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  • richardmitnick 1:35 pm on October 25, 2021 Permalink | Reply
    Tags: "Neutron star collisions are a “goldmine” of heavy elements study finds", Collisions between two neutron stars, Gravitational wave astronomy, ,   

    From The Massachusetts Institute of Technology (US) : “Neutron star collisions are a “goldmine” of heavy elements study finds” 

    MIT News

    From The Massachusetts Institute of Technology (US)

    October 25, 2021
    Jennifer Chu

    New research suggests binary neutron stars are a likely cosmic source for the gold, platinum, and other heavy metals we see today.
    Credits: A. Simonnet National Science Foundation (US)/Caltech/ MIT Advanced aLIGO (US)/Sonoma State University (US)/, edited by MIT News.

    Most elements lighter than iron are forged in the cores of stars. A star’s white-hot center fuels the fusion of protons, squeezing them together to build progressively heavier elements. But beyond iron, scientists have puzzled over what could give rise to gold, platinum, and the rest of the universe’s heavy elements, whose formation requires more energy than a star can muster.

    A new study by researchers at MIT and the University of New Hampshire finds that of two long-suspected sources of heavy metals, one is more of a goldmine than the other.

    The study, published today in The Astrophysical Journal Letters, reports that in the last 2.5 billion years, more heavy metals were produced in binary neutron star mergers, or collisions between two neutron stars, than in mergers between a neutron star and a black hole.

    The study is the first to compare the two merger types in terms of their heavy metal output, and suggests that binary neutron stars are a likely cosmic source for the gold, platinum, and other heavy metals we see today. The findings could also help scientists determine the rate at which heavy metals are produced across the universe.

    “What we find exciting about our result is that to some level of confidence we can say binary neutron stars are probably more of a goldmine than neutron star-black hole mergers,” says lead author Hsin-Yu Chen, a postdoc in MIT’s Kavli Institute for Astrophysics and Space Research (US).

    Chen’s co-authors are Salvatore Vitale, assistant professor of physics at MIT, and Francois Foucart of The University of New Hampshire (US).

    An efficient flash

    As stars undergo nuclear fusion, they require energy to fuse protons to form heavier elements. Stars are efficient in churning out lighter elements, from hydrogen to iron. Fusing more than the 26 protons in iron, however, becomes energetically inefficient.

    “If you want to go past iron and build heavier elements like gold and platinum, you need some other way to throw protons together,” Vitale says.

    Scientists have suspected supernovae might be an answer. When a massive star collapses in a supernova, the iron at its center could conceivably combine with lighter elements in the extreme fallout to generate heavier elements.

    In 2017, however, a promising candidate was confirmed, in the form a binary neutron star merger, detected for the first time by LIGO and Virgo, the gravitational-wave observatories in the United States and in Italy, respectively.

    Caltech/MIT Advanced aLigo at Hanford, WA(US), Livingston, LA(US) and VIRGO Gravitational Wave interferometer, near Pisa(IT).

    The detectors picked up gravitational waves, or ripples through space-time, that originated 130 million light years from Earth, from a collision between two neutron stars — collapsed cores of massive stars, that are packed with neutrons and are among the densest objects in the universe.

    The cosmic merger emitted a flash of light, which contained signatures of heavy metals.

    “The magnitude of gold produced in the merger was equivalent to several times the mass of the Earth,” Chen says. “That entirely changed the picture. The math showed that binary neutron stars were a more efficient way to create heavy elements, compared to supernovae.”

    UCSC All the Gold in the Universe.

    A binary goldmine

    Chen and her colleagues wondered: How might neutron star mergers compare to collisions between a neutron star and a black hole? This is another merger type that has been detected by LIGO and Virgo and could potentially be a heavy metal factory. Under certain conditions, scientists suspect, a black hole could disrupt a neutron star such that it would spark and spew heavy metals before the black hole completely swallowed the star.

    The team set out to determine the amount of gold and other heavy metals each type of merger could typically produce. For their analysis, they focused on LIGO and Virgo’s detections to date of two binary neutron star mergers and two neutron star – black hole mergers.

