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  • richardmitnick 3:27 pm on May 27, 2021 Permalink | Reply
    Tags: An experiment in which a quantum system consisting of two coupled atoms behaves surprisingly stable under electron bombardment., Decoherence is one of the greatest enemies of the quantum physicist., EurekaAlert, , , Quantum systems are considered extremely fragile. Even the smallest interactions with the environment can result in the loss of sensitive quantum effects., , The discovery could have far-reaching consequences for the development of quantum computers.   

    From Jülich Research Centre [Forschungszentrum Jülichs] (FZJ)(DE) via EurekaAlert : “Astonishing quantum experiment in Science raises questions” 

    From Jülich Research Centre [Forschungszentrum Jülichs] (FZJ)(DE)

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    eurekaalert-bloc

    EurekaAlert

    1
    Credit: Enrique Sahagún, Scixel.

    Quantum systems are considered extremely fragile. Even the smallest interactions with the environment can result in the loss of sensitive quantum effects. In the renowned journal Science, however, researchers from Delft University of Technology [Technische Universiteit Delft] (NL), RWTH AACHEN UNIVERSITY [Rheinisch-Westfaelische Technische Hochschule (DE) and Forschungszentrum Jülich now present an experiment in which a quantum system consisting of two coupled atoms behaves surprisingly stable under electron bombardment. The experiment provide an indication that special quantum states might be realised in a quantum computer more easily than previously thought.

    The so-called decoherence is one of the greatest enemies of the quantum physicist. Experts understand by this the decay of quantum states. This inevitably occurs when the system interacts with its environment. In the macroscopic world, this exchange is unavoidable, which is why quantum effects rarely occur in daily life. The quantum systems used in research, such as individual atoms, electrons or photons, are better shielded, but are fundamentally similarly sensitive.

    “Systems subject to quantum physics, unlike classical objects, are not sharply defined in all their properties. Instead, they can occupy several states at once. This is called superposition,” Markus Ternes explains. “A famous example is Schrödinger’s thought experiment with the cat, which is temporarily dead and alive at the same time. However, the superposition breaks down as soon as the system is disturbed or measured. What is left then is only a single state, which is the measured value,” says the quantum physicist from Forschungszentrum Jülich and RWTH Aachen University.

    Given this context, the experiment that researchers at TU Delft have now carried out seems all the more astonishing. Using a new method, they succeeded for the first time in real-time observing how two coupled atoms freely exchange quantum information, switching back and forth between different states in a flip-flop interaction.

    “Each atom carries a small magnetic moment called spin. These spins influence each other, like compass needles do when you bring them close. If you give one of them a push, they will start moving together in a very specific way,” explains Sander Otte, head of the Delft team that performed the experiment.

    On a large scale, this kind of information exchange between atoms can lead to fascinating phenomena. Various forms of quantum technologies are based on these. A classical example is superconductivity: the effect where some materials lose all electrical resistivity below a critical temperature.

    Unconventional approach

    To observe this interaction between atoms, Otte and his team chose a rather direct way: Using a scanning tunnelling microscope, they placed two titanium atoms next to each other at a distance of just over one nanometre – one millionth of a millimetre. At that distance, the atoms are just able to feel each other’s spin. If you would now twist one of the two spins, the conversation will start by itself.

    Usually, this twist is performed by sending very precise radio signals to the atoms. This so-called spin resonance technique – which is quite reminiscent of the working principle of an MRI scanner found in hospitals – is used successfully in research on quantum bits. Among other things, quantum bits in certain types of quantum computers are programmed in such a way. However, the method has a disadvantage. “It is simply too slow,” says PhD student Lukas Veldman, lead author on the Science publication. “You have barely started twisting the one spin before the other starts to rotate along. This way you can never investigate what happens upon placing the two spins in opposite directions.”

    So the researchers tried something unorthodox: they rapidly inverted the spin of one of the two atoms with a sudden burst of electric current. To their surprise, this drastic approach resulted in a beautiful quantum interaction, exactly by the book. During the pulse, electrons collide with the atom, causing its spin to rotate. Otte: “But we always assumed that during this process, the delicate quantum information – the so-called coherence – was lost. After all, the electrons that you send are incoherent: the history of each electron prior to the collision is slightly different and this chaos is transferred to the atom’s spin, destroying any coherence.”

    The fact that this now seems not to be true was cause for some debate. Apparently, each random electron, regardless of its past, can initiate a superposition: a specific combination of elementary quantum states which is fully known and which forms the basis for almost any form of quantum technology. The aspect that these electrons are still connected to their environment via their history is obviously irrelevant. What is at stake here, then, is the violation of a principle of quantum physics, according to which every measurement irretrievably destroys the superposition of quantum states.

    “The crux is that it depends on the perspective,” argues Markus Ternes, co-author of the Science paper. “The electron inverts the spin of one atom causing it to point, say, to the left. You could view this as a measurement, erasing all quantum memory. But from the point of view of the combined system comprising both atoms, the resulting situation is not so mundane at all. For the two atoms together, the new state constitutes a perfect superposition, enabling the exchange of information between them. Crucially for this to happen is that both spins become entangled: a particular quantum state in which they share more information about each other than classically possible.”

    The discovery could have far-reaching consequences for the development of quantum computers, whose function is based on the entanglement and superposition of quantum states. If one follows the findings, one could get away with being slightly less careful when initializing quantum states than previously thought. For Otte and his team at TU Delft, however, the result is above all the starting point of further exciting experiments. Veldman: “Here we used two atoms, but what happens if you use three? Or ten, or a thousand? Nobody can predict that, because the computing power [for simulating such] numbers is not sufficient.”

    See the full article here.

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    Please help promote STEM in your local schools.

    Stem Education Coalition

    Jülich Research Centre[Forschungszentrum Jülich] is a member of the Helmholtz Association of German Research Centres [Helmholtz-Gemeinschaft Deutscher Forschungszentren ](DE) and is one of the largest interdisciplinary research centres in Europe. It was founded on 11 December 1956 by the state of North Rhine-Westphalia as a registered association, before it became “Kernforschungsanlage Jülich GmbH” or Nuclear Research Centre Jülich in 1967. In 1990, the name of the association was changed to “Forschungszentrum Jülich GmbH”. It has close collaborations with RWTH Aachen in the form of Jülich-Aachen Research Alliance (JARA).

    Jülich Research Centre [Forschungszentrum Jülichs](FZJ)(DE) is situated in the middle of the Stetternich Forest in Jülich (Kreis Düren, Rheinland) and covers an area of 2.2 square kilometres.

    Jülich Research Centre [Forschungszentrum Jülichs](FZJ)(DE) employs more than 5,700 members of staff (2015) and works within the framework of the disciplines physics, chemistry, biology, medicine and engineering on the basic principles and applications in the areas of health, information, environment and energy. Amongst the members of staff, there are approx. 1,500 scientists including 400 PhD students and 130 diploma students. Around 600 people work in the administration and service areas, 500 work for project management agencies, and there are 1,600 technical staff members, while around 330 trainees are completing their training in more than 20 professions.

    More than 800 visiting scientists come to Forschungszentrum Jülich every year from about 50 countries.

     
  • richardmitnick 5:08 pm on May 19, 2021 Permalink | Reply
    Tags: "A revolutionary method to drastically reduce stray light on space telescopes", EurekaAlert, , Space based Astronomy and Earth Observation, Space engineering, University of Liege [Université de Liège] (BE)   

    From University of Liege [Université de Liège] (BE) via EurekaAlert : “A revolutionary method to drastically reduce stray light on space telescopes” 

    From University of Liege [Université de Liège] (BE)

    via

    eurekaalert-bloc

    EurekaAlert

    Lionel Clermont
    Lionel.Clermont@uliege.be
    32-043-824-600

    A team of researchers at the Centre Spatial de Liège (CSL) of the University of Liège has just developed a method to identify the contributors and origins of stray light on space telescopes. This is a major advance in the field of space engineering that will help in the acquisition of even finer space images and the development of increasingly efficient space instruments. This study has just been published in the journal Scientific Reports.

