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  • richardmitnick 10:41 am on February 26, 2020 Permalink | Reply
    Tags: , , , , , CH3CN and CH3C15N Titan’s atmosphere., , Cosmic rays coming from outside the Solar System affect the chemical reactions involved in the formation of nitrogen-bearing organic molecules., , , , Radio Astronomy, Titan is attracting much interest because of its unique atmosphere with a number of organic molecules that form a pre-biotic environment., We suppose that galactic cosmic rays play an important role in the atmospheres of other solar system bodies.   

    From ALMA: “Galactic Cosmic Rays Affect Titan’s Atmosphere” 

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

    18 February, 2020

    Valeria Foncea
    Education and Public Outreach Officer
    Joint ALMA Observatory Santiago – Chile
    Phone: +56 2 2467 6258
    Cell phone: +56 9 7587 1963
    Email: valeria.foncea@alma.cl

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

    Bárbara Ferreira
    ESO Public Information Officer
    Garching bei München, Germany
    Phone: +49 89 3200 6670
    Email: pio@eso.org

    Iris Nijman
    Public Information Officer
    National Radio Astronomy Observatory Charlottesville, Virginia – USA
    Cell phone: +1 (434) 249 3423
    Email: alma-pr@nrao.edu

    1
    Optical image of Titan taken by NASA Cassini spacecraft. Credit: NASA/JPL-Caltech/Space Science Institute.

    NASA/ESA/ASI Cassini-Huygens Spacecraft

    2
    ALMA spectra of CH3CN and CH3C15N Titan’s atmosphere. Dotted vertical lines indicate the frequency of emission lines of two molecules predicted by a theoretical model. Credit: Iino et al. (The University of Tokyo.)

    Planetary scientists using the Atacama Large Millimeter/submillimeter Array (ALMA) revealed the secrets of the atmosphere of Titan, the largest moon of Saturn. The team found a chemical footprint in Titan’s atmosphere indicating that cosmic rays coming from outside the Solar System affect the chemical reactions involved in the formation of nitrogen-bearing organic molecules.

    Cosmic rays produced by high-energy astrophysics sources (ASPERA collaboration – AStroParticle ERAnet)

    This is the first observational confirmation of such processes, and impacts the understanding of the intriguing environment of Titan.

    Titan is attracting much interest because of its unique atmosphere with a number of organic molecules that form a pre-biotic environment.

    Takahiro Iino, a scientist at the University of Tokyo, and his team used ALMA to reveal the chemical processes in Titan’s atmosphere. They found faint but firm signals of acetonitrile (CH3CN) and its rare isotopomer CH3C15N in the ALMA data.

    “We found that the abundance of 14N in acetonitrile is higher than those in other nitrogen bearing species such as HCN and HC3N,” says Iino. “It well matches the recent computer simulation of chemical processes with high energy cosmic rays.”

    There are two important players in the chemical processes of the atmosphere: ultraviolet (UV) light from the Sun and cosmic rays coming from outside the Solar System. In the upper stratosphere, UV light selectively destroys nitrogen molecules containing 15N because UV light with the specific wavelength that interacts with 14N14N is neutralized at that altitude due to the strong absorption. Thus, nitrogen-bearing species produced at that altitude tend to exhibit a high 15N abundance. On the other hand, cosmic rays penetrate deeper and interact with nitrogen molecules containing only 14N. As a result, there is a difference in the abundance of molecules with 14N and 15N. The team revealed that acetonitrile in the lower stratosphere is more abundant in 14N than those of other previously measured nitrogen-bearing molecules.

    “We suppose that galactic cosmic rays play an important role in the atmospheres of other solar system bodies,” says Hideo Sagawa, an associate professor at Kyoto Sangyo University and a member of the research team. “The process could be universal, so understanding the role of cosmic rays in Titan is crucial in overall planetary science.”

    Titan is one of the most popular objects in ALMA observations. The data obtained with ALMA needs to be calibrated to remove fluctuations due to variations of on-site weather and mechanical glitches. For referencing, the observatory staff often points the telescope at bright sources, such as Titan, from time to time in science observations. Therefore, a large amount of Titan data is stored in the ALMA Science Archive. Iino and his team have dug into the archive and re-analyzed the Titan data and found subtle fingerprints of very tiny amounts of CH3C15N.

    More information

    These observation results are published as T. Iino et al. in The Astrophysical Journal.

    The research team members are: Takahiro Iino (The University of Tokyo), Hideo Sagawa (Kyoto Sangyo University) and Takashi Tsukagoshi (National Astronomical Observatory of Japan).

    This research was supported by the JSPS KAKENHI (No. 17K14420 and 19K14782), the Telecommunication Advancement Foundation, and the Astrobiology Center, National Institutes of Natural Sciences.

    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
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  • richardmitnick 1:41 pm on February 24, 2020 Permalink | Reply
    Tags: , , , , , , New binary millisecond pulsar discovered in NGC 6205", , Radio Astronomy   

    From Chinese Academy of Sciences via phys.org: “New binary millisecond pulsar discovered in NGC 6205 with FAST Radio Telescope” 

    From Chinese Academy of Sciences

    via


    phys.org

    February 24, 2020
    Tomasz Nowakowski

    1
    Positions of the six pulsars in the GC M13, marked with red circles with letters. Credit: Wang et al., 2020.

    Using the Five-hundred-meter Aperture Spherical radio Telescope (FAST), astronomers have detected a new binary millisecond pulsar (MSP) in the globular cluster NGC 6205. The newly found pulsar received designation PSR J1641+3627F. The finding is reported in a paper published February 14 on the arXiv pre-print repository.

    FAST [Five-hundred-meter Aperture Spherical Telescope] radio telescope, with phased arrays from CSIRO engineers Australia [located in the Dawodang depression in Pingtang County, Guizhou Province, south China

    Pulsars are highly magnetized, rotating neutron stars emitting a beam of electromagnetic radiation. The most rapidly rotating pulsars, with rotation periods below 30 milliseconds, are known as millisecond pulsars (MSPs).

    Dame Susan Jocelyn Bell Burnell, discovered pulsars with radio astronomy. Jocelyn Bell at the Mullard Radio Astronomy Observatory, Cambridge University, taken for the Daily Herald newspaper in 1968. Denied the Nobel.

    Astronomers believe that MSPs form in binary systems when the initially more massive component turns into a neutron star that is then spun-up due to accretion of matter from the secondary star. Observations conducted so far seem to support this theory, as more than a half of known MSPs have been found to have stellar companions.

