is also a triumph of the astronomers’ resourcefulness. They joined hands and brains to achieve what they could not have done separately. And while their measurement settles a long-standing question—yes, black holes really do have event horizons!—it is also the start of further exploration. Physicists hope that the observations will help them understand better the extreme conditions in the accretion disk, the role of magnetic fields in jet formation, and the way supermassive black holes affect galaxy formation.

    When the Pope received Giotto’s circle, it was not the image itself that impressed him. It was the courtier’s report that the artist produced it without the aid of a compass. This first image of a black hole, too, is remarkable not so much for its appearance, but for its origin. A black sphere, spanning 40 billion kilometers, drawn on a background of hot gas by the greatest artist of all: Nature herself.

    See the full article here .


    Please help promote STEM in your local schools.

    Stem Education Coalition

    Welcome to Nautilus. We are delighted you joined us. We are here to tell you about science and its endless connections to our lives. Each month we choose a single topic. And each Thursday we publish a new chapter on that topic online. Each issue combines the sciences, culture and philosophy into a single story told by the world’s leading thinkers and writers. We follow the story wherever it leads us. Read our essays, investigative reports, and blogs. Fiction, too. Take in our games, videos, and graphic stories. Stop in for a minute, or an hour. Nautilus lets science spill over its usual borders. We are science, connected.

  • richardmitnick 4:34 pm on April 8, 2019 Permalink | Reply
    Tags: "International SKA science conference kicks off", , , , , Radio Astronomy,   

    From SKA: “International SKA science conference kicks off” 

    SKA South Africa

    From SKA


    Mathieu Isidro
    Deputy Communications & Outreach Manager
    SKA Organisation
    Email: m.isidro@skatelescope.org
    Phone: +44 (0) 7824 016 126

    Close to 300 astronomers from 20 countries have come together in Cheshire, UK for the international SKA science conference New Science enabled by New Techniques in the SKA era, looking at the breadth of science the SKA will enable and the latest science from current SKA-related facilities around the world. The meeting is organised by the SKA Organisation and hosted near the SKA Global Headquarters at Jodrell Bank.

    Three days are dedicated to talks covering recent results with the newly operational SKA precursor telescopes ASKAP and MeerKAT as well as MWA and HERA and SKA pathfinder facilities such as LOFAR [all images below]. Two days are also dedicated to discussions around the future key science projects with the SKA telescopes to allow group to form collaborations and prepare themselves.

    “We are delighted to receive our colleagues from around the globe here in the UK” said the Chair of the Scientific Organising Committee Evan Keane “We’re expecting to hear about exciting results from the SKA’s pathfinder and precursor facilities as well as to have crucial discussions on some of the future observing programmes, covering the whole breadth of science to be done with the SKA ”

    See the full article here .


    Please help promote STEM in your local schools.

    Stem Education Coalition

    SKA ASKAP Pathefinder Telescope

    SKA Meerkat telescope, 90 km outside the small Northern Cape town of Carnarvon, SA

    SKA Meerkat Telescope

    Murchison Widefield Array,SKA Murchison Widefield Array, Boolardy station in outback Western Australia, at the Murchison Radio-astronomy Observatory (MRO)

    SKA Murchison Wide Field Array

    SKA Hera at SKA South Africa

    SKA Pathfinder – LOFAR location at Potsdam via Google Images

    About SKA

    The Square Kilometre Array will be the world’s largest and most sensitive radio telescope. The total collecting area will be approximately one square kilometre giving 50 times the sensitivity, and 10 000 times the survey speed, of the best current-day telescopes. The SKA will be built in Southern Africa and in Australia. Thousands of receptors will extend to distances of 3 000 km from the central regions. The SKA will address fundamental unanswered questions about our Universe including how the first stars and galaxies formed after the Big Bang, how dark energy is accelerating the expansion of the Universe, the role of magnetism in the cosmos, the nature of gravity, and the search for life beyond Earth. Construction of phase one of the SKA is scheduled to start in 2016. The SKA Organisation, with its headquarters at Jodrell Bank Observatory, near Manchester, UK, was established in December 2011 as a not-for-profit company in order to formalise relationships between the international partners and centralise the leadership of the project.

    The Square Kilometre Array (SKA) project is an international effort to build the world’s largest radio telescope, led by SKA Organisation. The SKA will conduct transformational science to improve our understanding of the Universe and the laws of fundamental physics, monitoring the sky in unprecedented detail and mapping it hundreds of times faster than any current facility.

    Already supported by 10 member countries – Australia, Canada, China, India, Italy, New Zealand, South Africa, Sweden, The Netherlands and the United Kingdom – SKA Organisation has brought together some of the world’s finest scientists, engineers and policy makers and more than 100 companies and research institutions across 20 countries in the design and development of the telescope. Construction of the SKA is set to start in 2018, with early science observations in 2020.

  • richardmitnick 10:11 am on April 8, 2019 Permalink | Reply
    Tags: , , , , , Radio Astronomy, VLA Makes First Direct Image of Key Feature of Powerful Radio Galaxies   

    From National Radio Astronomy Observatory: “VLA Makes First Direct Image of Key Feature of Powerful Radio Galaxies” 

    From National Radio Astronomy Observatory

    NRAO Banner

    April 2, 2019

    Dave Finley, Public Information Officer
    (575) 835-7302

    Artist’s conception of the dusty, doughnut-shaped object surrounding the supermassive black hole, disk of material orbiting the black hole, and jets of material ejected by the disk, at the center of a galaxy. Credit: Bill Saxton, NRAO/AUI/NSF

    Artist’s conception of active galactic nucleus, with labels. Credit: Bill Saxton, NRAO/AUI/NSF

    VLA image of the central region of the powerful radio galaxy Cygnus A, showing the doughnut-shaped torus surrounding the black hole and accretion disk. Credit: Carilli et al., NRAO/AUI/NSF


    VLA image of Cygnus A’s central region, with labels.
    Credit: Carilli et al., NRAO/AUI/NSF

    Astronomers used the National Science Foundation’s Karl G. Jansky Very Large Array (VLA) to make the first direct image of a dusty, doughnut-shaped feature surrounding the supermassive black hole at the core of one of the most powerful radio galaxies in the Universe — a feature first postulated by theorists nearly four decades ago as an essential part of such objects.