    1
    Stray light decomposition by ultrafast time-of-flight imaging.
    Credit: Lionel Clermont / Centre Spatial de Liège / Université de Liège

    Space telescopes are becoming more and more powerful. Technological developments in recent years have made it possible, for example, to observe objects further and further into the universe or to measure the composition of the Earth’s atmosphere with ever greater precision. However, there is still one factor limiting the performance of these telescopes: stray light. A phenomenon that has been known fora long time, stray light results in light reflections (ghost reflections between lenses, scattering, etc.) that damage the quality of images and often lead to blurred images. Until now, the methods for checking and characterizing this stray light during the development phase of the telescopes have been very limited, making it possible to “just” know whether or not the instrument was sensitive to the phenomenon, forcing engineers to revise all their calculations in positive cases, leading to considerable delays in the commissioning of these advanced tools.

    Researchers at the Centre Spatial de Liège (CSL), in collaboration with the University of Strasbourg [Université de Strasbourg](FR), have just developed a revolutionary method for solving this problem by using a femto-second pulsed laser to send light beams to illuminate the telescope. “Stray light rays take (in the telescope) different optical paths from the rays that form the image,” explains Lionel Clermont, an expert in space optical systems and stray light at CSL. Thanks to this, and using an ultra-fast detector (of the order of 10^-9 seconds of resolution, i.e. a thousandth of a millionth of a second), we are measuring the image and the different stray light effects at different times. In addition to this decomposition, we can identify each of the contributors using their arrival times, which are directly related to the optical path, and thus know the origin of the problem.” The CSL engineers have now demonstrated the effectiveness of this method in a paper, just published in the journal Scientific Reports, in which they present the first film showing ghost reflections in a refractive telescope arriving at different times. “We have also been able to use these measurements to reverse engineer theoretical models,” says Lionel Clermont, “which will make it possible, for example, to build better image processing models in the future.” By correlating these measurements with numerical models, the scientists will now be able to determine precisely the origin of the stray light and thus act accordingly to improve the system, both by improving the hardware and with the development of correction algorithms.

    More than just a scientific curiosity, this method developed at the CSL could well lead to a small revolution in the field of high-performance space instruments. “We have already received a great deal of interest from the European Space Agency [Agence spatiale européenne][Europäische Weltraumorganisation](EU) and from industrialists in the space sector,” says Marc Georges, an expert in metrology and lasers at CSL and co-author of the study. This method responds to an urgent problem that has been unresolved until now.” In the near future, CSL researchers intend to continue the development of this method, to increase its TRL (Technology Readiness Level) and bring it to an industrial level. An industrial application is already planned for the FLEX (Fluorescence Explorer) project, an earth observation telescope that is part of ESA’s Living Planet Program. The researchers hope to be able to apply it to scientific instruments as well.

    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 Liège [Université de Liège] (BE), is a major public university of the French Community of Belgium based in Liège, Wallonia, Belgium. Its official language is French. As of 2020, ULiège is ranked in the 301–350 category worldwide according to Times Higher Education, 451st by QS World University Rankings, and between the 201th and 300th place by the Academic Ranking of World Universities. More than 2000 people, academics, scientists and technicians, are involved in research of a wide variety of subjects from basic research to applied research.

    The University was founded in 1817 by William I of the Netherlands, then King of the United Kingdom of the Netherlands, and by his Minister of Education, Anton Reinhard Falck. The foundation of the university was the result of a long intellectual tradition which dates back to the origins of the Bishopric of Liège. Beginning in the eleventh century, the influence of the prince-bishops of Liège attracted students and prominent scientists and philosophers, such as Petrarch, to study in its libraries. The reputation of its medieval schools gave the city the reputation as a new Athens.

    A 17 March 1808 decree by Napoleon I concerning the organization of an imperial university indicated Liège as the site of a new academy to be composed of a Faculty of Arts and a Faculty of Science—the first university charter for Liège. Ultimately, Liège owes its university to William I of the Netherlands, who remembered the city’s prestigious legacy of teaching and culture when he decided to establish a new university on Walloon soil.

    Nearly 200 years later, settled to some extent in the Sart-Tilman [fr] district of Liège, the University of Liège belongs to the French community of Belgium. The University is located at the edge of the River Meuse, in the center of the Island, the Latin Quarter of Liège. In 2009, the Agronomical University of Gembloux (FUSAGx), based in Gembloux, in the Province of Namur, integrated ULiège. It has adopted a new name for academics as well as research, namely Gembloux Agro-Bio Tech.

     
  • richardmitnick 11:58 am on November 21, 2020 Permalink | Reply
    Tags: "New electronic chip delivers smarter light-powered AI", , Combining the core software needed to drive artificial intelligence with image-capturing hardware in a single electronic device., Different functionalities such as imaging or memory storage are achieved by shining different colours of light on the chip., EurekaAlert, , Neurorobotics, , Royal Melbourne Institute of Technology (AU), Smarter and smaller autonomous technologies like drones and robotics plus smart wearables and bionic implants like artificial retinas., The prototype delivered brain-like functionality in one powerful device.   

    From Royal Melbourne Institute of Technology (AU) via EurekaAlert: “New electronic chip delivers smarter, light-powered AI” 

    From Royal Melbourne Institute of Technology (AU)

    via

    eurekaalert-bloc

    EurekaAlert

    18-Nov-2020

    Gosia Kaszubska
    gosia.kaszubska@rmit.edu.au
    61-417-510-735

    Prototype tech shrinks AI to deliver brain-like functionality in one powerful device.

    1
    The light-powered AI chip – prototype technology that brings together imaging, processing, machine learning and memory.
    Credit: RMIT University.

    Researchers have developed artificial intelligence technology that brings together imaging, processing, machine learning and memory in one electronic chip, powered by light.

    The prototype shrinks artificial intelligence technology by imitating the way that the human brain processes visual information.

    The nanoscale advance combines the core software needed to drive artificial intelligence with image-capturing hardware in a single electronic device.

    With further development, the light-driven prototype could enable smarter and smaller autonomous technologies like drones and robotics, plus smart wearables and bionic implants like artificial retinas.

    The study, from an international team of Australian, American and Chinese researchers led by RMIT University, is published in the journal Advanced Materials.

    Lead researcher Associate Professor Sumeet Walia, from RMIT, said the prototype delivered brain-like functionality in one powerful device.

    “Our new technology radically boosts efficiency and accuracy by bringing multiple components and functionalities into a single platform,” Walia who also co-leads the Functional Materials and Microsystems Research Group said.

    “It’s getting us closer to an all-in-one AI device inspired by nature’s greatest computing innovation – the human brain.

    “Our aim is to replicate a core feature of how the brain learns, through imprinting vision as memory.

    “The prototype we’ve developed is a major leap forward towards neurorobotics, better technologies for human-machine interaction and scalable bionic systems.”

    Total package: advancing AI

    Typically artificial intelligence relies heavily on software and off-site data processing.

    The new prototype aims to integrate electronic hardware and intelligence together, for fast on-site decisions.

    “Imagine a dash cam in a car that’s integrated with such neuro-inspired hardware – it can recognise lights, signs, objects and make instant decisions, without having to connect to the internet,” Walia said.

    “By bringing it all together into one chip, we can deliver unprecedented levels of efficiency and speed in autonomous and AI-driven decision-making.”