    The researchers first estimated the mass of each object in each merger, as well as the rotational speed of each black hole, reasoning that if a black hole is too massive or slow, it would swallow a neutron star before it had a chance to produce heavy elements. They also determined each neutron star’s resistance to being disrupted. The more resistant a star, the less likely it is to churn out heavy elements. They also estimated how often one merger occurs compared to the other, based on observations by LIGO, Virgo, and other observatories.

    Finally, the team used numerical simulations developed by Foucart, to calculate the average amount of gold and other heavy metals each merger would produce, given varying combinations of the objects’ mass, rotation, degree of disruption, and rate of occurrence.

    On average, the researchers found that binary neutron star mergers could generate two to 100 times more heavy metals than mergers between neutron stars and black holes. The four mergers on which they based their analysis are estimated to have occurred within the last 2.5 billion years. They conclude then, that during this period, at least, more heavy elements were produced by binary neutron star mergers than by collisions between neutron stars and black holes.

    The scales could tip in favor of neutron star-black hole mergers if the black holes had high spins, and low masses. However, scientists have not yet observed these kinds of black holes in the two mergers detected to date.

    Chen and her colleagues hope that, as LIGO and Virgo resume observations next year, more detections will improve the team’s estimates for the rate at which each merger produces heavy elements. These rates, in turn, may help scientists determine the age of distant galaxies, based on the abundance of their various elements.

    “You can use heavy metals the same way we use carbon to date dinosaur remains,” Vitale says. “Because all these phenomena have different intrinsic rates and yields of heavy elements, that will affect how you attach a time stamp to a galaxy. So, this kind of study can improve those analyses.”

    This research was funded, in part, by NASA, the National Science Foundation, and the LIGO Laboratory.

    See the full article here .

    Please help promote STEM in your local schools.

    Stem Education Coalition

    MIT Seal

    USPS “Forever” postage stamps celebrating Innovation at MIT.

    MIT Campus

    The Massachusetts Institute of Technology (US) is a private land-grant research university in Cambridge, Massachusetts. The institute has an urban campus that extends more than a mile (1.6 km) alongside the Charles River. The institute also encompasses a number of major off-campus facilities such as the MIT Lincoln Laboratory (US), the MIT Bates Research and Engineering Center (US), and the Haystack Observatory (US), as well as affiliated laboratories such as the Broad Institute of MIT and Harvard(US) and Whitehead Institute (US).

    Founded in 1861 in response to the increasing industrialization of the United States, Massachusetts Institute of Technology (US) adopted a European polytechnic university model and stressed laboratory instruction in applied science and engineering. It has since played a key role in the development of many aspects of modern science, engineering, mathematics, and technology, and is widely known for its innovation and academic strength. It is frequently regarded as one of the most prestigious universities in the world.

    As of December 2020, 97 Nobel laureates, 26 Turing Award winners, and 8 Fields Medalists have been affiliated with MIT as alumni, faculty members, or researchers. In addition, 58 National Medal of Science recipients, 29 National Medals of Technology and Innovation recipients, 50 MacArthur Fellows, 80 Marshall Scholars, 3 Mitchell Scholars, 22 Schwarzman Scholars, 41 astronauts, and 16 Chief Scientists of the U.S. Air Force have been affiliated with The Massachusetts Institute of Technology (US) . The university also has a strong entrepreneurial culture and MIT alumni have founded or co-founded many notable companies. Massachusetts Institute of Technology (US) is a member of the Association of American Universities (AAU).

    Foundation and vision

    In 1859, a proposal was submitted to the Massachusetts General Court to use newly filled lands in Back Bay, Boston for a “Conservatory of Art and Science”, but the proposal failed. A charter for the incorporation of the Massachusetts Institute of Technology, proposed by William Barton Rogers, was signed by John Albion Andrew, the governor of Massachusetts, on April 10, 1861.

    Rogers, a professor from the University of Virginia (US), wanted to establish an institution to address rapid scientific and technological advances. He did not wish to found a professional school, but a combination with elements of both professional and liberal education, proposing that:

    “The true and only practicable object of a polytechnic school is, as I conceive, the teaching, not of the minute details and manipulations of the arts, which can be done only in the workshop, but the inculcation of those scientific principles which form the basis and explanation of them, and along with this, a full and methodical review of all their leading processes and operations in connection with physical laws.”