    Now, a team of astronomers led by Lin Wang of CAS (Chinese Academy of Sciences) Key Laboratory of FAST in China, reports the detection of a new MSP in the bright globular cluster NGC 6205 (also known as M13), which is located some 23,150 light years away in the constellation of Hercules. The discovery was made as part of FAST observations of NGC 6205 that also monitored other pulsars in this cluster.

    “In this paper, we present the discovery of the binary pulsar PSR J1641+3627F (M13F) and timing solutions of all the known pulsars in the GC M13,” the astronomers wrote in the paper.

    According to the study, PSR J1641+3627F has a spin period of approximately 3.0 milliseconds and an orbital period of 1.38 days. This means that it has the second shortest spin period and the longest orbital period among the six pulsars that have been discovered in NGC 6205 (the other five are designated PSR J1641+3627A to E).

    FAST observations show that PSR J1641+3627F has a dispersion measure of around 30.4 parsecs/cm3. It was noted that this is close to the average dispersion measure value of other known pulsars in NGC 6205. The mass of the companion object is estimated to be around 0.16 solar masses, what suggests a white dwarf.

    The research also found that PSR J1641+3627F is located at the edge of the cluster core and its spin period derivative is typical for MSPs in globular clusters. However, the system’s eccentricity is, according to the astronomers, relatively small when compared to typical MSP-white dwarf systems.

    In general, the researchers concluded that all the discovered binary systems in NGC 6205 have relatively low eccentricities when compared to typical globular cluster pulsars and the eccentricities were found to decrease with distance from the cluster core.

    “This is consistent with what is expected as this cluster has a very low encounter rate per binary,” the authors of the paper underlined.

    See the full article here .

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    About Science X in 100 words

    Science X™ 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 (Physorg.com), Science X’s readership has grown steadily to include 5 million scientists, researchers, and engineers every month. Science X publishes approximately 200 quality articles every day, offering some of the most comprehensive coverage of sci-tech developments world-wide. Science X community members enjoy access to many personalized features such as social networking, a personal home page set-up, article comments and ranking, the ability to save favorite articles, a daily newsletter, and other options.
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    The Chinese Academy of Sciences is the linchpin of China’s drive to explore and harness high technology and the natural sciences for the benefit of China and the world. Comprising a comprehensive research and development network, a merit-based learned society and a system of higher education, CAS brings together scientists and engineers from China and around the world to address both theoretical and applied problems using world-class scientific and management approaches.

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    As it builds on its proud record, CAS aims for a bright future as one of the world’s top S&T research and development organizations.

     
  • richardmitnick 12:23 pm on February 20, 2020 Permalink | Reply
    Tags: "How Newborn Stars Prepare for the Birth of Planets", , , , , , , , Planet-forming disks around very young stars in the Orion Molecular Clouds., Radio Astronomy, This survey- called VLA/ALMA Nascent Disk and Multiplicity (VANDAM)- is the largest survey of young stars and their disks to date.   

    From ALMA: “How Newborn Stars Prepare for the Birth of Planets” 

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

    From ALMA

    20 February, 2020

    Valeria Foncea
    Education and Public Outreach Officer
    Joint ALMA Observatory Santiago – Chile
    Phone: +56 2 2467 6258
    Cell phone: +56 9 7587 1963
    Email: valeria.foncea@alma.cl

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

    Bárbara Ferreira
    ESO Public Information Officer
    Garching bei München, Germany
    Phone: +49 89 3200 6670
    Email: pio@eso.org

    Iris Nijman
    Public Information Officer
    National Radio Astronomy Observatory Charlottesville, Virginia – USA
    Cell phone: +1 (434) 249 3423
    Email: alma-pr@nrao.edu

    1
    VANDAM survey
    ALMA and the VLA observed more than 300 protostars and their young protoplanetary disks in Orion. This image shows a subset of stars, including a few binaries. The ALMA and VLA data compliment each other: ALMA sees the outer disk structure (visualized in blue), and the VLA observes the inner disks and star cores (orange).

    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)

    An international team of astronomers used two of the most powerful radio telescopes in the world to create more than three hundred images of planet-forming disks around very young stars in the Orion Clouds. These images reveal new details about the birthplaces of planets and the earliest stages of star formation.

    Most of the stars in the universe are accompanied by planets. These planets are born in rings of dust and gas, called protoplanetary disks. Even very young stars are surrounded by these disks. Astronomers want to know exactly when these disks start to form, and what they look like. But young stars are very faint, and there are dense clouds of dust and gas surrounding them in stellar nurseries. Only highly sensitive radio telescope arrays can spot the tiny disks around these infant stars amidst the densely packed material in these clouds.

    For this new research, astronomers pointed both the Atacama Large Millimeter/submillimeter Array (ALMA) and the National Science Foundation’s Karl G. Jansky Very Large Array (VLA) to a region in space where many stars are born: the Orion Molecular Clouds. This survey, called VLA/ALMA Nascent Disk and Multiplicity (VANDAM), is the largest survey of young stars and their disks to date.

    Very young stars, also called protostars, form in clouds of gas and dust in space. The first step in the formation of a star is when these dense clouds collapse due to gravity. As the cloud collapses, it begins to spin – forming a flattened disk around the protostar. Material from the disk continues to feed the star and make it grow. Eventually, the left-over material in the disk is expected to form planets.

    Many aspects about these first stages of star formation, and how the disk forms, are still unclear. But this new survey provides some missing clues as the VLA and ALMA peered through the dense clouds and observed hundreds of protostars and their disks in various stages of their formation.

    Young planet-forming disks

    “This survey revealed the average mass and size of these very young protoplanetary disks,” said John Tobin of the National Radio Astronomy Observatory (NRAO) in Charlottesville, Virginia, and leader of the survey team. “We can now compare them to older disks that have been studied intensively with ALMA as well.”

    What Tobin and his team found, is that very young disks can be similar in size, but are on average much more massive than older disks. “When a star grows, it eats away more and more material from the disk. This means that younger disks have a lot more raw material from which planets could form. Possibly bigger planets already start to form around very young stars.”

    Four special protostars

    Among hundreds of survey images, four protostars looked different than the rest and caught the scientists’ attention. “These newborn stars looked very irregular and blobby,” said team member Nicole Karnath of the University of Toledo, Ohio (now at SOFIA Science Center). “We think that they are in one of the earliest stages of star formation and some may not even have formed into protostars yet.”

    It is special that the scientists found four of these objects. “We rarely find more than one such irregular object in one observation,” added Karnath, who used these four infant stars to propose a schematic pathway for the earliest stages of star formation. “We are not entirely sure how old they are, but they are probably younger than ten thousand years.”

