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  • richardmitnick 10:29 pm on June 29, 2022 Permalink | Reply
    Tags: , , , , , Cosmic Rays, , "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.

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    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 8:12 pm on May 26, 2022 Permalink | Reply
    Tags: "Researchers hunt for one-pole magnets by combining cosmic rays and particle accelerators", , , , By re-analyzing data from a wide range of experimental monopole searches the researchers identified novel limits on monopoles across a wide range of masses., Cosmic Rays, , Paul Dirac theorized the existence of one-pole “magnetic monopoles" – particles comparable to electrons but with a magnetic charge., , The interdisciplinary research required bringing together expertise from several distinct corners of science - including accelerator physics; neutrino interactions and cosmic rays., , These results and source of monopoles studied by the researchers will serve as a useful benchmark for interpreting subsequent future monopole searches at terrestrial laboratories.   

    From The Kavli Institute for the Physics and Mathematics of the Universe (IPMU) [カブリ数物連携宇宙研](JP) at The University of Tokyo [東京大学](JP): “Researchers hunt for one-pole magnets by combining cosmic rays and particle accelerators” 

    KavliFoundation

    From The Kavli Institute for the Physics and Mathematics of the Universe (IPMU) [カブリ数物連携宇宙研](JP) at The University of Tokyo [東京大学](JP)

    Kavli IPMU

    May 26, 2022

    Research contact
    Volodymyr Takhistov
    Project Researcher / Kavli IPMU Fellow
    Kavli Institute for the Physics and Mathematics of the Universe (Kavli IPMU), The University of Tokyo
    E-mail:volodymyr.takhistov@ipmu.jp

    Media contact
    Motoko Kakubayashi
    Press officer
    Kavli Institute for the Physics and Mathematics of the Universe (Kavli IPMU), The University of Tokyo
    E-mail:press@ipmu.jp

    Some of the world’s most powerful particle accelerators have helped researchers draw new leading limits on the existence of long theorized magnetic monopoles from the collisions of energetic cosmic rays bombarding the Earth’s atmosphere, reports a new study published in Physical Review Letters.

    1
    Figure 1. Schematic illustration of magnetic compass and hypothetical magnetic monopole (Credit: Kavli IPMU)

    Magnets are intimately familiar to everyone, with wide-ranging applications within daily life, from TVs and computers to kids toys. However, breaking any magnet, such as a navigation compass needle consisting of north and south poles in half, will result in just two smaller two-pole magnets. This mystery has eluded researchers for decades since 1931, when physicist Paul Dirac theorized the existence of one-pole “magnetic monopoles” – particles comparable to electrons but with a magnetic charge.

    To explore whether magnetic monopoles exist, an international team of researchers, including the University of Tokyo’s Kavli Institute for the Physics and Mathematics of the Universe (Kavli IPMU) Fellow Volodymyr Takhistov, studied available data from a variety of terrestrial experiments and have carried out the most sensitive searches to date for monopoles over a broad range of possible masses. The researchers focused on an unusual source of monopoles – atmospheric collisions of cosmic rays that have been occurring for eons.

    The interdisciplinary research required bringing together expertise from several distinct corners of science – including accelerator physics, neutrino interactions and cosmic rays.

    Cosmic ray collisions with the atmosphere have already played a central role in advancing science, especially the exploration of ghostly neutrinos. This lead to Kavli IPMU Senior Fellow Takaaki Kajita’s 2015 Nobel Prize in Physics for the discovery by the Super-Kamiokande experiment that neutrinos oscillate in flight, implying that they have mass.

    Partially inspired by the results of Super-Kamiokande, the team set to work on monopoles. Particularly intriguing were light monopoles with masses around the electroweak scale, which can be readily accessible to conventional particle accelerators.

    By carrying out simulations of cosmic ray collisions, analogously to particle collisions at the LHC at CERN, the researchers obtained a persistent beam of light monopoles raining down upon different terrestrial experiments.

    2
    Figure 2. A schematic illustration of magnetic monopole (M) production from collisions of cosmic rays with the Earth’s atmosphere. (Credit: Volodymyr Takhistov)

    This unique source of monopoles is especially interesting, as it is independent of any pre-existing monopoles such as those potentially left over as relics from the early Universe, and covers a broad range of energies.

    By re-analyzing data from a wide range of previous experimental monopole searches, the researchers identified novel limits on monopoles across a wide range of masses, including those beyond the reach of conventional collider monopole searches.

    These results and source of monopoles studied by the researchers will serve as a useful benchmark for interpreting subsequent future monopole searches at terrestrial laboratories.

    Details of their study were published in Physical Review Letters on 17 May, 2022.

    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 Kavli Institute for the Physics and Mathematics of the Universe (IPMU) [カブリ数物連携宇宙研](JP) at The University of Tokyo [東京大学](JP) is an international research institute with English as its official language. The goal of the institute is to discover the fundamental laws of nature and to understand the Universe from the synergistic perspectives of mathematics, astronomy, and theoretical and experimental physics. The Institute for the Physics and Mathematics of the Universe (IPMU) was established in October 2007 under the World Premier International Research Center Initiative (WPI) of the Ministry of Education, Sports, Science and Technology in Japan with the University of Tokyo as the host institution. IPMU was designated as the first research institute within the University of Tokyo Institutes for Advanced Study (UTIAS) in January 2011. It received an endowment from The Kavli Foundation and was renamed the “Kavli Institute for the Physics and Mathematics of the Universe” in April 2012. Kavli IPMU is located on the Kashiwa campus of the University of Tokyo, and more than half of its full-time scientific members come from outside Japan.

    The Kavli Foundation, based in Oxnard, California, is dedicated to the goals of advancing science for the benefit of humanity and promoting increased public understanding and support for scientists and their work.

    The Foundation’s mission is implemented through an international program of research institutes, professorships, and symposia in the fields of astrophysics, nanoscience, neuroscience, and theoretical physics as well as prizes in the fields of astrophysics, nanoscience, and neuroscience.

     
  • richardmitnick 11:26 am on December 6, 2021 Permalink | Reply
    Tags: , Astrophysicists believe the heliosphere protects the planets within our solar system from powerful radiation emanating from supernovas-the final explosions of dying stars throughout the universe., , , , Cosmic Rays, , SHIELD combines theory; modeling; and observations to build comprehensive models.   

    From Boston University (US) : “Another Breakthrough for Team Studying Our Solar System’s Protective Bubble” 

    From Boston University (US)

    December 3, 2021
    Kat J. McAlpine

    Astrophysicists on BU’s NASA-funded SHIELD team reach another milestone on their quest to understand the heliosphere.

    1
    New research led by BU astrophysicist Merav Opher could explain why the heliosphere, a protective magnetic “force field” emanating from our sun and encompassing our solar system, is likely unstable and irregularly shaped. “The universe is not quiet,” Opher says. “Our BU model doesn’t try to cut out the chaos.” Image courtesy of Merav Opher, et. al.

    A multi-institutional team of astrophysicists headquartered at Boston University, led by BU astrophysicist Merav Opher, has made a breakthrough discovery in our understanding of the cosmic forces that shape the protective bubble surrounding our solar system—a bubble that shelters life on Earth and is known by space researchers as the heliosphere.

    Astrophysicists believe the heliosphere protects the planets within our solar system from powerful radiation emanating from supernovas-the final explosions of dying stars throughout the universe.

    They believe the heliosphere extends far beyond our solar system, but despite the massive buffer against cosmic radiation that the heliosphere provides Earth’s life-forms, no one really knows the shape of the heliosphere—or, for that matter, the size of it.