    The Rogers Plan reflected the German research university model, emphasizing an independent faculty engaged in research, as well as instruction oriented around seminars and laboratories.

    Early developments

    Two days after Massachusetts Institute of Technology (US) was chartered, the first battle of the Civil War broke out. After a long delay through the war years, MIT’s first classes were held in the Mercantile Building in Boston in 1865. The new institute was founded as part of the Morrill Land-Grant Colleges Act to fund institutions “to promote the liberal and practical education of the industrial classes” and was a land-grant school. In 1863 under the same act, the Commonwealth of Massachusetts founded the Massachusetts Agricultural College, which developed as the University of Massachusetts Amherst (US)). In 1866, the proceeds from land sales went toward new buildings in the Back Bay.

    Massachusetts Institute of Technology (US) was informally called “Boston Tech”. The institute adopted the European polytechnic university model and emphasized laboratory instruction from an early date. Despite chronic financial problems, the institute saw growth in the last two decades of the 19th century under President Francis Amasa Walker. Programs in electrical, chemical, marine, and sanitary engineering were introduced, new buildings were built, and the size of the student body increased to more than one thousand.

    The curriculum drifted to a vocational emphasis, with less focus on theoretical science. The fledgling school still suffered from chronic financial shortages which diverted the attention of the MIT leadership. During these “Boston Tech” years, Massachusetts Institute of Technology (US) faculty and alumni rebuffed Harvard University (US) president (and former MIT faculty) Charles W. Eliot’s repeated attempts to merge MIT with Harvard College’s Lawrence Scientific School. There would be at least six attempts to absorb MIT into Harvard. In its cramped Back Bay location, MIT could not afford to expand its overcrowded facilities, driving a desperate search for a new campus and funding. Eventually, the MIT Corporation approved a formal agreement to merge with Harvard, over the vehement objections of MIT faculty, students, and alumni. However, a 1917 decision by the Massachusetts Supreme Judicial Court effectively put an end to the merger scheme.

    In 1916, the Massachusetts Institute of Technology (US) administration and the MIT charter crossed the Charles River on the ceremonial barge Bucentaur built for the occasion, to signify MIT’s move to a spacious new campus largely consisting of filled land on a one-mile-long (1.6 km) tract along the Cambridge side of the Charles River. The neoclassical “New Technology” campus was designed by William W. Bosworth and had been funded largely by anonymous donations from a mysterious “Mr. Smith”, starting in 1912. In January 1920, the donor was revealed to be the industrialist George Eastman of Rochester, New York, who had invented methods of film production and processing, and founded Eastman Kodak. Between 1912 and 1920, Eastman donated $20 million ($236.6 million in 2015 dollars) in cash and Kodak stock to MIT.

    Curricular reforms

    In the 1930s, President Karl Taylor Compton and Vice-President (effectively Provost) Vannevar Bush emphasized the importance of pure sciences like physics and chemistry and reduced the vocational practice required in shops and drafting studios. The Compton reforms “renewed confidence in the ability of the Institute to develop leadership in science as well as in engineering”. Unlike Ivy League schools, Massachusetts Institute of Technology (US) catered more to middle-class families, and depended more on tuition than on endowments or grants for its funding. The school was elected to the Association of American Universities (US)in 1934.

    Still, as late as 1949, the Lewis Committee lamented in its report on the state of education at Massachusetts Institute of Technology (US) that “the Institute is widely conceived as basically a vocational school”, a “partly unjustified” perception the committee sought to change. The report comprehensively reviewed the undergraduate curriculum, recommended offering a broader education, and warned against letting engineering and government-sponsored research detract from the sciences and humanities. The School of Humanities, Arts, and Social Sciences and the MIT Sloan School of Management were formed in 1950 to compete with the powerful Schools of Science and Engineering. Previously marginalized faculties in the areas of economics, management, political science, and linguistics emerged into cohesive and assertive departments by attracting respected professors and launching competitive graduate programs. The School of Humanities, Arts, and Social Sciences continued to develop under the successive terms of the more humanistically oriented presidents Howard W. Johnson and Jerome Wiesner between 1966 and 1980.