    To be defined as a typical (class 0) protostar, stars should not only have a flattened rotating disk surrounding them, but also an outflow – spewing away material in opposite directions – that clears the dense cloud surrounding the stars and makes them optically visible. This outflow is important, because it prevents stars from spinning out of control while they grow. But when exactly these outflows start to happen, is an open question in astronomy.

    One of the infant stars in this study, called HOPS 404, has an outflow of only two kilometers (1.2 miles) per second (a typical protostar-outflow of 10-100 km/s or 6-62 miles/s). “It is a big puffy sun that is still gathering a lot of mass, but just started its outflow to lose angular momentum to be able to keep growing,” explained Karnath. “This is one of the smallest outflows that we have seen and it supports our theory of what the first step in forming a protostar looks like.”

    Combining ALMA and VLA

    The exquisite resolution and sensitivity provided by both ALMA and the VLA were crucial to understand both the outer and inner regions of protostars and their disks in this survey. While ALMA can examine the dense dusty material around protostars in great detail, the images from the VLA made at longer wavelengths were essential to understand the inner structures of the youngest protostars at scales smaller than our solar system.

    “The combined use of ALMA and the VLA has given us the best of both worlds,” said Tobin. “Thanks to these telescopes, we start to understand how planet formation begins.”

    The National Radio Astronomy Observatory is a facility of the National Science Foundation, operated under cooperative agreement by Associated Universities, Inc.

    More Information

    This research was presented in two papers:

    The VLA/ALMA Nascent Disk and Multiplicity (VANDAM) Survey of Orion Protostars. A Statistical Characterization of Class 0 and I Protostellar Disks,” by J. Tobin et al., The Astrophysical Journal.

    “Detection of Irregular, Sub-mm Opaque Structures in the Orion Molecular Clouds: Protostars within 10000 years of formation?,” by N. Karnath et al., The Astrophysical Journal.

    2
    Observed protostars in Orion Molecular Clouds
    This image shows the Orion Molecular Clouds, the target of the VANDAM survey. Yellow dots are the locations of the observed protostars on a blue background image made by Herschel. Side panels show nine young protostars imaged by ALMA (blue) and the VLA (orange). Credit: ALMA (ESO/NAOJ/NRAO), J. Tobin; NRAO/AUI/NSF, S. Dagnello; Herschel/ESA

    4
    Schematic showing the formation of protostars
    This schematic shows a proposed pathway (top row) for the formation of protostars, based on four very young protostars (bottom row) observed by VLA (orange) and ALMA (blue). Step 1 represents the collapsing fragment of gas and dust. In step 2, an opaque region starts to form in the cloud. In step 3, a hydrostatic core starts to form due to an increase in pressure and temperature, surrounded by a disk-like structure and the beginning of an outflow. Step 4 depicts the formation of a class 0 protostar inside the opaque region, that may have a rotationally supported disk and more well-defined outflows. Step 5 is a typical class 0 protostar with outflows that have broken through the envelope (making it optically visible), an actively accreting, rotationally supported disk. In the bottom row, white contours are the protostar outflows as seen with ALMA.
    Credit: ALMA (ESO/NAOJ/NRAO), N. Karnath; NRAO/AUI/NSF, B. Saxton and S. Dagnello

    5
    Star chart of constellation Orion and observed protostars
    The Orion Molecular Clouds (blue, as seen with Herschel) are located in the constellation Orion. Red dots show the locations of the observed protostars in the VANDAM survey.
    Credit: IAU; Sky & Telescope magazine; NRAO/AUI/NSF, S. Dagnello; Herschel/ESA; ALMA (ESO/NAOJ/NRAO), J. Tobin

    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 6:51 pm on February 18, 2020 Permalink | Reply
    Tags: "LOFAR pioneers new way to study exoplanet environments", , Astronomers have discovered unusual radio waves coming from the nearby red dwarf star GJ1151., , , , , Radio Astronomy, The radio emission from a star-planet interaction has been predicted for over thirty-years but this is the first time astronomers have been able to discern its signature.   

    From Netherlands Institute for Radio Astronomy (ASTRON): “LOFAR pioneers new way to study exoplanet environments” 

    ASTRON bloc

    From Netherlands Institute for Radio Astronomy (ASTRON)

    17/02/2020

    Using the Dutch-led Low Frequency Array (LOFAR) radio telescope, astronomers have discovered unusual radio waves coming from the nearby red dwarf star GJ1151. The radio waves bear the tell-tale signature of aurorae caused by an interaction between a star and its planet. The radio emission from a star-planet interaction has been predicted for over thirty-years but this is the first time astronomers have been able to discern its signature. This method, only possible with a sensitive radio telescope like LOFAR, opens the door to a new way of discovering exoplanets in the habitable zone and studying the environment they exist in.

    Red dwarfs are the most abundant type of star in our Milky Way, but much smaller and cooler than our own Sun. This means for a planet to be habitable, it has to be significantly closer to its star than the Earth is to the Sun. Red dwarfs also have much stronger magnetic fields than the Sun, which means, a habitable planet around a red dwarf is exposed to intense magnetic activity. This can heat the planet and even erode its atmosphere. The radio emissions associated with this process are one of the few tools available to gauge the potency of this effect.

    “The motion of the planet through a red dwarf’s strong magnetic field acts like an electric engine much in the same way a bicycle dynamo works. This generates a huge current that powers aurorae and radio emission on the star.” says Dr Harish Vedantham, the lead author of the study [Nature Astronomy] and a Netherlands Institute for Radio Astronomy (ASTRON) staff scientist.

    1
    Thanks to the Sun’s weak magnetic field and the larger distance to the planets, similar currents are not generated in the solar system. However, the interaction of Jupiter’s moon Io with Jupiter’s magnetic field generates a similarly bright radio emission, even outshining the Sun at sufficiently low frequencies.

    “We adapted the knowledge from decades of radio observations of Jupiter to the case of this star” said Dr Joe Callingham, ASTRON postdoctoral fellow and co-author of the study. “A scaled up version of Jupiter-Io has long been predicted to exist in the form of a star-planet system, and the emission we observed fits the theory very well.”


    Video showing the science behind the discovery

    The group is now concentrating on finding similar emission from other stars. “We now know that nearly every red-dwarf hosts terrestrial planets, so there must be other stars showing similar emission. We want to know how this impacts our search for another Earth around another star” says Dr Callingham.

