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  • richardmitnick 10:38 am on October 5, 2022 Permalink | Reply
    Tags: "Magnetic nano mosaics", "Skyrmion lattices", , For about ten years magnetic skyrmions - particle-like stable magnetic whirls that can form in certain materials and possess fascinating properties - have been a focus of research., , Physics team from the universities of Kiel and Hamburg discovers new class of magnetic lattices., , , , The University of Hamburg [Universität Hamburg] (DE)   

    From The Kiel University [Christian-Albrechts-Universität zu Kiel] (DE) And The University of Hamburg [Universität Hamburg] (DE): “Magnetic nano mosaics” 

    From The Kiel University [Christian-Albrechts-Universität zu Kiel] (DE)

    And

    1

    The University of Hamburg [Universität Hamburg] (DE)

    10.5.22

    PD Dr. Kirsten von Bergmann
    Institute for Nanostructure and Solid State Physics
    University of Hamburg
    040 / 42838-6295
    kirsten.von.bergmann@physik.uni-hamburg.de

    Professor Dr. Stefan Heinze
    Institute of Theoretical Physics and Astrophysics
    Kiel University
    0431 / 880-4127
    heinze@theo-physik.uni-kiel.de

    Press Contact:
    Julia Siekmann
    Science Communication Officer
    Research area Kiel Nano Surface and Interface Sciences
    jsiekmann@uv.uni-kiel.de
    +49 (0)431/880-4855

    Physics team from the universities of Kiel and Hamburg discovers new class of magnetic lattices.

    1
    The image shows the different orientation of atomic “bar magnets” of an iron film: In a magnetic mosaic lattice (above), they are oriented in groups either upwards (purple) or downwards (white). In the skyrmion lattice (below), on the other hand, they point in all directions. © André Kubetzka.

    2
    A measurement using spin-polarised scanning tunnelling microscopy (SP-STM) makes the hexagonal arrangement in the magnetic mosaic lattice visible on the nanometre scale. Due to a twist of the mosaic lattice on the atomic lattice, two rotational domains appear which deviate from each other by about 13° (see markings and graphs on the right). © André Kubetzka.

    For about ten years, magnetic skyrmions – particle-like, stable magnetic whirls that can form in certain materials and possess fascinating properties – have been a focus of research: electrically easily controlled and only a few nanometers in size, they are suitable for future applications in spin electronics, quantum computers or neuromorphic chips. These magnetic whirls were first found in regular lattices, so-called “skyrmion lattices”, and later individual skyrmions were also observed at the University of Hamburg. Researchers from Kiel University and the University of Hamburg have now discovered a new class of spontaneously occurring magnetic lattices. They are related to skyrmion lattices, but their “atomic bar magnets” on the nanometer scale are oriented differently. A fundamental understanding of how such complex spin structures form, how they are arranged and remain stable is also needed for future applications. The results are published in the current issue of Nature Communications [below].

    Quantum mechanical interactions

    Attaching magnets to a refrigerator or reading data from a hard drive is only possible because of a quantum mechanical exchange interaction between the atomic bar magnets on the microscopic scale. This interaction, discovered by Werner Heisenberg in 1926, explains not only the parallel alignment of atomic bar magnets in ferromagnets, but also the occurrence of other magnetic configurations, such as antiferromagnets. Today many other magnetic interactions are known, which has led to a variety of possible magnetic states and new research questions. This is also important for skyrmion lattices. Here the atomic bar magnets show in all spatial directions, which is only possible due to the competition of different interactions.

    “In our measurements, we found a hexagonal arrangement of magnetic contrasts, and at first we thought that was also a skyrmion lattice. Only later did it become clear that it could be a nanoscale magnetic mosaic,” says PD Dr. Kirsten von Bergmann. With her team from the University of Hamburg, she experimentally studied thin metallic films of iron and rhodium using spin-polarized scanning tunneling microscopy. This allows magnetic structures to be imaged down to the atomic scale. The observed magnetic lattices occurred spontaneously as in a ferromagnet, i.e., without an applied magnetic field. “With a magnetic field, we can invert the mosaic lattices, because the opposing spins only partially compensate for each other,” explains Dr. André Kubetzka, also from the University of Hamburg.

