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  • richardmitnick 8:34 am on July 1, 2022 Permalink | Reply
    Tags: "RTGs": Radioisotope thermoelectric generators, "The Voyager probes are not fully powering down ... yet", , Astronomy, , , , , NASA is following a strategic plan to keep their oldest explorers going for as long as possible.,   

    From “Astronomy Magazine” : “The Voyager probes are not fully powering down … yet” 

    From “Astronomy Magazine”

    June 23, 2022
    Caitlyn Buongiorno

    The Voyager spacecraft have been flying through space for nearly 45 years, so seeing recent headlines that these interstellar pioneers are powering down understandably caused some waves.

    But are the Voyager spacecraft really about to be shut down?

    To clarify the situation, Astronomy reached out to the mission press officer Calla Cofield who was quick to correct the impression, saying, “nothing new is starting now.” She went on to explain that NASA is following a strategic plan to keep their oldest explorers going for as long as possible.

    Keeping the lights on

    The twin Voyager spacecraft left Earth nearly five decades ago; Voyager 2 left our planet Aug. 20, 1977, with Voyager 1 following shortly after on Sept. 5. Both spacecraft are powered by three radioisotope thermoelectric generators (RTGs) and have a host of instruments collecting and sending scientific data back to Earth. (In Voyager 1’s case it takes about 20 hours and 33 minutes for that data to reach us!)

    The RTGs aboard the Voyager spacecraft turn heat into electricity in order to power the probes. That heat comes from the decay of plutonium-238 radioisotopes. However, at this point in their lifetimes, the generators are producing about 40 percent less electricity than when they were first launched.

    To keep them running for as long as possible, NASA began aggressively planning which systems to shut off in 2019. But the agency has been tackling the problem of diminishing power for decades now. “After 45 years in flight,” says Cofield, “the power budget is getting to the point where the team has to turn off whatever they can to keep the spacecraft running and doing science.”

    3
    NASA lists the instruments that have been powered down on the mission website. Credit: NASA/JPL-Caltech; https://voyager.jpl.nasa.gov/mission/status/

    Over the last three years, this has involved turning off the heaters to five of the probes’ scientific instruments.”Amazingly, all five have continued to operate well below the temperatures they were tested at!” says Cofield.

    The Voyager Science Steering Group will make further decisions on maintaining the power budget for the Voyager mission this August. According to Cofield, the creativity and innovation of the engineering team means that, in theory, the plans could stretch the Voyager missions into the 2030s — half a century longer than the probes were originally expected to last. However, that would require the team to turn off even more scientific instruments at some point.

    So, at least as it stands now, the Voyager spacecraft aren’t going anywhere (other than interstellar space) any time soon!

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    Astronomy is a magazine about the science and hobby of astronomy. Based near Milwaukee in Waukesha, Wisconsin, it is produced by Kalmbach Publishing. Astronomy’s readers include those interested in astronomy and those who want to know about sky events, observing techniques, astrophotography, and amateur astronomy in general.

    Astronomy was founded in 1973 by Stephen A. Walther, a graduate of The University of Wisconsin–Stevens Point and amateur astronomer. The first issue, August 1973, consisted of 48 pages with five feature articles and information about what to see in the sky that month. Issues contained astrophotos and illustrations created by astronomical artists. Walther had worked part time as a planetarium lecturer at The University of Wisconsin–Milwaukee and developed an interest in photographing constellations at an early age. Although even in childhood he was interested to obsession in Astronomy, he did so poorly in mathematics that his mother despaired that he would ever be able to earn a living. However, he graduated in Journalism from the University of Wisconsin Stevens Point, and as a senior class project he created a business plan for a magazine for amateur astronomers. With the help of his brother David, he was able to bring the magazine to fruition. He died in 1977.

     
  • richardmitnick 9:56 am on June 30, 2022 Permalink | Reply
    Tags: "The latest astronomy news and events from ICRAR", Astronomy, , , ,   

    From The International Centre for Radio Astronomy Research – ICRAR (AU): “The latest astronomy news and events from ICRAR” 

    ICRAR Logo

    From The International Centre for Radio Astronomy Research – ICRAR (AU)

    6.30.22

    The past few months have seen a number of outputs, resulting from several years of work on the SKA-Low prototype arrays AAVS2 and EDA2. A two-day online workshop convened by SKAO in February focused on SKA-Low; the ICRAR engineering team made major contributions to that meeting. A special issue on the SKA Observatory appeared in the SPIE Journal of Astronomical Telescopes, Instruments and Systems; of the 24 papers in total, one-quarter had ICRAR authorship. In April and May, we hosted visitors from SKAO HQ for the first time since COVID closed our borders back in March 2020. Several very useful discussions were held on the present technical status of SKA-Low and the pending start of construction work. We have also been interacting frequently with SKAO staff in Perth, whose numbers are growing rapidly at present.

    After the ratification of the SKA software contracts we started contributing to the official agile software development construction process as the YANDA team, which includes our colleagues from CSIRO. The YANDA team focuses on three areas of expertise: Real-time calibration, algorithmic development and workflow development and execution. Large scale processing is quite complex and involves many individual, iterative steps, or processing functions, which are arranged in workflows, depending on the science goals. This is where our workflow development, management and execution system DALiuGE comes into play. We have also worked on integrating a large set of additional processing functions developed by YANDA and other Data Processor teams to make them available for the development of these workflows.

    In other areas, ICRAR’s Data Intensive Astronomy team has delivered several projects with the Oceans Institute to perform ocean swell and current forecasts. Another highlight is the project with the CRC for Honey Bee Products to classify and quantify honey based on Thin-Layer Chromatography traces. The same technology is currently in widespread use in COVID19 rapid antigen test kits.

    Congratulations to our early career researcher Dr Maria Kovaleva, who has been awarded a Fulbright Scholarship to visit the United States later in the year. She will be working with the group at Brigham Young University on phased array antennas. Congratulations also to PhD candidate Ruby Wright who was awarded a Fulbright Visiting Scholarship to take to the Flatiron Institute in New York this year.

    See the full article here .

    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    The ICRAR(AU) is an equal joint venture between Curtin University and The University of Western Australia with funding support from the State Government of Western Australia. The Centre’s headquarters are located at UWA, with research nodes at both UWA and the Curtin Institute for Radio Astronomy (CIRA).
    ICRAR(AU) has strong support from the government of Australia and is working closely with industry and the astronomy community, including CSIRO(AU) and the Australian Telescope National Facility, ICRAR is:

    Playing a key role in the international Square Kilometre Array (SKA) project, the world’s biggest ground-based telescope array.

    Attracting some of the world’s leading researchers in radio astronomy, who will also contribute to national and international scientific and technical programs for SKA and ASKAP.

    Australia Telescope National Facility – radio telescopes included in the Facility include the Australia Telescope Compact Array, the Parkes Observatory, Mopra Radio Telescope Observatory and the Australian Square Kilometre Array Pathfinder.

    STCA CSIRO Australia Compact Array (AU), 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.

    CSIRO-Commonwealth Scientific and Industrial Research Organization (AU) Parkes Observatory [Murriyang, the traditional Indigenous name], located 20 kilometres north of the town of Parkes, New South Wales, Australia, 414.80m above sea level.

    NASA Canberra Deep Space Communication Complex, AU, Deep Space Network. Credit: NASA.

    CSIRO Canberra campus.

    ESA DSA 1, hosts a 35-metre deep-space antenna with transmission and reception in both S- and X-band and is located 140 kilometres north of Perth, Western Australia, near the town of New Norcia.

    Enhancing Australia’s position in the international SKA program by contributing to the development process for the SKA in scientific, technological and operational areas.
    Promoting scientific, technical, commercial and educational opportunities through public outreach, educational material, training students and collaborative developments with national and international educational organisations.
    Establishing and maintaining a pool of emerging and top-level scientists and technologists in the disciplines related to radio astronomy through appointments and training.
    Making world-class contributions to SKA science, with emphasis on the signature science themes associated with surveys for neutral hydrogen and variable (transient) radio sources.
    Making world-class contributions to SKA capability with respect to developments in the areas of Data Intensive Science and support for the Murchison Radio-astronomy Observatory.

    SKA

    SKA- Square Kilometer Array.

    SKA Square Kilometre Array low frequency at Murchison Widefield Array, Boolardy station in outback Western Australia on the traditional lands of the Wajarri peoples.

    EDGES telescope in a radio quiet zone at the Murchison Radio-astronomy Observatory in Western Australia, on the traditional lands of the Wajarri peoples.

     
  • richardmitnick 9:11 am on June 30, 2022 Permalink | Reply
    Tags: "On the march toward nanohertz gravitational waves using millisecond pulsars", Astronomy, , , , , , Pulsar named PSR J2241–5236,   

    From The International Centre for Radio Astronomy Research – ICRAR (AU): “On the march toward nanohertz gravitational waves using millisecond pulsars” 

    ICRAR Logo

    From The International Centre for Radio Astronomy Research – ICRAR (AU)

    June 28, 2022

    Dilpreet Kaur, a PhD candidate at ICRAR-Curtin, has recently used telescopes in Australia and India to conduct research relating to detecting gravitational waves using an array of pulsars.

    Ever since their discovery in 1967, pulsars have amazed astronomers with their extreme physical conditions and environments as well as their wide-ranging applications for physics.

    Fast-spinning, highly magnetised, tiny but very dense stars, pulsar signals appear in the form of trains of regular pulses, when their radio emission beams point toward earth; they are arguably amongst the most widely exploited astrophysical objects.

    Pulsars have been used to test and further advance a number of physical theories since their discovery; a high-profile application of these fascinating objects is the search for the signatures of ultra-low-frequency gravitational waves, and is a key science driver for the Square Kilometre Array (SKA) project that is now closer to construction.

    Ground-based Gravitational-wave detectors are restricted in the range and types of objects they can detect given the size of such detectors.

    For instance, the 4 km arms of the Laser Interferometer Gravitational-wave Observatory (LIGO) located in the United States is most sensitive to gravitational waves in the kiloHertz to Hertz range of frequencies, and these are produced by mergers of pairs of black hole roughly 30 to 100 times more massive than our Sun.

    ___________________________________________________________________
    Caltech /MIT Advanced aLigo

    Caltech/MIT Advanced aLigo Hanford, WA, USA installation.

    Caltech/MIT Advanced aLigo detector installation Livingston, LA, USA.

    SXS – Simulating eXtreme Spacetimes

    Gravitational waves. Credit: MPG Institute for Gravitational Physics [Max-Planck-Institut für Gravitationsphysik] (Albert Einstein Institute) (DE)/W.Benger-Zib

    Gravity is talking. Lisa will listen. Dialogos of Eide.

    European Space Agency(EU)/National Aeronautics and Space Administration (US) eLISA space based, the future of gravitational wave research.
    3
    This graphic shows the masses of all of LIGO’s announced gravitational wave detections, as well as black holes and neutron stars previously obtained through electromagnetic observations.
    LIGO-Virgo-Kagra/Aaron Geller/Northwestern.
    ___________________________________________________________________

    But to detect even more massive mergers and events, like the mergers of large galaxies as they formed and evolved in the early stages of the universe, we need to go into the nanohertz range where the wavelength is much longer, and hence requires more sensitive, and large, detectors than we currently have.

    The good news is we don’t have to build a colossal detector through the planet or in orbit.

    The “building blocks” for our detector already exist in nature, and are waiting to be exploited: they are millisecond pulsars, i.e. pulsars that spin at rates of several hundred times per second, the fastest one spinning at a rate faster than that of a kitchen blender!

    Pulsars are like interstellar lighthouses for astronomers, with millisecond pulsars spinning at rates of several rotations a second, and therefore can be precisely timed, often with precisions of a millionth of a second, or even down to ten-millionth, in the best-case scenario.

    These repeating, and astonishingly regular, flashes of radio light can be used to build a Pulsar Timing Array (PTA) – a celestial distribution of pulsars that can be regularly timed with very high precisions, in our quest to detect ultra-low-frequency gravitational waves.

    With such highly predictable intervals of these pulses, it is possible correlate timing data sets from different pulsars (and from different telescopes) to search for the signatures of gravitational background – something produced by millions of supermassive black-hole pair mergers, as the galaxies harbouring them merged in the early history of the universe.

    By monitoring several of these pulsars over many years, astronomers are hoping to detect the telltale signature of this gravitational wave background pervading through our universe. The signal strength is however expected to be much fainter due to the very large distances, of the order of billions of light years.