    The technology builds on an earlier prototype chip from the RMIT team, which used light to create and modify memories.

    New built-in features mean the chip can now capture and automatically enhance images, classify numbers, and be trained to recognise patterns and images with an accuracy rate of over 90%.

    The device is also readily compatible with existing electronics and silicon technologies, for effortless future integration.

    Seeing the light: how the tech works

    The prototype is inspired by optogenetics, an emerging tool in biotechnology that allows scientists to delve into the body’s electrical system with great precision and use light to manipulate neurons.

    The AI chip is based on an ultra-thin material – black phosphorous – that changes electrical resistance in response to different wavelengths of light.

    The different functionalities such as imaging or memory storage are achieved by shining different colours of light on the chip.

    Study lead author Dr Taimur Ahmed, from RMIT, said light-based computing was faster, more accurate and required far less energy than existing technologies.

    “By packing so much core functionality into one compact nanoscale device, we can broaden the horizons for machine learning and AI to be integrated into smaller applications,” Ahmed said.

    “Using our chip with artificial retinas, for example, would enable scientists to miniaturise that emerging technology and improve accuracy of the bionic eye.

    “Our prototype is a significant advance towards the ultimate in electronics: a brain-on-a-chip that can learn from its environment just like we do.”

    This work was performed in part at the Micro Nano Research Facility (MNRF) at RMIT, with support from the RMIT Microscopy and Microanalysis Research Facility (RMMF), National Computational Infrastructure Australia (NCI), Multimodal Australian Sciences Imaging and Visualisation Environment (MASSIVE) and Pawsey Supercomputing Facility.

    See the full article here.

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

    Please help promote STEM in your local schools.

    Stem Education Coalition

    RMIT University (AU), formerly known as Royal Melbourne Institute of Technology (RMIT) and Melbourne Technical College, is a public research university based in Melbourne, Australia.

    Founded by Francis Ormond in 1887, RMIT began as a night school offering classes in art, science, and technology, in response to the industrial revolution in Australia. It was a private college for more than a hundred years before merging with the Phillip Institute of Technology to become a public university in 1992. It has an enrollment of around 87,000 higher and vocational education students, making it the largest dual-sector education provider in Australia. With an annual revenue of around A$1.3 billion, it is also one of the wealthiest universities in Australia. It is rated a five star university by Quacquarelli Symonds (QS) and is ranked 17th in the World for art and design subjects in the QS World University Rankings, making it the top art and design university in Australia.

    Its main campus is situated on the northern edge of the historic Hoddle Grid in the city centre of Melbourne. It also has two satellite campuses in the northern suburbs of Brunswick and Bundoora and a international language site on Bourke Street, situated on the Williams base of the Royal Australian Air Force, in the western suburb of Point Cook. Beyond Melbourne, it has a research site near the Grampians National Park in the rural city of Hamilton. Outside Australia, it has a presence in Asia and Europe. In Asia, it has two branch campuses in the Vietnamese cities of Hanoi and Ho Chi Minh City as well as teaching partnerships in China, Hong Kong, Indonesia, Singapore and Sri Lanka. In Europe, it has a coordinating centre in the Spanish city of Barcelona.

     
  • richardmitnick 8:41 am on June 6, 2020 Permalink | Reply
    Tags: "Finnish researchers have discovered a new type of matter inside neutron stars", , , , , EurekaAlert, Exotic quark matter inside the cores of the largest neutron stars., , , , Quark matter,   

    From University of Helsinki via EurekaAlert: “Finnish researchers have discovered a new type of matter inside neutron stars” 

    From University of Helsinki

    via

    eurekaalert-bloc

    EurekaAlert

    1
    Confirming the existence of quark cores inside neutron stars has been one of the most important goals of neutron star physics for the last 40 years. Credit: Jyrki Hokkanen, CSC – IT Center for Science

    A Finnish research group has found strong evidence for the presence of exotic quark matter inside the cores of the largest neutron stars in existence. The conclusion was reached by combining recent results from theoretical particle and nuclear physics to measurements of gravitational waves from neutron star collisions.

    All normal matter surrounding us is composed of atoms, whose dense nuclei, comprising protons and neutrons, are surrounded by negatively charged electrons. Inside what are called neutron stars, atomic matter is, however, known to collapse into immensely dense nuclear matter, in which the neutrons and protons are packed together so tightly that the entire star can be considered one single enormous nucleus.

    Up until now, it has remained unclear whether inside the cores of the most massive neutron stars nuclear matter collapses into an even more exotic state called quark matter, in which the nuclei themselves no longer exist. Researchers from the University of Helsinki now claim that the answer to this question is yes. The new results were published in the prestigious journal Nature Physics.

    “Confirming the existence of quark cores inside neutron stars has been one of the most important goals of neutron star physics ever since this possibility was first entertained roughly 40 years ago,” says Associate Professor Aleksi Vuorinen from the University of Helsinki’s Department of Physics.

    Existence very likely

    With even large-scale simulations run on supercomputers unable to determine the fate of nuclear matter inside neutron stars, the Finnish research group proposed a new approach to the problem. They realised that by combining recent findings from theoretical particle and nuclear physics with astrophysical measurements, it might be possible to deduce the characteristics and identity of matter residing inside neutron stars.

    In addition to Vuorinen, the group includes doctoral student Eemeli Annala from Helsinki, as well as their colleagues Tyler Gorda from the University of Virginia, Aleksi Kurkela from CERN, and Joonas Nättilä from Columbia University.

    According to the study, matter residing inside the cores of the most massive stable neutron stars bears a much closer resemblance to quark matter than to ordinary nuclear matter. The calculations indicate that in these stars the diameter of the core identified as quark matter can exceed half of that of the entire neutron star. However, Vuorinen points out that there are still many uncertainties associated with the exact structure of neutron stars. What does it mean to claim that quark matter has almost certainly been discovered?

    “There is still a small but nonzero chance that all neutron stars are composed of nuclear matter alone. What we have been able to do, however, is quantify what this scenario would require. In short, the behaviour of dense nuclear matter would then need to be truly peculiar. For instance, the speed of sound would need to reach almost that of light,” Vuorinen explains.

    Radius determination from gravitational wave observations

    A key factor contributing to the new findings was the emergence of two recent results in observational astrophysics: the measurement of gravitational waves from a neutron star merger and the detection of very massive neutron stars, with masses close to two solar masses.

    In the autumn of 2017, the LIGO and Virgo observatories detected, for the first time, gravitational waves generated by two merging neutron stars.

    MIT /Caltech Advanced aLigo


    VIRGO Gravitational Wave interferometer, near Pisa, Italy

    This observation set a rigorous upper limit for a quantity called tidal deformability, which measures the susceptibility of an orbiting star’s structure to the gravitational field of its companion. This result was subsequently used to derive an upper limit for the radii of the colliding neutron stars, which turned out to be roughly 13 km.

    Similarly, while the first observation of a neutron star dates back all the way to 1967, accurate mass measurements of these stars have only been possible for the past 20 years or so. Most stars with accurately known masses fall inside a window of between 1 and 1.7 stellar masses, but the past decade has witnessed the detection of three stars either reaching or possibly even slightly exceeding the two-solar-mass limit.

    Further observations expected

    Somewhat counterintuitively, information about neutron star radii and masses has already considerably reduced the uncertainties associated with the thermodynamic properties of neutron star matter. This has also enabled completing the analysis presented by the Finnish research group in their Nature Physics article.

    In the new analysis, the astrophysical observations were combined with state-of-the-art theoretical results from particle and nuclear physics. This enabled deriving an accurate prediction for what is known as the equation of state of neutron star matter, which refers to the relation between its pressure and energy density. An integral component in this process was a well-known result from general relativity, which relates the equation of state to a relation between the possible values of neutron star radii and masses.