    “How is this relevant for society? The bubble that surrounds us, produced by the sun, offers protection from galactic cosmic rays, and the shape of it can affect how those rays get into the heliosphere,” says James Drake, an astrophysicist at The University of Maryland (US) who collaborates with Opher. “There’s lots of theories, but of course, the way that galactic cosmic rays can get in can be impacted by the structure of the heliosphere—does it have wrinkles and folds and that sort of thing?”

    Cosmic rays produced by high-energy astrophysics sources ASPERA collaboration AStroParticle ERAnet.

    Opher’s team has constructed some of the most compelling computer simulations of the heliosphere, based on models built on observable data and theoretical astrophysics. At BU, in the Center for Space Physics, Opher, a College of Arts & Sciences professor of astronomy, leads a NASA DRIVE (Diversity, Realize, Integrate, Venture, Educate) Science Center that’s supported by $1.3 million in NASA funding. That team, made up of experts Opher recruited from 11 other universities and research institutes, develops predictive models of the heliosphere in an effort the team calls SHIELD (Solar-wind with Hydrogen Ion Exchange and Large-scale Dynamics).

    Since BU’S NASA DRIVE Science Center first received funding in 2019, Opher’s SHIELD team has hunted for answers to several puzzling questions: What is the overall structure of the heliosphere? How do its ionized particles evolve and affect heliospheric processes? How does the heliosphere interact and influence the interstellar medium, the matter and radiation that exists between stars? And how do cosmic rays get filtered by, or transported through, the heliosphere?

    “SHIELD combines theory; modeling; and observations to build comprehensive models,” Opher says. “All these different components work together to help understand the puzzles of the heliosphere.”

    And now a paper published by Opher and collaborators in The Astrophysical Journal reveals that neutral hydrogen particles streaming from outside our solar system most likely play a crucial role in the way our heliosphere takes shape.

    In their latest study, Opher’s team wanted to understand why heliospheric jets—blooming columns of energy and matter that are similar to other types of cosmic jets found throughout the universe—become unstable. “Why do stars and black holes—and our own sun—eject unstable jets?” Opher says. “We see these jets projecting as irregular columns, and [astrophysicists] have been wondering for years why these shapes present instabilities.”

    2
    Is this what the heliosphere looks like? BU-led research suggests so. The size and shape of the magnetic “force field” that protects our solar system from deadly cosmic rays has long been debated by astrophysicists. Image courtesy of Merav Opher, et. al.

    Similarly, SHIELD models predict that the heliosphere, traveling in tandem with our sun and encompassing our solar system, doesn’t appear to be stable. Other models of the heliosphere developed by other astrophysicists tend to depict the heliosphere as having a comet-like shape, with a jet—or a “tail”—streaming behind in its wake. In contrast, Opher’s model suggests the heliosphere is shaped more like a croissant or even a donut.

    The reason for that? Neutral hydrogen particles, so-called because they have equal amounts of positive and negative charge that net no charge at all.

    “They come streaming through the solar system,” Opher says. Using a computational model like a recipe to test the effect of ‘neutrals’ on the shape of the heliosphere, she “took one ingredient out of the cake—the neutrals—and noticed that the jets coming from the sun, shaping the heliosphere, become super stable. When I put them back in, things start bending, the center axis starts wiggling, and that means that something inside the heliospheric jets is becoming very unstable.”

    Instability like that would theoretically cause disturbance in the solar winds and jets emanating from our sun, causing the heliosphere to split its shape—into a croissant-like form. Although astrophysicists haven’t yet developed ways to observe the actual shape of the heliosphere, Opher’s model suggests the presence of neutrals slamming into our solar system would make it impossible for the heliosphere to flow uniformly like a shooting comet. And one thing is for sure—neutrals are definitely pelting their way through space.

    Drake, a coauthor on the new study, says Opher’s model “offers the first clear explanation for why the shape of the heliosphere breaks up in the northern and southern areas, which could impact our understanding of how galactic cosmic rays come into Earth and the near-Earth environment.” That could affect the threat that radiation poses to life on Earth and also for astronauts in space or future pioneers attempting to travel to Mars or other planets.

    “The universe is not quiet,” Opher says. “Our BU model doesn’t try to cut out the chaos, which has allowed me to pinpoint the cause [of the heliosphere’s instability]…. The neutral hydrogen particles.”

    Specifically, the presence of the neutrals colliding with the heliosphere triggers a phenomenon well known by physicists, called the Rayleigh-Taylor instability, which occurs when two materials of different densities collide, with the lighter material pushing against the heavier material. It’s what happens when oil is suspended above water, and when heavier fluids or materials are suspended above lighter fluids. Gravity plays a role and gives rise to some wildly irregular shapes. In the case of the cosmic jets, the drag between the neutral hydrogen particles and charged ions creates a similar effect as gravity. The “fingers” seen in the famous Horsehead Nebula, for example, are caused by the Rayleigh-Taylor instability.

    Horsehead Nebula Credit NASA/ ESA Hubble.

    “This finding is a really major breakthrough, it’s really set us in a direction of discovering why our model gets its distinct croissant-shaped heliosphere and why other models don’t,” Opher says.

    See the full article here .

    See also the related post from The University of Maryland (US) here.

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

    Please help promote STEM in your local schools.

    Stem Education Coalition

    Boston University is a private research university in Boston, Massachusetts. The university is nonsectarian but has a historical affiliation with the United Methodist Church. It was founded in 1839 by Methodists with its original campus in Newbury, Vermont, before moving to Boston in 1867.

    The university now has more than 4,000 faculty members and nearly 34,000 students, and is one of Boston’s largest employers. It offers bachelor’s degrees, master’s degrees, doctorates, and medical, dental, business, and law degrees through 17 schools and colleges on three urban campuses. The main campus is situated along the Charles River in Boston’s Fenway-Kenmore and Allston neighborhoods, while the Boston University Medical Campus is located in Boston’s South End neighborhood. The Fenway campus houses the Wheelock College of Education and Human Development, formerly Wheelock College, which merged with BU in 2018.

    BU is a member of the Boston Consortium for Higher Education (US) and the Association of American Universities (US). It is classified among “R1: Doctoral Universities – Very High Research Activity”.

    Among its alumni and current or past faculty, the university counts eight Nobel Laureates, 23 Pulitzer Prize winners, 10 Rhodes Scholars, six Marshall Scholars, nine Academy Award winners, and several Emmy and Tony Award winners. BU also has MacArthur, Fulbright, and Truman Scholars, as well as American Academy of Arts and Sciences (US) and National Academy of Sciences (US) members, among its past and present graduates and faculty. In 1876, BU professor Alexander Graham Bell invented the telephone in a BU lab.

    The Boston University Terriers compete in the NCAA Division I. BU athletic teams compete in the Patriot League, and Hockey East conferences, and their mascot is Rhett the Boston Terrier. Boston University is well known for men’s hockey, in which it has won five national championships, most recently in 2009.

    Research

    In FY2016, the University reported in $368.9 million in sponsored research, comprising 1,896 awards to 722 faculty investigators. Funding sources included the National Science Foundation (US), the National Institutes of Health (US), the Department of Defense (US), the European Commission of the European Union, the Susan G. Komen Foundation (US), and the federal Health Resources and Services Administration (US). The University’s research enterprise encompasses dozens of fields, but its primary focus currently lies in seven areas: Data Science, Engineering Biology, Global Health, Infectious Diseases, Neuroscience, Photonics, and Urban Health.