    But detecting these ultra-low frequency waves is easier said than done.

    1
    From Earth, pulsar signals have their arrival times altered depending on the nature of the interstellar medium (ISM) between us and them, making monitoring these celestial objects quite tedious.

    The ISM is weird and complex; it behaves subtly differently from pulsar to pulsar, and can even give rise to effects such as chromatic (i.e. frequency-dependent) dispersion in the arrival times of pulsar signals as they interact with the free electrons on their journey to the telescope.

    This dispersion effect manifests as a parabolic sweep in arrival times at the telescope, and even though the density of electrons is incredibly small, the 1000s of light years the pulsar signals travel through can amount to measurable changes in the signal’s arrival times.

    In principle, this effect could be precisely measured with advances in telescope instrumentation, but it’s only one of several subtleties that need to be accounted for.

    Due to pulsars whizzing in space with high velocities of the order of a million km per hour, and the arrival times being measured with a precision better than a microsecond, observations separated in time will probe different parts of the ISM; in principle, they may also change depending on where they are located at the time – in relation to earth’s rotation and our orbit, resulting in slightly varying readings of the ISM called Dispersion Measure or DM, which is the total electron content in the path between the pulsar and telescope.

    Based on early observations of pulsars with the Murchison Widefield Array (MWA)[below], a team led by ICRAR-Curtin PhD candidate Dilpreet Kaur undertook concerted multi-telescope observing campaigns of one of the high-priority pulsars targeted for Pulsar Timing Arrays.

    This pulsar, catchily named PSR J2241–5236, spins at a rate of more than 450 times per second, and on each rotation, its signal is visible to us for about 5% of its rotation period – roughly ~150 microseconds.

    Using data collected at the MWA in Western Australia, the Giant Metre-wave Radio Telescope in India, and the Parkes (Murriyang) radio telescope in New South Wales [below], within a span of less than 24-hours, Dilpreet & team were able to measure, calibrate, and analyse these arrival time perturbations and obtain high-precision measurements of DM, to reveal a clear frequency dependence.

    These results present the first definitive proof predictions that the Dispersion Measure can vary with the frequency the observer uses to detect these stellar objects.

    It’s part of a long process of understanding how pulsar signals vary in their arrival times, and learn how to mitigate these variations as we march toward the ultimate goal of PTAs, i.e. the detection of nanohertz-frequency gravitational waves.

    The analysis and results reporting this was published in The Astrophysical Journal Letters last month.

    See the full article here .

    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    The ICRAR(AU) is an equal joint venture between Curtin University and The University of Western Australia with funding support from the State Government of Western Australia. The Centre’s headquarters are located at UWA, with research nodes at both UWA and the Curtin Institute for Radio Astronomy (CIRA).
    ICRAR(AU) has strong support from the government of Australia and is working closely with industry and the astronomy community, including CSIRO(AU) and the Australian Telescope National Facility, ICRAR is:

    Playing a key role in the international Square Kilometre Array (SKA) project, the world’s biggest ground-based telescope array.

    Attracting some of the world’s leading researchers in radio astronomy, who will also contribute to national and international scientific and technical programs for SKA and ASKAP.

    Australia Telescope National Facility – radio telescopes included in the Facility include the Australia Telescope Compact Array, the Parkes Observatory, Mopra Radio Telescope Observatory and the Australian Square Kilometre Array Pathfinder.

    STCA CSIRO Australia Compact Array (AU), 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.

    CSIRO-Commonwealth Scientific and Industrial Research Organization (AU) Parkes Observatory [Murriyang, the traditional Indigenous name], located 20 kilometres north of the town of Parkes, New South Wales, Australia, 414.80m above sea level.

    NASA Canberra Deep Space Communication Complex, AU, Deep Space Network. Credit: NASA.

    CSIRO Canberra campus.

    ESA DSA 1, hosts a 35-metre deep-space antenna with transmission and reception in both S- and X-band and is located 140 kilometres north of Perth, Western Australia, near the town of New Norcia.

    Enhancing Australia’s position in the international SKA program by contributing to the development process for the SKA in scientific, technological and operational areas.
    Promoting scientific, technical, commercial and educational opportunities through public outreach, educational material, training students and collaborative developments with national and international educational organisations.
    Establishing and maintaining a pool of emerging and top-level scientists and technologists in the disciplines related to radio astronomy through appointments and training.
    Making world-class contributions to SKA science, with emphasis on the signature science themes associated with surveys for neutral hydrogen and variable (transient) radio sources.
    Making world-class contributions to SKA capability with respect to developments in the areas of Data Intensive Science and support for the Murchison Radio-astronomy Observatory.

    SKA

    SKA- Square Kilometer Array.

    SKA Square Kilometre Array low frequency at Murchison Widefield Array, Boolardy station in outback Western Australia on the traditional lands of the Wajarri peoples.

    EDGES telescope in a radio quiet zone at the Murchison Radio-astronomy Observatory in Western Australia, on the traditional lands of the Wajarri peoples.

     
  • richardmitnick 10:29 pm on June 29, 2022 Permalink | Reply
    Tags: , , Astronomy, , , , , "The puzzling link between star formation and radio emission in galaxies", To understand the formation and evolution of galaxies like our Milky Way it is of particular importance to know the amount of newly formed stars in both nearby and distant galaxies., Astronomers often use a link between the infrared and radio radiation of galaxies.   

    From The Leibniz Institute for Astrophysics [Leibniz-Institut für Astrophysik](DE) : “The puzzling link between star formation and radio emission in galaxies” 

    From The Leibniz Institute for Astrophysics [Leibniz-Institut für Astrophysik](DE)

    June 29, 2022

    Prof. Dr. Christoph Pfrommer
    Science contact
    Phone: +49 331 7499 513
    cpfrommer@aip.de

    Maria Werhahn
    Science contact
    Phone: +49 331 7499 240
    mwerhahn@aip.de

    Sarah Hönig
    Media contact
    Phone: +49 331 7499 803
    presse@aip.de

    1
    Simulation of a forming disk galaxy, in which cosmic rays are accelerated by supernova remnants and then escape into the interstellar medium. Cross sections of the disk (top) and vertical sections (bottom) show the number density of cosmic ray electrons in steady state (left), magnetic field strength (middle) and radio synchrotron brightness. Credit: Werhahn/AIP.

    On the 50th anniversary of the discovery of a close connection between star formation in galaxies and their infrared and radio radiation, researchers at the Leibniz Institute for Astrophysics Potsdam (AIP) have now deciphered the underlying physics. To this end, they used novel computer simulations of galaxy formation with a complete modeling of cosmic rays.

    To understand the formation and evolution of galaxies like our Milky Way it is of particular importance to know the amount of newly formed stars in both nearby and distant galaxies. For this purpose, astronomers often use a link between the infrared and radio radiation of galaxies, which has already been discovered 50 years ago: the energetic radiation of young, massive stars that form in the densest regions of galaxies is absorbed by surrounding dust clouds and re-emitted as low-energy infrared radiation. Eventually, when their fuel supply is exhausted, these massive stars explode as supernovae at the end of their lives. In this explosion, the outer stellar envelope is ejected into the environment, which accelerates a few particles of the interstellar medium to very high energies, giving rise to so-called cosmic rays. In the galaxy’s magnetic field, these fast particles, traveling at nearly the speed of light, emit very low-energy radio radiation with a wavelength of a few centimetres to metres. Through this chain of processes, newly-forming stars, infrared radiation and radio radiation from galaxies are closely linked.

    Although this relation is often used in astronomy, the exact physical conditions are not yet clear. Previous attempts to explain it usually failed in one prediction: if high-energy cosmic rays are indeed responsible for the radio radiation of these galaxies, the theory predicts very steep radio spectra – high emission at low radio frequencies – that do not match observations. To get to the bottom of this mystery, a team of researchers at AIP has now, for the first time, realistically simulated these processes of a forming galaxy on a computer and calculated the cosmic ray energy spectra.

    “During the formation of the galactic disk, cosmic magnetic fields are amplified so that they match the strong observed galactic magnetic fields,” explains Professor Christoph Pfrommer, head of the section Cosmology and High-Energy Astrophysics at AIP. When cosmic ray particles in magnetic fields emit radio radiation, it loses part of its energy on its way to us. As a result, the radio spectrum becomes flatter at low frequencies. At high frequencies, in addition to the radio emission of cosmic rays, the radio emission of the interstellar medium, which has a flatter spectrum, also contributes. The sum of these two processes can therefore perfectly explain the observed flat radio radiation of the whole galaxy as well as the emission of the central regions. This also explains the mystery of why the infrared and radio radiation of galaxies are so well linked. “This allows us to better determine the number of newly formed stars from the observed radio emission in galaxies, which will help us to further unravel the story of star formation in the universe,” concludes Maria Werhahn, PhD student at AIP and first author of one of the studies.

    Science papers:

    MNRAS

    MNRAS

    See the full article here.

    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    The Leibniz Institute for Astrophysics Potsdam (DE) is a German research institute. It is the successor of the Berlin Observatory founded in 1700 and of the Astrophysical Observatory Potsdam (AOP) founded in 1874. The latter was the world’s first observatory to emphasize explicitly the research area of astrophysics. The AIP was founded in 1992, in a re-structuring following the German reunification.

    The AIP is privately funded and member of the Leibniz Association. It is located in Babelsberg in the state of Brandenburg, just west of Berlin, though the Einstein Tower solar observatory and the great refractor telescope on Telegrafenberg in Potsdam belong to the AIP.

    The key topics of the AIP are cosmic magnetic fields (magnetohydrodynamics) on various scales and extragalactic astrophysics. Astronomical and astrophysical fields studied at the AIP range from solar and stellar physics to stellar and galactic evolution to cosmology.

    The institute also develops research technology in the fields of spectroscopy and robotic telescopes. It is a partner of the Large Binocular Telescope in Arizona, has erected robotic telescopes in Tenerife and the Antarctic, develops astronomical instrumentation for large telescopes such as the VLT of the ESO. Furthermore, work on several e-Science projects are carried out at the AIP.

    LBT-U Arizona Large Binocular Telescope Interferometer, or LBTI, is a ground-based instrument connecting two 8-meter class telescopes on Mount Graham, Arizona, USA, Altitude 3,221 m (10,568 ft.) to form the largest single-mount telescope in the world. The interferometer is designed to detect and study stars and planets outside our solar system. Credit: NASA/JPL-Caltech.

    European Southern Observatory(EU) , Very Large Telescope at Cerro Paranal in the Atacama Desert •ANTU (UT1; The Sun ) •KUEYEN (UT2; The Moon ) •MELIPAL (UT3; The Southern Cross ), and •YEPUN (UT4; Venus – as evening star). Elevation 2,635 m (8,645 ft) from above Credit J.L. Dauvergne & G. Hüdepohl atacama photo.

    Main research areas

    Magnetohydrodynamics (MHD): Magnetic fields and turbulence in stars, accretion disks and galaxies; computer simulations ao dynamos, magnetic instabilities and magnetic convection
    Solar physics: Observation of sunspots and of solar magnetic field with spectro-polarimetry; Helioseismology and hydrodynamic numerical models; Study of coronal plasma processes by means of radio astronomy; Operation of the Observatory for Solar Radio Astronomy (OSRA) in Tremsdorf, with four radio antennas in different frequency bands from 40 MHz to 800 MHz
    Stellar physics: Numerical simulations of convection in stellar atmospheres, determination of stellar surface parameters and chemical abundances, winds and dust shells of red giants; Doppler tomography of stellar surface structures, development of robotic telescopes, as well as simulation of magnetic flux tubes
    Star formation and the interstellar medium: Brown dwarfs and low-mass stars, circumstellar disks, Origin of double and multiple-star systems
    Galaxies and quasars: Mother galaxies and surroundings of quasars, development of quasars and active galactic cores, structure and the story of the origin of the Milky Way, numerical computer simulations of the origin and development of galaxies
    Cosmology: Numerical simulation of the formation of large-scale structures. Semi-analytic models of galaxy formation and evolution. Predictions for future large observational surveys.

     
  • richardmitnick 10:03 pm on June 29, 2022 Permalink | Reply
    Tags: "Falling stardust and wobbly jets explain blinking gamma ray bursts", , Astronomy, , , , ,   

    From Northwestern University: “Falling stardust and wobbly jets explain blinking gamma ray bursts” 

    Northwestern U bloc

    From Northwestern University

    June 29, 2022
    Amanda Morris

    New simulation also shows gamma ray bursts are 10 times more rare than previously thought.