    Since the autumn of 2017, a number of new neutron star mergers have been observed, and LIGO and Virgo have quickly become an integral part of neutron star research. It is precisely this rapid accumulation of new observational information that plays a key role in improving the accuracy of the new findings of the Finnish research group, and in confirming the existence of quark matter inside neutron stars. With further observations expected in the near future, the uncertainties associated with the new results will also automatically decrease.

    “There is reason to believe that the golden age of gravitational wave astrophysics is just beginning, and that we will shortly witness many more leaps like this in our understanding of nature,” Vuorinen rejoices.

    See the full article here .

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

    Please help promote STEM in your local schools.

    Stem Education Coalition

    U Helsinki main building

    University of Helsinki, Viikki campus focusing on biological sciences

    The University of Helsinki (Finnish: Helsingin yliopisto, Swedish: Helsingfors universitet, Latin: Universitas Helsingiensis, abbreviated UH)is a university located in Helsinki, Finland since 1829, but was founded in the city of Turku (in Swedish Åbo) in 1640 as the Royal Academy of Åbo, at that time part of the Swedish Empire. It is the oldest and largest university in Finland with the widest range of disciplines available. Around 36,500 students are currently enrolled in the degree programs of the university spread across 11 faculties and 11 research institutes.

    As of 1 August 2005, the university complies with the harmonized structure of the Europe-wide Bologna Process and offers Bachelor, Master, Licenciate, and Doctoral degrees. Admission to degree programmes is usually determined by entrance examinations, in the case of bachelor’s degrees, and by prior degree results, in the case of master and postgraduate degrees. Entrance is particularly selective (circa 15% of the yearly applicants are admitted). It has been ranked a top 100 university in the world according to the 2016 ARWU, QS and THE rankings.

    The university is bilingual, with teaching by law provided both in Finnish and Swedish. Since Swedish, albeit an official language of Finland, is a minority language, Finnish is by far the dominating language at the university. Teaching in English is extensive throughout the university at Master, Licentiate, and Doctoral levels, making it a de facto third language of instruction.

    Remaining true to its traditionally strong Humboldtian ethos, the University of Helsinki places heavy emphasis on high-quality teaching and research of a top international standard. It is a member of various prominent international university networks, such as Europaeum, UNICA, the Utrecht Network, and is a founding member of the League of European Research Universities.

     
  • richardmitnick 12:39 pm on September 7, 2019 Permalink | Reply
    Tags: A very abstract and novel mathematical theory called "topological data analysis" (TDA) enters the stage., Artificial systems can now learn to recognise virtually any individual fish moving in a tank in the midst of a large number of other almost identical fish which are also moving., Artificial vision machines can learn to recognize complex images spectacularly faster by using a mathematical theory that was developed 25 years ago by one of this new study's co-authors., EurekaAlert, Much as these machines have been increasingly successful at pattern recognition the fact is that nobody really knows what goes on inside them as they learn their task., The Champalimaud Centre for the Unknown Lisbon Portugal, The intelligibility of artificial intelligence is necessary for its interaction and integration with biological intelligence., The machines we're talking about are in fact electronic models of networks of biological neurons., They are basically black boxes. You feed them something they spit out something and if you designed your electronic circuits properly... you'll get the correct answer., Think of TDA as being a mathematical tool for finding meaningful internal structure (topological features) in any complex "object".   

    From Champalimaud Centre for the Unknown via EurekaAlert: “Novel math could bring machine learning to the next level” 

    eurekaalert-bloc

    From EurekaAlert

    1
    The Champalimaud Centre for the Unknown, Lisbon, Portugal. http://first.fchampalimaud.org/en/the-foundation/champalimaud-centre-unknown/

    2-Sep-2019
    Maria Joao Soares
    mjsoares@jlma.pt
    http://www.fchampalimaud.org/

    2
    The new approach allows artificial intelligence to learn to recognize transformed images much faster. Credit Diogo Matias.

    A team of Italian mathematicians, including one who is also a neuroscientist from the Champalimaud Centre for the Unknown (CCU), in Lisbon, Portugal, has shown that artificial vision machines can learn to recognize complex images spectacularly faster by using a mathematical theory that was developed 25 years ago by one of this new study’s co-authors. Their results have been published in the journal Nature Machine Intelligence.

    During the last decades, machine vision performance has exploded. For example, these artificial systems can now learn to recognise virtually any human face – or to identify any individual fish moving in a tank, in the midst of a large number of other almost identical fish which are also moving.

    The machines we’re talking about are, in fact, electronic models of networks of biological neurons, and their aim is to simulate the functioning of our brain, which is as good as it gets at performing these visual tasks – and this, without any conscious effort on our part.

    But how do these neural networks actually learn? In the case of face recognition, for instance, they do it by acquiring experience about what human faces look like in the form of a series of portraits. More specifically, after being digitized into a matrix of pixel values (think about your computer monitor’s RGB system), each image is “crunched” inside the neural network, which then manages to extract general, meaningful features, from the set of sample faces (such as the eyes, mouth, nose, etc).

    This learning (deep learning, in its more modern development) then enables the machine to spit out another set of values, which will in turn enable it, for instance, to identify a face it has never seen before in a databank of faces (much like a fingerprint database), and therefore to predict who that face belongs to with great accuracy.

    The story of Clever Hans

    But, before the neural network can begin to perform this well, though, it is typically necessary to present it with thousands of faces (i.e. matrices of numbers). Moreover, much as these machines have been increasingly successful at pattern recognition, the fact is that nobody really knows what goes on inside them as they learn their task. They are, basically, black boxes. You feed them something, they spit out something, and if you designed your electronic circuits properly… you’ll get the correct answer.

    What this means is that it is not possible to determine which or how many features the machine is actually extracting from the initial data – and not even how many of those features are really meaningful for face recognition. “To illustrate this, consider the paradigm of the wise horse”, says first author of the study Mattia Bergomi, who works in the Systems Neuroscience Lab at the CCU.

    The story dates from the early years of the 20th century. It’s about a horse in Germany called Clever Hans that, so his master claimed, had learned to do arithmetics and announce the result of additions, subtractions, etc. by tapping one of its front hooves on the ground the right number of times. Everyone who witnessed the horse’s performance was convinced he could count (the event was even reported by the New York Times). But then, in 1907, a German psychologist showed that the horse was in fact picking up unconscious cues in his master’s body language that were telling it when to stop tapping…

    “It’s the same with machine learning; there is no control over how it works or what it has learned during training”, Bergomi explains. The machine having no a priori knowledge of faces, it just somehow does its stuff – and it works.

    This led the researchers to ask: could there be a way to inject some knowledge of the real world (about faces or other objects) into the neural network, before training, in order to cause it explore a more limited space of possible features instead of considering them all – including those that are impossible in the real world? “We wanted to control the space of learned features”, Bergomi points out. “It’s similar to the difference between a mediocre chess player and an expert: the first sees all possible moves, while the latter only sees the good ones”, he adds.

    Another way of putting it, he says, is by saying that “our study addresses the following simple question: When we train a deep neural network to distinguish road signs, how can we tell the network that its job will be much easier if it only has to care about simple geometrical shapes such as circles and triangles?”.

    The scientists reasoned that this approach would substantially reduce training time – and, not less importantly, give them a “whiff” of what the machine might be doing to obtain its results. “Allowing humans to drive the learning process of learning machines is fundamental to move towards a more intelligible artificial intelligence and reduce the skyrocketing cost in time and resources that current neural networks require in order to be trained”, he remarks.

    What’s in a shape?

