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  • richardmitnick 12:34 pm on August 29, 2017 Permalink | Reply
    Tags: , , , , Max Planck Institute for Radio Astronomy   

    From Max Planck Institute for Radio Astronomy: “The detection of magnetic fields in a galaxy 5 billion light years away” 


    Max Planck Institute for Radio Astronomy

    August 25, 2017
    Dr. Sui Ann Mao
    Phone:+49 228 525-246
    Email:
    mao@mpifr-bonn.mpg.de

    Max-Planck-Institut für Radioastronomie, Bonn
    Dr. Rainer Beck
    Phone:+49 228 525-323
    rbeck@mpifr-bonn.mpg.de

    Max-Planck-Institut für Radioastronomie, Bonn
    Dr. Olaf Wucknitz
    Phone:+49 228 525-481
    wucknitz@mpifr-bonn.mpg.de

    Max-Planck-Institut für Radioastronomie, Bonn
    Dr. Norbert Junkes
    Press and Public Outreach
    Phone:+49 228 525-399
    njunkes@mpifr-bonn.mpg.de

    August 25, 2017

    Astronomers obtain major clues for solving the origin of cosmic magnetism.

    Magnetic fields play an important role in the physics of the interstellar medium in galaxies, but they are very difficult to observe at vast distances corresponding to large look-back times in the cosmic history. An international team of astronomers led by Sui Ann Mao from the Max Planck Institute for Radio Astronomy in Bonn, Germany was able to measure the magnetic field in a galaxy beyond the local volume, as seen 4.6 billion light years away at a redshift of 0.439. The galaxy, acting as the lens in the gravitational lensing system CLASS B1152+199, is the most distant galaxy to-date in which a large-scale coherent magnetic field has been observed. This measurement provides new insights into the origin and evolution of magnetic fields in the Universe.

    The results are published on August 28 in Nature Astronomy, Advanced Online Publication.

    2

    Fig. 1:Left: Hubble Space Telescope image of the gravitational lensing system CLASS B1152+199. The background quasar is lensed by the foreground galaxy into two images A and B. Right: Faraday rotation of the lensed images. Image A probes a sight line through the less dense outskirts of the lensing galaxy with a weaker magnetic field, while Image B probes through a sight line closer to the center of the galaxy with higher gas density and stronger magnetic field.
    © Sui Ann Mao, with HST image obtained from the Hubble Legacy Archive (Rusin et al. 2002, MNRAS, 330, 205-211).

    Using observations of a gigantic cosmic lens carried out with the Karl G. Jansky Very Large Array, a team of astronomers has detected coherent magnetic fields in a galaxy as seen almost five billion light years away.

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

    These measurements provide new clues about a problem at the frontiers of cosmology: the nature and origin of the magnetic fields that play an important role in the evolution of galaxies.

    3
    Schematic view of the lensing system: the distant quasar located 7.9 billion light-years away is gravitationally lensed by the foreground galaxy 4.6 billion light-years away. Sightlines toward images A and B probe different magnetic fields and gas conditions through different parts of the lensing galaxy.
    © Sui Ann Mao

    When a background quasar and a foreground distant galaxy are closely aligned along the line of sight as in the system CLASS B1152+199, light from the quasar is gravitationally lensed by the foreground galaxy, forming two separate images as seen from Earth. One can use the light from the quasar passing through different parts of the lensing galaxy to study magnetic fields in a galaxy we otherwise cannot see. The team measured a property of the radio waves called polarization that changes when passing through the magnetic field of the foreground galaxy. The astronomers measured this change, the so-called Faraday rotation effect, of the two lensed quasar images to show that the distant lensing galaxy hosts a coherent large-scale magnetic field.

    The detection of a strong coherent magnetic field in a galaxy when the universe was about two-thirds of its current age allows the team to measure how fast these fields grow in galaxies. “Although this distant galaxy had less time to build up its magnetic field compared to local galaxies, it still managed to do so”, says Sui Ann Mao, leader of a Minerva research group at the Max Planck Institute for Radio Astronomy in Bonn, the lead author of the study. “The results of our study support the idea that galaxy magnetic fields are generated by a dynamo process.” she adds.