    Surprising: Magnetically different alignment

    Based on these measurements, the group of Prof. Dr. Stefan Heinze (Kiel University) performed quantum mechanical calculations on the supercomputers of the North German High Performance Computing Network (HLRN). They show that in the investigated iron films the tilting of the atomic bar magnets in a lattice of magnetic vortices, i.e. in all spatial directions, is very unfavorable. Instead, a nearly parallel or antiparallel alignment of neighboring atomic bar magnets is favored.

    “This result completely surprised us. A lattice of skyrmions was thus no longer an option to explain the experimental observations,” says Mara Gutzeit, doctoral researcher and first author of the study. The development of an atomistic spin model made clear that it must be a novel class of magnetic lattices, which the researchers called “mosaic lattices”. “We found out that these mosaic-like magnetic structures are caused by higher-order exchange terms, predicted only a few years ago,” says Dr. Soumyajyoti Haldar from the group of Kiel.

    “The study impressively shows how diverse spin structures can be and that a close collaboration between experimentally and theoretically working research groups can be really helpful for their understanding. In this field a few more surprises can be expected in the future,” states Professor Stefan Heinze.

    Science paper:
    Nature Communications
    See the science paper for instructive images.
    _________________________________________________
    About spin electronics:

    In addition to the charge of the electrons, spin electronics also uses their so-called spin. This electron spin is a quantum mechanical property and can be understood in simplified terms as the rotation of the electrons around their own axis. This is linked to a magnetic moment that leads to the formation of “atomic bar magnets” (atomic spins) in magnetic materials. They are suitable for processing and storing information. Through targeted electrical manipulation, it would be possible to create faster, more energy-saving and more powerful components for information technology.

    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 University of Hamburg [Universität Hamburg] (DE) is the largest institution for research and education in northern Germany. As one of the country’s largest universities, we offer a diverse range of degree programs and excellent research opportunities. The University boasts numerous interdisciplinary projects in a broad range of fields and an extensive partner network of leading regional, national, and international higher education and research institutions.
    Sustainable science and scholarship

    Universität Hamburg is committed to sustainability. All our faculties have taken great strides towards sustainability in both research and teaching.
    Excellent research

    As part of the Excellence Strategy of the Federal and State Governments, Universität Hamburg has been granted clusters of excellence for 4 core research areas: Advanced Imaging of Matter (photon and nanosciences), Climate, Climatic Change, and Society (CliCCS) (climate research), Understanding Written Artefacts (manuscript research) and Quantum Universe (mathematics, particle physics, astrophysics, and cosmology).

    An equally important core research area is Infection Research, in which researchers investigate the structure, dynamics, and mechanisms of infection processes to promote the development of new treatment methods and therapies.
    Outstanding variety: over 170 degree programs

    Universität Hamburg offers approximately 170 degree programs within its eight faculties:

    Faculty of Law
    Faculty of Business, Economics and Social Sciences
    Faculty of Medicine
    Faculty of Education
    Faculty of Mathematics, Informatics and Natural Sciences
    Faculty of Psychology and Human Movement Science
    Faculty of Business Administration (Hamburg Business School).

    Universität Hamburg is also home to several museums and collections, such as the Zoological Museum, the Herbarium Hamburgense, the Geological-Paleontological Museum, the Loki Schmidt Garden, and the Hamburg Observatory.
    History

    Universität Hamburg was founded in 1919 by local citizens. Important founding figures include Senator Werner von Melle and the merchant Edmund Siemers. Nobel Prize winners such as the physicists Otto Stern, Wolfgang Pauli, and Isidor Rabi taught and researched at the University. Many other distinguished scholars, such as Ernst Cassirer, Erwin Panofsky, Aby Warburg, William Stern, Agathe Lasch, Magdalene Schoch, Emil Artin, Ralf Dahrendorf, and Carl Friedrich von Weizsäcker, also worked here.

    The Kiel University [ Christian-Albrechts-Universität zu Kiel ] (DE) was founded back in 1665. It is Schleswig-Holstein’s oldest, largest and best-known university, with over 26,000 students and around 3,000 members of staff. It is also the only fully-fledged university in the state. Seven Nobel prize winners have worked here. The CAU has been successfully taking part in the Excellence Initiative since 2006. The Cluster of Excellence The Future Ocean, which was established in cooperation with the GEOMAR [Helmholtz-Zentrum für Ozeanforschung Kiel](DE) in 2006, is internationally recognized. The second Cluster of Excellence “Inflammation at Interfaces” deals with chronic inflammatory diseases. The Kiel Institute for the World Economy is also affiliated with Kiel University. The university has a great reputation for its focus on public international law. The oldest public international law institution in Germany and Europe – the Walther Schuecking Institute for International Law – is based in Kiel.