    Jet wobbles as it escapes a collapsar.

    A Northwestern University-led team of astrophysicists has developed the first-ever full 3D simulation of an entire evolution of a jet formed by a collapsing star, or a “collapsar.”

    Because these jets generate gamma ray bursts (GRBs) — the most energetic and luminous events in the universe since the Big Bang — the simulations have shed light on these peculiar, intense bursts of light. Their new findings include an explanation for the longstanding question of why GRBs are mysteriously punctuated by quiet moments — blinking between powerful emissions and an eerily quiet stillness. The new simulation also shows that GRBs are even rarer than previously thought.

    The new study was published today (June 29) in The Astrophysical Journal Letters. It marks the first full 3D simulation of the entire evolution of a jet — from its birth near the black hole to its emission after escaping from the collapsing star. The new model also is the highest-ever resolution simulation of a large-scale jet.

    “These jets are the most powerful events in the universe,” said Northwestern’s Ore Gottlieb, who led the study. “Previous studies have tried to understand how they work, but those studies were limited by computational power and had to include many assumptions. We were able to model the entire evolution of the jet from the very beginning — from its birth by a black hole — without assuming anything about the jet’s structure. We followed the jet from the black hole all the way to the emission site and found processes that have been overlooked in previous studies.”

    Gottlieb is a Rothschild Fellow in Northwestern’s Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA). He coauthored the paper with CIERA member Sasha Tchekhovskoy, an assistant professor of physics and astronomy at Northwestern’s Weinberg College of Arts and Sciences.

    Weird wobbling

    The most luminous phenomenon in the universe, GRBs emerge when the core of a massive star collapses under its own gravity to form a black hole. As gas falls into the rotating black hole, it energizes — launching a jet into the collapsing star. The jet punches the star until finally escaping from it, accelerating at speeds close to the speed of light. After breaking free from the star, the jet generates a bright GRB.

    “The jet generates a GRB when it reaches about 30 times the size of the star — or a million times the size of the black hole,” Gottlieb said. “In other words, if the black hole is the size of a beach ball, the jet needs to expand over the entire size of France before it can produce a GRB.”

    Due to the enormity of this scale, previous simulations have been unable to model the full evolution of the jet’s birth and subsequent journey. Using assumptions, all previous studies found that the jet propagates along one axis and never deviates from that axis.

    But Gottlieb’s simulation showed something very different. As the star collapses into a black hole, material from that star falls onto the disk of magnetized gas that swirls around the black hole. The falling material causes the disk to tilt, which, in turn, tilts the jet. As the jet struggles to realign with its original trajectory, it wobbles inside the collapsar.

    This wobbling provides a new explanation for why GRBs blink. During the quiet moments, the jet doesn’t stop — its emission beams away from Earth, so telescopes simply cannot observe it.

    “Emission from GRBs is always irregular,” Gottlieb said. “We see spikes in emission and then a quiescent time that lasts for a few seconds or more. The entire duration of a GRB is about one minute, so these quiescent times are a non-negligible fraction of the total duration. Previous models were not able to explain where these quiescent times were coming from. This wobbling naturally gives an explanation to that phenomenon. We observe the jet when its pointing at us. But when the jet wobbles to point away from us, we cannot see its emission. This is part of Einstein’s theory of relativity.”

    Rare becomes more rare

    These wobbly jets also provide new insights into the rate and nature of GRBs. Although previous studies estimated that about 1% of collapsars produce GRBs, Gottlieb believes that GRBs are actually much more rare.

    If the jet were constrained to moving along one axis, then it would only cover a thin slice of the sky — limiting the likelihood of observing it. But the wobbly nature of the jet means that astrophysicists can observe GRBs at different orientations, increasing the likelihood of spotting them. According to Gottlieb’s calculations, GRBs are 10 times more observable than previously thought, which means that astrophysicists are missing 10 times fewer GRBs than previously thought.

    1

    “The idea is that we observe GRBs on the sky in a certain rate, and we want to learn about the true rate of GRBs in the universe,” Gottlieb explained. “The observed and true rates are different because we can only see the GRBs that are pointing at us. That means we need to assume something about the angle that these jets cover on the sky, in order to infer the true rate of GRBs. That is, what fraction of GRBs we are missing. Wobbling increases the number of detectable GRBs, so the correction from the observed to true rate is smaller. If we miss fewer GRBs, then there are fewer GRBs overall in the sky.”

    If this is true, Gottlieb posits, then most of the jets either fail to be launched at all or never succeed in escaping from the collapsar to produce a GRB. Instead, they remain buried inside.

    Mixed energy

    The new simulations also revealed that some of the magnetic energy in the jets partially converts to thermal energy. This suggests that the jet has a hybrid composition of magnetic and thermal energies, which produce the GRB. In a major step forward in understanding the mechanisms that power GRBs, this is the first time researchers have inferred the jet composition of GRBs at the time of emission.

    “Studying jets enables us to ‘see’ what happens deep inside the star as it collapses,” Gottlieb said. “Otherwise, it’s difficult to learn what happens in a collapsed star because light cannot escape from the stellar interior. But we can learn from the jet emission — the history of the jet and the information that it carries from the systems that launch them.”

    The major advance of the new simulation partially lies in its computational power. Using the code “H-AMR” on supercomputers at the Oak Ridge Leadership Computing Facility in Oak Ridge, Tennessee, the researchers developed the new simulation, which uses graphical processing units (GPUs) instead of central processing units (CPUs). Extremely efficient at manipulating computer graphics and image processing, GPUs accelerate the creation of images on a display.

    See the full article here .

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    Please help promote STEM in your local schools.

    Stem Education Coalition

    Northwestern South Campus
    South Campus

    Northwestern University is a private research university in Evanston, Illinois. Founded in 1851 to serve the former Northwest Territory, the university is a founding member of the Big Ten Conference.

    On May 31, 1850, nine men gathered to begin planning a university that would serve the Northwest Territory.

    Given that they had little money, no land and limited higher education experience, their vision was ambitious. But through a combination of creative financing, shrewd politicking, religious inspiration and an abundance of hard work, the founders of Northwestern University were able to make that dream a reality.

    In 1853, the founders purchased a 379-acre tract of land on the shore of Lake Michigan 12 miles north of Chicago. They established a campus and developed the land near it, naming the surrounding town Evanston in honor of one of the University’s founders, John Evans. After completing its first building in 1855, Northwestern began classes that fall with two faculty members and 10 students.
    Twenty-one presidents have presided over Northwestern in the years since. The University has grown to include 12 schools and colleges, with additional campuses in Chicago and Doha, Qatar.

    Northwestern is known for its focus on interdisciplinary education, extensive research output, and student traditions. The university provides instruction in over 200 formal academic concentrations, including various dual degree programs. The university is composed of eleven undergraduate, graduate, and professional schools, which include the Kellogg School of Management, the Pritzker School of Law, the Feinberg School of Medicine, the Weinberg College of Arts and Sciences, the Bienen School of Music, the McCormick School of Engineering and Applied Science, the Medill School of Journalism, the School of Communication, the School of Professional Studies, the School of Education and Social Policy, and The Graduate School. As of fall 2019, the university had 21,946 enrolled students, including 8,327 undergraduates and 13,619 graduate students.

    Valued at $12.2 billion, Northwestern’s endowment is among the largest university endowments in the United States. Its numerous research programs bring in nearly $900 million in sponsored research each year.

    Northwestern’s main 240-acre (97 ha) campus lies along the shores of Lake Michigan in Evanston, 12 miles north of Downtown Chicago. The university’s law, medical, and professional schools, along with its nationally ranked Northwestern Memorial Hospital, are located on a 25-acre (10 ha) campus in Chicago’s Streeterville neighborhood. The university also maintains a campus in Doha, Qatar and locations in San Francisco, California, Washington, D.C. and Miami, Florida.

    As of October 2020, Northwestern’s faculty and alumni have included 1 Fields Medalist, 22 Nobel Prize laureates, 40 Pulitzer Prize winners, 6 MacArthur Fellows, 17 Rhodes Scholars, 27 Marshall Scholars, 23 National Medal of Science winners, 11 National Humanities Medal recipients, 84 members of the American Academy of Arts and Sciences, 10 living billionaires, 16 Olympic medalists, and 2 U.S. Supreme Court Justices. Northwestern alumni have founded notable companies and organizations such as the Mayo Clinic, The Blackstone Group, Kirkland & Ellis, U.S. Steel, Guggenheim Partners, Accenture, Aon Corporation, AQR Capital, Booz Allen Hamilton, and Melvin Capital.

    The foundation of Northwestern University can be traced to a meeting on May 31, 1850, of nine prominent Chicago businessmen, Methodist leaders, and attorneys who had formed the idea of establishing a university to serve what had been known from 1787 to 1803 as the Northwest Territory. On January 28, 1851, the Illinois General Assembly granted a charter to the Trustees of the North-Western University, making it the first chartered university in Illinois. The school’s nine founders, all of whom were Methodists (three of them ministers), knelt in prayer and worship before launching their first organizational meeting. Although they affiliated the university with the Methodist Episcopal Church, they favored a non-sectarian admissions policy, believing that Northwestern should serve all people in the newly developing territory by bettering the economy in Evanston.

    John Evans, for whom Evanston is named, bought 379 acres (153 ha) of land along Lake Michigan in 1853, and Philo Judson developed plans for what would become the city of Evanston, Illinois. The first building, Old College, opened on November 5, 1855. To raise funds for its construction, Northwestern sold $100 “perpetual scholarships” entitling the purchaser and his heirs to free tuition. Another building, University Hall, was built in 1869 of the same Joliet limestone as the Chicago Water Tower, also built in 1869, one of the few buildings in the heart of Chicago to survive the Great Chicago Fire of 1871. In 1873 the Evanston College for Ladies merged with Northwestern, and Frances Willard, who later gained fame as a suffragette and as one of the founders of the Woman’s Christian Temperance Union (WCTU), became the school’s first dean of women (Willard Residential College, built in 1938, honors her name). Northwestern admitted its first female students in 1869, and the first woman was graduated in 1874.

    Northwestern fielded its first intercollegiate football team in 1882, later becoming a founding member of the Big Ten Conference. In the 1870s and 1880s, Northwestern affiliated itself with already existing schools of law, medicine, and dentistry in Chicago. Northwestern University Pritzker School of Law is the oldest law school in Chicago. As the university’s enrollments grew, these professional schools were integrated with the undergraduate college in Evanston; the result was a modern research university combining professional, graduate, and undergraduate programs, which gave equal weight to teaching and research. By the turn of the century, Northwestern had grown in stature to become the third largest university in the United States after Harvard University and the University of Michigan.

    Under Walter Dill Scott’s presidency from 1920 to 1939, Northwestern began construction of an integrated campus in Chicago designed by James Gamble Rogers, noted for his design of the Yale University campus, to house the professional schools. The university also established the Kellogg School of Management and built several prominent buildings on the Evanston campus, including Dyche Stadium, now named Ryan Field, and Deering Library among others. In the 1920s, Northwestern became one of the first six universities in the United States to establish a Naval Reserve Officers Training Corps (NROTC). In 1939, Northwestern hosted the first-ever NCAA Men’s Division I Basketball Championship game in the original Patten Gymnasium, which was later demolished and relocated farther north, along with the Dearborn Observatory, to make room for the Technological Institute.

    After the golden years of the 1920s, the Great Depression in the United States (1929–1941) had a severe impact on the university’s finances. Its annual income dropped 25 percent from $4.8 million in 1930-31 to $3.6 million in 1933-34. Investment income shrank, fewer people could pay full tuition, and annual giving from alumni and philanthropists fell from $870,000 in 1932 to a low of $331,000 in 1935. The university responded with two salary cuts of 10 percent each for all employees. It imposed hiring and building freezes and slashed appropriations for maintenance, books, and research. Having had a balanced budget in 1930-31, the university now faced deficits of roughly $100,000 for the next four years. Enrollments fell in most schools, with law and music suffering the biggest declines. However, the movement toward state certification of school teachers prompted Northwestern to start a new graduate program in education, thereby bringing in new students and much needed income. In June 1933, Robert Maynard Hutchins, president of the University of Chicago, proposed a merger of the two universities, estimating annual savings of $1.7 million. The two presidents were enthusiastic, and the faculty liked the idea; many Northwestern alumni, however, opposed it, fearing the loss of their Alma Mater and its many traditions that distinguished Northwestern from Chicago. The medical school, for example, was oriented toward training practitioners, and alumni feared it would lose its mission if it were merged into the more research-oriented University of Chicago Medical School. The merger plan was ultimately dropped. In 1935, the Deering family rescued the university budget with an unrestricted gift of $6 million, bringing the budget up to $5.4 million in 1938-39. This allowed many of the previous spending cuts to be restored, including half of the salary reductions.