    The team is using images from the ongoing survey of the northern sky called the LOFAR Two Metre Sky Survey (LoTSS) of which Dr Tim Shimwell, ASTRON staff scientist and a co-author of the study, is the principal scientist. “With LOFAR’s sensitivity, we expect to find around 100 of such systems in the solar neighborhood. LOFAR will be the best game in town for such science until the Square Kilometre Array comes online.” says Dr Shimwell.

    The group expects this new method of detecting exoplanets will open up a new way of understanding the environment of exoplanets. “The long-term aim is to determine what impact the star’s magnetic activity has on an exoplanet’s habitability, and radio emissions are a big piece of that puzzle.” said Dr Vedantham. “Our work has shown that this is viable with the new generation of radio telescopes, and put us on an exciting path.”

    See the full article here .

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    LOFAR is a radio telescope composed of an international network of antenna stations and is designed to observe the universe at frequencies between 10 and 250 MHz. Operated by ASTRON, the network includes stations in the Netherlands, Germany, Sweden, the U.K., France, Poland and Ireland.

    ASTRON LOFAR Radio Antenna Bank, Netherlands

    ASTRON-Westerbork Synthesis Radio Telescope
    Westerbork Synthesis Radio Telescope (WSRT)

    ASTRON was founded in 1949, as the Foundation for Radio radiation from the Sun and Milky Way (SRZM). Its original charge was to develop and operate radio telescopes, the first being systems using surplus wartime radar dishes. The organisation has grown from twenty employees in the early 1960’s to about 180 staff members today.

     
  • richardmitnick 5:04 pm on February 18, 2020 Permalink | Reply
    Tags: "ALMA Explores Possible Interacting Twin Disks", , , , , , , , Radio Astronomy   

    From AAS NOVA: “ALMA Explores Possible Interacting Twin Disks” 

    AASNOVA

    From AAS NOVA

    17 February 2020
    Susanna Kohler

    1
    Artist’s impression of one of the two stars in the FU Orionis binary system, surrounded by an accreting disk of material. What has caused this star — and others like it — to dramatically brighten? [NASA/JPL-Caltech]

    Some young stars seem to spend a brief portion of their lives undergoing dramatic, flaring outbursts. A new study has used the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile to get the closest look yet at one of these systems — possibly identifying the cause of the flares.

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

    2
    Artist’s impression of a young star throwing a temper tantrum as it suddenly increases its accretion rate and flares. [Caltech/T. Pyle (IPAC)]

    Young Stellar Temper Tantrums

    FU Orionis (FU Ori, for short) objects are young, pre-main-sequence stars that grow suddenly brighter — by several magnitudes! — over the span of perhaps a year. These flaring states can last on the order of decades, and they’re thought to be related to a period of increased accretion onto the star during its early years. A star may gain a significant portion of its final mass during these events.

    Beyond this general picture, there’s much we don’t understand about how or why this increase in accretion occurs. Does every star undergo a FU Ori phase early in its lifetime, accumulating extra mass in spurts and brightening each time it does? Or do only some stars behave this way? What causes the change in accretion rate? What ends this phase?

    The first step to answering some of these questions is to obtain high-resolution images of FU Ori objects so that we can better explore their structure and behavior. In a new study, a team of scientists led by Sebastián Pérez (University of Santiago, Chile; University of Chile) has used ALMA to capture a detailed look at the archetypal FU Ori system for which these objects were named.

    Signs of Interaction

    3
    ALMA continuum observations show the dust of the two disks surrounding the binary stars of FU Orionis. Each disk is about 11 AU in radius. [Pérez et al. 2020]

    FU Orionis is a binary pair of young stars that lies roughly 1,360 light-years away in the constellation of Orion. Pérez and collaborators’ ALMA observations of the system resolved, for the first time, the disks of accreting dust surrounding each of the young stars. Modeling of these disks allowed the authors to infer that they are roughly 11 AU in radius and their separation is perhaps 250 AU.

    Observations of the gas in the disks reveal its kinematics, demonstrating that the rotation of each disk is somewhat asymmetric and skewed. The authors propose that this indicates some sort of close encounter for the disks — perhaps the flyby of another star within this crowded star-forming region, or possibly even the direct interaction of the two disks of the binary with each other.

    An elongated arc of gas may connect the two components, further strengthening the argument that the two disks are interacting. And close passes between the disks of a binary or perturbations from a flyby could easily increase the accretion rate onto the stars, fueling the FU Ori outburst that we now observe.

    Several other FU Ori systems are in known binaries, providing additional targets that we can follow up with to test whether disk interactions can truly explain these objects’ sudden, dramatic flares. Meanwhile, ALMA continues to play an important role in helping us to explore how stars form and evolve.

    Citation

    “Resolving the FU Orionis System with ALMA: Interacting Twin Disks?,” Sebastián Pérez et al 2020 ApJ 889 59.
    https://iopscience.iop.org/article/10.3847/1538-4357/ab5c1b

    See the full article here .


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    1

    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 2:25 pm on February 12, 2020 Permalink | Reply
    Tags: "Understanding the Impact of Satellite Constellations on Astronomy", , , , , , , Radio Astronomy   

    From International Astronomical Union: “Understanding the Impact of Satellite Constellations on Astronomy” 

    IAU bloc

    From International Astronomical Union

    2.12.20

    Piero Benvenuti
    Advisor, IAU Executive Committee
    piero.benvenuti@unipd.it

    Connie Walker
    President Commission B7
    cwalker@noao.edu

    Lars Lindberg Christensen
    IAU Press Officer
    Tucson, USA
    Tel: +1 520 318 8590
    Cell: +1 520 461 0433
    lchristensen@aura-astronomy.org

    2
    Starlink satellites on the way to parking orbit

    In June 2019, the International Astronomical Union expressed concern about the negative impact that the planned mega-constellations of communication satellites may have on astronomical observations and on the pristine appearance of the night sky when observed from a dark region. We here present a summary of the current understanding of the impact of these satellite constellations.

    Following the statement of June 2019, IAU’s Commission B7 Protection of Existing and Potential Observatory Sites and the Executive Committee Working Group Dark and Quiet Sky Protection were asked by the IAU Executive Committee to assess the situation and to start discussions with the companies that are responsible for launching and operating the mega-constellations in order to study measures to mitigate their interference.

    Commission B7 has requested the input of astronomers from different organisations (Vera C. Rubin Observatory, U. Michigan, CAHA, ESO and ESA) skilled in modeling the frequency, location and brightness of satellite mega-constellations. Some of those results are presented below. The results of the simulations, given the large number of parameters involved and the associated assumptions and uncertainties, are to be considered preliminary.