    History

    The University of Kiel was founded under the name Christiana Albertina on 5 October 1665 by Christian Albert, Duke of Holstein-Gottorp. The citizens of the city of Kiel were initially quite sceptical about the upcoming influx of students, thinking that these could be “quite a pest with their gluttony, heavy drinking and their questionable character” (German: mit Fressen, Sauffen und allerley leichtfertigem Wesen sehr ärgerlich seyn). But those in the city who envisioned economic advantages of a university in the city won, and Kiel thus became the northernmost university in the German Holy Roman Empire.

    After 1773, when Kiel had come under Danish rule, the university began to thrive, and when Kiel became part of Prussia in the year 1867, the university grew rapidly in size. The university opened one of the first botanical gardens in Germany (now the Alter Botanischer Garten Kiel), and Martin Gropius designed many of the new buildings needed to teach the growing number of students.

    The Christiana Albertina was one of the first German universities to obey the Gleichschaltung in 1933 and agreed to remove many professors and students from the school, for instance Ferdinand Tönnies or Felix Jacoby. During World War II, the University of Kiel suffered heavy damage, therefore it was later rebuilt at a different location with only a few of the older buildings housing the medical school.

    In 2019, it was announced it has banned full-face coverings in classrooms, citing the need for open communication that includes facial expressions and gestures.

    Faculties

    Faculty of Theology
    Faculty of Law
    Faculty of Business, Economics and Social Sciences
    Faculty of Medicine
    Faculty of Arts and Humanities
    Faculty of Mathematics and Natural Sciences
    Faculty of Agricultural Science and Nutrition
    Faculty of Engineering

     
  • richardmitnick 9:43 am on July 2, 2022 Permalink | Reply
    Tags: "Characterizing the materials for next-generation quantum computers with nonlinear optical spectroscopy", , , , , The University of Hamburg [Universität Hamburg] (DE)   

    From The University of Hamburg [Universität Hamburg] (DE) and The University of California-Irvine via “phys.org” : “Characterizing the materials for next-generation quantum computers with nonlinear optical spectroscopy” 

    1

    From The University of Hamburg [Universität Hamburg] (DE)

    and

    UC Irvine bloc

    The University of California-Irvine

    via

    “phys.org”

    July 1, 2022

    1
    Imaginary part of the 2D spectrum of the Kitaev ring in (a) the topologically trivial phase with μ=0.005Λ, w=Δ=0.495Λ, and (b) the nontrivial phase with μ=0.495Λ and w=Δ=0.005Λ for N=60. Credit: Physical Review Letters (2022).

    Researchers at the Department of Physics and the Cluster of Excellence “CUI: Advanced Imaging of Matter” of Universität Hamburg and the University of California-Irvine have recently proposed a new way to characterize topological superconductors by means of multi-THz-pulse experiments.

    This opens a pathway to unambiguously identifying predicted exotic states of matter and can aid in the design of novel materials for future devices that carry and process quantum information.

    Scientists around the world are working to build scalable quantum computers based on solid-state matter. One such class of materials are topological superconductors. They are purported to host a particular kind of collective quantum state, the non-abelian anyons in the form of Majorana fermions at their boundaries. By shuffling these quasiparticles around in networks of quantum wires, researchers can construct logical quantum gates, the building blocks of quantum computers.

    Bulk instead of boundary properties

    Early signatures of the existence of Majoranas were reported on the basis of measurements of quantum transport, but later these studies turned out to be unreliable because Majoranas can easily be confused with trivial boundary excitations. The new theory takes a different approach. Instead of investigating the Majoranas at the boundaries of the device, the bulk material is addressed. Due to the so-called “bulk-boundary correspondence,” Majoranas are intimately connected to the topology of the bulk band structure of the superconductor. In some sense, the particle excitations in the bulk material experience a “twist” with the Majoranas at the boundaries. This strong interlinking can be studied by means of two-dimensional THz spectroscopy, a technique widely used in molecules and bulk matter.

    “Unlike ‘linear’ absorption spectroscopy, nonlinear multi-pulse experiments allow us to study the optical response of excited particles and thus help to reveal this ‘twisting’ clearly, with unique signatures of the exotic topological state in the 2D spectra,” says Prof. Dr. Michael Thorwart of Universität Hamburg and scientist in the Cluster of Excellence.