    Massachusetts Institute of Technology (US)‘s involvement in military science surged during World War II. In 1941, Vannevar Bush was appointed head of the federal Office of Scientific Research and Development and directed funding to only a select group of universities, including MIT. Engineers and scientists from across the country gathered at Massachusetts Institute of Technology (US)’s Radiation Laboratory, established in 1940 to assist the British military in developing microwave radar. The work done there significantly affected both the war and subsequent research in the area. Other defense projects included gyroscope-based and other complex control systems for gunsight, bombsight, and inertial navigation under Charles Stark Draper’s Instrumentation Laboratory; the development of a digital computer for flight simulations under Project Whirlwind; and high-speed and high-altitude photography under Harold Edgerton. By the end of the war, Massachusetts Institute of Technology (US) became the nation’s largest wartime R&D contractor (attracting some criticism of Bush), employing nearly 4000 in the Radiation Laboratory alone and receiving in excess of $100 million ($1.2 billion in 2015 dollars) before 1946. Work on defense projects continued even after then. Post-war government-sponsored research at MIT included SAGE and guidance systems for ballistic missiles and Project Apollo.

    These activities affected Massachusetts Institute of Technology (US) profoundly. A 1949 report noted the lack of “any great slackening in the pace of life at the Institute” to match the return to peacetime, remembering the “academic tranquility of the prewar years”, though acknowledging the significant contributions of military research to the increased emphasis on graduate education and rapid growth of personnel and facilities. The faculty doubled and the graduate student body quintupled during the terms of Karl Taylor Compton, president of Massachusetts Institute of Technology (US) between 1930 and 1948; James Rhyne Killian, president from 1948 to 1957; and Julius Adams Stratton, chancellor from 1952 to 1957, whose institution-building strategies shaped the expanding university. By the 1950s, Massachusetts Institute of Technology (US) no longer simply benefited the industries with which it had worked for three decades, and it had developed closer working relationships with new patrons, philanthropic foundations and the federal government.

    In late 1960s and early 1970s, student and faculty activists protested against the Vietnam War and Massachusetts Institute of Technology (US)’s defense research. In this period Massachusetts Institute of Technology (US)’s various departments were researching helicopters, smart bombs and counterinsurgency techniques for the war in Vietnam as well as guidance systems for nuclear missiles. The Union of Concerned Scientists was founded on March 4, 1969 during a meeting of faculty members and students seeking to shift the emphasis on military research toward environmental and social problems. Massachusetts Institute of Technology (US) ultimately divested itself from the Instrumentation Laboratory and moved all classified research off-campus to the MIT (US) Lincoln Laboratory facility in 1973 in response to the protests. The student body, faculty, and administration remained comparatively unpolarized during what was a tumultuous time for many other universities. Johnson was seen to be highly successful in leading his institution to “greater strength and unity” after these times of turmoil. However six Massachusetts Institute of Technology (US) students were sentenced to prison terms at this time and some former student leaders, such as Michael Albert and George Katsiaficas, are still indignant about MIT’s role in military research and its suppression of these protests. (Richard Leacock’s film, November Actions, records some of these tumultuous events.)

    In the 1980s, there was more controversy at Massachusetts Institute of Technology (US) over its involvement in SDI (space weaponry) and CBW (chemical and biological warfare) research. More recently, Massachusetts Institute of Technology (US)’s research for the military has included work on robots, drones and ‘battle suits’.