    Commission B7 has requested the input of astronomers from different organisations (Vera C. Rubin Observatory, U. Michigan, CAHA, ESO and ESA) skilled in modeling the frequency, location and brightness of satellite mega-constellations. Some of those results are presented below. The results of the simulations, given the large number of parameters involved and the associated assumptions and uncertainties, are to be considered preliminary.

    While there is large uncertainty about the future number of satellites, some simulations were conducted on the basis of a large sample of over 25 000 satellites from representative satellite constellations from different companies. With this sample, the number of satellites above the horizon at any given time would be between ~1500 and a few thousand, depending on the latitude. Most of these will appear very close to the horizon, only a few of them passing directly overhead; for instance, about 250 to 300 would have an elevation of more than 30 degrees over the horizon (i.e. where the sky is clear from obstructions, and where most of the astronomical observations are performed). The vast majority of these will be too faint to be visible to the naked eye [1] [2] [4]

    When the Sun is 18 degrees below the horizon (i.e. when the night becomes dark), the number of illuminated satellites above the horizon would be around 1000 (with around 160 at elevations higher than 30 degrees). The numbers decrease further towards the middle of the night, when more satellites are in the Earth’s shadow (e.g., no reflected sunlight) [1] [2] [4] .

    At the moment it is difficult to predict how many of the illuminated satellites will be visible to the naked eye, because of uncertainties in their actual reflectivity (also since experiments are being carried out by SpaceX to reduce the reflectivity of a Starlink satellite by adopting different coatings). The appearance of the pristine night sky, particularly when observed from dark sites, will nevertheless be altered, because the new satellites could be significantly brighter than existing orbiting man-made objects. The interference with the uncontaminated view of the night sky will be particularly important in the regions of the sky close to the horizon and less evident at high elevation [1] [2].

    The prominent trains of satellites (“strings of pearls”), often seen in images and videos, are significant immediately after launch and during the orbit-raising phase when they are considerably brighter than they are at their operational altitude and orientation. The global effect depends on how long the satellites are in this phase and on the frequency of launches [2].

    Apart from their naked-eye visibility, it is estimated that the trails of the constellation satellites will be bright enough to saturate modern detectors on large telescopes. Wide-field scientific astronomical observations will therefore be severely affected. For instance, in the case of modern fast wide-field surveys, like the ones to be carried out by the Rubin Observatory (formerly known as LSST), it is estimated that up to 30% of the 30-second images during twilight hours will be affected. Instruments with a smaller field of view would be less affected. In theory, the effects of the new satellites could be mitigated by accurately predicting their orbits and interrupting observations, when necessary, during their passage. Data processing could then be used to further “clean” the resulting images. However, the large number of trails could create significant and complicated overheads to the scheduling and operation of astronomical observations [1] [3] [4].

    A summary of the findings and of the actions that have so far been undertaken is presented in a specific IAU Theme.

    The focus of this Statement has been on the optical wavelengths. This is not to underplay the effect on the radio and submillimetre wavelength ranges, which is still under investigation. The IAU considers the consequences of satellite constellations worrisome. They will have a negative impact on the progress of ground-based astronomy, radio, optical and infrared, and will require diverting human and financial resources from basic research to studying and implementing mitigating measures.

    A great deal of attention is also being given to the protection of the uncontaminated view of the night sky from dark places, which should be considered a non-renounceable world human heritage. This is one of the main messages communicated on the dedicated IAU–UNESCO web site on astronomical heritage.

    In order to mitigate the impacts of satellite constellations that may interfere with professional and amateur astronomical observations, the IAU, in close collaboration with the American Astronomical Society (AAS), will continue to initiate discussions with space agencies and private companies that are planning to launch and operate currently planned and future satellite constellations.

    The IAU notes that currently there are no internationally agreed rules or guidelines on the brightness of orbiting manmade objects. While until now this was not considered a priority topic, it is now becoming increasingly relevant. Therefore the IAU will regularly present its findings at the meetings of the UN Committee for Peaceful Uses of Outer Space (COPUOS), bringing the attention of the world Government representatives to the threats posed by any new space initiative on astronomy and science in general. In addition, the specific theme of the mega-satellites will be included in the Programme of the IAU/UNOOSA/IAC Conference Dark and Quiet Skies for Science and Society, which will be held in Santa Cruz de La Palma, Canary Islands, Spain, on 5–8 October 2020.

    The IAU stresses that technological progress is only made possible by parallel advances in scientific knowledge. Satellites would neither operate nor properly communicate without essential contributions from astronomy and physics. It is in everybody’s interest to preserve and support the progress of fundamental science such as astronomy, celestial mechanics, orbital dynamics and relativity.

    Notes

    [1] Hainaut, Olivier (ESO), 2020, On the impact of satellite mega-constellations on astronomical observations, submitted for publication in Astronomy & Astrophysics.

    [2] Seitzer, Pat (University of Michigan), 2020, Presentation to the US National Science Foundation Astronomy and Astrophysics Advisory Committee

    [3] Tyson, Tony (Vera C. Rubin Observatory), 2020, private communication.

    [4] Galadí-Enríquez, David (Calar Alto Observatory), 2020, Geometric simulation of the visibility of Starlink satellite constellation from ground-based optical observatories: LSST as a case study, progress report, private communication.

    See the full article here .

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    The International Astronomical Union (IAU) was founded in 1919. Its mission is to promote and safeguard the science of astronomy in all its aspects through international cooperation. Its individual members — structured into Divisions, Commissions, and Working Groups — are professional astronomers from all over the world, at the Ph.D. level and beyond, who are active in professional research and education in astronomy. The IAU has 12422 members. The Individual Members Directory contains 10364 names in 97 countries worldwide (These Individual Members are labeled as “active” in the IAU database: they have a valid, public email, and are affiliated to at least one Division.). Of those 74 are National Members. In addition, the IAU collaborates with various scientific organizations all over the world.

    The IAU is the international astronomical organisation that brings together more than 13 500 professional astronomers from more than 100 countries worldwide. Its mission is to promote and safeguard astronomy in all its aspects, including research, communication, education and development, through international cooperation. The IAU also serves as the internationally recognised authority for assigning designations to celestial bodies and the surface features on them. Founded in 1919, the IAU is the world’s largest professional body for astronomers.

    The long-term policy of the IAU is defined by the General Assembly and implemented by the Executive Committee, while day-to-day operations are directed by the IAU Officers. The focal point of its activities is the IAU Secretariat, hosted by the Institut d’Astrophysique de Paris, France. The scientific and educational activities of the IAU are organized by its 9 Scientific Divisions and, through them, its 35 specialized Commissions covering the full spectrum of astronomy, along with its 32 Working Groups.