    Appearing in Physical Review Letters, the theory proposal formulates an important step between the detection of the most basic but not fully characterizing properties of Majoranas and the yet too ambitious demonstration of the logical gate operations with non-abelian anyons in the form of braiding of Majorana states.

    “Such optical techniques yield spectroscopic information beyond imaging and allow for an undoubtful characterization of topological materials. As such, they might build a bridge to their faraway applications in quantum technologies,” adds Felix Gerken, lead author and Ph.D. student at the CUI-Graduate School of the Cluster of Excellence.

    See the full article here .

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

    Please help promote STEM in your local schools.

    Stem Education Coalition

    Since 1965, the University of California-Irvine has combined the strengths of a major research university with the bounty of an incomparable Southern California location. UCI’s unyielding commitment to rigorous academics, cutting-edge research, and leadership and character development makes the campus a driving force for innovation and discovery that serves our local, national and global communities in many ways.

    With more than 29,000 undergraduate and graduate students, 1,100 faculty and 9,400 staff, UCI is among the most dynamic campuses in the University of California system. Increasingly a first-choice campus for students, UCI ranks among the top 10 U.S. universities in the number of undergraduate applications and continues to admit freshmen with highly competitive academic profiles.

    UCI fosters the rigorous expansion and creation of knowledge through quality education. Graduates are equipped with the tools of analysis, expression and cultural understanding necessary for leadership in today’s world.

    Consistently ranked among the nation’s best universities – public and private – UCI excels in a broad range of fields, garnering national recognition for many schools, departments and programs. Times Higher Education ranked UCI No. 1 among universities in the U.S. under 50 years old. Three UCI researchers have won Nobel Prizes – two in chemistry and one in physics.

    The university is noted for its top-rated research and graduate programs, extensive commitment to undergraduate education, and growing number of professional schools and programs of academic and social significance. Recent additions include highly successful programs in public health, pharmaceutical sciences and nursing science; an expanding education school; and a law school already ranked among the nation’s top 10 for its scholarly impact.

    The University of Hamburg [Universität Hamburg] (DE) is the largest institution for research and education in northern Germany. As one of the country’s largest universities, we offer a diverse range of degree programs and excellent research opportunities. The University boasts numerous interdisciplinary projects in a broad range of fields and an extensive partner network of leading regional, national, and international higher education and research institutions.
    Sustainable science and scholarship

    Universität Hamburg is committed to sustainability. All our faculties have taken great strides towards sustainability in both research and teaching.
    Excellent research

    As part of the Excellence Strategy of the Federal and State Governments, Universität Hamburg has been granted clusters of excellence for 4 core research areas: Advanced Imaging of Matter (photon and nanosciences), Climate, Climatic Change, and Society (CliCCS) (climate research), Understanding Written Artefacts (manuscript research) and Quantum Universe (mathematics, particle physics, astrophysics, and cosmology).

    An equally important core research area is Infection Research, in which researchers investigate the structure, dynamics, and mechanisms of infection processes to promote the development of new treatment methods and therapies.
    Outstanding variety: over 170 degree programs

    Universität Hamburg offers approximately 170 degree programs within its eight faculties:

    Faculty of Law
    Faculty of Business, Economics and Social Sciences
    Faculty of Medicine
    Faculty of Education
    Faculty of Mathematics, Informatics and Natural Sciences
    Faculty of Psychology and Human Movement Science
    Faculty of Business Administration (Hamburg Business School).

    Universität Hamburg is also home to several museums and collections, such as the Zoological Museum, the Herbarium Hamburgense, the Geological-Paleontological Museum, the Loki Schmidt Garden, and the Hamburg Observatory.
    History

    Universität Hamburg was founded in 1919 by local citizens. Important founding figures include Senator Werner von Melle and the merchant Edmund Siemers. Nobel Prize winners such as the physicists Otto Stern, Wolfgang Pauli, and Isidor Rabi taught and researched at the University. Many other distinguished scholars, such as Ernst Cassirer, Erwin Panofsky, Aby Warburg, William Stern, Agathe Lasch, Magdalene Schoch, Emil Artin, Ralf Dahrendorf, and Carl Friedrich von Weizsäcker, also worked here.