    The University’s strategic plan calls for the removal of barriers between previously siloed departments, schools, and fields. The result has been an increasing emphasis by the University on interdisciplinary work and the creation of multidisciplinary centers such as the Rajen Kilachand Center for Integrated Life Sciences & Engineering, a $140 million, nine-story research facility that has brought together life scientists, engineers, and physicians from the Medical and Charles River Campuses; the Institute for Health Systems Innovation & Policy, a cross-campus initiative combining business, health law, medicine, and public policy; a neurophotonics center that combines photonics and neuroscience to study the brain; and the Software and Application Innovation Lab, where technologists work with colleagues in the arts and humanities and together develop digital research tools. The University also made a large investment in an emerging field, when it created a new university-wide academic unit called the Faculty of Computing & Data Sciences in 2019 and began construction of the nineteen-story Center for Computing & Data Sciences, slated to open in 2022.

    In 2003, the National Institute of Allergy and Infectious Diseases awarded Boston University a grant to build one of two National Biocontainment Laboratories. The National Emerging Infectious Diseases Laboratories (NEIDL) was created to study emerging infectious diseases that pose a significant threat to public health. NEIDL has biosafety level 2, 3, and 4 (BSL-2, BSL-3, and BSL-4, respectively) labs that enable researchers to work safely with the pathogens. BSL-4 labs are the highest level of biosafety labs and work with diseases with a high risk of aerosol transmission.

    The strategic plan also encouraged research collaborations with industry and government partners. In 2016, as part of a broadbased effort to solve the critical problem of antibiotic resistance, the US Department of Health & Human Services selected the Boston University School of Law (LAW)—and Kevin Outterson, a BU professor of law—to lead a $350 million trans-Atlantic public-private partnership called CARB-X to foster the preclinical development of new antibiotics and antimicrobial rapid diagnostics and vaccines.

    That same year, BU researcher Avrum Spira joined forces with Janssen Research & Development and its Disease Interception Accelerator group. Spira—a professor of medicine, pathology and laboratory medicine, and bioinformatics—has spent his career at BU pursuing a better, and earlier, way to diagnose pulmonary disorders and cancers, primarily using biomarkers and genomic testing. In 2015, under a $13.7 million Defense Department grant, Spira’s efforts to identify which members of the military will develop lung cancer and COPD caught the attention of Janssen, part Johnson & Johnson. They are investing $10.1 million to collaborate with Spira’s lab with the hope that his discoveries—and potential therapies—could then apply to the population at large.

    In its effort to increase diversity and inclusion, Boston University appointed Ibram X. Kendi in July 2020 as a history professor and the director and founder of its newly established Center for Antiracist Research. The university also appointed alumna Andrea Taylor as its first senior diversity officer.

     
  • richardmitnick 1:35 pm on November 18, 2021 Permalink | Reply
    Tags: "Wait-and-See and Go-and-Get-The Modes of Astrophysics", , , , Cosmic Background Radiation, Cosmic Rays, ,   

    From The Kavli Foundation : “Wait-and-See and Go-and-Get-The Modes of Astrophysics” 

    KavliFoundation

    From The Kavli Foundation

    Nov 10, 2021
    Adam Hadhazy

    Unlike many other scientific disciplines, astrophysics can count on a certain generosity shown by nature. Our planet Earth is constantly graced by light arriving from celestial entities, from as close as the moon, the sun, the planets, and other objects in the solar system, outward to the stars throughout our galaxy, and farther and farther out to billions of galaxies, and even all the way back to the universe’s oldest light, the afterglow of the Big Bang.

    CMB per European Space Agency(EU) Planck.

    Cosmic Background Radiation per ESA/Planck

    Heavier bits of particles than light, known as cosmic rays, as well as the lightest particles of all, neutrinos, also make it all the way to us from across great cosmic divides.

    Cosmic rays produced by high-energy astrophysics sources ASPERA collaboration AStroParticle ERAnet.

    Neutrinos. Credit: J-PARC T2K Neutrino Experiment.

    We’ve even figured out how to wrangle the ultra-subtle (by the time they reach us) ripples in the fabric of spacetime, dubbed gravitational waves, that are heaved out by cataclysmic events like black hole collisions.

    Artist’s by now iconic conception of two merging black holes similar to those detected by LIGO. Credit: Aurore Simonnet /Caltech MIT Advanced aLIGO(US)/Sonoma State University (US).

    _____________________________________________________________________________________
    LIGOVIRGOKAGRA

    Caltech /MIT Advanced aLigo

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

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

    VIRGO Gravitational Wave interferometer, near Pisa, Italy

    KAGRA Large-scale Cryogenic Gravitational Wave Telescope Project (JP)
    _____________________________________________________________________________________

    LIGO Virgo Kagra Masses in the Stellar Graveyard. Credit: Frank Elavsky and Aaron Geller at Northwestern University(US)

    Quite simply, all we need do to catch these information-loaded incoming signals is to look and listen with our telescopes; build it, so to speak, and they will come. Earth’s atmosphere does block out various forms of light and particles, so to catch everything the universe is throwing our way, we often send space telescopes aloft. Yet as well as this wait-and-see approach works, it is not enough for the business of planetary science, a field intimately tied into broader astrophysics. To really understand what’s in our solar system—and extrapolate from there to all other space rocks and phenomena in all other solar systems—we have to go and get a closer look. Not enough light or other conveyer of information can reach us from the surfaces of solar system bodies to tell us what, say, the rocks on the moon or Mars are fully made of, or what Pluto actually looks like. We’ve accordingly sent astronauts to the moon and rovers to Mars, and sent a probe, called New Horizons, on a nine-year-voyage to finally see Pluto’s face.

    National Aeronautics Space Agency(USA) New Horizons(US) spacecraft

    This modus operandi continues now with the Lucy spacecraft, which will let us get up close and personal with the most numerous set of solar system objects yet to be visited, called the Trojan asteroids.
    NASA depiction of Lucy Mission to Jupiter’s Trojans

    Alas, the laws of physics practically limit this active form of exploration, of going-and-getting, to just our solar system; even a probe somehow launched with the energetically unobtainable velocities in remote spitting distance of the speed of light would take decades, if not centuries to reach the nearest stars and exoplanets. We must therefore continue to hone our abilities to reap the harvest of the bounteous cosmic energy and matter that freely come to us right here on Earth.

    On the trail of inflation with the BICEP experiment

    BICEP 3 at the South Pole.

    Inflation is a highly compelling theory that addresses multiple issues in cosmology, explaining how our universe looks the way it does.

    _____________________________________________________________________________________
    Inflation

    4
    Alan Guth, from M.I.T., who first proposed cosmic inflation

    Lamda Cold Dark Matter Accerated Expansion of The universe http scinotions.com the-cosmic-inflation-suggests-the-existence-of-parallel-universes Alex Mittelmann, Coldcreation.

    Alan Guth’s notes:
    Alan Guth’s original notes on inflation
    _____________________________________________________________________________________

    Researchers at The Kavli Institute for Particle Astrophysics and Cosmology KIPAC at Stanford University (US) have been on the hunt for a predicted signal left by inflation on the oldest light in the universe, known as the cosmic microwave background, or CMB [above]. Inflation supposes that the universe underwent a titanic expansion in size a mere trillionth of a trillionth of a trillionth into its existence during the Big Bang. This dramatic event should have generated ripples in spacetime, known as gravitational waves, that in turn would have left signatures in the CMB. A telescope located at the South Pole is running the so-called BICEP experiment [above], searching for these signatures. In the latest set of results from BICEP, the researchers announced they did not find the eagerly sought signatures. But, in the process, the researchers have constrained the properties these hypothetical waves would have. It’s a null result, but such results are integral for knowing when something, has in fact, been discovered. The hunt will go on.