    Like other American research universities, Northwestern was transformed by World War II (1939–1945). Regular enrollment fell dramatically, but the school opened high-intensity, short-term programs that trained over 50,000 military personnel, including future president John F. Kennedy. Northwestern’s existing NROTC program proved to be a boon to the university as it trained over 36,000 sailors over the course of the war, leading Northwestern to be called the “Annapolis of the Midwest.” Franklyn B. Snyder led the university from 1939 to 1949, and after the war, surging enrollments under the G.I. Bill drove dramatic expansion of both campuses. In 1948, prominent anthropologist Melville J. Herskovits founded the Program of African Studies at Northwestern, the first center of its kind at an American academic institution. J. Roscoe Miller’s tenure as president from 1949 to 1970 saw an expansion of the Evanston campus, with the construction of the Lakefill on Lake Michigan, growth of the faculty and new academic programs, and polarizing Vietnam-era student protests. In 1978, the first and second Unabomber attacks occurred at Northwestern University. Relations between Evanston and Northwestern became strained throughout much of the post-war era because of episodes of disruptive student activism, disputes over municipal zoning, building codes, and law enforcement, as well as restrictions on the sale of alcohol near campus until 1972. Northwestern’s exemption from state and municipal property-tax obligations under its original charter has historically been a source of town-and-gown tension.

    Although government support for universities declined in the 1970s and 1980s, President Arnold R. Weber was able to stabilize university finances, leading to a revitalization of its campuses. As admissions to colleges and universities grew increasingly competitive in the 1990s and 2000s, President Henry S. Bienen’s tenure saw a notable increase in the number and quality of undergraduate applicants, continued expansion of the facilities and faculty, and renewed athletic competitiveness. In 1999, Northwestern student journalists uncovered information exonerating Illinois death-row inmate Anthony Porter two days before his scheduled execution. The Innocence Project has since exonerated 10 more men. On January 11, 2003, in a speech at Northwestern School of Law’s Lincoln Hall, then Governor of Illinois George Ryan announced that he would commute the sentences of more than 150 death-row inmates.

    In the 2010s, a 5-year capital campaign resulted in a new music center, a replacement building for the business school, and a $270 million athletic complex. In 2014, President Barack Obama delivered a seminal economics speech at the Evanston campus.

    Organization and administration

    Governance

    Northwestern is privately owned and governed by an appointed Board of Trustees, which is composed of 70 members and, as of 2011, has been chaired by William A. Osborn ’69. The board delegates its power to an elected president who serves as the chief executive officer of the university. Northwestern has had sixteen presidents in its history (excluding interim presidents). The current president, economist Morton O. Schapiro, succeeded Henry Bienen whose 14-year tenure ended on August 31, 2009. The president maintains a staff of vice presidents, directors, and other assistants for administrative, financial, faculty, and student matters. Kathleen Haggerty assumed the role of interim provost for the university in April 2020.

    Students are formally involved in the university’s administration through the Associated Student Government, elected representatives of the undergraduate students, and the Graduate Student Association, which represents the university’s graduate students.

    The admission requirements, degree requirements, courses of study, and disciplinary and degree recommendations for each of Northwestern’s 12 schools are determined by the voting members of that school’s faculty (assistant professor and above).

    Undergraduate and graduate schools

    Evanston Campus:

    Weinberg College of Arts and Sciences (1851)
    School of Communication (1878)
    Bienen School of Music (1895)
    McCormick School of Engineering and Applied Science (1909)
    Medill School of Journalism (1921)
    School of Education and Social Policy (1926)
    School of Professional Studies (1933)

    Graduate and professional

    Evanston Campus

    Kellogg School of Management (1908)
    The Graduate School

    Chicago Campus

    Feinberg School of Medicine (1859)
    Kellogg School of Management (1908)
    Pritzker School of Law (1859)
    School of Professional Studies (1933)

    Northwestern University had a dental school from 1891 to May 31, 2001, when it closed.

    Endowment

    In 1996, Princess Diana made a trip to Evanston to raise money for the university hospital’s Robert H. Lurie Comprehensive Cancer Center at the invitation of then President Bienen. Her visit raised a total of $1.5 million for cancer research.

    In 2003, Northwestern finished a five-year capital campaign that raised $1.55 billion, exceeding its fundraising goal by $550 million.

    In 2014, Northwestern launched the “We Will” campaign with a fundraising goal of $3.75 billion. As of December 31, 2019, the university has received $4.78 billion from 164,026 donors.

    Sustainability

    In January 2009, the Green Power Partnership (sponsored by the EPA) listed Northwestern as one of the top 10 universities in the country in purchasing energy from renewable sources. The university matches 74 million kilowatt hours (kWh) of its annual energy use with Green-e Certified Renewable Energy Certificates (RECs). This green power commitment represents 30 percent of the university’s total annual electricity use and places Northwestern in the EPA’s Green Power Leadership Club. The Initiative for Sustainability and Energy at Northwestern (ISEN), supporting research, teaching and outreach in these themes, was launched in 2008.

    Northwestern requires that all new buildings be LEED-certified. Silverman Hall on the Evanston campus was awarded Gold LEED Certification in 2010; Wieboldt Hall on the Chicago campus was awarded Gold LEED Certification in 2007, and the Ford Motor Company Engineering Design Center on the Evanston campus was awarded Silver LEED Certification in 2006. New construction and renovation projects will be designed to provide at least a 20% improvement over energy code requirements where feasible. At the beginning of the 2008–09 academic year, the university also released the Evanston Campus Framework Plan, which outlines plans for future development of the university’s Evanston campus. The plan not only emphasizes sustainable building construction, but also focuses on reducing the energy costs of transportation by optimizing pedestrian and bicycle access. Northwestern has had a comprehensive recycling program in place since 1990. The university recycles over 1,500 tons of waste, or 30% of all waste produced on campus, each year. All landscape waste at the university is composted.

    Academics

    Education and rankings

    Northwestern is a large, residential research university, and is frequently ranked among the top universities in the United States. The university is a leading institution in the fields of materials engineering, chemistry, business, economics, education, journalism, and communications. It is also prominent in law and medicine. Accredited by the Higher Learning Commission and the respective national professional organizations for chemistry, psychology, business, education, journalism, music, engineering, law, and medicine, the university offers 124 undergraduate programs and 145 graduate and professional programs. Northwestern conferred 2,190 bachelor’s degrees, 3,272 master’s degrees, 565 doctoral degrees, and 444 professional degrees in 2012–2013. Since 1951, Northwestern has awarded 520 honorary degrees. Northwestern also has chapters of academic honor societies such as Phi Beta Kappa (Alpha of Illinois), Eta Kappa Nu, Tau Beta Pi, Eta Sigma Phi (Beta Chapter), Lambda Pi Eta, and Alpha Sigma Lambda (Alpha Chapter).

    The four-year, full-time undergraduate program comprises the majority of enrollments at the university. Although there is no university-wide core curriculum, a foundation in the liberal arts and sciences is required for all majors; individual degree requirements are set by the faculty of each school. The university heavily emphasizes interdisciplinary learning, with 72% of undergrads combining two or more areas of study. Northwestern’s full-time undergraduate and graduate programs operate on an approximately 10-week academic quarter system with the academic year beginning in late September and ending in early June. Undergraduates typically take four courses each quarter and twelve courses in an academic year and are required to complete at least twelve quarters on campus to graduate. Northwestern offers honors, accelerated, and joint degree programs in medicine, science, mathematics, engineering, and journalism. The comprehensive doctoral graduate program has high coexistence with undergraduate programs.

    Despite being a mid-sized university, Northwestern maintains a relatively low student to faculty ratio of 6:1.

    Research

    Northwestern was elected to the Association of American Universities in 1917 and is classified as an R1 university, denoting “very high” research activity. Northwestern’s schools of management, engineering, and communication are among the most academically productive in the nation. The university received $887.3 million in research funding in 2019 and houses over 90 school-based and 40 university-wide research institutes and centers. Northwestern also supports nearly 1,500 research laboratories across two campuses, predominately in the medical and biological sciences.

    Northwestern is home to the Center for Interdisciplinary Exploration and Research in Astrophysics, Northwestern Institute for Complex Systems, Nanoscale Science and Engineering Center, Materials Research Center, Center for Quantum Devices, Institute for Policy Research, International Institute for Nanotechnology, Center for Catalysis and Surface Science, Buffet Center for International and Comparative Studies, the Initiative for Sustainability and Energy at Northwestern, and the Argonne/Northwestern Solar Energy Research Center among other centers for interdisciplinary research.

    Student body

    Northwestern enrolled 8,186 full-time undergraduate, 9,904 full-time graduate, and 3,856 part-time students in the 2019–2020 academic year. The freshman retention rate for that year was 98%. 86% of students graduated after four years and 92% graduated after five years. These numbers can largely be attributed to the university’s various specialized degree programs, such as those that allow students to earn master’s degrees with a one or two year extension of their undergraduate program.

    The undergraduate population is drawn from all 50 states and over 75 foreign countries. 20% of students in the Class of 2024 were Pell Grant recipients and 12.56% were first-generation college students. Northwestern also enrolls the 9th-most National Merit Scholars of any university in the nation.

    In Fall 2014, 40.6% of undergraduate students were enrolled in the Weinberg College of Arts and Sciences, 21.3% in the McCormick School of Engineering and Applied Science, 14.3% in the School of Communication, 11.7% in the Medill School of Journalism, 5.7% in the Bienen School of Music, and 6.4% in the School of Education and Social Policy. The five most commonly awarded undergraduate degrees are economics, journalism, communication studies, psychology, and political science. The Kellogg School of Management’s MBA, the School of Law’s JD, and the Feinberg School of Medicine’s MD are the three largest professional degree programs by enrollment. With 2,446 students enrolled in science, engineering, and health fields, the largest graduate programs by enrollment include chemistry, integrated biology, material sciences, electrical and computer engineering, neuroscience, and economics.

    Athletics

    Northwestern is a charter member of the Big Ten Conference. It is the conference’s only private university and possesses the smallest undergraduate enrollment (the next-smallest member, the University of Iowa, is roughly three times as large, with almost 22,000 undergraduates).

    Northwestern fields 19 intercollegiate athletic teams (8 men’s and 11 women’s) in addition to numerous club sports. 12 of Northwestern’s varsity programs have had NCAA or bowl postseason appearances. Northwestern is one of five private AAU members to compete in NCAA Power Five conferences (the other four being Duke, Stanford, USC, and Vanderbilt) and maintains a 98% NCAA Graduation Success Rate, the highest among Football Bowl Subdivision schools.

    In 2018, the school opened the Walter Athletics Center, a $270 million state of the art lakefront facility for its athletics teams.

    Nickname and mascot

    Before 1924, Northwestern teams were known as “The Purple” and unofficially as “The Fighting Methodists.” The name Wildcats was bestowed upon the university in 1924 by Wallace Abbey, a writer for the Chicago Daily Tribune, who wrote that even in a loss to the University of Chicago, “Football players had not come down from Evanston; wildcats would be a name better suited to “[Coach Glenn] Thistletwaite’s boys.” The name was so popular that university board members made “Wildcats” the official nickname just months later. In 1972, the student body voted to change the official nickname to “Purple Haze,” but the new name never stuck.

    The mascot of Northwestern Athletics is “Willie the Wildcat”. Prior to Willie, the team mascot had been a live, caged bear cub from the Lincoln Park Zoo named Furpaw, who was brought to the playing field on game days to greet the fans. After a losing season however, the team decided that Furpaw was to blame for its misfortune and decided to select a new mascot. “Willie the Wildcat” made his debut in 1933, first as a logo and then in three dimensions in 1947, when members of the Alpha Delta fraternity dressed as wildcats during a Homecoming Parade.