    Here’s where a very abstract and novel mathematical theory, called “topological data analysis” (TDA), enters the stage. The first steps in the development of TDA were taken in 1992 by the italian mathematician Patrizio Frosini, co-author of the new study and currently at the University of Bologna. “Topology is one of the purest forms of math”, says Bergomi. “And until recently, people thought that Topology would not be applied to anything concrete for a long time. Until TDA became famous in the last few years.”

    Topology is a sort of extended geometry that, instead of measuring lines and angles in rigid shapes (such as triangles, squares, cones, etc.), seeks to classify highly complex objects according to their shape. For a topologist, for example, a donut and a mug are the same object: one can be deformed into the other by stretching or compression.

    Now, the thing is, current neural networks are not good at topology. For instance, they do not recognize rotated objects. To them, the same object will look completely different every time it is rotated. That is precisely why the only solution is to make these networks “memorise” each configuration separately – by the thousands. And it is precisely what the authors were planning to avoid by using TDA.

    Think of TDA as being a mathematical tool for finding meaningful internal structure (topological features), in any complex “object” that can be represented as a huge set of numbers, by looking at the data through certain well-chosen “lenses” or filters. The data itself can be about faces, financial transactions or cancer survival rates. For faces in particular, by applying TDA, it becomes possible to teach a neural network to recognize faces without having to present it with each of the different orientations faces might assume in space. The machine will now recognize all faces as being a face, even in different rotated positions.

    It’s a 5! No, it’s a 7!

    In their study, the scientists tested the benefits of combining machine learning and TDA by teaching a neural network to recognise hand-written digits. The results speak for themselves.

    As these networks are bad topologists and handwriting can be very ambiguous, two different hand-written digits may prove indistinguishable for current machines – and conversely, two instances of the same hand-written digit may be seen by them as different.

    That is why, to be performed by today’s vision machines, this task requires presenting the network, which knows nothing about digits in the world, with thousands of images of each of the 10 digits, written with all sorts of slants, calligraphies, etc..

    To inject knowledge about digits, the team built a set of a priori features that they considered meaningful (in other words, a set of “lenses” through which the network would “see” the digits), and forced the machine to choose among these lenses to look at the images. And what happened was that the number of images (that is, the time) needed for the TDA-enhanced neural network to learn to distinguish 5’s from 7’s – however badly written -, while maintaining its predictive power, dropped down to less than 50! “What we mathematically describe in our study is how to enforce certain symmetries, and this provides a strategy to build machine learning agents that are able to learn salient features from a few examples, by taking advantage of the knowledge injected as constraints”, says Bergomi.

    Does this mean that the inner workings of learning machines which mimic the brain will become more transparent in the future, enabling new insights on the inner workings of the brain itself? In any case, this is one of Bergomi’s goals. “The intelligibility of artificial intelligence is necessary for its interaction and integration with biological intelligence”, he says. He is currently working, in collaboration with his colleague Pietro Vertechi, also from the Systems Neuroscience Lab at CCU, on developing a new kind of neural network architecture that will allow humans to swiftly inject high-level knowledge into these networks to control and speed up their training.

    See the full article here .

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  • richardmitnick 10:49 am on October 27, 2018 Permalink | Reply
    Tags: , Bose star, , , EurekaAlert, Institute for Nuclear Physics of the Russian Academy of Sciences, , Russian physicists observe dark matter forming droplets   

    From EurekaAlert: “Russian physicists observe dark matter forming droplets” 

    eurekaalert-bloc

    From EurekaAlert

    22-Oct-2018

    Dmitry Levkov
    levkov@ms2.inr.ac.ru

    Researchers developed a mathematical model describing motion of dark matter particles inside the smallest galaxy halos.

    Caterpillar Project A Milky-Way-size dark-matter halo and its subhalos circled, an enormous suite of simulations . Griffen et al. 2016

    They observed that over time, the dark matter may form spherical droplets of quantum condensate. Previously this was considered impossible, as fluctuations of the gravity field produced by dark matter particles were ignored. The study is published in Physical Review Letters.

    Dark matter is a hypothetical form of matter that does not emit electromagnetic radiation.

    Women in STEM – Vera Rubin

    Fritz Zwicky discovered Dark Matter when observing the movement of the Coma Cluster

    Coma cluster via NASA/ESA Hubble

    But most of the real work was done by Vera Rubin

    Fritz Zwicky from http:// palomarskies.blogspot.com

    Astronomer Vera Rubin at the Lowell Observatory in 1965, worked on Dark Matter (The Carnegie Institution for Science)

    Vera Rubin measuring spectra, worked on Dark Matter (Emilio Segre Visual Archives AIP SPL)

    Vera Rubin, with Department of Terrestrial Magnetism (DTM) image tube spectrograph attached to the Kitt Peak 84-inch telescope, 1970. https://home.dtm.ciw.edu

    This property hinders dark matter searches and makes it hard even to prove its existence. The speed of dark matter particles is low, which is why they are retained by galaxies. They interact with each other and with the ordinary matter so weakly that only their gravity field can be sensed, otherwise the dark matter does not manifest itself in any way. Each galaxy is surrounded by a dark matter shell (halo) of much larger size and mass.

    1
    Left image: initial moment, when the gas is mixed; right image: the moment shortly after the formation of a Bose star. The colour indicates density: white-blue-green-yellow, from sparse to dense. Credit Dmitry Levkov

    Most cosmologists believe that dark matter particles have large mass, hence their speed is high. Yet, back in the 1980s it was realized that under special conditions these particles may be produced in the early Universe with almost zero speed, regardless of their mass. They might also be very light. As a consequence, the distances at which the quantum nature of these particles becomes apparent can be huge. Instead of the nanometer scales that are usually required to observe quantum phenomena in laboratories, the “quantum” scale for such particles may be comparable to the size of the central part of our galaxy.

    The researchers observed that the dark matter particles, if they are bosons with sufficiently small mass, may form a Bose-Einstein condensate in the small galaxy halos or in even smaller substructures due to their gravitational interactions. Such substructures include halos of dwarf galaxies – systems of several billion stars bound together by gravitational forces, and miniclusters – very small systems formed only by dark matter. The Bose-Einstein condensate is a state of quantum particles in which they all occupy the lowest energy level, having the smallest energy. The Bose-Einstein condensate can be produced in the lab at low temperatures from ordinary atoms. This state of matter exhibits unique properties, such as superfluidity: the ability to pass through tiny cracks or capillaries without friction. Light dark matter in the galaxy has low speed and huge concentration. Under these conditions, it should eventually form a Bose-Einstein condensate. But in order for this to happen, dark matter particles must interact with each other, while as far as we know, they interact only gravitationally.

    “In our work, we simulated motion of a quantum gas of light gravitationally interacting dark matter particles. We started from a virialized state with maximal mixing, which is kind of opposite to the Bose-Einstein condensate. After a very long period, 100,000 times longer than the time needed for a particle to cross the simulation volume, the particles spontaneously formed a condensate, which immediately shaped itself into a spherical droplet, a Bose star, under the effect of gravity,” said one of the authors, Dmitry Levkov, Ph.D. in Physics, Senior Researcher at the Institute for Nuclear Research of the Russian Academy of Sciences.

    Dr. Levkov and his colleagues, Alexander Panin and Igor Tkachov from the Institute for Nuclear Physics of the Russian Academy of Sciences, concluded that Bose-Einstein condensate may form in the centres of halos of dwarf galaxies in a time smaller than the lifetime of the Universe. This means that Bose stars could populate them now.

    The authors were the first who saw the formation of the Bose-Einstein condensate from light dark matter in computer simulations. In previous numerical studies, the condensate was already present in the initial state, and Bose stars arose from it. According to one hypothesis, the Bose condensate could have formed in the early Universe long before the formation of galaxies or miniclusters, but reliable evidence for that is currently lacking. The authors demonstrated that the condensate is formed in the centres of small halos, and they plan to investigate condensation in the early Universe in further studies.