    Despite great progress in cosmology, how the Universe became magnetized remains an unsolved problem. It is generally recognized that the original magnetic fields in no way resemble the fields we see today in galaxies, but have been amplified and reconfigured by dynamo processes tied to circulation and turbulence within the interstellar gas. Describing the dynamo, particularly how it imparts large-scale structures to the magnetic field, is itself a largely unsolved problem. “Our measurements have provided the most stringent test to-date of how dynamos operate in galaxies”, says Ellen Zweibel from the University of Wisconsin Madison, USA.

    “This finding is exciting – it is the first time we can reliably derive both the magnetic field strength and its configuration in a distant galaxy,” says Sui Ann Mao. The strong lensing system CLASS B1152+199 is now the record holder of the highest redshift galaxy for which this magnetic field information is available. “Our work demonstrates the power of strong gravitational lensing and broadband radio polarimetric observations in revealing magnetic fields in the high redshift universe,” she concludes.

    See the full article here .

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    MPIFR/Effelsberg Radio Telescope, Germany

    The Max Planck Institute for Radio Astronomy (German: Max-Planck-Institut für Radioastronomie) is located in Bonn, Germany. It is one of 80 institutes in the Max Planck Society (German: Max-Planck-Gesellschaft).

    By combining the already existing radio astronomy faculty of the University of Bonn led by Otto Hachenberg with the new Max Planck institute the Max Planck Institute for Radio Astronomy was formed. In 1972 the 100-m radio telescope in Effelsberg was opened. The institute building was enlarged in 1983 and 2002.

    The institute was founded in 1966 by the Max-Planck-Gesellschaft as the “Max-Planck-Institut für Radioastronomie” (MPIfR).

    The foundation of the institute was closely linked to plans in the German astronomical community to construct a competitive large radio telescope in (then) West Germany. In 1964, Professors Friedrich Becker, Wolfgang Priester and Otto Hachenberg of the Astronomische Institute der Universität Bonn submitted a proposal to the Stiftung Volkswagenwerk for the construction of a large fully steerable radio telescope.

    In the same year the Stiftung Volkswagenwerk approved the funding of the telescope project but with the condition that an organization should be found, which would guarantee the operations. It was clear that the operation of such a large instrument was well beyond the possibilities of a single university institute.

    Already in 1965 the Max-Planck-Gesellschaft (MPG) decided in principle to found the Max-Planck-Institut für Radioastronomie. Eventually, after a series of discussions, the institute was officially founded in 1966.

    The Max Planck Society for the Advancement of Science (German: Max-Planck-Gesellschaft zur Förderung der Wissenschaften e. V.; abbreviated MPG) is a formally independent non-governmental and non-profit association of German research institutes founded in 1911 as the Kaiser Wilhelm Society and renamed the Max Planck Society in 1948 in honor of its former president, theoretical physicist Max Planck. The society is funded by the federal and state governments of Germany as well as other sources.

    According to its primary goal, the Max Planck Society supports fundamental research in the natural, life and social sciences, the arts and humanities in its 83 (as of January 2014)[2] Max Planck Institutes. The society has a total staff of approximately 17,000 permanent employees, including 5,470 scientists, plus around 4,600 non-tenured scientists and guests. Society budget for 2015 was about €1.7 billion.

    The Max Planck Institutes focus on excellence in research. The Max Planck Society has a world-leading reputation as a science and technology research organization, with 33 Nobel Prizes awarded to their scientists, and is generally regarded as the foremost basic research organization in Europe and the world. In 2013, the Nature Publishing Index placed the Max Planck institutes fifth worldwide in terms of research published in Nature journals (after Harvard, MIT, Stanford and the US NIH). In terms of total research volume (unweighted by citations or impact), the Max Planck Society is only outranked by the Chinese Academy of Sciences, the Russian Academy of Sciences and Harvard University. The Thomson Reuters-Science Watch website placed the Max Planck Society as the second leading research organization worldwide following Harvard University, in terms of the impact of the produced research over science fields.