    Traditions

    Northwestern’s official motto, “Quaecumque sunt vera,” was adopted by the university in 1890. The Latin phrase translates to “Whatsoever things are true” and comes from the Epistle of Paul to the Philippians (Philippians 4:8), in which St. Paul admonishes the Christians in the Greek city of Philippi. In addition to this motto, the university crest features a Greek phrase taken from the Gospel of John inscribed on the pages of an open book, ήρης χάριτος και αληθείας or “the word full of grace and truth” (John 1:14).
    Alma Mater is the Northwestern Hymn. The original Latin version of the hymn was written in 1907 by Peter Christian Lutkin, the first dean of the School of Music from 1883 to 1931. In 1953, then Director-of-Bands John Paynter recruited an undergraduate music student, Thomas Tyra (’54), to write an English version of the song, which today is performed by the Marching Band during halftime at Wildcat football games and by the orchestra during ceremonies and other special occasions.
    Purple became Northwestern’s official color in 1892, replacing black and gold after a university committee concluded that too many other universities had used these colors. Today, Northwestern’s official color is purple, although white is something of an official color as well, being mentioned in both the university’s earliest song, Alma Mater (1907) (“Hail to purple, hail to white”) and in many university guidelines.
    The Rock, a 6-foot high quartzite boulder donated by the Class of 1902, originally served as a water fountain. It was painted over by students in the 1940s as a prank and has since become a popular vehicle of self-expression on campus.
    Armadillo Day, commonly known as Dillo Day, is the largest student-run music festival in the country. The festival is hosted every Spring on Northwestern’s Lakefront.
    Primal Scream is held every quarter at 9 p.m. on the Sunday before finals week. Students lean out of windows or gather in courtyards and scream to help relieve stress.
    In the past, students would throw marshmallows during football games, but this tradition has since been discontinued.

    Philanthropy

    One of Northwestern’s most notable student charity events is Dance Marathon, the most established and largest student-run philanthropy in the nation. The annual 30-hour event is among the most widely-attended events on campus. It has raised over $1 million for charity every year since 2011 and has donated a total of $13 million to children’s charities since its conception.

    The Northwestern Community Development Corps (NCDC) is a student-run organization that connects hundreds of student volunteers to community development projects in Evanston and Chicago throughout the year. The group also holds a number of annual community events, including Project Pumpkin, a Halloween celebration that provides over 800 local children with carnival events and a safe venue to trick-or-treat each year.

    Many Northwestern students participate in the Freshman Urban Program, an initiative for students interested in community service to work on addressing social issues facing the city of Chicago, and the university’s Global Engagement Studies Institute (GESI) programs, including group service-learning expeditions in Asia, Africa, or Latin America in conjunction with the Foundation for Sustainable Development.

    Several internationally recognized non-profit organizations were established at Northwestern, including the World Health Imaging, Informatics and Telemedicine Alliance, a spin-off from an engineering student’s honors thesis.
    Media

    Print

    Established in 1881, The Daily Northwestern is the university’s main student newspaper and is published on weekdays during the academic year. It is directed entirely by undergraduate students and owned by the Students Publishing Company. Although it serves the Northwestern community, the Daily has no business ties to the university and is supported wholly by advertisers.
    North by Northwestern is an online undergraduate magazine established in September 2006 by students at the Medill School of Journalism. Published on weekdays, it consists of updates on news stories and special events throughout the year. It also publishes a quarterly print magazine.
    Syllabus is the university’s undergraduate yearbook. It is distributed in late May and features a culmination of the year’s events at Northwestern. First published in 1885, the yearbook is published by Students Publishing Company and edited by Northwestern students.
    Northwestern Flipside is an undergraduate satirical magazine. Founded in 2009, it publishes a weekly issue both in print and online.
    Helicon is the university’s undergraduate literary magazine. Established in 1979, it is published twice a year: a web issue is released in the winter and a print issue with a web complement is released in the spring.
    The Protest is Northwestern’s quarterly social justice magazine.

    The Northwestern division of Student Multicultural Affairs supports a number of publications for particular cultural groups including Ahora, a magazine about Hispanic and Latino/a culture and campus life; Al Bayan, published by the Northwestern Muslim-cultural Student Association; BlackBoard Magazine, a magazine centered around African-American student life; and NUAsian, a magazine and blog on Asian and Asian-American culture and issues.
    The Northwestern University Law Review is a scholarly legal publication and student organization at Northwestern University School of Law. Its primary purpose is to publish a journal of broad legal scholarship. The Law Review publishes six issues each year. Student editors make the editorial and organizational decisions and select articles submitted by professors, judges, and practitioners, as well as student pieces. The Law Review also publishes scholarly pieces weekly on the Colloquy.
    The Northwestern Journal of Technology and Intellectual Property is a law review published by an independent student organization at Northwestern University School of Law.
    The Northwestern Interdisciplinary Law Review is a scholarly legal publication published annually by an editorial board of Northwestern undergraduates. Its mission is to publish interdisciplinary legal research, drawing from fields such as history, literature, economics, philosophy, and art. Founded in 2008, the journal features articles by professors, law students, practitioners, and undergraduates. It is funded by the Buffett Center for International and Comparative Studies and the Office of the Provost.

    Web-based

    Established in January 2011, Sherman Ave is a humor website that often publishes content on Northwestern student life. Most of its staff writers are current Northwestern undergraduates writing under various pseudonyms. The website is popular among students for its interviews of prominent campus figures, Freshman Guide, and live-tweeting coverage of football games. In Fall 2012, the website promoted a satiric campaign to end the Vanderbilt University football team’s custom of clubbing baby seals.
    Politics & Policy is dedicated to the analysis of current events and public policy. Established in 2010 by students at the Weinberg College of Arts and Sciences, School of Communication, and Medill School of Journalism, the publication reaches students on more than 250 college campuses around the world. Run entirely by undergraduates, it is published several times a week and features material ranging from short summaries of events to extended research pieces. The publication is financed in part by the Buffett Center.
    Northwestern Business Review is a campus source for business news. Founded in 2005, it has an online presence as well as a quarterly print schedule.
    TriQuarterly Online (formerly TriQuarterly) is a literary magazine published twice a year featuring poetry, fiction, nonfiction, drama, literary essays, reviews, blog posts, and art.
    The Queer Reader is Northwestern’s first radical feminist and LGBTQ+ publication.

    Radio, film, and television

    WNUR (89.3 FM) is a 7,200-watt radio station that broadcasts to the city of Chicago and its northern suburbs. WNUR’s programming consists of music (jazz, classical, and rock), literature, politics, current events, varsity sports (football, men’s and women’s basketball, baseball, softball, and women’s lacrosse), and breaking news on weekdays.
    Studio 22 is a student-run production company that produces roughly ten films each year. The organization financed the first film Zach Braff directed, and many of its films have featured students who would later go into professional acting, including Zach Gilford of Friday Night Lights.
    Applause for a Cause is currently the only student-run production company in the nation to create feature-length films for charity. It was founded in 2010 and has raised over $5,000 to date for various local and national organizations across the United States.
    Northwestern News Network is a student television news and sports network, serving the Northwestern and Evanston communities. Its studios and newsroom are located on the fourth floor of the McCormick Tribune Center on Northwestern’s Evanston campus. NNN is funded by the Medill School of Journalism.

     
  • richardmitnick 4:24 pm on June 28, 2022 Permalink | Reply
    Tags: "A sanitizer in the galactic centre region", A long-term study of the chemical composition of Sgr B2 was started that took advantage of the high angular resolution and sensitivity provided by ALMA., An outstanding star forming region in our Galaxy where many molecules were detected in the past is Sagittarius B2 (Sgr B2)., Astronomy, , , , , , Investigation of the chemical composition of Sgr B2 began more than 15 years ago with the IRAM 30-m telescope., Iso-propanol was observed in a “delivery room” of stars-the massive star-forming region Sagittarius B2 which is located near the centre of our Milky Way., One difficulty in the identification of organic molecules is the spectral confusion. Each molecule emits radiation at specific frequencies-its spectral "fingerprint"-known from laboratory measurements, , Thanks to ALMA's high angular resolution it was possible to isolate very narrow spectral lines-five times more narrow than the lines detected on larger scales with the IRAM 30-m radio telescope!, The "Cologne Database for Molecular Spectroscopy (CDMS)" provides spectroscopic data to detect these molecules contributed by many groups and has been instrumental in their detection in many cases., The ALMA observations have led to the identification of three new organic molecules., The bigger the molecule the more spectral lines at different frequencies it produces., The goal of the present work is to understand how organic molecules form in the interstellar medium., The latest result within this ALMA project is now the detection of propanol (C3H7OH)., The molecular cloud is the target of an extensive investigation of its chemical composition with the ALMA telescope., , The search for molecules in space has been going on for more than 50 years. To date astronomers have identified 276 molecules in the interstellar medium., To date astronomers have identified 276 molecules in the interstellar medium., With the advent of the Atacama Large Millimeter/submillimeter Array (ALMA) ten years ago it became possible to go beyond what could be achieved toward Sgr B2 with a single-dish telescope.   

    From The MPG Institute for Radio Astronomy [MPG Institut für Radioastronomie](DE): “A sanitizer in the galactic centre region” 

    From The MPG Institute for Radio Astronomy [MPG Institut für Radioastronomie](DE)

    June 28, 2022

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

    Dr. Arnaud Belloche
    Max Planck Institute for Radio Astronomy, Bonn
    +49 228 525-376
    belloche@mpifr-bonn.mpg.de

    Prof. Dr. Karl M. Menten
    Director at the Institute and Head of the “Millimeter and Submillimeter Astronomy” Research Dept.
    Max Planck Institute for Radio Astronomy, Bonn
    +49 228 525-471
    kmenten@mpifr-bonn.mpg.de

    Interstellar detection of iso-propanol in Sagittarius B2

    Many of us have probably already – literally – handled the chemical compound iso-propanol: it can used as an antiseptic, a solvent or a cleaning agent. But this substance is not only found on Earth: researchers led by Arnaud Belloche from the Max Planck Institute for Radio Astronomy in Bonn have now detected the molecule in interstellar space for the first time. It was observed in a “delivery room” of stars-the massive star-forming region Sagittarius B2 which is located near the centre of our Milky Way. The molecular cloud is the target of an extensive investigation of its chemical composition with the ALMA telescope in the Chilean Atacama Desert.

    1
    Alcohol in space: the position of star-forming molecular cloud Sagittarius B2 (Sgr B2) close to the central source of the Milky Way, Sgr A*. The image, taken from the GLOSTAR Galactic Plane Survey (Effelsberg & VLA) shows radio sources in the Galactic centre region. The isomers propanol and iso-propanol were both detected in Sgr B2 using the ALMA telescope.
    © GLOSTAR (Bruntaler et al. 2021, Astronomy & Astrophysics): Background image. Wikipedia (public domain): Propanol and isopropanol models.

    The search for molecules in space has been going on for more than 50 years. To date astronomers have identified 276 molecules in the interstellar medium. The “Cologne Database for Molecular Spectroscopy (CDMS)” provides spectroscopic data to detect these molecules contributed by many research groups and has been instrumental in their detection in many cases.

    The goal of the present work is to understand how organic molecules form in the interstellar medium, in particular in regions where new stars are born, and how complex these molecules can be. The underlying motivation is to establish connections to the chemical composition of bodies in the Solar system such as comets, as delivered for instance by the Rosetta mission to comet 67P/Churyumov–Gerasimenko a few years ago.

    An outstanding star forming region in our Galaxy where many molecules were detected in the past is Sagittarius B2 (Sgr B2), which is located close to the famous source Sgr A*, the supermassive black hole in the centre of our Galaxy.

    “Our group began to investigate the chemical composition of Sgr B2 more than 15 years ago with the IRAM 30-m telescope”, says Arnaud Belloche from the Max Planck Institute for Radio Astronomy (MPIfR) in Bonn/Germany, the leading author of the detection paper.

    “These observations were successful and led in particular to the first interstellar detection of several organic molecules, among many other results.”

    With the advent of the Atacama Large Millimeter/submillimeter Array (ALMA) ten years ago it became possible to go beyond what could be achieved toward Sgr B2 with a single-dish telescope and a long-term study of the chemical composition of Sgr B2 was started that took advantage of the high angular resolution and sensitivity provided by ALMA.

    So far, the ALMA observations have led to the identification of three new organic molecules (iso-propyl cyanide, N-methylformamide, urea) since 2014. The latest result within this ALMA project is now the detection of propanol (C3H7OH).