    The scientists pointed out that the Bose stars may produce Fast Radio Bursts that currently have no quantitative explanation. Light dark matter particles called “axions” interact with electromagnetic field very weakly and can decay into radiophotons. This effect is vanishingly small, but inside the Bose star it may be resonantly amplified like in a laser and could lead to giant radio bursts.

    “The next obvious step is to predict the number of the Bose stars in the Universe and calculate their mass in models with light dark matter,” concluded Dmitry Levkov.

    See the full article here .

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  • richardmitnick 1:13 pm on July 14, 2018 Permalink | Reply
    Tags: , , EurekaAlert, ,   

    From U Hawaii via Eureka Alert: Late to the Party, but “Hawaii telescopes help unravel long-standing cosmic mystery” 

    U Hawaii

    From University of Hawaii Manoa

    via

    EurekAlert!

    12-Jul-2018

    Astronomers and physicists around the world, including in Hawaii, have begun to unravel a long-standing cosmic mystery. Using a vast array of telescopes in space and on Earth, they have identified a source of cosmic rays.

    Artist’s impression of a blazar emitting neutrinos and gamma rays via IceCube and NASA

    Blazar. NASA Fermi Gamma ray Space Telescope. Credits M. Weiss/ CfA

    NASA/Fermi LAT

    NASA/Fermi Gamma Ray Space Telescope

    Astronomers and physicists around the world, including in Hawaii, have begun to unravel a long-standing cosmic mystery. Using a vast array of telescopes in space and on Earth, they have identified a source of cosmic rays–highly energetic particles that continuously rain down on Earth from space.

    In a paper published this week in the journal Science, scientists have, for the first time, provided evidence for a known blazar, designated TXS 0506+056, as a source of high-energy neutrinos. At 8:54 p.m. on September 22, 2017, the National Science Foundation-supported IceCube neutrino observatory at the South Pole detected a high energy neutrino from a direction near the constellation Orion. Just 44 seconds later an alert went out to the entire astronomical community.

    U Wisconsin ICECUBE neutrino detector at the South Pole

    IceCube employs more than 5000 detectors lowered on 86 strings into almost 100 holes in the Antarctic ice NSF B. Gudbjartsson, IceCube Collaboration

    Lunar Icecube

    IceCube DeepCore annotated

    IceCube PINGU annotated


    DM-Ice II at IceCube annotated

    The All Sky Automated Survey for SuperNovae team (ASAS-SN), an international collaboration headquartered at Ohio State University, immediately jumped into action. ASAS-SN uses a network of 20 small, 14-centimeter telescopes in Hawaii, Texas, Chile and South Africa to scan the visible sky every 20 hours looking for very bright supernovae. It is the only all-sky, real-time variability survey in existence.

    ASAS-SN Brutus at lcogt site Hawaii

    LCOGT Las Cumbres Observatory Global Telescope Network, Haleakala Hawaii, USA, Elevation 10,023 ft (3,055 m)

    “When ASAS-SN receives an alert from IceCube, we automatically find the first available ASAS-SN telescope that can see that area of the sky and observe it as quickly as possible,” said Benjamin Shappee, an astronomer at the University of Hawaii’s Institute for Astronomy and an ASAS-SN core member.

    On September 23, only 13 hours after the initial alert, the recently commissioned ASAS-SN unit at McDonald Observatory in Texas [image of exas unit N/A] mapped the sky in the area of the neutrino detection. Those observations and the more than 800 images of the same part of the sky taken since October 2012 by the first ASAS-SN unit, located on Maui’s Haleakala, showed that TXS 0506+056 had entered its highest state since 2012.

    “The IceCube detection and the ASAS-SN detection combined with gamma-ray detections from NASA’s Fermi gamma-ray space telescope and the MAGIC telescopes that show TXS 0506+056 was undergoing the strongest gamma-ray flare in a decade, indicate that this could be the first identified source of high-energy neutrinos, and thus a cosmic-ray source,” said Anna Franckowiak, ASAS-SN and IceCube team member, Helmholtz Young Investigator, and staff scientist at DESY in Germany.

    MAGIC Cherenkov telescope array at the Roque de los Muchachos Observatory on the island of La Palma, in the Canaries, Spain, sited on a volcanic peak 2,267 metres (7,438 ft) above sea level

    Since they were first detected more than one hundred years ago, cosmic rays have posed an enduring mystery: What creates and launches these particles across such vast distances? Where do they come from?

    One of the best suspects have been quasars, supermassive black holes at the centers of galaxies that are actively consuming gas and dust.

    Quasar. ESO/M. Kornmesser

    Quasars are among the most energetic phenomena in the universe and can form relativistic jets where elementary particles are accelerate and launched at nearly the speed of light. If that jet happens to be pointed toward Earth, the light from the jet outshines all other emission from the host galaxy and the highly accelerated particles are launched toward the Milky Way. This specific type of quasar is called a blazar [above].

    However, because cosmic rays are charged particles, their paths cannot be traced directly back to their places of origin. Due to the powerful magnetic fields that fill space, they don’t travel along a straight path. Luckily, the powerful cosmic accelerators that produce them also emit neutrinos, which are uncharged and unaffected by even the most powerful magnetic fields. Because they rarely interact with matter and have almost no mass, these “ghost particles” travel nearly undisturbed from their cosmic accelerators, giving scientists an almost direct pointer to their source.

    “Crucially, the presence of neutrinos also differentiates between two types of gamma-ray sources: those that accelerate only cosmic-ray electrons, which do not produce neutrinos, and those that accelerate cosmic-ray protons, which do,” said John Beacom, an astrophysicist at the Ohio State University and an ASAS-SN member.

    Detecting the highest energy neutrinos requires a massive particle detector, and the National Science Foundation-supported IceCube observatory [above] is the world’s largest. The detector is composed of more than 5,000 light sensors arranged in a grid, buried in a cubic kilometer of deep, pristine ice a mile beneath the surface at the South Pole. When a neutrino interacts with an atomic nucleus, it creates a secondary charged particle, which, in turn, produces a characteristic cone of blue light that is detected by IceCube’s grid of photomultiplier tubes. Because the charged particle and the light it creates stay essentially true to the neutrino’s original direction, they give scientists a path to follow back to the source.

    About 20 observatories on Earth and in space have also participated in this discovery. This includes the 8.4-meter Subaru Telescope on Maunakea, which was used to observe the host galaxy of TXS 0506+056 in an attempt to measure its distance, and thus determine the intrinsic luminosity, or energy output, of the blazar.


    NAOJ/Subaru Telescope at Mauna Kea Hawaii, USA,4,207 m (13,802 ft) above sea level

    These observations are difficult, because the blazar jet is much brighter than the host galaxy. Disentangling the jet and the host requires the largest telescopes in the world, like those on Maunakea.

    “This discovery demonstrates how the many different telescopes and detectors around and above the world can come together to tell us something amazing about our Universe. This also emphasizes the critical role that telescopes in Hawaii play in that community,” said Shappee.

    See the full article here .


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    System Overview

    The University of Hawai‘i System includes 10 campuses and dozens of educational, training and research centers across the Hawaiian Islands. As the public system of higher education in Hawai‘i, UH offers opportunities as unique and diverse as our Island home.

    The 10 UH campuses and educational centers on six Hawaiian Islands provide unique opportunities for both learning and recreation.

    UH is the State’s leading engine for economic growth and diversification, stimulating the local economy with jobs, research and skilled workers.