    Demolition derby in a nascent solar system

    The later stages of planetary formation are theorized to be violent periods, marked by cataclysmic collisions between worlds as solar systems settle down into a stable configuration. Our own moon is thought to be the product of such a collision between a nascent Earth and a Mars-sized body lost to history. Now researchers at The MIT Kavli Institute for Astrophysics and Space Research (US) think they have spotted this same kind of planetary demolition derby happening in an alien solar system. That system, designated HD 172555, had been known to have large and varied dust signatures, originally attributed to a major planetary impact or an asteroid belt. The plot has recently thickened. In association with that dusty debris, MKI researchers and colleagues have newly reported the signature of a carbon monoxide gas ring. The presence of all that gas and dust suggest that two bodies collided, with one or both possessing considerable atmospheres. It’s a remarkable new finding and once more shows that what happened here historically in our solar system is likely not unusual; whether that extends to the formation of life, though, remains a big question.

    From neutrinos to gravitational waves

    Takaaki Kajita has had a full scientific life. A Principal Investigator at the Kavli Institute for the Physics and Mathematics of the Universe since 2007, Kajita won a Nobel Prize Physics in 2015 for his breakthrough work showing that neutrinos spontaneously change a property called flavor, revealing that the squirrely subatomic particles do in fact have mass. Yet as a recent article in Physics World relates, despite his success with neutrinos, Kajita wanted to enter into a new field, and did so in 2008. He began working on the experiment that has become Japan’s first gravitational-wave hunting instrument, known as KAGRA [above]. Kajita, who now serves as the KAGRA project’s principal investigator, is looking forward to the detector carrying on its observing campaign next year.

    Neutron star mergers more of a goldmine than neutron star and black hole smashups.

    MKI researchers have provided new insights on the origins of natural chemical elements heavier than iron. The nuclear fusion in stars produces most of the elements lighter than iron, including familiar elements like carbon and oxygen. But nuclear fusion factories cannot get hot and compacted enough to go past iron. Researchers have thus worked out that the extreme conditions created when ultra-dense stellar remnants called neutron stars collide must be what leads to the formation or gold, platinum, and other heavy elements, generally up through uranium. Similarly extreme conditions also occur when neutron stars and even more compact objects, black holes, cataclysmically meet. An analysis of these two kinds of mergers, presented in a recent study, bears out that at least over the last 2.5 billion years of cosmic history, neutron star mergers have been the dominant way the universe has forged heavy elements. The novel findings will help in constraining how, where, and when heavy elements—which are rarer than lighter elements—appeared in and became distributed throughout the cosmos, and with certain abundances cropping up here on Earth.

    Lucy mission delving into the Solar System’s origins begins

    In mid-October, NASA launched an exciting new mission, dubbed Lucy [above]. The Lucy spacecraft will make humanity’s first-ever visit to the Trojan asteroids—enigmatic space rocks clustered in two bunches in front of and behind the planet Jupiter in its orbit.

    The inner Solar System, from the Sun to Jupiter. Also includes the asteroid belt (the white donut-shaped cloud), the Hildas (the orange “triangle” just inside the orbit of Jupiter), the Jupiter trojans (green), and the near-Earth asteroids. The group that leads Jupiter are called the “Greeks” and the trailing group are called the “Trojans” The image is looking down on the ecliptic plane as would have been seen on 1 September 2006 .

    The Trojans are pristine time capsules from the early solar system, preserving chemical evidence of the conditions when our local worlds took shape over four eons ago. The project scientist for the Lucy mission is Richard Binzel, who is an affiliated faculty member of MKI. He points out that materials visible on the asteroids Lucy will visit could date back 4.56 billion years, right to the very dawn of our solar system and older than any samples we could study from the moon or find on Earth. The Trojans could shed light on the origin of carbon-containing compounds, so-called organics, necessary for the rise of life. The spacecraft will reach its first of several Trojan targets in 2027.

    See the full article here .


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    Please help promote STEM in your local schools.

    Stem Education Coalition

    The Kavli Foundation based in Oxnard, California is dedicated to the goals of advancing science for the benefit of humanity and promoting increased public understanding and support for scientists and their work.

    The Foundation’s mission is implemented through an international program of research institutes; professorships; and symposia in the fields of astrophysics; nanoscience; neuroscience; and theoretical physics as well as prizes in the fields of astrophysics; nanoscience; and neuroscience.

    The Kavli Foundation was established in December 2000 by its founder and benefactor Fred Kavli a Norwegian business leader and philanthropist who made his money by creating Kavlico- a company that made sensors; and by investing in real estate in southern California and Nevada. David Auston, a former president of Case Western Reserve University(US) and former Bell Labs scientist, was the first president of the Kavli Foundation and is largely credited with the vision of the scientific investments. Kavli died in 2013 and his foundation is currently actively involved in establishing research institutes at universities throughout the United States, in Europe, and in Asia.

    To date, the Kavli Foundation has made grants to establish Kavli Institutes on the campuses of 16 major universities. In addition to the Kavli Institutes, six Kavli professorships have been established: two at University of California, Santa Barbara(US), one each at University of California, Los Angeles (US), University of California, Irvine, Columbia University (US), Cornell University (US), and California Institute of Technology (US).

    The Kavli Institutes

    Astrophysics

    The Kavli Institute for Particle Astrophysics and Cosmology at Stanford University
    The Kavli Institute for Cosmological Physics, University of Chicago
    The Kavli Institute for Astrophysics and Space Research at the Massachusetts Institute of Technology
    The Kavli Institute for Astronomy and Astrophysics at Peking University
    The Kavli Institute for Cosmology at the University of Cambridge
    The Kavli Institute for the Physics and Mathematics of the Universe at the University of Tokyo

    Nanoscience

    The Kavli Institute for Nanoscale Science at Cornell University
    The Kavli Institute of Nanoscience at Delft University of Technology in the Netherlands
    The Kavli Nanoscience Institute at the California Institute of Technology
    The Kavli Institute for Bionano Science and Technology at Harvard University
    The Kavli Energy NanoSciences Institute at University of California, Berkeley and the Lawrence Berkeley National Laboratory

    Neuroscience

    The Kavli Institute for Brain Science at Columbia University
    The Kavli Institute for Brain & Mind at the University of California, San Diego
    The Kavli Institute for Neuroscience at Yale University
    The Kavli Institute for Systems Neuroscience at the Norwegian University of Science and Technology
    The Kavli Neuroscience Discovery Institute at Johns Hopkins University
    The Kavli Neural Systems Institute at The Rockefeller University
    The Kavli Institute for Fundamental Neuroscience at the University of California, San Francisco

    Theoretical physics

    Kavli Institute for Theoretical Physics at the University of California, Santa Barbara
    The Kavli Institute for Theoretical Physics China at the Chinese Academy of Sciences

     
  • richardmitnick 3:46 pm on May 24, 2021 Permalink | Reply
    Tags: "Confirming a Cosmic-Ray Bump", , Cosmic Rays,   

    From Physics (US) : “Confirming a Cosmic-Ray Bump” 

    About Physics

    From Physics (US)

    May 18, 2021
    Katherine Wright

    The DArk Matter Particle Explorer has made the most precise measurements of galactic cosmic rays to date.

    1
    For over 5 years, the DArk Matter Particle Explorer (DAMPE)[Chinese Academy of Sciences] has orbited Earth measuring cosmic rays.