    Propanol is an alcohol, and is now the largest in this class of molecules that has been detected in interstellar space. This molecule exists in two forms (“isomers”), depending on which carbon atom the hydroxyl (OH) functional group is attached to: 1) normal-propanol, with OH bound to a terminal carbon atom of the chain, and 2) iso-propanol, with OH bound to the central carbon atom in the chain. Iso-propanol is also well known as the key ingredient in hand sanitizers on Earth. Both isomers of propanol in Sgr B2 were identified in the ALMA data set. It is the first time that iso-propanol is detected in the interstellar medium, and the first time that normal-propanol is detected in a star forming region. The first interstellar detection of normal-propanol was obtained shortly before the ALMA detection by a Spanish research team with single-dish radio telescopes in a molecular cloud not far from Sgr B2. The detection of iso-propanol toward Sgr B2, however, was only possible with ALMA.

    “The detection of both isomers of propanol is uniquely powerful in determining the formation mechanism of each. Because they resemble each other so much, they behave physically in very similar ways, meaning that the two molecules should be present in the same places at the same times”, says Rob Garrod from the University of Virginia. “The only open question is the exact amounts that are present – this makes their interstellar ratio far more precise than would be the case for other pairs of molecules. It also means that the chemical network can be tuned much more carefully to determine the mechanisms by which they form.”

    The ALMA telescope network was essential for the detection of both isomers of propanol toward Sgr B2, thanks to its high sensitivity, its high angular resolution, and its broad frequency coverage. One difficulty in the identification of organic molecules in the spectra of star forming regions is the spectral confusion. Each molecule emits radiation at specific frequencies-its spectral “fingerprint”-which is known from laboratory measurements.

    “The bigger the molecule the more spectral lines at different frequencies it produces. In a source like Sgr B2, there are so many molecules contributing to the observed radiation that their spectra overlap and it is difficult to disentangle their fingerprints and identify them individually”, says Holger Müller from Cologne University where laboratory work especially on normal-propanol was performed.

    Thanks to ALMA’s high angular resolution it was possible to isolate parts of Sgr B2 that emit very narrow spectral lines-five times more narrow than the lines detected on larger scales with the IRAM 30-m radio telescope! The narrowness of these lines reduces the spectral confusion, and this was key for the identification of both isomers of propanol in Sgr B2. The sensitivity of ALMA also played a key role: it would not have been possible to identify propanol in the collected data if the sensitivity had been just twice worse.

    This research is a long-standing effort to probe the chemical composition of sites in Sgr B2 where new stars are being formed, and thereby understand the chemical processes at work in the course of star formation. The goal is to determine the chemical composition of the star forming sites, and possibly identify new interstellar molecules. “Propanol has long been on our list of molecules to search for, but it is only thanks to the recent work done in our laboratory to characterize its rotational spectrum that we could identify its two isomers in a robust way”, says Oliver Zingsheim, also from Cologne University.

    Detecting closely related molecules that slightly differ in their structure (such as normal- and iso-propanol or, as was done in the past: normal- and iso-propyl cyanide) and measuring their abundance ratio allows the researchers to probe specific parts of the chemical reaction network that leads to their production in the interstellar medium.

    “There are still many unidentified spectral lines in the ALMA spectrum of Sgr B2 which means that still a lot of work is left to decipher its chemical composition. In the near future, the expansion of the ALMA instrumentation down to lower frequencies will likely help us to reduce the spectral confusion even further and possibly allow the identification of additional organic molecules in this spectacular source”, concludes Karl Menten, Director at the MPIfR and Head of its Millimeter and Submillimeter Astronomy research department.

    Science paper:
    Astronomy & Astrophysics

    See the full article here .

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    Stem Education Coalition

    MPIFR campus

    Effelsberg Radio Telescope- a radio telescope in the Ahr Hills (part of the Eifel) in Bad Münstereifel(DE)

    The MPG Institute for Radio Astronomy [MPG Institut für Radioastronomie] (DE) is located in Bonn, Germany. It is one of 80 institutes in the MPG Society.

    By combining the already existing radio astronomy faculty of the University of Bonn led by Otto Hachenberg with the new MPG institute the MPG 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 MPG Society as the “MPG Institut für Radioastronomie (MPIfR) (DE)”.

    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 MPG Society decided in principle to found the MPG Institut für Radioastronomie. Eventually, after a series of discussions, the institute was officially founded in 1966.

    MPG Society for the Advancement of Science [MPG Gesellschaft zur Förderung der Wissenschaften e. V.] 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 MPG Society supports fundamental research in the natural, life and social sciences, the arts and humanities in its 83 (as of January 2014) MPG 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 MPG Institutes focus on excellence in research. The MPG 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 MPG institutes fifth worldwide in terms of research published in Nature journals (after Harvard University, The Massachusetts Institute of Technology, Stanford University and The National Institutes of Health). In terms of total research volume (unweighted by citations or impact), the Max Planck Society is only outranked by The Chinese Academy of Sciences [中国科学院](CN), The Russian Academy of Sciences [Росси́йская акаде́мия нау́к](RU) and Harvard University. The Thomson Reuters-Science Watch website placed the MPG Society as the second leading research organization worldwide following Harvard University, in terms of the impact of the produced research over science fields.

    The MPG Society and its predecessor Kaiser Wilhelm Society hosted several renowned scientists in their fields, including Otto Hahn, Werner Heisenberg, and Albert Einstein.

    History

    The organization was established in 1911 as the Kaiser Wilhelm Society, or Kaiser-Wilhelm-Gesellschaft (KWG), a non-governmental research organization named for the then German emperor. The KWG was one of the world’s leading research organizations; its board of directors included scientists like Walther Bothe, Peter Debye, Albert Einstein, and Fritz Haber. In 1946, Otto Hahn assumed the position of President of KWG, and in 1948, the society was renamed the Max Planck Society (MPG) after its former President (1930–37) Max Planck, who died in 1947.

    The MPG Society has a world-leading reputation as a science and technology research organization. In 2006, the Times Higher Education Supplement rankings of non-university research institutions (based on international peer review by academics) placed the MPG Society as No.1 in the world for science research, and No.3 in technology research (behind AT&T Corporation and The DOE’s Argonne National Laboratory.

    The domain mpg.de attracted at least 1.7 million visitors annually by 2008 according to a Compete.com study.

    MPG Institutes and research groups

    The MPG Society consists of over 80 research institutes. In addition, the society funds a number of Max Planck Research Groups (MPRG) and International Max Planck Research Schools (IMPRS). The purpose of establishing independent research groups at various universities is to strengthen the required networking between universities and institutes of the Max Planck Society.
    The research units are primarily located across Europe with a few in South Korea and the U.S. In 2007, the Society established its first non-European centre, with an institute on the Jupiter campus of Florida Atlantic University (US) focusing on neuroscience.
    The MPG Institutes operate independently from, though in close cooperation with, the universities, and focus on innovative research which does not fit into the university structure due to their interdisciplinary or transdisciplinary nature or which require resources that cannot be met by the state universities.

    Internally, MPG Institutes are organized into research departments headed by directors such that each MPI has several directors, a position roughly comparable to anything from full professor to department head at a university. Other core members include Junior and Senior Research Fellows.

    In addition, there are several associated institutes:
    International Max Planck Research Schools
    Together with the Association of Universities and other Education Institutions in Germany, the Max Planck Society established numerous International Max Planck Research Schools (IMPRS) to promote junior scientists:

    • Cologne Graduate School of Ageing Research, Cologne
    • International Max Planck Research School for Intelligent Systems, at the Max Planck Institute for Intelligent Systems located in Tübingen and Stuttgart
    • International Max Planck Research School on Adapting Behavior in a Fundamentally Uncertain World (Uncertainty School), at the Max Planck Institutes for Economics, for Human Development, and/or Research on Collective Goods
    • International Max Planck Research School for Analysis, Design and Optimization in Chemical and Biochemical Process Engineering, Magdeburg
    • International Max Planck Research School for Astronomy and Cosmic Physics, Heidelberg at the MPI for Astronomy
    • International Max Planck Research School for Astrophysics, Garching at the MPI for Astrophysics
    • International Max Planck Research School for Complex Surfaces in Material Sciences, Berlin
    • International Max Planck Research School for Computer Science, Saarbrücken
    • International Max Planck Research School for Earth System Modeling, Hamburg
    • International Max Planck Research School for Elementary Particle Physics, Munich, at the MPI for Physics
    • International Max Planck Research School for Environmental, Cellular and Molecular Microbiology, Marburg at the Max Planck Institute for Terrestrial Microbiology
    • International Max Planck Research School for Evolutionary Biology, Plön at the Max Planck Institute for Evolutionary Biology
    • International Max Planck Research School “From Molecules to Organisms”, Tübingen at the Max Planck Institute for Developmental Biology
    • International Max Planck Research School for Global Biogeochemical Cycles, Jena at the Max Planck Institute for Biogeochemistry
    • International Max Planck Research School on Gravitational Wave Astronomy, Hannover and Potsdam MPI for Gravitational Physics
    • International Max Planck Research School for Heart and Lung Research, Bad Nauheim at the Max Planck Institute for Heart and Lung Research
    • International Max Planck Research School for Infectious Diseases and Immunity, Berlin at the Max Planck Institute for Infection Biology
    • International Max Planck Research School for Language Sciences, Nijmegen
    • International Max Planck Research School for Neurosciences, Göttingen
    • International Max Planck Research School for Cognitive and Systems Neuroscience, Tübingen
    • International Max Planck Research School for Marine Microbiology (MarMic), joint program of the Max Planck Institute for Marine Microbiology in Bremen, the University of Bremen, the Alfred Wegener Institute for Polar and Marine Research in Bremerhaven, and the Jacobs University Bremen
    • International Max Planck Research School for Maritime Affairs, Hamburg
    • International Max Planck Research School for Molecular and Cellular Biology, Freiburg
    • International Max Planck Research School for Molecular and Cellular Life Sciences, Munich
    • International Max Planck Research School for Molecular Biology, Göttingen
    • International Max Planck Research School for Molecular Cell Biology and Bioengineering, Dresden
    • International Max Planck Research School Molecular Biomedicine, program combined with the ‘Graduate Programm Cell Dynamics And Disease’ at the University of Münster and the Max Planck Institute for Molecular Biomedicine
    • International Max Planck Research School on Multiscale Bio-Systems, Potsdam
    • International Max Planck Research School for Organismal Biology, at the University of Konstanz and the Max Planck Institute for Ornithology
    • International Max Planck Research School on Reactive Structure Analysis for Chemical Reactions (IMPRS RECHARGE), Mülheim an der Ruhr, at the Max Planck Institute for Chemical Energy Conversion
    • International Max Planck Research School for Science and Technology of Nano-Systems, Halle at Max Planck Institute of Microstructure Physics
    • International Max Planck Research School for Solar System Science at the University of Göttingen hosted by MPI for Solar System Research
    • International Max Planck Research School for Astronomy and Astrophysics, Bonn, at the MPI for Radio Astronomy (formerly the International Max Planck Research School for Radio and Infrared Astronomy)
    • International Max Planck Research School for the Social and Political Constitution of the Economy, Cologne
    • International Max Planck Research School for Surface and Interface Engineering in Advanced Materials, Düsseldorf at Max Planck Institute for Iron Research GmbH
    • International Max Planck Research School for Ultrafast Imaging and Structural Dynamics, Hamburg

    Max Planck Schools

    • Max Planck School of Cognition
    • Max Planck School Matter to Life
    • Max Planck School of Photonics

    Max Planck Center

    • The Max Planck Centre for Attosecond Science (MPC-AS), POSTECH Pohang
    • The Max Planck POSTECH Center for Complex Phase Materials, POSTECH Pohang

    Max Planck Institutes

    Among others:
    • Max Planck Institute for Neurobiology of Behavior – caesar, Bonn
    • Max Planck Institute for Aeronomics in Katlenburg-Lindau was renamed to Max Planck Institute for Solar System Research in 2004;
    • Max Planck Institute for Biology in Tübingen was closed in 2005;
    • Max Planck Institute for Cell Biology in Ladenburg b. Heidelberg was closed in 2003;
    • Max Planck Institute for Economics in Jena was renamed to the Max Planck Institute for the Science of Human History in 2014;
    • Max Planck Institute for Ionospheric Research in Katlenburg-Lindau was renamed to Max Planck Institute for Aeronomics in 1958;
    • Max Planck Institute for Metals Research, Stuttgart
    • Max Planck Institute of Oceanic Biology in Wilhelmshaven was renamed to Max Planck Institute of Cell Biology in 1968 and moved to Ladenburg 1977;
    • Max Planck Institute for Psychological Research in Munich merged into the Max Planck Institute for Human Cognitive and Brain Sciences in 2004;
    • Max Planck Institute for Protein and Leather Research in Regensburg moved to Munich 1957 and was united with the Max Planck Institute for Biochemistry in 1977;
    • Max Planck Institute for Virus Research in Tübingen was renamed as Max Planck Institute for Developmental Biology in 1985;
    • Max Planck Institute for the Study of the Scientific-Technical World in Starnberg (from 1970 until 1981 (closed)) directed by Carl Friedrich von Weizsäcker and Jürgen Habermas.
    • Max Planck Institute for Behavioral Physiology
    • Max Planck Institute of Experimental Endocrinology
    • Max Planck Institute for Foreign and International Social Law
    • Max Planck Institute for Physics and Astrophysics
    • Max Planck Research Unit for Enzymology of Protein Folding
    • Max Planck Institute for Biology of Ageing

     
  • richardmitnick 12:55 pm on June 28, 2022 Permalink | Reply
    Tags: "Unraveling a meteorite mystery reveals Solar System origin story", Astronomy, , , ,   

    From The Carnegie Institution for Science: “Unraveling a meteorite mystery reveals Solar System origin story” 

    Carnegie Institution for Science

    From The Carnegie Institution for Science

    June 28, 2022

    The violent event that likely preceded our Solar System’s formation holds the solution to a longstanding meteorite mystery, says new work from Carnegie’s Alan Boss published in The Astrophysical Journal [no link found, no access to scientists].