    Recent history

    Massachusetts Institute of Technology (US) has kept pace with and helped to advance the digital age. In addition to developing the predecessors to modern computing and networking technologies, students, staff, and faculty members at Project MAC, the Artificial Intelligence Laboratory, and the Tech Model Railroad Club wrote some of the earliest interactive computer video games like Spacewar! and created much of modern hacker slang and culture. Several major computer-related organizations have originated at MIT since the 1980s: Richard Stallman’s GNU Project and the subsequent Free Software Foundation were founded in the mid-1980s at the AI Lab; the MIT Media Lab was founded in 1985 by Nicholas Negroponte and Jerome Wiesner to promote research into novel uses of computer technology; the World Wide Web Consortium standards organization was founded at the Laboratory for Computer Science in 1994 by Tim Berners-Lee; the MIT OpenCourseWare project has made course materials for over 2,000 Massachusetts Institute of Technology (US) classes available online free of charge since 2002; and the One Laptop per Child initiative to expand computer education and connectivity to children worldwide was launched in 2005.

    Massachusetts Institute of Technology (US) was named a sea-grant college in 1976 to support its programs in oceanography and marine sciences and was named a space-grant college in 1989 to support its aeronautics and astronautics programs. Despite diminishing government financial support over the past quarter century, MIT launched several successful development campaigns to significantly expand the campus: new dormitories and athletics buildings on west campus; the Tang Center for Management Education; several buildings in the northeast corner of campus supporting research into biology, brain and cognitive sciences, genomics, biotechnology, and cancer research; and a number of new “backlot” buildings on Vassar Street including the Stata Center. Construction on campus in the 2000s included expansions of the Media Lab, the Sloan School’s eastern campus, and graduate residences in the northwest. In 2006, President Hockfield launched the MIT Energy Research Council to investigate the interdisciplinary challenges posed by increasing global energy consumption.

    In 2001, inspired by the open source and open access movements, Massachusetts Institute of Technology (US) launched OpenCourseWare to make the lecture notes, problem sets, syllabi, exams, and lectures from the great majority of its courses available online for no charge, though without any formal accreditation for coursework completed. While the cost of supporting and hosting the project is high, OCW expanded in 2005 to include other universities as a part of the OpenCourseWare Consortium, which currently includes more than 250 academic institutions with content available in at least six languages. In 2011, Massachusetts Institute of Technology (US) announced it would offer formal certification (but not credits or degrees) to online participants completing coursework in its “MITx” program, for a modest fee. The “edX” online platform supporting MITx was initially developed in partnership with Harvard and its analogous “Harvardx” initiative. The courseware platform is open source, and other universities have already joined and added their own course content. In March 2009 the Massachusetts Institute of Technology (US) faculty adopted an open-access policy to make its scholarship publicly accessible online.

    Massachusetts Institute of Technology (US) has its own police force. Three days after the Boston Marathon bombing of April 2013, MIT Police patrol officer Sean Collier was fatally shot by the suspects Dzhokhar and Tamerlan Tsarnaev, setting off a violent manhunt that shut down the campus and much of the Boston metropolitan area for a day. One week later, Collier’s memorial service was attended by more than 10,000 people, in a ceremony hosted by the Massachusetts Institute of Technology (US) community with thousands of police officers from the New England region and Canada. On November 25, 2013, Massachusetts Institute of Technology (US) announced the creation of the Collier Medal, to be awarded annually to “an individual or group that embodies the character and qualities that Officer Collier exhibited as a member of the Massachusetts Institute of Technology (US) community and in all aspects of his life”. The announcement further stated that “Future recipients of the award will include those whose contributions exceed the boundaries of their profession, those who have contributed to building bridges across the community, and those who consistently and selflessly perform acts of kindness”.

    In September 2017, the school announced the creation of an artificial intelligence research lab called the MIT-IBM Watson AI Lab. IBM will spend $240 million over the next decade, and the lab will be staffed by MIT and IBM scientists. In October 2018 MIT announced that it would open a new Schwarzman College of Computing dedicated to the study of artificial intelligence, named after lead donor and The Blackstone Group CEO Stephen Schwarzman. The focus of the new college is to study not just AI, but interdisciplinary AI education, and how AI can be used in fields as diverse as history and biology. The cost of buildings and new faculty for the new college is expected to be $1 billion upon completion.

    The Caltech/MIT Advanced aLIGO (US) was designed and constructed by a team of scientists from California Institute of Technology (US), Massachusetts Institute of Technology (US), and industrial contractors, and funded by the National Science Foundation (US) .

    MIT/Caltech Advanced aLigo .