     
  • richardmitnick 12:13 pm on July 15, 2017 Permalink | Reply
    Tags: , Angular momentum, , , , , Elliptical galaxies, , EurekaAlert, Shedding light on galaxies' rotation secrets,   

    From EurekaAlert: “Shedding light on galaxies’ rotation secrets” 

    eurekaalert-bloc

    EurekaAlert

    13-Jul-2017

    Media Contact
    Donato Ramani
    ramani@sissa.it
    39-342-802-2237
    http://www.sissa.it/

    Spiral galaxies are strongly rotating whereas the rotation velocity of ellipticals is much lower. A new study investigates the reasons of such a dichotomy revealing that it is imprinted at formation.

    Scuola Internazionale Superiore di Studi Avanzati

    1
    Spiral galaxies are found to be strongly rotating, with an angular momentum higher by a factor of about 5 than ellipticals. What is the origin of such a difference?
    Credit Wikimedia Common.

    The dichotomy concerns the so-called angular momentum (per unit mass), that in physics is a measure of size and rotation velocity. Spiral galaxies are found to be strongly rotating, with an angular momentum higher by a factor of about 5 than ellipticals. What is the origin of such a difference? An international research team investigated the issue in a study just published in the Astrophysical Journal. The team was led by SISSA Ph.D. student JingJing Shi under the supervision of Prof. Andrea Lapi and Luigi Danese, and in collaboration with Prof. Huiyuan Wang from USTC (Hefei) and Dr. Claudia Mancuso from IRA-INAF (Bologna). The researchers inferred from observations the amount of gas fallen into the central region of a developing galaxy, where most of the star formation takes places.

    The outcome is that in elliptical galaxies only about 40% of the available gas fell into that central region. More relevantly, this gas fueling star formation was characterized by a rather low angular momentum since the very beginning. This is in stark contrast with the conditions found in spirals, where most of the gas ending up in stars had an angular momentum appreciably higher. In this vein, the researchers have traced back the dichotomy in the angular momentum of spiral and elliptical galaxies to their different formation history. Elliptical galaxies formed most of their stars in a fast collapse where angular momentum is dissipated. This process is likely stopped early on by powerful gas outflows from supernova explosions, stellar winds and possibly even from the central supermassive black hole. For spirals, on the other hand, the gas infelt slowly conserving its angular momentum and stars formed steadily along a timescale comparable to the age of the Universe.

    “Till recent years, in the paradigm of galaxy formation and evolution, elliptical galaxies were thought to have formed by the merging of stellar disks in the distant Universe. Along this line, their angular momentum was thought to be the result of dissipative processes during such merging events” say the researchers. Recently, this paradigm had been challenged by far-infrared/sub-millimeter observations brought about by the advent of space observatories like Herschel and ground based interferometers like the Atacama Large Millimeter Array (ALMA).

    ESA/Herschel spacecraft

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

    These observations have the power of penetrating through interstellar dust and so to unveil the star formation processes in the very distant, dusty galaxies, that constituted the progenitors of local ellipticals. “The net outcome from these observations is that the stars populating present-day ellipticals are mainly formed in a fast dissipative collapse in the central regions of dusty starforming galaxies. After a short timescale of less than 1 billion years the star formation has been quenched by powerful gas outflows”. Despite this change of perspective, the origin of the low angular momentum observed in local ellipticals still remained unclear.

    “This study reconciles the low angular momentum observed in present-day ellipticals with the new paradigm emerging from Herschel and ALMA observations of their progenitors” conclude the scientists. “We demonstrated that the low angular momentum of ellipticals is mainly originated by nature in the central regions during the early galaxy formation process, and not nurtured substantially by the environment via merging events, as envisaged in previous theories”.

    See the full article here .

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    EurekAlert!, the premier online news source focusing on science, health, medicine and technology, is a free service for reporters worldwide.

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  • richardmitnick 6:07 pm on February 21, 2017 Permalink | Reply
    Tags: , , EurekaAlert, , MASTER Global Robotic Network, Supermassive black hole in the center of a galaxy known to astronomers as NGC 2617   

    From EurekaAlert: “Changes of supermassive black hole in the center of NGC 2617 galaxy” 

    eurekaalert-bloc

    EurekaAlert

    20-Feb-2017
    Lomonosov Moscow State University

    Astrophysicists study surprising changes in the appearance of a supermassive black hole.

    1
    Members of the Sternberg Astronomical Institute of the Lomonosov Moscow State University have been studying changes in the appearance of emission from around the supermassive black hole in the center of a galaxy known to astronomers as NGC 2617. The center of this galaxy, underwent dramatic changes in its appearance several years ago: it became much brighter and things that had not been seen before were seen. This sort of dramatic change can give us valuable information for understanding what the surroundings of a giant black hole are like and what is going on near the black hole. The results of these investigations have been published in the Monthly Notices of the Royal Astronomical Society, one of the world’s top-rated astronomical journals.

    Most galaxies such as our own have a giant black hole in their central nuclei. These monstrous holes have masses ranging from a million to a billion times the mass of our sun. The black hole in our galaxy is inactive, but in some galaxies, the black hole is swallowing gas that is spiraling into it and emitting enormous amounts of radiation. These galaxies are called “active galactic nuclei” or AGNs for short. The energy output from around the black holes of these AGNs can exceed that of the hundreds of billions of stars in the rest of the galaxy. Just how these galaxies get their supermassive black holes is a major mystery.

    The nuclei of galaxies where the supermassive black holes are vigorously swallowing gas are classified into two types: those where we get a direct view of the matter spiraling into the black hole at a speed that is thousands of times faster than the speed of sound, and those where the inner regions are obscured by dust and we only see more slowly moving gas much further from the black hole.

    For decades astronomers have wondered why we see the innermost regions of some active galactic nuclei but not others. A popular explanation of the two types of active galactic nuclei is that they are really the same but they appear to be different to us because we are viewing them from different angles. If they are face-on we can see the hot gas spiraling into the black hole directly. If the active galactic nucleus is tilted, then dust around the nucleus blocks our view and we can only see the more slowly moving gas a light year or more away.

    The leader of the international research team involved in the investigation, Viktor Oknyansky, a Senior Researcher at the Sternberg Astronomical Institute of the Lomonosov Moscow State University says: “Cases of object transition from one type to the other turn out to be a definite problem for this orientation model. In 1984 we found a change in the appearance of another active galactic nucleus known as NGC 4151. It was one of few known cases of this kind in the past. We now know of several dozen active galactic nuclei that have changed their type. In our recent study we have focused on one of the best cases — NGC 2617.”

    Oknyansky continues: “In 2013 a team of researchers in the US found that NGC 2617 had changed being an active galaxy where the inner regions were hidden to one where the inner regions were now exposed. We didn’t not know how long it would remain in this new unveiled state. It could last for only a short period of time or, on the other hand, for dozens of years. The title of the paper by the US astronomers was “The man behind the curtain…” When we began our study we didn’t know how long the curtain would remain open, but we’ve titled our paper “The curtain remains open…”, because we are continuing to see into the inner regions of NGC 2617.

    According to the authors there is no accepted explanation so far of what could cause us to start seeing down to the inner regions of an active galactic nucleus when it was previously hidden.

    Viktor Oknyansky comments: “It’s clear that this phenomenon isn’t very rare, on the contrary, we think it’s quite typical. We consider various possible explanations. One is that perhaps a star has come too close to the black hole and has been torn apart. However, the disruption of a star by a black hole is very rare and we don’t think that such events can explain the observed frequency of type changes of active galactic nuclei. Instead we favour a model where the black hole has started swallowing gas more rapidly. As the material spirals in towards the black holes it emits strong radiation. We speculate that this intense radiation destroys some of the dust surrounding the nucleus and permits us to see the inner regions.”