    The key activity of the IAU is the organization of scientific meetings. Every year the IAU sponsors nine international IAU Symposia. The IAU Symposium Proceedings series is the flagship of the IAU publications. Every three years the IAU holds a General Assembly, which offers six IAU Symposia, some 25 Joint Discussions and Special Sessions, and individual business and scientific meetings of Divisions, Commissions, and Working Groups. The proceedings of Joint Discussions and Special Sessions are published in the Highlights of Astronomy series. The reports of the GA business meetings are published in the Transactions of the IAU – B series.

     
  • richardmitnick 9:47 am on February 9, 2020 Permalink | Reply
    Tags: (SARAO)-South African Radio Astronomy Observatory, A massive $54 million expansion, , , , , Germany’s Max Planck Society, Radio Astronomy, ,   

    From Science Magazine: “This powerful observatory studying the formation of galaxies is getting a massive, $54 million expansion” 

    From Science Magazine

    Feb. 7, 2020
    Sarah Wild

    South Africa’s 64-dish MeerKAT telescope is set to grow by almost one-third, significantly increasing its sensitivity and ability to image the far reaches of the universe. The 20 new dishes come with a $54 million price tag, to be split evenly between the South African government and Germany’s Max Planck Society.

    1
    MeerKAT, which will get 20 new dishes by 2022, will eventually become part of the Square Kilometre Array, which will be the largest radio telescope in the world. South African Radio Astronomy Observatory


    SKA Square Kilometer Array


    SKA South Africa

    MeerKAT, a midfrequency dish array, is already the most sensitive telescope of its kind in the world [Nature]. Since its inauguration in 2018, it has captured the most detailed radio image of the center of the Milky Way and discovered giant radiation bubbles [Nature] within it.

    “The extended MeerKAT will be an even more powerful telescope to study the formation and evolution of galaxies throughout the history of the universe,” says Fernando Camilo, chief scientist at the South African Radio Astronomy Observatory (SARAO). Francisco Colomer, director of the Joint Institute for Very Long Baseline Interferometry European Research Infrastructure Consortium, says the expansion will “enhance an already impressive instrument.” The new dishes will have a slightly different design from the existing ones and a diameter of 15 meters instead of 13.5 meters.

    MeerKAT will eventually be folded into the Square Kilometre Array (SKA), which will be the largest radio telescope in the world; the new dishes, scheduled to come online in 2022, are designed to be part of SKA, says Rob Adam, SARAO’s managing director. SKA will comprise thousands of dishes across Africa and 1 million antennas in Australia and have a collecting area of 1 square kilometer, allowing scientists to look at the universe in unprecedented detail and investigate what happened immediately after the big bang, how galaxies form, and the nature of dark matter.

    SKA is now trying to attract funding and new partners for the project, whose initial phase is set to cost about $1 billion. Construction is scheduled to begin in 2021 [Nature]. SKA data may not be available to astronomers until the end of the decade; the expansion of MeerKAT will allow the astronomical community to stay busy in the meantime, Colomer says.

    South Africa’s contribution to MeerKAT will be counted toward the country’s pledge for the first phase of SKA, Adam says. Germany’s relationship with SKA is complicated. The country was a member of the SKA Organisation, tasked with overseeing the design phase of the telescope, but pulled out in 2014. The Max Planck Society rejoined the organization last year, but Germany isn’t among the seven member countries that signed a treaty to actually establish the SKA Observatory in August 2019. If it decides to join that group, the German funding for MeerKAT will also count toward the country’s contribution, Adam says.

    The additional dishes will increase MeerKAT’s computing requirements by an order of magnitude, but Adams says the extension coincides with a planned update to the telescope’s hardware that capitalizes on advances in computer technology.

    See the full article here .


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    Please help promote STEM in your local schools.

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  • richardmitnick 7:31 am on January 30, 2020 Permalink | Reply
    Tags: (MOU)-Memorandum of Understanding, , , , , CTA will comprise two arrays on different continents observing gamma rays: one in Chile at ESO’s Cerro Paranal and one in Spain on La Palma in the Canary Islands., , Radio Astronomy, , SKA will have radio telescopes in Australia and South Africa.,   

    From SKA: “SKA signs cooperation agreement with Čerenkov Telescope Array” 

    SKA South Africa


    From SKA

    29 January 2020

    The SKA Organisation (SKAO) [all telescope images below] will engage in closer collaboration with the Čerenkov Telescope Array Observatory (CTAO) under a new agreement signed by the two research infrastructures.

    2

    The Memorandum of Understanding (MOU) will facilitate greater sharing of knowledge and expertise in areas including engineering, science, technology and administration.

    SKAO and CTAO are both large international collaborations and have several member countries in common, including many European countries but also astronomy organisations in Australia and South Africa. Like the SKA, which will have radio telescopes in Australia and South Africa, CTA will also comprise two arrays on different continents observing gamma rays: one in Chile at ESO’s Cerro Paranal and one in Spain on La Palma in the Canary Islands.

    The two observatories are due to begin delivering science within just a few years of each other.

    Both have also begun transitions on the governance front; the SKA is becoming an intergovernmental organisation or IGO, while CTAO is becoming a European Research Infrastructure Consortium (ERIC).

    “Both the SKA and CTA are pushing the boundaries of what’s possible technically, scientifically and logistically, and some of the challenges that brings are common to both projects,” says Simon Berry, Director of Strategy for the SKA. “This MOU formalises our relationship, so we can keep learning from each other’s experiences and share expertise for the benefit of both observatories.”

    “In this age of multi-messenger astronomy, building alliances with observatories across the spectrum are critical to achieving our common missions to expand our view and understanding of the Universe,” says Federico Ferrini, CTAO Managing Director. “The CTAO-SKAO partnership was an obvious fit due to our vast similarities, and we are looking forward to the collaboration.”

    While the respective telescopes will observe opposite ends of the spectrum, there are exciting areas of scientific synergy between them. Both radio and gamma rays are a probe of the violent and variable universe, including the study of active galactic nuclei, transient events such as gamma-ray bursts and fast radio bursts, accretion into compact objects and gravitational wave counterparts.

    As the flagship very high-energy gamma-ray observatory for the coming decades, CTA is one of several next-generation facilities targeting other wavelengths or cosmic messengers (detections that do not use photons, such as neutrinos or gravitational waves) which will be complementary to the SKA. Coordinated observations between such facilities can give a more complete picture of astronomical sources and phenomena, resulting in greatly enhanced scientific discoveries.