    The raw material from which our Solar System was constructed was dispersed when the shock wave from an exploding supernova injected material into a cloud of dust and gas, causing it to collapse in on itself. In the aftermath of this event, most of the injected matter was gravitationally drawn into the center of the whirlwind, where the intense buildup of pressure enabled nuclear fusion to commence, and the Sun was born. The young star was surrounded by a rotating disk of the remaining gas and dust, from which the planets and other Solar System bodies—some of which eventually broke up to form asteroids and meteorites—coalesced.

    “The mystery arises from studying the isotopic composition of meteorites, which can be used as a laboratory to test theories of Solar System formation and evolution,” Boss explains.

    Isotopes are versions of elements with the same number of protons, but a different number of neutrons. Sometimes, as is the case with radioactive isotopes, the number of neutrons present in the nucleus can make the isotope unstable. To gain stability, the isotope releases energetic particles, which alters its number of protons and neutrons, transmuting it into another element, called a daughter isotope.

    Added Boss: “Because we know exactly how long this process takes for different radioactive isotopes, measuring the amount of daughter products in meteorites can tell us when, and possibly how, they formed.”

    For example, the iron isotope with an atomic weight of 60 is only produced in significant amounts by a supernova explosion and it takes 2.6 million years for half of the atoms to decay—its so-called “half-life”—to its daughter isotope, cobalt-60. So, when significant quantities of cobalt-60 are found in primitive meteorites called carbonaceous chondrites, this tells researchers that the raw material from which the chondrite was constructed contained the remnants of a supernova explosion that occurred just a couple million years prior to its formation.

    The chondrite record can be used to confirm the supernova origin story for our Solar System. But other, less-primitive, non-carbonaceous meteorites lack this iron-60 composition, which means that the material from which they formed did not originate in a stellar explosion. So, where did it come from?

    “No physical explanation has been offered for this dramatic change.” Boss said.

    He has been honing sophisticated models of our Solar System’s formation for several decades and was one of the originators of the supernova injection origin story. By extending the time period reflected in his simulations, he was able to show that after triggering the collapse that supplied the chondrites with iron-60, the supernova’s shock front sweeps away the interstellar dust beyond the resulting disk and accelerates the resulting protostar to a speed of several kilometers per second. This is sufficient to drive the young Sun to encounter a new patch of interstellar material that is depleted in iron-60 and other supernova-generated isotopes within a million years.

    “After having worked on the problem of supernova triggering and injection since the mid-90s, it was amazing to finally be able to link this model to the meteoric evidence,” Boss concluded. “It wraps this tale up with a neat bow.”

    1
    The left panel shows a cross section through the dense cloud core (orange) that is about to be struck by a supernova shock wave (dark green) moving downward at 40 km/sec. The ambient molecular cloud gas and dust (yellow and light green) surrounding the cloud core on the left is swept away by the shock front, as shown on the right after 63,000 years, when the cloud core has been crushed by the shock front into forming the proto-Sun and protoplanetary disk on a much smaller scale than can be depicted here. The box is about 1/3 of a parsec in length. Courtesy: Alan Boss.

    See the full article here .


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    Carnegie Institution of Washington Bldg

    The Carnegie Institution for Science

    Andrew Carnegie established a unique organization dedicated to scientific discovery “to encourage in the broadest and most liberal manner investigation; research; and discovery and the application of knowledge to the improvement of mankind…” The philosophy was and is to devote the institution’s resources to “exceptional” individuals so that they can explore the most intriguing scientific questions in an atmosphere of complete freedom. Carnegie and his trustees realized that flexibility and freedom were essential to the institution’s success and that tradition is the foundation of the institution today as it supports research in the Earth, space, and life sciences.

    The The Carnegie Institution of Washington (the organization’s legal name), known also for public purposes as the Carnegie Institution for Science, is an organization in the United States established to fund and perform scientific research. The institution is headquartered in Washington, D.C. As of June 30, 2020, the Institution’s endowment was valued at $926.9 million. In 2018 the expenses for scientific programs and administration were $96.6 million.

    History

    When the United States joined World War II Vannevar Bush was president of the Carnegie Institution. Several months before on June 12, 1940 Bush had been instrumental in persuading President Franklin Roosevelt to create the National Defense Research Committee (later superseded by the Office of Scientific Research and Development) to mobilize and coordinate the nation’s scientific war effort. Bush housed the new agency in the Carnegie Institution’s administrative headquarters at 16th and P Streets, NW, in Washington, DC, converting its rotunda and auditorium into office cubicles. From this location Bush supervised, among many other projects the Manhattan Project. Carnegie scientists cooperated with the development of the proximity fuze and mass production of penicillin.

    Research

    Carnegie scientists continue to be involved with scientific discovery. Composed of six scientific departments on the East and West Coasts the Carnegie Institution for Science is involved presently with six main topics: Astronomy at the Department of Terrestrial Magnetism (Washington, D.C.) and the Observatories of the Carnegie Institution of Washington (Pasadena, CA and Las Campanas, Chile); Earth and planetary science also at the Department of Terrestrial Magnetism and the Geophysical Laboratory (Washington, D.C.); Global Ecology at the Department of Global Ecology (Stanford, CA); Genetics and developmental biology at the Department of Embryology (Baltimore, MD); Matter at extreme states also at the Geophysical Laboratory; and Plant science at the Department of Plant Biology (Stanford, CA).

    Mt Wilson Hooker 100 inch Telescope, Mount Wilson, California, Altitude 1,742 m (5,715 ft). Credit: Huntington Library in San Marino, California. Credit: Huntington Library in San Marino, California

    Carnegie 6.5 meter Magellan Baade and Clay Telescopes located at Carnegie’s Las Campanas Observatory, Chile. over 2,500 m (8,200 ft) high.

    Carnegie Las Campanas 2.5 meter Irénée Dupont telescope, Atacama Desert, over 2,500 m (8,200 ft) high approximately 100 kilometres (62 mi) northeast of the city of La Serena,Chile.[/caption]


    Carnegie Institution 1-meter Swope telescope at Las Campanas, Chile, 100 kilometres (62 mi) northeast of the city of La Serena, near the north end of a 7 km (4.3 mi) long mountain ridge, Cerro Las Campanas, near the southern end and over 2,500 m (8,200 ft) high, at Las Campanas, Chile.

     
  • richardmitnick 7:39 pm on June 27, 2022 Permalink | Reply
    Tags: "Exoplanet mission given £30m boost", Astronomy, , , , ,   

    From Cardiff University [Prifysgol Caerdydd] (WLS) : “Exoplanet mission given £30m boost” 

    From Cardiff University [Prifysgol Caerdydd] (WLS)

    27 June 2022

    1
    Artist’s impression of exoplanet in front of star. Credit: ESA/ATG medialab, CC BY-SA 3.0 IGO

    The UK Government has announced an investment of £30m in the Ariel space mission to explore the atmospheres of exoplanets.

    Due to launch in 2029, Ariel’s mission is to understand the links between a planet’s chemical composition, its formation and evolution, and its host star, by characterising the atmospheres of 1,000 known planets outside our solar system.

    Ariel, the Atmospheric Remote-sensing Infrared Exoplanet Large-survey, will provide a step-change in our understanding of what exoplanets are made of, how they were formed and how they evolve.

    Scientific data will be released to the scientific community and general public at regular intervals throughout its planned four-year operational phase.

    Ariel is being developed by a 17-country international team led by Professor Giovanna Tinetti of University College London, with other UK organisations including Cardiff University, the University of Oxford and the Science and Technology Facilities Council’s (STFC) RAL Space at the Harwell Space Cluster in Oxfordshire.

    Scientists within the School of Physics and Astronomy are participating in the mission performance analysis and in defining, testing and fine-tuning the complex algorithms that will process the data returned from Ariel.

    UK Science Minister George Freeman said: “This is an incredibly important commitment for UK space science and technology, marking a major milestone for the National Space Strategy and boosting our ambitions to grow our £16.5 billion commercial space sector.

    “By investing £30m and taking the helm of the entire Ariel consortium – the first time in a decade that we have secured leadership for a mission of this magnitude – we are putting the UK at the heart of international space research, providing new opportunities for space businesses and academics across the country.”

    Professor Matt Griffin, Head of the Cardiff Astronomy Instrumentation Group and UK Co-PI in the Ariel Consortium said: “With Ariel we are entering an exciting new era in our investigation of extrasolar planets, in which we’ll find out much more about their atmospheres and how they form and develop.

    “As a highly advanced and ambitious space mission it needs stable long-term investment and it’s great news that the UK Government and the UK Space Agency have made that commitment.”

    See the full article here .


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    Stem Education Coalition

    Cardiff Unversity [Prifysgol Caerdydd] (WLS) is a public research university in Cardiff, Wales. Founded in 1883 as the University College of South Wales and Monmouthshire (University College Cardiff from 1972), it became a founding college of the University of Wales in 1893. It merged with the University of Wales Institute of Science and Technology (UWIST) in 1988 to form the University of Wales College, Cardiff (University of Wales, Cardiff from 1996). In 1997 it received its own degree-awarding powers, but held them in abeyance. The college adopted the public name Cardiff University in 1999; in 2005 this became its legal name, when it became an independent university and began awarding its own degrees.

    Cardiff University is the third oldest university in Wales and contains three colleges: Arts, Humanities and Social Sciences; Biomedical and Life Sciences; and Physical Sciences and Engineering. It is the only Welsh member of the Russell Group of research-intensive British universities. In 2018–2019, Cardiff had a turnover of £537.1 million, including £116.0 million in research grants and contracts. It has an undergraduate enrolment of 23,960 and a total enrolment of 33,190 (according to HESA data for 2018/19) making it one of the ten largest UK universities. The Cardiff University Students’ Union works to promote student interests in the university and further afield.

    Discussions on the founding of a university college in South Wales began in 1879, when a group of Welsh and English MPs urged the government to consider the poor provision of higher and intermediate education in Wales and “the best means of assisting any local effort which may be made for supplying such deficiency.”

    In October 1881, William Gladstone’s government appointed a departmental committee to conduct “an enquiry into the nature and extent of intermediate and higher education in Wales”, chaired by Lord Aberdare and consisting of Viscount Emlyn, Reverend Prebendary H. G. Robinson, Henry Richard, John Rhys and Lewis Morris. The Aberdare Report, as it came to be known, took evidence from a wide range of sources and over 250 witnesses and recommended a college each for North Wales and South Wales, the latter to be located in Glamorgan and the former to be the established University College of Wales in Aberystwyth (now Aberystwyth University). The committee cited the unique Welsh national identity and noted that many students in Wales could not afford to travel to University in England or Scotland. It advocated a national degree-awarding university for Wales, composed of regional colleges, which should be non-sectarian in nature and exclude the teaching of theology.