     
  • richardmitnick 5:12 pm on September 19, 2016 Permalink | Reply
    Tags: , , Max Planck Institute for Radio Astronomy, , , Twin jets pinpoint the heart of an active galaxy   

    From phys.org: “Twin jets pinpoint the heart of an active galaxy” 

    physdotorg
    phys.org

    September 19, 2016
    No writer credit

    1
    3-mm GMVA image of the galaxy NGC 1052 showing a compact region at the centre and two jets (bottom), and sketch of the system with an accretion disk and two regions of entangled magnetic fields forming two powerful jets (top). The compact region in the image pinpoints the location of the supermassive black hole at the heart of NGC 1052, and the enormous magnetic fields surrounding the event horizon trigger the two powerful jets observed with our radio telescopes. Credit: Anne-Kathrin Baczko et al., Astronomy & Astrophysics

    An international team of astronomers has measured the magnetic field in the vicinity of a supermassive black hole. A bright and compact feature of only 2 light days in size was directly observed by a world-wide ensemble of millimeter-wave radio telescopes in the heart of the active galaxy NGC 1052. The observations yield a magnetic field value at the event horizon of the central black hole between 0.02 and 8.3 Tesla. The team, led by the PhD student Anne-Kathrin Baczko, believes that such a large magnetic field provides enough magnetic energy to power the strong relativistic jets in active galaxies. The results are published in the present issue of Astronomy & Astrophysics.

    The technique used to investigate the inner details of NGC 1052 is known as very-long-baseline interferometry, and has the potential to locate compact jet cores at sizes close to the event horizon of the powering black hole. The black hole itself remains invisible. Usually, the black hole position can only be inferred indirectly by tracking the wavelength-dependent jet-core position, which converges to the jet base at zero wavelength. The unknown offset from the jet base and the black hole makes it difficult to measure fundamental physical properties in most galaxies. The striking symmetry observed in the reported observations between both jets in NGC1052 allows the astronomers to locate the true center of activitiy inside the central feature, which makes, with the exception of our Galactic Centre, the most precisely known location of a super massive black hole in the universe. Anne-Kathrin Baczko, who performed this work at the Universities of Erlangen-Nürnberg and Würzburg and at the Max-Planck-Institut für Radioastronomie, says: “NGC 1052 is a true key source, since it pinpoints directly and unambiguously the position of a supermassive black hole in the nearby universe.”

    NGC 1052 is an elliptical galaxy in a distance of approximately 60 million light years in the direction of the constellation Cetus (the Whale).

    2
    Three telescopes participating in the Global Millimetre VLBI Array (GMVA): MPIfR’s Effelsberg 100m (above), IRAM’s Pico Veleta 30m (lower left) and Plateau de Bure 15m telescopes (lower right). Credit: IRAM (Pico Veleta & Plateau de Bure); Norbert Junkes (Effelsberg & compilation)

    The magnetic field by the supermassive black hole was determined measuring the compactness and the brightness of the central region of the elliptical galaxy NGC 1052. This feature is as compact as 57 microarcseconds in diameter, equivalent to the size of a DVD on the surface of the moon. This amazing resolution was obtained by the Global mm-VLBI Array, a network of radio telescopes in Europe, the USA, and East Asia, that is managed by the Max-Planck-Institut für Radioastronomie. “It yields unprecedented image sharpness, and is soon to be applied to get event-horizon scales in nearby objects”, says Eduardo Ros from the MPI für Radioastronomie and collaborator in the project.

    The unique powerful twin jets at a close distance, similar to the well-known active galaxy M 87, puts NGC 1052 in the pole position for future observations of nearby powerful galaxies in the oncoming era opened by the addition of ALMA, the Atacama Large Millimetre array, to the world-wide networks in radio interferometry.

    The observation may help solving the long-standing mystery of how the powerful relativistic jets are formed, that can be seen in many active galaxies. The result has important astrophysical implications, since we see that jets can be driven by the extraction of magnetic energy from a rapidly rotating supermassive black hole.

    More information: A.-K. Baczko et al. A highly magnetized twin-jet base pinpoints a supermassive black hole, Astronomy & Astrophysics (2016). DOI: 10.1051/0004-6361/201527951

    See the full article here .

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    About Phys.org in 100 Words

    Phys.org™ (formerly Physorg.com) is a leading web-based science, research and technology news service which covers a full range of topics. These include physics, earth science, medicine, nanotechnology, electronics, space, biology, chemistry, computer sciences, engineering, mathematics and other sciences and technologies. Launched in 2004, Phys.org’s readership has grown steadily to include 1.75 million scientists, researchers, and engineers every month. Phys.org publishes approximately 100 quality articles every day, offering some of the most comprehensive coverage of sci-tech developments world-wide. Quancast 2009 includes Phys.org in its list of the Global Top 2,000 Websites. Phys.org community members enjoy access to many personalized features such as social networking, a personal home page set-up, RSS/XML feeds, article comments and ranking, the ability to save favorite articles, a daily newsletter, and other options.

     
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