     
  • richardmitnick 5:10 pm on February 24, 2022 Permalink | Reply
    Tags: "Colossal Shock Wave Rippling Across Space Is Bigger Than Our Entire Galaxy", , The INAF - Institute of Space Astrophysics and Cosmic Physics of Milano [Istituto Nazionale di Astrofisica ] (IT), The University of Hamburg [Universität Hamburg] (DE)   

    From The University of Hamburg [Universität Hamburg] (DE) and The INAF – Institute of Space Astrophysics and Cosmic Physics of Milano [Istituto Nazionale di Astrofisica ] (IT) via Science Alert (AU): “Colossal Shock Wave Rippling Across Space Is Bigger Than Our Entire Galaxy” 

    1
    From The University of Hamburg [Universität Hamburg] (DE)

    and

    The INAF – Institute of Space Astrophysics and Cosmic Physics of Milano [Istituto Nazionale di Astrofisica ] (IT)

    via

    ScienceAlert

    Science Alert (AU)

    24 FEBRUARY 2022
    MICHELLE STARR

    1
    The main shock of Abell 3667 compared to the Milky Way. Credit: Francesco de Gasperin/SARAO – South African Radio Astronomy Observatory (SA))

    A billion years ago, an absolutely monstrous collision of two clusters of galaxies produced a pair of shock waves of absolutely epic proportions.

    Today, the structures gleam brightly in radio wavelengths, so huge they could easily engulf the Milky Way galaxy’s estimated 100,000 light-year diameter, stretching up to 6.5 million light-years through intergalactic space.

    Now, using the MeerKAT radio telescope in South Africa, a team of astronomers has made the most detailed study of these radio structures yet, gaining new insight into some of the most massive events in the Universe.

    “These structures are full of surprises and much more complex than what we initially thought,” says astronomer Francesco de Gasperin of the University of Hamburg in Germany and the National Institute for Astrophysics in Italy.

    “The shock waves act as giant particle accelerators that accelerate electrons to speeds close to the speed of light. When these fast electrons cross a magnetic field they emit the radio waves that we see.

    “The shocks are threaded by an intricate pattern of bright filaments that trace the location of giant magnetic field lines and the regions where electrons are accelerated.”

    2
    The magnetic fields of the main shock. Credit: Francesco de Gasperin/SARAO.

    Galaxy clusters are the largest structures in the Universe that are bound together by gravity. They can be absolutely gigantic, containing hundreds or thousands of individual galaxies. Galaxies and galaxy clusters travel along filaments of the cosmic web to cluster nodes, where they join together to form even larger clusters.

    These epic events happen at high velocities, generating cluster-scale shock waves that propagate through space, also at high velocities.

    This particular cluster, called Abell 3667, is still coming together. At least 550 galaxies have been associated with it, and the shock waves are propagating through it at velocities around 1,500 kilometers per second (930 miles per second).

    The shocks that are associated with cluster mergers are known as radio relics, and they can be used to probe the properties of the intergalactic space within the cluster, known as the intracluster medium, and intracluster dynamics.

    Abell 3667, at around 700 million light-years away, is relatively close to us, and also quite massive, which means it’s an excellent target for such probes.

    4
    Both radio relics of Abell 3667. Credit: Francesco de Gasperin/SARAO.

    Because the cluster is in the southern sky, astronomers were able to look at it with one of the most sensitive radio telescopes in the world. MeerKAT is a precursor to and pathfinder for the Square Kilometre Array (SKA) that is currently being developed across Australia and South Africa to provide an unprecedented radio eye on the sky.

    MeerKAT’s observations, and those of the Australian Square Kilometer Array Pathfinder, are giving us a taste of the future; not just for the SKA, projected to see first light in 2027, but what we can find now.

    “Our observations have unveiled the complexity of the interplay between the thermal and non-thermal components in the most active regions of a merging cluster,” the researchers write in their study.

    “Both the intricate internal structure of radio relics and the direct detection of magnetic draping around the merging bullet are powerful examples of the non-trivial magnetic properties of the intracluster medium. Thanks to its sensitivity to polarized radiation, MeerKAT will be transformational in the study of these complex phenomena.”

    The research has been published in Astronomy & Astrophysics.

    See the full article here .

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

    Please help promote STEM in your local schools.