    After the recommendation was published, Cardiff Corporation sought to secure the location of the college in Cardiff, and on 12 December 1881 formed a University College Committee to aid the matter. There was competition to be the site between Swansea and Cardiff. On 12 March 1883, after arbitration, a decision was made in Cardiff’s favour. This was strengthened by the need to consider the interests of Monmouthshire, at that time not legally incorporated into Wales, and the greater sum received by Cardiff in support of the college, through a public appeal that raised £37,000 and a number of private donations, notably from the Lord Bute and Lord Windsor. In April Lord Aberdare was appointed as the College’s first president. The possible locations considered included Cardiff Arms Park, Cathedral Road, and Moria Terrace, Roath, before the site of the Old Royal Infirmary buildings on Newport Road was chosen.

    The University College of South Wales and Monmouthshire opened on 24 October 1883 with courses in Biology, Chemistry, English, French, German, Greek, History, Latin, Mathematics and Astronomy, Music, Welsh, Logic and Philosophy, and Physics. It was incorporated by Royal Charter the following year, this being the first in Wales to allow the enrollment of women, and specifically forbidding religious tests for entry. John Viriamu Jones was appointed as the University’s first Principal at the age of 27. As Cardiff was not an independent university and could not award its own degrees, it prepared its students for examinations of the University of London or for further study at Oxford or Cambridge.

    In 1888 the University College at Cardiff and that of North Wales (now Bangor University) proposed to the University College Wales at Aberystwyth joint action to gain a university charter for Wales, modelled on that of Victoria University, a confederation of new universities in Northern England. Such a charter was granted to the new University of Wales in 1893, allowing the colleges to award degrees as members. The Chancellor was set ex officio as the Prince of Wales, and the position of operational head would rotate among heads of the colleges.

    In 1885, Aberdare Hall opened as the first hall of residence, allowing women access to the university. This moved to its current site in 1895, but remains a single-sex hall. In 1904 came the appointment of the first female associate professor in the UK, Millicent Mackenzie, who in 1910 became the first female full professor at a fully chartered UK university.

    In 1901 Principal Jones persuaded Cardiff Corporation to give the college a five-acre site in Cathays Park (instead of selling it as they would have done otherwise). Soon after, in 1905, work on a new building commenced under the architect W. D. Caröe. Money ran short for the project, however. Although the side-wings were completed in the 1960s, the planned Great Hall has never been built. Caroe sought to combine the charm and elegance of his former (Trinity College, Cambridge) with the picturesque balance of many Oxford colleges. On 14 October 1909 the “New College” building in Cathays Park (now Main Building) was opened in a ceremony involving a procession from the “Old College” in Newport Road.

    In 1931, the School of Medicine, founded as part of the college in 1893 along with the Departments of Anatomy, Physiology, Pathology, Pharmacology, was split off to form the Welsh National School of Medicine, which was renamed in 1984 the University of Wales College of Medicine.

    In 1972, the institution was renamed University College Cardiff.

     
  • richardmitnick 4:37 pm on June 27, 2022 Permalink | Reply
    Tags: "(almost) No Time (for stars) to Die", , Astronomy, , ,   

    From astrobites : “(almost) No Time (for stars) to Die” 

    Astrobites bloc

    From astrobites

    Jun 27, 2022
    Sahil Hegde

    Title: Constraints on the Explosion Timescale of Core-Collapse Supernovae Based on Systematic Analysis of Light Curves

    Authors: Sei Saito, Masaomi Tanaka, Ryo Sawada, Takashi J. Moriya

    First Author’s Institution: Astronomical Institute, Tohoku University, Sendai 980-8578, Japan

    Status: Accepted to ApJ [open access]

    Despite their being some of the most luminous and notable astronomical phenomena – with the first recorded observations dating back thousands of years (e.g. SN 185) – describing successful supernova (SN) explosions is still an open question in astronomy. Broadly, supernovae (SNe) can be classified into Types I and II based on the presence of hydrogen in their spectra. The prevailing explosion mechanism across these two classes (except for Type Ia SNe) is believed to be a process known as core collapse. For stars with masses greater than 6-8 times the mass of the Sun, eventually the stellar core evolves to a point at which nuclear fusion is unable to provide sufficient pressure support to balance the star’s gravitational contraction. At this point, the stellar core collapses until it reaches huge densities – material the mass of the Sun is squished into a region the size of a city – and the contraction is stopped. The outer layers of the star and the core rebound off of the newfound pressure support in the neutron star core and drive an outward propagating shock wave. As this shock passes through the layers of the parent star, disintegrating heavy elements like iron, it loses energy, and astronomers struggle to definitively explain how to maintain a sufficiently energetic shock that is able to propagate to the surface of the star. In other words, in many early models, the shock stalls and fails to reach the stellar surface!

    There are a variety of theories that have been proposed to explain this issue, the most popular of these being that absorption of neutrinos behind the shock wave is able to rejuvenate the failing shock. However, because we cannot directly observe the shock propagating through the star, we must instead rely on proxies, such as the light curve produced by the SN, to distinguish between various models. SN light curves, such as those shown in Figure 1, show a sharp brightening and dimming around a characteristic peak luminosity across the spectrum (though the specific features of the curve depend on the SN type).

    1
    Figure 1: The observed light curve (colored points) in various bands (different colors) with interpolation fit overlaid (colored curves) for an example SN, SN 2004ex. (Adapted from Figure 2 in the paper.)

    For SNe with minimal hydrogen envelopes – a group known as Stripped Envelope SNe (SESNe) – it is believed that the peak brightness (which is the energy released by the star) is directly connected to the energy released in the radioactive decay of Nickel-56 to Iron-56, so the mass of Nickel-56 in the explosion is crucially related to the observed light curve. Therefore, any good model to describe how to manufacture successful SN explosions needs to also be able to produce the requisite amount of Nickel-56 to explain our observations.

    It also turns out that the amount of nickel that is generated in the explosion is inversely related to the explosion timescale and various theoretical models for the explosion produce a variety of predictions for this explosion timescale and thus the nickel mass. Today’s authors seek to contextualize this range of theoretical predictions by placing a bound on the explosion timescale directly from observations of SNe.

    Crunching the Numbers

    To compile observational data, the authors of today’s paper use photometric data of SNe from the Open Supernova Catalog, which contains over 800 SESNe with data in several filters. Of these, roughly 400 had enough observations in every filter that interpolated light curves, such as the example given in Figure 1, could be constructed. Because the Open Supernova Catalog also provides the luminosity distance (the relationship between the absolute and apparent magnitude) of these sources, the authors are able to fit a blackbody spectrum to the estimated spectral energy distribution across the various photometric bands. This allows them to sum up the flux over the observed wavelength range, ultimately yielding the bolometric (wavelength-summed) light curves for these SNe, that they will later use in conjunction with analytic models to estimate various properties of the explosion. From this, they measure the peak bolometric magnitude, Mpeak, and a characteristic decline timescale that describes the time it takes the luminosity to drop by 0.5 mag from Mpeak. Ultimately, this process, combined with their data cleaning steps, yields 82 bolometric light curves, depicted in Figure 2.

    2
    Figure 2: The final 82 bolometric light curves generated by the authors’ processing pipeline. Different colors correspond to different types of SNe. (Adapted from Figure 5 in the paper.)

    How Do We Use These Measurements?

    As we discussed earlier, the key measurement to be made, the nickel mass, is directly connected to the observed light curves and thus to Mpeak. The amount of nickel that can be produced in the supernova explosion also depends on the amount of material available from the start – namely, the properties of the parent star. Therefore, the authors also compute how much material is ejected in the explosion, which can be estimated from the decline timescale measured from the light curve. The decline timescale is set by the velocity of the ejected material, its composition, and its mass, so they can make some reasonable assumptions about the velocity and the composition to estimate the ejecta mass.

    To connect these observations to an estimate of the explosion timescale, the authors run a series of hydrodynamical and nucleosynthesis calculations to generate predictions of the nickel mass and ejecta mass for various explosion timescales. In particular, they model the explosion with a one-dimensional hydrodynamical simulation and use the nucleosynthesis code to track the formation of nickel. These simulations can be described by the mass of ejected material and the explosion timescale, so they compute the nickel mass produced for various reasonable values of the explosion timescale and ejecta masses that span the observed range.

    3
    Figure 3: Upper bound on modeled relationship between nickel mass MNi and ejecta mass Mej for various explosion timescales (blue curves). Gray points represent observational estimates for this relationship for two types of SNe. A dashed line representing MNi = 0.2 Mej is shown for reference. (Adapted from Figure 10 in the paper.)

    So How Much Time is This Really?

    In Figure 3, the authors show the results of the modeled relation between nickel mass and ejecta mass for various explosion timescales (blue curves). Due to the uncertainties in the models, these are upper limits so the models account for the observations (gray points) that fall below the lines. From this, the authors argue that the curves corresponding to 0.1-0.3 second explosion timescales account for a majority of the observed nickel masses, whereas the 1 second timescale bound allows for <50% of the data. This comparison places constraints on future models of core collapse SNe, dictating that observed nickel masses require very rapid timescales for these explosions to occur. Evidently, like Mr. Bond, these massive stars have (almost) no time to die.

    See the full article here .


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    What do we do?

    Astrobites is a daily astrophysical literature journal written by graduate students in astronomy. Our goal is to present one interesting paper per day in a brief format that is accessible to undergraduate students in the physical sciences who are interested in active research.
    Why read Astrobites?

    Reading a technical paper from an unfamiliar subfield is intimidating. It may not be obvious how the techniques used by the researchers really work or what role the new research plays in answering the bigger questions motivating that field, not to mention the obscure jargon! For most people, it takes years for scientific papers to become meaningful.

    Our goal is to solve this problem, one paper at a time. In 5 minutes a day reading Astrobites, you should not only learn about one interesting piece of current work, but also get a peek at the broader picture of research in a new area of astronomy.

     
  • richardmitnick 3:52 pm on June 27, 2022 Permalink | Reply
    Tags: "X-Ray Fireworks Linked to Fast Radio Bursts", , Astronomy, , , , , , Research has suggested that these bursts might come from magnetars-a type of neutron star with a magnetic field about a thousand trillion times stronger than Earth’s.   

    From “Physics” : “X-Ray Fireworks Linked to Fast Radio Bursts” 

    About Physics

    From “Physics”

    June 24, 2022
    Sophia Chen

    Predictions indicate that when a neutron star radiates a burst of radio waves, interactions of the burst with the star’s magnetic field should produce observable x rays.

    1
    dracozlat/stock.adobe.com

    For more than a decade, astronomers have been puzzling over observations of milliseconds-long radio signals called fast radio bursts. In recent years research has suggested that these bursts might come from magnetars-a type of neutron star with a magnetic field about a thousand trillion times stronger than Earth’s. However, the mechanism by which magnetars produce fast radio bursts remains unclear. Now, Andrei Beloborodov of Columbia University has theoretically investigated the interaction between a radio burst’s strong electromagnetic waves and the magnetized particles around a magnetar [1]. He found that the radio waves scatter off the particles more strongly than previously thought, which could inform models looking to constrain the origin and location of fast radio bursts.

    In the region of space immediately surrounding a magnetar, a fast radio burst can be modeled as an electromagnetic wave immersed in a magnetic field. When the strength of the magnetic field is much larger than the amplitude of the radio wave—as is the case close to a magnetar’s surface—the wave is predicted to be minimally scattered by the plasma. But this condition no longer applies once the radio burst propagates some distance from the magnetar. Instead, the amplitude of the wave becomes much larger than the magnetic field.

    In that regime, Beloborodov found that the electromagnetic wave undergoes strong scattering. This scattering can inhibit the radio burst’s escape, as it causes the wave to drastically lose energy. Wave scattering also generates large quantities of electron-positron pairs that then get accelerated by the electromagnetic waves. This process causes the pairs to emit x-ray “fireworks.” Astronomers could potentially observe these fireworks to constrain models of fast radio bursts.

    [1] Phys. Rev. Lett. 128, 255003 (2022).

    See the full article here .

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    Please help promote STEM in your local schools.

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    Physicists are drowning in a flood of research papers in their own fields and coping with an even larger deluge in other areas of physics. How can an active researcher stay informed about the most important developments in physics? Physics highlights a selection of papers from the Physical Review journals. In consultation with expert scientists, the editors choose these papers for their importance and/or intrinsic interest. To highlight these papers, Physics features three kinds of articles: Viewpoints are commentaries written by active researchers, who are asked to explain the results to physicists in other subfields. Focus stories are written by professional science writers in a journalistic style and are intended to be accessible to students and non-experts. Synopses are brief editor-written summaries. Physics provides a much-needed guide to the best in physics, and we welcome your comments.

     
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