    See the full article here .

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

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

    SKA Hera at SKA South Africa

    SKA Pathfinder – LOFAR location at Potsdam via Google Images

    About SKA

    The Square Kilometre Arraywill 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 6:17 pm on January 22, 2020 Permalink | Reply
    Tags: "The riddle of the heavenly bursts", , , , , , , Radio Astronomy   

    From Max Planck Institute for Radio Astronomy: “The riddle of the heavenly bursts” 


    From Max Planck Institute for Radio Astronomy

    January 20, 2020
    Dr. Laura Spitler
    Max Planck Institute for Radio Astronomy, Bonn
    +49 228 525-314
    lspitler@mpifr-bonn.mpg.de

    Dr. Norbert Junkes
    Press and public relations
    Max Planck Institute for Radio Astronomy, Bonn
    +49 2 28525-399
    njunkes@mpifr-bonn.mpg.de

    Time and again, radio telescopes register extremely short bursts of radiation in the depths of space.

    This cosmic lightning storm is happening all around us. Somewhere in the earthly sky, there is a pulse that flashes and extinguishes in the next moment. These bursts, which must be measured with radio telescopes and last one thousandth of a second, are one of the greatest mysteries of astrophysics. Scientists doubt that militant aliens are fighting “Star Wars” in the vastness of space. But where do these phenomena – dubbed “fast radio bursts” by the experts – come from?

    Text: Helmut Hornung

    2
    The radio telescope in Effelsberg is also part of the European VLBI network that searches for radio bursts. © MPI for Radio Astronomy / Norbert Tacken

    In the city of Parkes, gigantic lattice mesh bowl rises into the sky.

    CSIRO/Parkes Observatory, located 20 kilometres north of the town of Parkes, New South Wales, Australia, 414.80m above sea level

    In 2001, this 64-metre diameter radio telescope (once the largest fully mobile radio telescope in the southern hemisphere) registered a mysterious radio burst – and nobody noticed it! It wasn’t until five years later that astrophysicist Duncan Lorimer and his student David Narkevic found the signature of the signal in the telescope data more or less by chance. Even then, the specialists could not make sense of the phenomenon. But this was not the only “Lorimer burst”.

    “We now know of more than a hundred”, says Laura Spitler. Since March 2019, the researcher has headed a Lise Meitner group on this topic at the Max Planck Institute for Radio Astronomy. Spitler has dedicated herself to these fleeting flickers in space for many years. Under her leadership, an international team discovered the first fast radio burst (FRB) on the northern celestial sphere in the Fuhrmann constellation in 2014. Astronomers had used the dish of the Arecibo telescope on Puerto Rico.


    NAIC Arecibo Observatory operated by University of Central Florida, Yang Enterprises and UMET, Altitude 497 m (1,631 ft).

    The antenna, which measures 305 m in diameter, is firmly anchored in a natural valley and can only ever focus on a relatively small section of the firmament.

    “Statistically speaking, there should be only seven eruptions per minute spread across the sky. It therefore takes a lot of luck to align your telescope to the right position at the right time”, said Spitler after the discovery was announced. Both the properties of the radio bursts and their frequency derived from the measurements were in high agreement with what astronomers had found out about all the previously observed eruptions.

    In fact, statistical assumptions were confirmed; according to these, approx. 10,000 of these unusual cosmic phenomena were thought to flare up in the earthly firmament each day. The surprisingly large number results from calculations of how much of the sky would have to be observed and for how long in order to explain the comparatively few discoveries made so far.

    The Arecibo measurement also removed the last doubts about whether the radio bursts really came from the depths of the universe. After the first registered bursts, scientists concluded that they were being generated in an area far outside the Milky Way. This was deduced from an effect called plasma dispersion. When radio signals travel a long distance through the universe, they encounter numerous free electrons located in the space between the stars.

    Ultimately, the speed of propagation of radio waves at lower frequencies decreases in a characteristic manner. For example, during the aforementioned radiation burst discovered with the Arecibo telescope, this dispersion was three times larger than one would expect from a source within the Milky Way. If the source were located in the galaxy, interstellar matter would contribute roughly 33% for the Arecibo source.


    A repeating Fast Radio Burst from a spiral galaxy
    Scientists on the trail of radio flashes – an explanatory video in English

    But what is the origin of the radio bursts? The astrophysicists have designed various scenarios, all more or less exotic. Many of them revolve around neutron stars. These are the remnants of massive explosions of massive suns as supernovae, only 30 km in size. In these spheres, matter is so densely packed that on Earth, one teaspoonful of its matter would weigh about as much as the Zugspitze massif. The neutron stars rotate quickly around their axes. Some of them have exceptionally strong magnetic fields.

    For example, fast radio bursts could occur during a supernova – but also during the fusion of two neutron stars in a close binary star system – when the magnetic fields of the two individual stars collapse. In addition, a neutron star could collapse further into a black hole, emitting a burst.

    These scientific scripts sound plausible at first glance. However, they have one flaw: They predict only one radio burst at a time. “If the flash was generated in a cataclysmic event that destroys the source, only one burst per source can be expected”, says Laura Spitler. Indeed, in the early years, there were always single outbreaks – until in 2014 a burst called FRB 121102 went online. In 2016, Spitler and her team observed this to be the first “repeater”, a burst with repeating pulses. “This refuted all models that explain FRB as the consequence of a catastrophic event”, says Spitler.

    The FRB 121102, discovered at the Arecibo telescope, was further observed by the researchers with the Very Large Array in New Mexico.

    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)

    After 80 hours of measuring time, they registered nine bursts and determined the position with an accuracy of one arc second. At this position in the sky, there is a permanently radiating radio source; optical images show a faint galaxy about three billion light years away.

    With a diameter of only 13,000 light years, this star system is one of the dwarfs; the Milky Way is about ten times larger. “However, many new stars and perhaps even particularly large ones are born in this galaxy. This could be an indication of the source of the radio bursts”, says Spitler.

    The researcher thinks of pulsars – cosmic lighthouses that regularly emit radio radiation.

    Dame Susan Jocelyn Bell Burnell, discovered pulsars with radio astronomy. Jocelyn Bell at the Mullard Radio Astronomy Observatory, Cambridge University, taken for the Daily Herald newspaper in 1968. Denied the Nobel.

    Behind them are again fast rotating neutron stars with strong magnetic fields. If the axis of rotation and the axis of the magnetic field of such an object deviate from each other, a bundled radio beam can be produced. Each time this natural spotlight sweeps across the Earth, astronomers measure a short pulse.