    Stem Education Coalition

    2

    The University of Hamburg [Universität Hamburg] (DE) is the largest institution for research and education in northern Germany. As one of the country’s largest universities, we offer a diverse range of degree programs and excellent research opportunities. The University boasts numerous interdisciplinary projects in a broad range of fields and an extensive partner network of leading regional, national, and international higher education and research institutions.
    Sustainable science and scholarship

    Universität Hamburg is committed to sustainability. All our faculties have taken great strides towards sustainability in both research and teaching.
    Excellent research

    As part of the Excellence Strategy of the Federal and State Governments, Universität Hamburg has been granted clusters of excellence for 4 core research areas: Advanced Imaging of Matter (photon and nanosciences), Climate, Climatic Change, and Society (CliCCS) (climate research), Understanding Written Artefacts (manuscript research) and Quantum Universe (mathematics, particle physics, astrophysics, and cosmology).

    An equally important core research area is Infection Research, in which researchers investigate the structure, dynamics, and mechanisms of infection processes to promote the development of new treatment methods and therapies.
    Outstanding variety: over 170 degree programs

    Universität Hamburg offers approximately 170 degree programs within its eight faculties:

    Faculty of Law
    Faculty of Business, Economics and Social Sciences
    Faculty of Medicine
    Faculty of Education
    Faculty of Mathematics, Informatics and Natural Sciences
    Faculty of Psychology and Human Movement Science
    Faculty of Business Administration (Hamburg Business School).

    Universität Hamburg is also home to several museums and collections, such as the Zoological Museum, the Herbarium Hamburgense, the Geological-Paleontological Museum, the Loki Schmidt Garden, and the Hamburg Observatory.
    History

    Universität Hamburg was founded in 1919 by local citizens. Important founding figures include Senator Werner von Melle and the merchant Edmund Siemers. Nobel Prize winners such as the physicists Otto Stern, Wolfgang Pauli, and Isidor Rabi taught and researched at the University. Many other distinguished scholars, such as Ernst Cassirer, Erwin Panofsky, Aby Warburg, William Stern, Agathe Lasch, Magdalene Schoch, Emil Artin, Ralf Dahrendorf, and Carl Friedrich von Weizsäcker, also worked here.

     
  • richardmitnick 9:45 am on January 3, 2022 Permalink | Reply
    Tags: "The Tiny Dots in This Image Aren't Stars or Galaxies. They're Black Holes", , , , , LOFAR/LOL Survey, LoLSS: LOFAR LBA Sky Survey, , , The Leiden University [Universiteit Leiden] (NL), The University of Hamburg [Universität Hamburg] (DE)   

    From The University of Hamburg [Universität Hamburg] (DE) and The Leiden University [Universiteit Leiden] (NL) via Science Alert (US) : “The Tiny Dots in This Image Aren’t Stars or Galaxies. They’re Black Holes” 

    1
    From The University of Hamburg [Universität Hamburg] (DE)

    and

    The Leiden University [Universiteit Leiden] (NL)

    via

    ScienceAlert

    Science Alert (US)

    2 JANUARY 2022
    MICHELLE STARR

    1
    Credit: LOFAR/LOL Survey.

    The image above may look like a fairly normal picture of the night sky, but what you’re looking at is a lot more special than just glittering stars. Each of those white dots is an active supermassive black hole.

    And each of those black holes is devouring material at the heart of a galaxy millions of light-years away – that’s how they could be pinpointed at all.

    Totaling 25,000 such dots, astronomers created the most detailed map to date of black holes at low radio frequencies in early 2021, an achievement that took years and a Europe-sized radio telescope to compile.

    “This is the result of many years of work on incredibly difficult data,” explained astronomer Francesco de Gasperin [Astronomy & Astrophysics] of the University of Hamburg in Germany. “We had to invent new methods to convert the radio signals into images of the sky.”

    2
    Credit: LOFAR/LOL Survey.

    When they’re just hanging out not doing much, black holes don’t give off any detectable radiation, making them much harder to find. When a black hole is actively accreting material – spooling it in from a disc of dust and gas that circles it much as water circles a drain [Physical Review Letters] – the intense forces involved generate radiation across multiple wavelengths that we can detect across the vastness of space.

    What makes the above image so special is that it covers the ultra-low radio wavelengths, as detected by the LOw Frequency ARray (LOFAR) in Europe. This interferometric network consists of around 20,000 radio antennas, distributed throughout 52 locations across Europe.

    ASTRON Institute for Radio Astronomy(NL) LOFAR Radio Antenna Bank(NL)

    ASTRON (NL) LOFAR European Map.

    Currently, LOFAR is the only radio telescope network capable of deep, high-resolution imaging at frequencies below 100 megahertz, offering a view of the sky like no other. This data release, covering four percent of the Northern sky, was the first for the network’s ambitious plan to image the entire Northern sky in ultra-low-frequencies, the LOFAR LBA Sky Survey (LoLSS).