    Oknyansky continues: “Study of these rapid changes of type is very important for understanding what is going on around supermassive black holes that are rapidly swallowing gas. So, what we have concentrated on is getting observations of the various types of radiation emitted by NGC 2617. This has involved a large-scale effort.”

    The observational data for the project were obtained using the MASTER Global Robotic Network operated by Professor Vladimir Lipunov and his team, the new 2.5-m telescope located near Kislovodsk, a 2-m telescope of the observatory in Azerbajan, the Swift X-ray satellite, and some other telescopes. This research has been conducted in cooperation with colleagues from Azerbaijan, the USA, Finland, Chili, Israel and the South Africa.

    1
    MASTER GLOBAL Robotic Net

    NASA/SWIFT Telescope
    NASA/SWIFT Telescope

    See the full article here .

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    EurekAlert!, the premier online news source focusing on science, health, medicine and technology, is a free service for reporters worldwide.

    Since 1996, EurekAlert! has served as the leading destination for scientific organizations seeking to disseminate news to reporters and the public. Today, thousands of reporters around the globe rely on EurekAlert! as a source of ideas, background information, and advance word on breaking news stories.

    More than 1,000 peer-reviewed journals, universities, medical centers, government agencies and public relations firms have used EurekAlert! to distribute their news. EurekAlert! is an authoritative and comprehensive research news source for journalists all over the world.

     
  • richardmitnick 11:35 am on February 11, 2017 Permalink | Reply
    Tags: , , Big data for the universe, EurekaAlert, , The Reference Catalog of galaxy SEDs   

    From EurekaAlert: “Big data for the universe” 

    eurekaalert-bloc

    EurekaAlert

    9-Feb-2017
    Lomonosov Moscow State University

    1
    IMAGE: RCSED design. Credit: Ivan Zolotukhin

    Astronomers at Lomonosov Moscow State University in cooperation with their French colleagues and with the help of citizen scientists have released «The Reference Catalog of galaxy SEDs» (RCSED), which contains value-added information about 800,000 galaxies. The catalog is accessible on the web and its description has been published in the Astrophysical Journal Supplement (impact factor — 11.257). Two co-authors of the research paper are undergraduate students at the Faculty of Physics, Lomonosov Moscow State University. While still working on the catalog, the team has published a few research papers based on the data from it, including a study published by the prestigious interdisciplinary journal Science.

    What can one learn using RCSED and why is it unique?

    RCSED describes properties of 800,000 galaxies derived from the elaborated data analysis. For every galaxy, it presents its stellar composition, brightness at ultraviolet, optical, and near-infrared wavelengths. From RCSED, one can also access galaxy spectra obtained by the Sloan Digital Sky Survey, measurements of spectral lines, and properties determined from them, such as the chemical composition of stars and gas, contained in those galaxies. This makes RCSED the first catalog of its kind, which contains results of detailed homogeneous analysis for such large number of objects. Dr. Igor Chilingarian, an astronomer at Smithsonian Astrophysical Observatory, USA and a Lead Researcher at Sternberg Astronomical Institute, Lomonosov Moscow State University says: “For every galaxy we also provide a small cutout image from three sky surveys, which show how the galaxy looks at different wavelengths. This provides us with the data for further investigations.” Dr. Ivan Katkov, a Senior Researcher at Sternberg Astronomical Institute adds: “The analysis of emission line profiles presented in RCSED is substantially more detailed and accurate then the data published in other catalogs”

    RCSED is really flexible and very easy to use. By simply entering the object name or its coordinates in the search field, the web site will provide in a single page all the information referring to that object contained in the catalog. One can also use the catalog through Virtual Observatory applications such as TOPCAT. The RCSED web site also provides tutorials including the one, which describes a technique that Igor Chilingarian and Ivan Zolotukhin exploited to discover new compact elliptical galaxies, which were later published in the research paper «Isolated compact elliptical galaxies: Stellar systems that ran away».

    Another interesting detail about RCSED is that the team actively used the help of citizen scientists to develop the project web site. And among them there were high-level experts in software development and web design, who have daytime jobs in the largest Russian IT-companies. Dr. Ivan Zolotukhin, a Researcher at Sternberg Astronomical Institute, explains: “Programmers sometimes get burnt out by their routine work, and they would like to do something interesting and pleasant in their spare time, for instance, to help scientists. We are very grateful to them, they have become important members of our team and significantly strengthened our project. It’s been always interesting for us to cooperate with IT specialists and we have a lot more projects where they can contribute. So if you use git, program in Python or know HTML/CSS, love stars, have a bit of spare time and are willing to help an international research team – please, contact us using the address published on the web page.

    Dr. Ivan Katkov adds: “The RCSED catalog became possible thanks to the application of an interdisciplinary Big Data approach as we had to apply very complex scientific algorithms to a large dataset in a massively parallel way. Eventually, the expertise and resources available at large IT companies would undoubtedly allow researchers to significantly increase the quality and the quantity of research results and to make many important discoveries in astrophysics”.

    The fact that the RCSED catalog has attracted serious interest in the scientific community even during its assembly phase proves its great potential. During the last three years several external researchers were given the access to the catalog on request and, using RCSED data, published over a dozen of articles in professional peer-reviewed journals (Astrophysical Journal, Astronomy & Astrophysics, MNRAS). The catalog is the world largest homogeneous value-added dataset for nearby galaxies, containing information collected with ground-based and space telescopes. The unique research material for extragalactic astrophysics contained in RCSED will certainly help astrophysicists to achieve new interesting scientific results, some of which would probably qualify for publication in the interdisciplinary journals Science and Nature.

    RCSED expansion prospects: one million galaxies will be there soon.

    The current release of the RCSED catalog could have comprised a larger number of galaxies or contained extra bits of information about the currently included objects, but at this moment the scientists have decided to focus on well-characterized datasets, which are described in detail and have known advantages and disadvantages. However, taking into account the project importance for extragalactic astronomy and observational cosmology, the RCSED team is going to move forward and expand the catalog in the near future.

    There are two principal directions of further RCSED development: the galaxy sample expansion and incorporating new data for existing objects. The team considers a possibility to include near- and mid-infrared data from the WIS? satellite all-sky survey for the entire galaxy sample. However, this requires some additional methodical work in order to homogenize the data for galaxies at different redshifts.

    Moreover, it is possible to expand the principal galaxy sample by including spectra from the latest data release of the SDSS-III survey. This will turn 800,000 to 1.5 million objects.

    Incorporating the publicly available spectral data from the Hectospec archive (Igor Chilingarian has played a major role in the Hectospec archive project) will add 300-400 thousand objects at larger distances, whose spectra were collected with the 6.5-meter MMT telescope in Arizona. The current RCSED release comprises mostly nearby galaxies (by cosmological measures), whose redshifts are smaller than 0.4, because SDSS did not include faint objects. Therefore, the early Universe is not represented in the catalog at all. The Hectospec archive will allow the team to move a little bit further in the cosmological distance scale until the redshift of 0.7. If they add several thousand galaxies from the DEEP2 survey conducted with the 10-meter Keck telescope in early 2000s, they could get insights into objects at redshift up-to 1.0, when the Universe was less than half of its present age.

    Igor Chilingarian concludes: “We shall be able to see the global picture in about ten years from now, when large surveys like DESI have collected 25-30 million galaxy spectra out to intermediate redshifts.”

    The RCSED project has been supported by the collaborative grant, provided by the Russian Foundation for Basic Research (RFBR) and The French National Center for Scientific Research (Centre National de la Recherche Scientifique, CNRS). On earlier stages the project was supported by the grants from the Russian Science Foundation (RScF), the President of the Russian Federation, along with French resources, available in the framework of the VO-Paris Data Center at the Paris Observatory.

    See the full article here .

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