    NRAO/Karl V Jansky Expanded Very Large Array, on the Plains of San Agustin fifty miles west of Socorro, NM, USA, at an elevation of 6970 ft (2124 m)

    The scientists studied Cygnus A, a galaxy some 760 million light-years from Earth. The galaxy harbors a black hole at its core that is 2.5 billion times more massive than the Sun. As the black hole’s powerful gravitational pull draws in surrounding material, it also propels superfast jets of material traveling outward at nearly the speed of light, producing spectacular “lobes” of bright radio emission.

    Black hole-powered “central engines” producing bright emission at various wavelengths, and jets extending far beyond the galaxy are common to many galaxies, but show different properties when observed. Those differences led to a variety of names, such as quasars, blazars, or Seyfert galaxies. To explain the differences, theorists constructed a “unified model” with a common set of features that would show different properties depending on the angle from which they are viewed.

    The unified model includes the central black hole, a rotating disk of infalling material surrounding the black hole, and the jets speeding outward from the poles of the disk. In addition, to explain why the same type of object looks different when viewed from different angles, a thick, dusty, doughnut-shaped “torus” is included, surrounding the inner parts. The torus obscures some features when viewed from the side, leading to apparent differences to the observer, even for intrinsically similar objects. Astronomers generically call this common set of features an active galactic nucleus (AGN).

    “The torus is an essential part of the AGN phenomenon, and evidence exists for such structures in nearby AGN of lower luminosity, but we’ve never before directly seen one in such a brightly-emitting radio galaxy,” said Chris Carilli, of the National Radio Astronomy Observatory (NRAO). “The torus helps explain why objects known by different names actually are the same thing, just observed from a different perspective,” he added.

    In the 1950s, astronomers discovered objects that strongly emitted radio waves, but appeared point-like, similar to distant stars, when later observed with visible-light telescopes. In 1963, Maarten Schmidt of Caltech discovered that one of these objects was extremely distant, and more such discoveries quickly followed. To explain how these objects, dubbed quasars, could be so bright, theorists suggested that they must be tapping the tremendous gravitational energy of supermassive black holes. The combination of black hole, the rotating disk, called an accretion disk, and the jets was termed the “central engine” responsible for the objects’ prolific outpourings of energy.

    The same type of central engine also appeared to explain the output of other types of objects, including radio galaxies, blazars, and Seyfert Galaxies. However, each showed a different set of properties. Theorists worked to develop a “unification scheme” to explain how the same thing could appear differently. In 1977, obscuration by dust was suggested as one element of that scheme. In a 1982 paper, Robert Antonucci, of the University of California, Santa Barbara, presented a drawing of an opaque torus — a doughnut-shaped object — surrounding the central engine. From that point on, an obscuring torus has been a common feature of astronomers’ unified view of all types of active galactic nuclei.

    “Cygnus A is the closest example of a powerful radio-emitting galaxy — 10 times closer than any other with comparably powerful radio emission. That proximity allowed us to find the torus in a high-resolution VLA image of the galaxy’s core,” said Rick Perley, also of NRAO. “Doing more work of this type on weaker and more distant objects will almost certainly need the order-of-magnitude improvement in sensitivity and resolution that the proposed Next Generation Very Large Array (ngVLA) would bring,” he added.

    The VLA observations directly revealed the gas in Cygnus A’s torus, which has a radius of nearly 900 light-years. Longstanding models for the torus suggest that the dust is in clouds embedded in the somewhat-clumpy gas.

    “It’s really great to finally see direct evidence of something that we’ve long presumed should be there,” Carilli said. “To more accurately determine the shape and composition of this torus, we need to do further observing. For example, the Atacama Large Millimeter/submillimeter Array (ALMA) can observe at the wavelengths that will directly reveal the dust,” he added.

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

    Carilli and Perley, with their colleagues Vivek Dhawan, also of NRAO, and Daniel Perley of Liverpool John Moores University in the UK, discovered the torus when following up their surprising discovery in 2016 of a new, bright object near the center of Cygnus A. That new object, they said, is most likely a second supermassive black hole that only recently encountered new material it could devour, causing it to produce bright emission the same way the central black hole does. The existence of the second black hole, they said, suggests that Cygnus A merged with another galaxy in the astronomically recent past.

    Cygnus A, so named because it is the most powerful radio-emitting object in the constellation Cygnus, was discovered in 1946 by English physicist and radio astronomer J.S. Hey. It was matched to a visible-light, giant galaxy by Walter Baade and Rudolf Minkowski in 1951. It became an early target for the VLA soon after its completion in the early 1980s. Detailed VLA images of Cygnus A published in 1984 produced major advances in astronomers’ understanding of such galaxies.

    The scientists are reporting their findings in the Astrophysical Journal Letters.

    See the full article here .


    Please help promote STEM in your local schools.

    Stem Education Coalition

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

    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), and the Very Long Baseline Array (VLBA)*.

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

    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.

    And the future Expanded Very Large Array (EVLA).

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