    It was designed to open the field of gravitational-wave astronomy through the detection of gravitational waves predicted by general relativity. Gravitational waves were detected for the first time by the LIGO detector in 2015. For contributions to the LIGO detector and the observation of gravitational waves, two Caltech physicists, Kip Thorne and Barry Barish, and Massachusetts Institute of Technology (US) physicist Rainer Weiss won the Nobel Prize in physics in 2017. Weiss, who is also an Massachusetts Institute of Technology (US) graduate, designed the laser interferometric technique, which served as the essential blueprint for the LIGO.

    The mission of Massachusetts Institute of Technology (US) is to advance knowledge and educate students in science, technology, and other areas of scholarship that will best serve the nation and the world in the twenty-first century. We seek to develop in each member of The Massachusetts Institute of Technology community the ability and passion to work wisely, creatively, and effectively for the betterment of humankind.

    • MIKE EYE 1:53 pm on October 25, 2021 Permalink | Reply

      Fellow Allstonian from across the River; just was wondering what the people who put on the time travelers convention @MIT think about the upcoming 2023 Third Phase of Montauk & Phi-Ex: what will happen that permenalty changes time forever??


  • richardmitnick 1:26 pm on October 18, 2021 Permalink | Reply
    Tags: "Uncovering the secrets of ultra-low frequency gravitational waves", Gravitational wave astronomy,   

    From University of Birmingham (UK) : “Uncovering the secrets of ultra-low frequency gravitational waves” 

    From University of Birmingham (UK)

    18 Oct 2021

    New methods of detecting ultra-low frequency gravitational waves can be combined with other, less sensitive measurements to deliver fresh insights into the early development of our universe, according to researchers at the University of Birmingham.

    An artist’s impression of the colliding bubbles that can produce extremely low frequency gravitational waves during a cosmological phase transition in the early Universe. Image credit: Riccardo Buscicchio.

    Gravitational waves – ripples in the fabric of Einstein’s spacetime – that cross the universe at the speed of light have all sorts of wavelengths, or frequencies. Scientists have not yet managed to detect gravitational waves at extremely low ‘nanohertz’ frequencies, but new approaches currently being explored are expected to confirm the first low frequency signals quite soon.

    The main method uses radio telescopes to detect gravitational waves using pulsars – exotic, dead stars, that send out pulses of radio waves with extraordinary regularity. Researchers at the North American Nanohertz Observatory for Gravitational Waves (US), for example, use pulsars to time to exquisite precision the rotation periods of a network, or array, of millisecond pulsars – astronomers’ best approximation of a network of perfect clocks – spread throughout our galaxy.

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

    These can be used to measure the fractional changes caused by gravitational waves as they spread through the universe.

    The question of what is producing these signals, however, has yet to be determined. Scientists in the University of Birmingham’s Institute for Gravitational Wave Astronomy, argue that it will be extremely difficult to settle on an answer using only data from pulsar timing arrays (PTAs).

    IPTA-International Pulsar Timing Array-Clockwise from upper left: Green Bank Radio Telescope (US), Arecibo Radio Telescope (US) no longer in service, Nancay Radio Telescope (FR), Lovell Radio Telescope Cheshire (UK), Parkes Radio Telescope (AU), LOFAR Radio Telescope Exloo (NL), GMRT Pune India, Westerbork Radio Telescope (NL), Effelsberg Radio Telescope (DE)

    Instead, in a letter published in Nature Astronomy, they suggest that combining this new data with observations made by other projects such as the European Space Agency’s Gaia mission, will help the different signals still lingering from the earliest periods of our universe to be disentangled and interpreted.

    The main theory for ultra-low frequency gravitational waves is that they are caused by a population of the supermassive black holes at the centre of merging galaxies. As galaxies merge, their central black holes pair up, forming binaries and generating gravitational waves. In this case, a detection of gravitational waves by PTA would offer exciting new ways to study the astrophysics of the assembly and growth of galaxies.

    But there are other possibilities too. Nanohertz gravitational waves could tell the story of our infant universe, well before galaxies and black holes form. In fact, it has been suggested that extremely low frequency gravitational wave signals could instead be generated shortly after the big bang by other processes; for example if the Universe underwent what physicists refer to as a phase transition at the correct temperature.