    The team behind the telescope has now analyzed 4.5 years of cosmic-ray data, finding spectral features that don’t match predictions Physical Review Letters. While similar features were hinted at in other experiments, the measurements by DAMPE have a higher precision and cover a wider range of energies than any other single experiment. The findings could help researchers uncover the origin of galactic cosmic rays.

    Cosmic rays consist mostly of protons and helium ions and are thought to emanate from supernovae. On their journey to Earth the rays are deflected by interstellar magnetic fields, making it hard to determine their sources. But researchers hope that by measuring the energy spectra of cosmic rays, they can extract some information about the supernovae that sent them flying and about the structure of our Galaxy.

    In their analysis, the DAMPE team analyzed the energy spectrum of detected helium ions. These particles had energies from 70 GeV to 80 TeV, an order of magnitude higher than those detected with the Alpha Magnetic Spectrometer aboard the International Space Station (see Focus: New Data Reveal the Heavy Side of Cosmic Rays) and 100 times higher than those seen with the PAMELA satellite (see Synopsis: Solar Cycle Affects Cosmic Ray Positrons).

    At around 1.3 TeV the team observed the intensity of the spectrum start to rise, peaking at about 34 TeV. The statistical significance of the finding is 4.3 sigma. Signs of such a bump have been seen before, but the uncertainties in previous data were too large to confirm the bump’s presence. The team says that they think the bump-like feature might be caused by a nearby supernova, but that remains unconfirmed.

    See the full article here .

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    Please help promote STEM in your local schools.

    Stem Education Coalition

    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 (US) 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.

     
  • richardmitnick 6:44 pm on January 31, 2021 Permalink | Reply
    Tags: "We may have found the most powerful particle accelerator in the galaxy", A source of gamma rays exceeding 200 TeV called HAWC J1825-134., , , , Charged particles traveling through interstellar space respond to our galaxy's magnetic field., Cosmic Rays, , Gamma rays shoot straight-line through the galaxy allowing us to directly pinpoint their origins., , , When cosmic rays accidentally strike a cloud of interstellar gas they can emit gamma rays.   

    From SPACE.com: “We may have found the most powerful particle accelerator in the galaxy” 

    From SPACE.com

    1.29.21
    Paul Sutter

    And it’s quite a surprising source.

    1
    This image, created using data from the European Space Agency’s Herschel and Planck space telescopes, shows a piece of the Taurus Molecular Cloud.© ESA/Herschel/Planck; J. D. Soler, MPIA.

    ESA/Herschel spacecraft active from 2009 to 2013.

    ESA/Planck 2009 to 2013

    Astronomers have long wondered where high-energy cosmic rays come from within our galaxy.

    And now, new observations with the High Altitude Water Cherenkov Experiment (HAWC) observatory reveal an unlikely candidate: an otherwise mundane giant molecular cloud.

    HAWC High Altitude Čerenkov Experiment, a US Mexico Europe collaboration located on the flanks of the Sierra Negra volcano in the Mexican state of Puebla at an altitude of 4100 meters(13,500ft), at WikiMiniAtlas 18°59′41″N 97°18′30.6″W. searches for cosmic rays.

    Taking the knee

    Cosmic rays are not rays at all but rather tiny particles cruising through the universe at nearly the speed of light. They can be made of electrons, protons or even ions of heavier elements. They are created in all sorts of high-energy processes throughout the cosmos, from supernova explosions to the mergers of stars to the final insane moments when gas gets sucked up by a black hole.

    Cosmic rays come in all sorts of energies, and generally speaking the higher-energy cosmic rays are rarer than their low-energy relatives. This relationship changes in a very slight way at a particular energy — 10^15 electron-volts — which is called the “knee.” The electron-volt, or eV, is just the way that particle physicists enjoy measuring energy levels. For comparison, the most powerful particle collider on Earth, the Large Hadron Collider, can achieve 13 X 10^12 eV, which is often denoted as 13 tera electron-volts, or 13 TeV.

    CERN (CH) LHC Map

    Above an energy of 10^15 eV, cosmic rays are much rarer than you would expect. This has led astronomers to believe that any cosmic rays at this energy level and higher come from outside the galaxy, while processes within the Milky Way are capable of producing cosmic rays up to and including 10^15 eV.

    For those of you keeping score at home, whatever is creating these cosmic rays would be in the “peta” range of Greek prefixes, and therefore over 1,000 times more powerful than our best particle accelerators — natural “PeVatrons” roaming the galaxy.

    A hawkeyed sleuth

    The mission is simple: find the source of PeV-scale cosmic rays in the Milky Way. But despite their energies, it’s hard to pinpoint their origins. That’s because cosmic rays are made of charged particles, and charged particles traveling through interstellar space respond to our galaxy’s magnetic field. Thus when you see a high-energy cosmic ray coming from a particular direction in the sky, you actually have no idea where it truly came from — its path has bent and curved over the course of its journey to Earth.

    But instead of hunting for cosmic rays directly, we can search for some of their relatives. When cosmic rays accidentally strike a cloud of interstellar gas, they can emit gamma rays, a high-energy form of radiation. These gamma rays shoot straight-line through the galaxy, allowing us to directly pinpoint their origins.

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

    So if we see a source of strong gamma-ray emission, we can look for nearby sources of PeV cosmic rays.

    This was the method employed by a team of researchers using HAWC, which is located on the Sierra Negra Volcano of south-central Mexico. HAWC “stares” up at the sky with a series of tanks filled with ultra-pure water. When high-energy particles or radiation enter the tanks, they emit a flash of blue light, allowing astronomers to trace back the source onto the sky.

    Detailed in a paper recently appearing in The Astrophysical Journal Letters, the astronomers found a source of gamma rays exceeding 200 TeV, which could only be created by even more powerful cosmic rays — the kinds of cosmic rays that reach up into the PeV scale. The source, called HAWC J1825-134, lies roughly in the direction of the galactic center. HAWC J1825-134 appears to us as a bright blotch of gamma rays, illuminated by some unknown fount of cosmic rays — perhaps the most powerful known source of cosmic rays in the Milky Way.

    An unlikely heavyweight

    A few of the usual suspect sources of high-energy cosmic rays sit within a few thousand light-years of HAWC J1825-134, but none of them can easily explain the signal.

    For example, the galactic center itself is a known generator of intense cosmic ray action, but it’s way too far away from HAWC J1825-134, so it has no bearing on this measurement.

    There are some supernova remnants, and supernovae sure are powerful. But all the supernovae in the region of HAWC J1825-134 went off ages ago — far too long in the past to be creating these high-energy cosmic rays now.

    Pulsars — the rapidly spinning dense remnant cores of massive stars — also produce copious amounts of cosmic rays. But those too sit too far away from the source of gamma rays — the energies of the electrons and protons coming off the pulsar just aren’t punchy enough to travel the thousands of light-years to the location of the gamma ray emission.

    Surprisingly, the source of these record-breaking cosmic rays appears to be none other than a giant molecular cloud. These clouds are giant, lumbering brutes, filled with dust and gas, that roam the galaxy. They occasionally contract in on themselves and turn into stars, but otherwise they can remain cool and loose for billions of years. Not causing anyone any serious threat — and barely even noticeable unless you have good infrared telescopes — they are the last place you would expect to find such insanely high energies.

    Located within the cloud complex is a cluster of newborn stars, but even the crankiest and loudest of baby stars aren’t thought to be powerful enough to launch cosmic rays like this. The researchers themselves admit that they don’t know how this cloud is doing it, but somehow, when nobody was paying attention, it generated some of the most powerful particles in the entire galaxy.