    The bursts of most radio pulsars are too weak for them to be detected from a great distance. This is not the case with the particularly short and extremely strong “giant pulses”. A prime example of this class of objects is the crab pulsar, which was born in a supernova explosion observed in 1054 AD.

    Supernova remnant Crab nebula. NASA/ESA Hubble

    X-ray picture of Crab pulsar, taken by Chandra

    Its pulses would be visible even from neighbouring galaxies.

    “A promising model suggests that fast radio bursts are much stronger and rarer than giant pulses from extragalactic neutron stars similar to the crab pulsar. Or even younger and more energetic ones like this one”, says Spitler. “The home galaxy of FRB 121102 fits this model because it has the potential to produce just the right stars to become neutron stars at the end of their lives”.

    But whether this model is correct is literally written in the stars. The clarification is not getting any easier. Nevertheless, the observations continue. For example, the radio antennas of the European VLBI network examined another repeater in summer 2019.

    European VLBI

    FRB 180916.J0158+65 showed no less than four radiation outbursts during the five-hour observation. Each lasted less than two milliseconds.

    The home of this radio burst is in a spiral galaxy about 500 million light-years away. This makes it the closest observed so far even though this distance seems “astronomical”. It also turns out that there is apparently a high rate of star births around the burst.

    The position in the galaxy differs from that of all other bursts investigated so far. In other words: Apparently, the FRB flare up in all kinds of cosmic regions and diverse environments. “This is one of the reasons why it is still unclear whether all bursts have the same source type or are generated by the same physical processes”, says Spitler. “The mystery of their origin remains”.

    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 8:12 am on January 17, 2020 Permalink | Reply
    Tags: , , , , , , , Radio Astronomy   

    From Commonwealth Scientific and Industrial Research Organisation -CSIRO: “Leading Australian telescopes to get technology upgrades” 

    CSIRO bloc

    From Commonwealth Scientific and Industrial Research Organisation -CSIRO

    17 Jan 2020
    Gabby Russell
    +61 2 9490 8002

    CSIRO/Parkes Observatory, located 20 kilometres north of the town of Parkes, New South Wales, Australia, 414.80m above sea level

    CSIRO’s iconic Parkes radio telescope – fondly known as ‘The Dish’ – will get a new receiver that will significantly increase the amount of sky it can see at any one time, enabling new science and supporting local innovation in the space sector.

    The receiver is one of two projects announced today that will deliver technology enhancements for Australia’s leading radio telescopes.

    Australian Research Council Linkage Infrastructure, Equipment and Facilities (LIEF) grants have been awarded for the development of a new receiver for the Parkes radio telescope, and a major upgrade for the Australia Telescope Compact Array near Narrabri in NSW.

    CSIRO Australia Compact Array, six radio telescopes at the Paul Wild Observatory, is an array of six 22-m antennas located about twenty five kilometres (16 mi) west of the town of Narrabri in Australia.

    Both telescopes are owned and operated by Australia’s national science agency, CSIRO, for use by astronomers in Australia and around the world.

    A $1.15M LIEF grant will support a $3M project to build a sensitive receiver called a ‘cryoPAF’ for the Parkes radio telescope.

    Once complete, the new cryoPAF will sit high above the Parkes telescope’s dish surface and receive radio signals reflected up from the dish.

    Its detectors will convert radio signals into electrical ones, which can be combined in different ways so that the telescope ‘looks’ in several different directions at once.

    The cryoPAF will be cooled to -253°C to reduce ‘noise’ in its electrical circuits, enhancing the ability to detect weak radio signals from the cosmos at frequencies from 700 MHz to 1.9 GHz.

    The grant was led by The University of Western Australia, which will coordinate construction and commissioning of the cryoPAF. CSIRO will design, build and install the instrument.

    There are five further research organisations involved in the project.

    Professor Lister Staveley-Smith from The University of Western Australia node of ICRAR, who led the grant application, said the cryoPAF has three times more field of view than the previous instrument, allowing quicker and more complete surveys of the sky.

    “The new receiver will help astronomers to study fast radio bursts and pulsar stars, and observe hydrogen gas throughout the Universe,” Professor Staveley-Smith said.

    A phased-array feed or PAF is a close-packed array of radio detectors.

    CSIRO has previously designed and built innovative phased-array feeds for its ASKAP telescope in Western Australia, and a test version of the cryoPAF was used successfully on the Parkes telescope in 2016.

    Director of CSIRO Astronomy and Space Science, Dr Douglas Bock, said that in addition to boosting the capabilities of the Parkes telescope, the cryoPAF receiver technology had the potential to create spin-off opportunities.

    “Phased arrays have found extensive use in defence radar, medical imaging and even optical laser beam steering, with emerging applications in satellite communications and telecommunications,” Dr Bock said.

    “Their further development at radio wavelengths has technology applications beyond radio astronomy with the potential to fuel the growth of space-related industries here in Australia.”

    A second LIEF grant, worth $530,000, will support a $2.6M upgrade of the Australia Telescope Compact Array.

    The existing digital signal processor will be replaced with a GPU-powered processor to double the bandwidth of the telescope’s signal electronics.

    The project is being led by Professor Ray Norris from Western Sydney University, working closely with CSIRO and seven other university partners.

    Professor Norris said the upgrade will enable Australian researchers to address major challenges in our understanding of the Universe, and make more ground-breaking discoveries, across broad areas of astrophysics.

    “The upgrade will enable the telescope to study radio counterparts to gravitational wave sources, and it will enable it to make detailed observations of initial discoveries made with the Australian Square Kilometre Array Pathfinder and other Australian telescopes,” Professor Norris said.

    CSIRO is a leader in radio astronomy technology development, working in close partnership with astronomers who use its telescopes as well as international observatory customers.

    “We’ve been developing specialised instrumentation for radio telescopes since the 1940s, when the field of radio astronomy first emerged, for our own and international telescopes,” Dr Bock said.

    “Through our close collaborations with research partners and our expertise in technology development, we’ll keep the telescopes at the cutting edge of science.”

    CSIRO owns and operates a wide range of science-ready national research facilities and infrastructure that is used by thousands of Australian and international researchers each year. The Parkes radio telescope and Australia Telescope Compact Array are part of the Australia Telescope National Facility, which is funded by the Australian Government.

    See the full article here .


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    Please help promote STEM in your local schools.

    Stem Education Coalition

    CSIRO campus

    CSIRO, the Commonwealth Scientific and Industrial Research Organisation, is Australia’s national science agency and one of the largest and most diverse research agencies in the world.

     
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