    Lead author, Dr Christopher Moore, said: “The first tentative hints of a gravitational wave signal using pulsar timing arrays might recently have been seen by NANOGrav and we expect the next few years to be a golden age for this type of science. The variety of explanations for these signals is exciting, but also a maze. We need a way to tell the different possible sources apart from each other. Currently, this is extremely difficult to do with pulsar timing array data alone.”

    Co-author Professor Alberto Vecchio said: “Pulsar timing arrays may offer unprecedented insights into ancient cosmological processes. Developing the sophisticated methods to interpret these insights will mean we can truly begin to understand how our universe was formed and took shape.”

    See the full article here .


    Please help promote STEM in your local schools.

    Stem Education Coalition

    University of Birmingham (UK) has been challenging and developing great minds for more than a century. Characterised by a tradition of innovation, research at the University has broken new ground, pushed forward the boundaries of knowledge and made an impact on people’s lives. We continue this tradition today and have ambitions for a future that will embed our work and recognition of the Birmingham name on the international stage.

    The University of Birmingham is a public research university located in Edgbaston, Birmingham, United Kingdom. It received its royal charter in 1900 as a successor to Queen’s College, Birmingham (founded in 1825 as the Birmingham School of Medicine and Surgery), and Mason Science College (established in 1875 by Sir Josiah Mason), making it the first English civic or ‘red brick’ university to receive its own royal charter. It is a founding member of both the Russell Group (UK) of British research universities and the international network of research universities, Universitas 21.

    The student population includes 23,155 undergraduate and 12,605 postgraduate students, which is the 7th largest in the UK (out of 169). The annual income of the institution for 2019–20 was £737.3 million of which £140.4 million was from research grants and contracts, with an expenditure of £667.4 million.

    The university is home to the Barber Institute of Fine Arts, housing works by Van Gogh, Picasso and Monet; the Shakespeare Institute; the Cadbury Research Library, home to the Mingana Collection of Middle Eastern manuscripts; the Lapworth Museum of Geology; and the 100-metre Joseph Chamberlain Memorial Clock Tower, which is a prominent landmark visible from many parts of the city. Academics and alumni of the university include former British Prime Ministers Neville Chamberlain and Stanley Baldwin, the British composer Sir Edward Elgar and eleven Nobel laureates.

    Scientific discoveries and inventions

    The university has been involved in many scientific breakthroughs and inventions. From 1925 until 1948, Sir Norman Haworth was Professor and Director of the Department of Chemistry. He was appointed Dean of the Faculty of Science and acted as Vice-Principal from 1947 until 1948. His research focused predominantly on carbohydrate chemistry in which he confirmed a number of structures of optically active sugars. By 1928, he had deduced and confirmed the structures of maltose, cellobiose, lactose, gentiobiose, melibiose, gentianose, raffinose, as well as the glucoside ring tautomeric structure of aldose sugars. His research helped to define the basic features of the starch, cellulose, glycogen, inulin and xylan molecules. He also contributed towards solving the problems with bacterial polysaccharides. He was a recipient of the Nobel Prize in Chemistry in 1937.

    The cavity magnetron was developed in the Department of Physics by Sir John Randall, Harry Boot and James Sayers. This was vital to the Allied victory in World War II. In 1940, the Frisch–Peierls memorandum, a document which demonstrated that the atomic bomb was more than simply theoretically possible, was written in the Physics Department by Sir Rudolf Peierls and Otto Frisch. The university also hosted early work on gaseous diffusion in the Chemistry department when it was located in the Hills building.

    Physicist Sir Mark Oliphant made a proposal for the construction of a proton-synchrotron in 1943, however he made no assertion that the machine would work. In 1945, phase stability was discovered; consequently, the proposal was revived, and construction of a machine that could surpass proton energies of 1 GeV began at the university. However, because of lack of funds, the machine did not start until 1953. The DOE’s Brookhaven National Laboratory (US) managed to beat them; they started their Cosmotron in 1952, and had it entirely working in 1953, before the University of Birmingham.