    See the full article here .

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  • richardmitnick 11:10 am on July 1, 2020 Permalink | Reply
    Tags: "Binary star as a cosmic particle accelerator", , , , Cosmic Rays, , , , , Very high-energy gamma radiation   

    From DESY: “Binary star as a cosmic particle accelerator” 

    From DESY

    2020/07/01

    Specialized telescope provides evidence of very high-energy gamma radiation from Eta Carinae.

    With a specialised telescope in Namibia a DESY-led team of researchers has proven a certain type of binary star as a new kind of source for very high-energy cosmic gamma-radiation. Eta Carinae is located 7500 light years away in the constellation Carina (the ship’s keel) in the Southern Sky and, based on the data collected, emits gamma rays with energies all the way up to 400 gigaelectronvolts (GeV), some 100 billion times more than the energy of visible light.

    1
    Eta Carinae. NASA

    The team headed by DESY’s Stefan Ohm, Eva Leser and Matthias Füßling is presenting its findings, made at the gamma-ray observatory High Energy Stereoscopic System (H.E.S.S.), in the journal Astronomy & Astrophysics. [see also in Astronomy and Astrophysics] specially created multimedia animation explains the phenomenon. “With such visualizations we want to make the fascination of research tangible,” emphasises DESY’s Director of Astroparticle Physics, Christian Stegmann.


    Animation: DESY, Science Communication Lab; Sound by Alva Noto.

    Eta Carinae is a binary system of superlatives, consisting of two blue giants, one about 100 times, the other about 30 times the mass of our sun. The two stars orbit each other every 5.5 years in very eccentric elliptical orbits, their separation varying approximately between the distance from our Sun to Mars and from the Sun to Uranus. Both these gigantic stars fling dense, supersonic stellar winds of charged particles out into space. In the process, the larger of the two loses a mass equivalent to our entire Sun in just 5000 years or so. The smaller one produces a fast stellar wind travelling at speeds around eleven million kilometres per hour (about one percent of the speed of light).

    A huge shock front is formed in the region where these two stellar winds collide, heating up the material in the wind to extremely high temperatures. At around 50 million degrees Celsius, this matter radiates brightly in the X-ray range. The particles in the stellar wind are not hot enough to emit gamma radiation, though. “However, shock regions like this are typically sites where subatomic particles are accelerated by strong prevailing electromagnetic fields,” explains Ohm, who is the head of the H.E.S.S. group at DESY.

    H.E.S.S. Čerenkov Telescope Array, located on the Cranz family farm, Göllschau, in Namibia, near the Gamsberg searches for cosmic rays, altitude, 1,800 m (5,900 ft)

    When particles are accelerated this rapidly, they can also emit gamma radiation. In fact, the satellites “Fermi”, operated by the US space agency NASA, and AGILE, belonging to the Italian space agency ASI, already detected high-energy gamma rays of up to about 10 GeV coming from Eta Carinae in 2009.

    NASA/Fermi LAT


    NASA/Fermi Gamma Ray Space Telescope

    Italian Space Agency AGILE Spacecraft

    Subatomic hailstorm

    Different models have been proposed to explain how this gamma radiation is produced,” Füßling reports. “It could be generated by accelerated electrons or by high-energy atomic nuclei.” Determining which of these two scenarios is correct is crucial: very energetic atomic nuclei account for the bulk of the so-called Cosmic Rays, a subatomic cosmic hailstorm striking Earth constantly from all directions. Despite intense research for more than 100 years, the sources of the Cosmic Rays are still not exhaustively known. Since the electrically charged atomic nuclei are deflected by cosmic magnetic fields as they travel through the universe, the direction from which they arrive at Earth no longer points back to their origin. Cosmic gamma rays, on the other hand, are not deflected. So, if the gamma rays emitted by a specific source can be shown to originate from high-energy atomic nuclei, one of the long-sought accelerators of cosmic particle radiation will have been identified.

    “In the case of Eta Carinae, electrons have a particularly hard time getting accelerated to high energies, because they are constantly being deflected by magnetic fields during their acceleration, which makes them lose energy again,” says Leser. “Very high-energy gamma radiation begins above the 100 GeV range, which is rather difficult to explain in Eta Carinae to stem from electron acceleration.” The satellite data already indicated that Eta Carinae also emits gamma radiation beyond 100 GeV, and H.E.S.S. has now succeeded in detecting such radiation up to energies of 400 GeV around the time of the close encounter of the two blue giants in 2014 and 2015. This makes the binary star the first known example of a source in which very high-energy gamma radiation is generated by colliding stellar winds.

    “The analysis of the gamma radiation measurements taken by H.E.S.S. and the satellites shows that the radiation can best be interpreted as the product of rapidly accelerated atomic nuclei,” says DESY’s PhD student Ruslan Konno, who has published a companion study, together with scientists from the Max Planck Institute for Nuclear Physics in Heidelberg. “This would make the shock regions of colliding stellar winds a new type of natural particle accelerator for cosmic rays.” With H.E.S.S., which is named after the discoverer of Cosmic Rays, Victor Franz Hess, and the upcoming Čerenkov Telescope Array (CTA), the next-generation gamma-ray observatory currently being built in the Chilean highlands, the scientists hope to investigate this phenomenon in greater detail and discover more sources of this kind.

    Čerenkov Telescope Array, http://www.isdc.unige.ch/cta/ at Cerro Paranal, located in the Atacama Desert of northern Chile searches for cosmic rays on Cerro Paranal at 2,635 m (8,645 ft) altitude, 120 km (70 mi) south of Antofagasta; and at at the Instituto de Astrofisica de Canarias (IAC), Roque de los Muchachos Observatory in La Palma, Spain

    Cosmic road trip

    Thanks to detailed observations of Eta Carinae at all wavelengths, the properties of the stars, their orbits and stellar winds have been determined relatively accurately. This has given astrophysicists a better picture of the binary star system and its history. To illustrate the new observations of Eta Carinae, the DESY astrophysicists have produced a video animation together with the animation specialists of the award-winning Science Communication Lab [above]. The computer-generated images are close to reality because the measured orbital, stellar and wind parameters were used for this purpose. The internationally acclaimed multimedia artist Carsten Nicolai, who uses the pseudonym Alva Noto for his musical works, created the sound for the animation.

    “I find science and scientific research extremely important,” says Nicolai, who sees close parallels in the creative work of artists and scientists. For him, the appeal of this work also lay in the artistic mediation of scientific research results: “particularly the fact that it is not a film soundtrack, but has a genuine reference to reality,” emphasizes the musician and artist. Together with the exclusively composed sound, this unique collaboration of scientists, animation artists and musician has resulted in a multimedia work that takes viewers on an extraordinary journey to a superlative double star some 7500 light years away.

    See the full article here .


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    desi

    DESY is one of the world’s leading accelerator centres. Researchers use the large-scale facilities at DESY to explore the microcosm in all its variety – from the interactions of tiny elementary particles and the behaviour of new types of nanomaterials to biomolecular processes that are essential to life. The accelerators and detectors that DESY develops and builds are unique research tools. The facilities generate the world’s most intense X-ray light, accelerate particles to record energies and open completely new windows onto the universe. 
That makes DESY not only a magnet for more than 3000 guest researchers from over 40 countries every year, but also a coveted partner for national and international cooperations. Committed young researchers find an exciting interdisciplinary setting at DESY. The research centre offers specialized training for a large number of professions. DESY cooperates with industry and business to promote new technologies that will benefit society and encourage innovations. This also benefits the metropolitan regions of the two DESY locations, Hamburg and Zeuthen near Berlin.