    Because it’s based on Earth, LOFAR does have a significant hurdle to overcome that doesn’t afflict space-based telescopes: the ionosphere. This is particularly problematic for ultra-low-frequency radio waves [Astronomy & Astrophysics], which can be reflected back into space. At frequencies below 5 megahertz, the ionosphere is opaque for this reason.

    The frequencies that do penetrate the ionosphere can vary according to atmospheric conditions. To overcome this problem, the team used supercomputers running algorithms to correct for ionospheric interference every four seconds. Over the 256 hours that LOFAR stared at the sky, that’s a lot of corrections.

    This is what has given us such a clear view of the ultra-low-frequency sky.

    “After many years of software development, it is so wonderful to see that this has now really worked out,” said astronomer Huub Röttgering of The Leiden Observatory [Sterrewacht Leiden](NL).

    Having to correct for the ionosphere has another benefit, too: It will allow astronomers to use LoLSS data to study the ionosphere itself. Ionospheric traveling waves, scintillations, and the relationship of the ionosphere with solar cycles could be characterized in much greater detail with the LoLSS. This will allow scientists to better constrain ionospheric models.

    And the survey will provide new data on all sorts of astronomical objects and phenomena, as well as possibly undiscovered or unexplored objects in the region below 50 megahertz.

    “The final release of the survey will facilitate advances across a range of astronomical research areas,” the researchers wrote in their paper.

    “[This] will allow for the study of more than 1 million low-frequency radio spectra, providing unique insights on physical models for galaxies, active nuclei, galaxy clusters, and other fields of research. This experiment represents a unique attempt to explore the ultra-low frequency sky at a high angular resolution and depth.”

    The results have been published in Astronomy & Astrophysics.

    See the full article here .

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

    Please help promote STEM in your local schools.

    Stem Education Coalition

    Universiteit Leiden Heijmans onderhoudt.

    The Leiden University [Universiteit Leiden] (NL) is a public research university in Leiden, Netherlands. Founded in 1575 by William, Prince of Orange as a reward to the town of Leiden for its defense against Spanish attacks during the Eighty Years’ War, it is the oldest institution of higher education in the Netherlands.

    Known for its historic foundations and emphasis on the social sciences, the university came into particular prominence during the Dutch Golden Age, when scholars from around Europe were attracted to the Dutch Republic due to its climate of intellectual tolerance and Leiden’s international reputation. During this time, Leiden became the home to individuals such as René Descartes, Rembrandt, Christiaan Huygens, Hugo Grotius, Baruch Spinoza and Baron d’Holbach.

    The university has seven academic faculties and over fifty subject departments while housing more than 40 national and international research institutes. Its historical primary campus consists of buildings scattered across the college town of Leiden, while a second campus located in The Hague houses a liberal arts college and several of its faculties. It is a member of The Coimbra Group Universities(EU), The Europaeum, and a founding member of The League of European Research Universities (EU).

    Leiden University consistently ranks among the top 100 universities in the world by major ranking tables. It was placed top 50 worldwide in thirteen fields of study in the 2020 QS World University Rankings: classics & ancient history, politics, archaeology, anthropology, history, pharmacology, law, public policy, public administration, religious studies, arts & humanities, linguistics, modern languages and sociology.

    The school has produced twenty-one Spinoza Prize Laureates and sixteen Nobel Laureates, including Enrico Fermi and Albert Einstein. It is closely associated with the Dutch Royal Family, with Queen Juliana, Queen Beatrix and King Willem-Alexander being alumni. Ten prime ministers of the Netherlands were also Leiden University alumni. Internationally, it is associated with nine foreign leaders, among them John Quincy Adams (the 6th President of the United States), two NATO Secretaries General, a President of the International Court of Justice, and a Prime Minister of the United Kingdom.

    In 1575, the emerging Dutch Republic did not have any universities in its northern heartland. The only other university in the Habsburg Netherlands was the University of Leuven [Universiteit Leuven](BE) in southern Leuven, firmly under Spanish control. The scientific renaissance had begun to highlight the importance of academic study, so Prince William founded the first Dutch university in Leiden, to give the Northern Netherlands an institution that could educate its citizens for religious purposes, but also to give the country and its government educated men in other fields. It is said the choice fell on Leiden as a reward for the heroic defence of Leiden against Spanish attacks in the previous year. Ironically, the name of Philip II of Spain, William’s adversary, appears on the official foundation certificate, as he was still the de jure count of Holland. Philip II replied by forbidding any subject to study in Leiden. Originally located in the convent of St Barbara, the university moved to the Faliede Bagijn Church in 1577 (now the location of the University museum) and in 1581 to the convent of the White Nuns, a site which it still occupies, though the original building was destroyed by fire in 1616.

    The presence within half a century of the date of its foundation of such scholars as Justus Lipsius; Joseph Scaliger; Franciscus Gomarus; Hugo Grotius; Jacobus Arminius; Daniel Heinsius; and Gerhard Johann Vossius rapidly made Leiden university into a highly regarded institution that attracted students from across Europe in the 17th century. Renowned philosopher Baruch Spinoza was based close to Leiden during this period and interacted with numerous scholars at the university. The learning and reputation of Jacobus Gronovius; Herman Boerhaave; Tiberius Hemsterhuis; and David Ruhnken, among others, enabled Leiden to maintain its reputation for excellence down to the end of the 18th century.

    At the end of the nineteenth century, Leiden University again became one of Europe’s leading universities. In 1896 the Zeeman effect was discovered there by Pieter Zeeman and shortly afterwards given a classical explanation by Hendrik Antoon Lorentz. At the world’s first university low-temperature laboratory, professor Heike Kamerlingh Onnes achieved temperatures of only one degree above absolute zero of −273 degrees Celsius. In 1908 he was also the first to succeed in liquifying helium and can be credited with the discovery of the superconductivity in metals.

    The University Library, which has more than 5.2 million books and fifty thousand journals, also has a number of internationally renowned special collections of western and oriental manuscripts, printed books, archives, prints, drawings, photographs, maps, and atlases. It houses the largest collections worldwide on Indonesia and the Caribbean. The research activities of the Scaliger Institute focus on these special collections and concentrate particularly on the various aspects of the transmission of knowledge and ideas through texts and images from antiquity to the present day.

    In 2005 the manuscript of Einstein on the quantum theory of the monatomic ideal gas (the Einstein-Bose condensation) was discovered in one of Leiden’s libraries.

    2

    The University of Hamburg [Universität Hamburg] (DE) is the largest institution for research and education in northern Germany. As one of the country’s largest universities, we offer a diverse range of degree programs and excellent research opportunities. The University boasts numerous interdisciplinary projects in a broad range of fields and an extensive partner network of leading regional, national, and international higher education and research institutions.

    Sustainable science and scholarship

    Universität Hamburg is committed to sustainability. All our faculties have taken great strides towards sustainability in both research and teaching.

    Excellent research

    As part of the Excellence Strategy of the Federal and State Governments, Universität Hamburg has been granted clusters of excellence for 4 core research areas: Advanced Imaging of Matter (photon and nanosciences), Climate, Climatic Change, and Society (CliCCS) (climate research), Understanding Written Artefacts (manuscript research) and Quantum Universe (mathematics, particle physics, astrophysics, and cosmology).

    An equally important core research area is Infection Research, in which researchers investigate the structure, dynamics, and mechanisms of infection processes to promote the development of new treatment methods and therapies.

    Outstanding variety: over 170 degree programs

    Universität Hamburg offers approximately 170 degree programs within its eight faculties:

    Faculty of Law
    Faculty of Business, Economics and Social Sciences
    Faculty of Medicine
    Faculty of Education
    Faculty of Mathematics, Informatics and Natural Sciences
    Faculty of Psychology and Human Movement Science
    Faculty of Business Administration (Hamburg Business School).

    Universität Hamburg is also home to several museums and collections, such as the Zoological Museum, the Herbarium Hamburgense, the Geological-Paleontological Museum, the Loki Schmidt Garden, and the Hamburg Observatory.
    History

    Universität Hamburg was founded in 1919 by local citizens. Important founding figures include Senator Werner von Melle and the merchant Edmund Siemers. Nobel Prize winners such as the physicists Otto Stern, Wolfgang Pauli, and Isidor Rabi taught and researched at the University. Many other distinguished scholars, such as Ernst Cassirer, Erwin Panofsky, Aby Warburg, William Stern, Agathe Lasch, Magdalene Schoch, Emil Artin, Ralf Dahrendorf, and Carl Friedrich von Weizsäcker, also worked here.

     
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