    DESY Petra III interior

    DESY Petra III

    DESY/FLASH

    H1 detector at DESY HERA ring

    DESY DORIS III

     
  • richardmitnick 2:38 pm on June 18, 2020 Permalink | Reply
    Tags: "Spotted: A Galactic PeVatron?", , Cosmic Rays, , More modest cosmic rays reach “only” peta-electron-volt (PeV) energies — that’s 10^15 eV., We’ve now identified a new potential galactic PeVatron: the remnant produced by a past supernova explosion just 2600 light-years from Earth.   

    From AAS NOVA: “Spotted: A Galactic PeVatron?” 

    AASNOVA

    From AAS NOVA

    17 June 2020
    Susanna Kohler

    HAWC High Altitude Čerenkov Experiment, />US Mexico Europe collaboration located on the flanks of the Sierra Negra volcano in the Mexican state of Puebla at an altitude of 4100 meters(13,500ft), at WikiMiniAtlas 18°59′41″N 97°18′30.6″W. searches for cosmic rays

    Speeding charged particles — far more energetic than any we can create in laboratory particle accelerators — constantly bombard the Earth’s atmosphere. But what extreme environments produce these high-energy particles? A new study may have identified one cosmic accelerator in our galaxy.

    Charged Arrivals

    At any given moment, protons and atomic nuclei are whizzing through our galaxy, sometimes at nearly the speed of light. These charged particles — cosmic rays —span a wide range of energies, with the most energetic packing the same punch as a 90 kilometer-per-hour (56 mph) baseball!

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

    More modest cosmic rays reach “only” peta-electron-volt (PeV) energies — that’s 10^15 eV, still more than 100 times more energetic than the particles accelerated by the record-holding Large Hadron Collider. We think that these PeV particles were produced somewhere within our own galaxy.

    If we could unravel their secrets, these cosmic rays could provide clues about how stars evolve and how energy is transported throughout the galaxy. First, however, we need to figure out where they came from. Are their sources supernova remnants? Microquasars? Superbubbles? What galactic PeVatrons accelerated these particles to their tremendous speeds?

    Road Map to a Birthplace

    Unfortunately, we can’t just trace cosmic rays backwards to figure out their origins. Because these particles are charged, their trajectories are deflected by interstellar magnetic fields — which means that the direction a cosmic ray arrived from probably isn’t the direction of its source.

    To address this challenge, high-energy astronomers search for more direct messengers that are produced as cosmic rays are accelerated — like extremely energetic gamma-ray radiation.

    When PeV particles accelerated by a galactic PeVatron collide with gas and dust in the vicinity of their origin, they should produce very high-energy tera-electron-volt (TeV, or 10^12 eV) gamma-ray photons. These photon by-products won’t be deflected by magnetic fields, so their arrival at gamma-ray observatories on Earth provides a clearer path back to the source of the PeV cosmic rays.

    2
    Top: significance map from HAWC showing the location of gamma-ray emission from near SNR G106.3+2.7. Bottom: Molecular hydrogen column density around the HAWC-detected source (shown in gray contours). The detectors VERITAS and Milagro have also observed very high-energy gamma-ray emission from this region; their detection centers are also marked. [Adapted from Albert et al. 2020]

    Hunting for Galactic Accelerators

    So how’s the search for these characteristic TeV gamma-rays going? With one possible success on the books so far — scientists think there’s a galactic PeVatron at the center of our galaxy, but we haven’t yet determined the source — we’ve now identified a new potential galactic PeVatron: the remnant produced by a past supernova explosion just 2,600 light-years from Earth.

    In a new publication, a team of scientists from the High-Altitude Water Čerenkov Gamma-Ray Observatory (HAWC) announces the detection of TeV gamma-ray emission from the same region as supernova remnant SNR G106.3+2.7.

    Though the team can’t rule out other causes of the emission, this signal has a spectrum that’s consistent with what we’d expect to be produced by PeV protons colliding with gas and dust. The origin near SNR G106.3+2.7 supports a picture in which charged particles can be accelerated across the shocks of supernova remnants and flung into space with PeV energies.

    So might the mystery of galactic PeVatrons be solved with supernova remnants? We don’t know for sure yet, but future high-energy gamma-ray observations are sure to help us further identify the sources of the speeding charged particles in our galaxy.

    Citation

    “HAWC J2227+610 and Its Association with G106.3+2.7, a New Potential Galactic PeVatron,” A. Albert et al 2020 ApJL 896 L29.
    https://iopscience.iop.org/article/10.3847/2041-8213/ab96cc

    See the full article here .


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    1

    AAS Mission and Vision Statement

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

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

    Adopted June 7, 2009

     
  • richardmitnick 9:34 am on March 18, 2020 Permalink | Reply
    Tags: "An Iced Cosmic-Ray Macchiato", , , , , Cosmic Rays,   

    From astrobites: “An Iced Cosmic-Ray Macchiato” 

    Astrobites bloc

    From astrobites

    1
    Artist’s impression of the shower of particles caused when a cosmic ray, a charged particle often produced by a distant astrophysical source, hits Earth’s upper atmosphere. [J. Yang/NSF]

    Title: Bottom-up Acceleration of Ultra-High-Energy Cosmic Rays in the Jets of Active Galactic Nuclei
    Authors: Rostom Mbarek and Damiano Caprioli
    First Author’s Institution: University of Chicago

    Status: Published in ApJ

    Our universe is littered with particles of unbelievably high energy, called cosmic rays. The most extreme of these particles carry the same amount of energy as a professional tennis serve, like the Oh-My-God Particle detected nearly 30 years ago. The catch: we don’t know exactly what processes can pack so much energy into a single particle. The authors of today’s article discuss how these particles might gain their energy in a way analogous to your morning trip to Dunkin’™.

    Cosmic Rays at a Glance

    Cosmic rays are atomic nuclei that have been accelerated to high energies in astrophysical environments, such as supernova remnants or active galactic nuclei. Although they might seem like a great tool in the multi-messenger astronomy toolbox, astronomy with cosmic rays is no simple task, as these particles get deflected by extragalactic magnetic fields.

    2
    Cosmic rays (red) consist of individual protons and nuclei of heavier elements. They are deflected by magnetic fields along their cosmological odysseys and can’t be used to point back to the place of their origin. [IceCube Neutrino Observatory]

    Despite efforts to pinpoint the origins of cosmic rays, especially those of the highest energies, we’ve come up empty-handed (check out these bites for previous studies: Galactic cosmic rays, cosmic-ray anisotropy).

    Even though we can’t measure where they come from, we do know their energies, and a variety of cosmic-ray experiments detect millions of these particles every year. Many of them are thousands to millions of times more energetic than the particles in the largest terrestrial particle accelerator, the Large Hadron Collider, but we don’t know how the highest energy cosmic rays get their energy.

    Cosmic-Ray Acceleration: Old News

    Many theories of cosmic-ray acceleration tend to revolve around the idea of Fermi acceleration. In this scenario, objects such as supernova remnants can create shocks, consisting of material moving together with supersonic speeds, and these shocks can accelerate particles to high energies. As a shock wave propagates, particles bounce back and forth across the shock boundary. Over time, successive bounces across the shock front lead to a net transfer of energy to the particles.

    While Fermi acceleration does a good job of explaining cosmic rays with moderate energies and has been a staple of models for decades, it has a few pitfalls, and many argue that it can’t provide the whole story for cosmic-ray acceleration at the highest energies.

    A Cosmic Cup o’ Joe

    The authors of today’s paper propose a new way of looking at cosmic-ray acceleration: the espresso mechanism. Why espresso? Because instead of gradually gaining energy over time, particles gain their energy from a single shot.

    3
    In the “espresso mechanism”, particles gain tremendous amounts of energy from entering a jet for a short period of time. Here, a particle with initial momentum and energy pi, Ei enters a jet with characteristic Lorentz factor Γ and leaves the jet with an energy equal to roughly Γ2Ei. [Caprioli et al. 2018]

    Consider an object with a jet, such as an active galaxy. If a low-energy cosmic ray enters the jet (or steam), then it can be shot down the barrel of the jet and get kicked out at much higher energy. In many cases, particle energies can increase by a factor Γ2, where Γ is the Lorentz factor (this reflects how fast the jet is moving). For some jets, this means particles can exit nearly 1,000 times as energetic as they were when they entered the jet.

    4
    In realistically modeled jets, material tends to clump in some regions, and these regions of overdensity (color scale in figure) cause the jet to locally move faster or slower. [Mbarek & Caprioli 2019]

    While this espresso scheme sounds great in principle, many previous calculations have relied on spherical cow treatments of jets, when in reality they are remarkably dynamic and complex structures.

    That’s where the authors of today’s paper come into play. These authors take a simple treatment of the espresso mechanism and complexify it by performing a full magnetohydrodynamic (MHD) simulation of ultrarelativistic jets. This takes factors like small-scale fluctuations of jet speed and jet density into account, to give a more accurate picture of the dynamics of jets.

    By simulating the full structure of jets, the authors find that complex environments don’t weaken the promises of espresso acceleration. In fact, the very imperfections that manifest in realistic jets can help with particle acceleration. What’s more, jet perturbations allow particles to receive double or even triple shots of energy.

    Throughout the paper, the authors describe the emergent spectra of espresso-accelerated cosmic rays. In doing this, they find that espresso acceleration is consistent with current measurements of ultra-high-energy cosmic rays in terms of energy, chemical composition, and spatial distributions, an accomplishment which no other model of cosmic-ray acceleration can boast.

    6

    Sample particle trajectories (black curves) are overlaid on top of slices of the jet, with jet velocity represented by the color in the top panels. Bottom panels show the amount of energy gained along the particle paths, showing that particles can leave jets with much more energy than they entered with. [Mbarek & Caprioli 2019]

    In light of all of this, it’s probably safe to say that the future of cosmic-ray science will be very caffeinated.

    See the full article here .


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    Please help promote STEM in your local schools.

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    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 10:17 am on February 28, 2020 Permalink | Reply
    Tags: "Stunning Images Capture Cosmic Ray Tracks", , Cosmic Rays, Cosmic rays are made mostly from the result of supernovae explosions and reaching us at nearly the speed of light., Losing more energy as it travels round and round the particle creates the curious circles in the images called “loopers.”, Particles with no electric charge always move in straight lines; however they cannot even be seen by the detector., , , STAR is only able to track charged particles which get pulled by the the detector’s magnetic field creating a curve., The “heart” of the STAR detector is its Time Projection Chamber- a four-meter-wide 4.2-meter-long cylinder filled with a gas mixture of argon and methane.   

    From Brookhaven National Lab: “Stunning Images Capture Cosmic Ray Tracks” 

    From Brookhaven National Lab

    February 26, 2020
    Erika Peters
    epeters@bnl.gov

    The beauty in science shines through at RHIC’s STAR detector [below] and makes a cosmic connection.

    1
    To help calibrate the STAR detector, physicists track and capture images of showers of cosmic rays streaming from space. Can you pick out which image shows tracks from a particle collision at RHIC (hint: the collision occurred at the center of the detector)?

    These images capture the movement and collisions of “cosmic rays”—mysterious particles originating somewhere in deep space—as they stream through the STAR detector at the Relativistic Heavy Ion Collider (RHIC) [below]. The results are profoundly beautiful.

    The rays, made mostly from the result of supernovae explosions and reaching us at nearly the speed of light, are not just things of beauty. Physicists conducting research at RHIC—a U.S. Department of Energy Office of Science user facility for nuclear physics research at Brookhaven National Laboratory—use their signals as a tool for calibrating the massive detectors collecting data for the collider’s physics experiments.

    The “heart” of the STAR detector is its Time Projection Chamber, a four-meter-wide, 4.2-meter-long cylinder filled with a gas mixture of argon and methane, explained Irakli Chakaberia, a research scientist on the STAR experiment. Each of the detector’s endcaps has 12 “sectors,” each with 72 padrows that sense electric charge, acting as a camera that can capture over 2,000 images a second. Tracing the trails of a shower of cosmic rays passing through the gas helps scientists know if their detector components are all working correctly.

    The higher the energy of the original cosmic track, the bigger the proliferation of the shower, creating what appear to be more “lively” images with many tracks in the chamber. How linear the path appears helps show the particle’s speed—the faster the particle moves, the straighter its path. Particles with no electric charge always move in straight lines; however, they cannot even be seen by the detector. STAR is only able to track charged particles, which get pulled by the the detector’s magnetic field, creating a curve. Those with lower momentum, called “soft” particles, are pulled more by the detector’s magnets and curve more than faster ones.

    “Based on the direction of the curve, we can tell whether the particle is positively or negatively charged,” Chakaberia said.

    When a cosmic ray particle collides with an atom of the gas in the detector, it might produce a “softer” particle moving with lower energy. Losing more energy as it travels round and round, the particle creates the curious circles in the images called “loopers.” Sometimes in the initial cascade, there are particles “soft” enough to loop around on their own.

    Even though physicists use powerful computers to analyze data from STAR, “nothing replaces an actual human eye,” Chakaberia said.

    “For example, when looking at some cosmic data, there was a case where tens of tracks were reconstructed in a single detector sector,” Chakaberia said. “This could, in principle, happen, but after checking the event display by eye it was obvious that it was a result of noise in that sector. The software couldn’t distinguish between the noise and real events to some degree. So these track displays help a lot to figure out what’s going on.”

    After cosmic rays have done their job testing and calibrating, STAR is ready to capture the thousands of tracks produced by ion collisions at RHIC. To increase the chance of two ions colliding, billions are aimed at each other with each pass through the detector, and the tracks reveal more of the beauty and the art that can be found in science. In this case, all the particle tracks emerge from the center of the detector, where the collision takes place. (Can you find the one ion-collision event in the images shown here?)

    Nuclear physicists analyze the ion-collision tracks to learn about a remarkable state of matter created in RHIC’s heavy-ion collisions. This “quark-gluon plasma” is a soup of particles that mimics what the universe was like just after the Big Bang. It’s a kind of cosmic connection: Scientists use a detector calibrated by particles from the cosmos to learn more about the marvelous and mystifying universe that created them.

    Research at RHIC/STAR is funded by the DOE Office of Science and by funders of the STAR collaboration listed here.

    See the full article here .


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    One of ten national laboratories overseen and primarily funded by the Office of Science of the U.S. Department of Energy (DOE), Brookhaven National Laboratory conducts research in the physical, biomedical, and environmental sciences, as well as in energy technologies and national security. Brookhaven Lab also builds and operates major scientific facilities available to university, industry and government researchers. The Laboratory’s almost 3,000 scientists, engineers, and support staff are joined each year by more than 5,000 visiting researchers from around the world. Brookhaven is operated and managed for DOE’s Office of Science by Brookhaven Science Associates, a limited-liability company founded by Stony Brook University, the largest academic user of Laboratory facilities, and Battelle, a nonprofit, applied science and technology organization.

     
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