    In 1947, Sir Peter Medawar was appointed Mason Professor of Zoology at the university. His work involved investigating the phenomenon of tolerance and transplantation immunity. He collaborated with Rupert E. Billingham and they did research on problems of pigmentation and skin grafting in cattle. They used skin grafting to differentiate between monozygotic and dizygotic twins in cattle. Taking the earlier research of R. D. Owen into consideration, they concluded that actively acquired tolerance of homografts could be artificially reproduced. For this research, Medawar was elected a Fellow of the Royal Society. He left Birmingham in 1951 and joined the faculty at University College London (UK), where he continued his research on transplantation immunity. He was a recipient of the Nobel Prize in Physiology or Medicine in 1960.

  • richardmitnick 12:50 pm on October 11, 2021 Permalink | Reply
    Tags: , , Gravitational wave astronomy, ,   

    From AAS NOVA : ” Merging Black Holes vs. Gas and Stars” 


    From AAS NOVA

    11 October 2021
    Kerry Hensley

    This simulated image shows a massive black hole at the center of a galaxy. Some massive black holes may be the result of mergers between the black holes hosted by two or more galaxies. Credit: D. Coe, J. Anderson,The National Aeronautics and Space Agency (US), The European Space Agency [Agence spatiale européenne][Europäische Weltraumorganisation](EU), and and R. van der Marel (Space Telescope Science Institute (US))]

    When galaxies merge, what happens to the massive black holes at their centers? Today’s article explores the math behind the merger.

    When galaxies merge, it shakes up star formation and sets the stage for a massive black hole merger. [NASA, ESA, the Hubble Heritage (STScI/The Association of Universities for Research in Astronomy (AURA)(US))-ESA/Hubble Collaboration, and A. Evans (The University of Virginia (US), Charlottesville/National Radio Astronomy Observatory (US)/Stony Brook University-SUNY (US))]

    An Emerging Question

    Two galaxies, adrift in the universe, pass near one another. If they become gravitationally entangled, the billion-year process of merging begins as they gradually coalesce into a single galaxy. As part of this process, the massive black holes at the centers of the colliding galaxies undergo a merger of their own.

    As these massive black holes begin their death spiral, they encounter other galactic material like stars and gas. While simulations have shown that interacting with nearby stars causes the black-hole binary to spiral inward more quickly, the results aren’t as clear when it comes to gaseous material. Some studies have found that the presence of gas hastens the merger, while others suggest that it delays the merger instead.

    The rate at which massive black holes merge has implications for upcoming gravitational-wave observatories, like the Laser Interferometer Space Antenna (LISA).

    Massive black-hole mergers at the centers of colliding galaxies are expected to be the loudest source of low-frequency gravitational waves in upcoming surveys — but if some process prevents these mergers, there may be nothing to listen to.

    Black Holes on Paper

    Elisa Bortolas (The University of Milano-Bicocca [Università degli Studi di Milano-Bicocca](IT)) and collaborators used a mathematical model of a black-hole merger to understand how interactions with stars and the presence of gas affect the inspiraling of the binary. Unlike most previous work, the set of differential equations developed by Bortolas and coauthors allowed for the effects of stars and gas to be considered simultaneously rather than separately.

    The authors find that stars and gas tend to compete with one another as the black holes merge. If the black-hole pair accretes only a little mass from the surrounding material, gravitational interactions with nearby stars cause the black-hole pair to tighten inward. If the accretion rate is higher, the presence of a gaseous disk works to expand the binary pair, delaying the merger. Eventually, though, the stars win out, and the binary pair draws close enough to shed massive amounts of energy in the form of gravitational waves, sending the black holes on a collision course.

    Looking Ahead to Future Detections

    The results from Bortolas and coauthors showed that while the presence of gas can delay a merger, it won’t prevent it altogether. Under the conditions the authors explored, the presence of gas increased the time to the merger by a factor of a few, but all mergers occurred within a few hundred million years.

    This is good news for LISA and other gravitational-wave detectors, and there are implications for the non-gravitational-wave detections of these events as well; the presence of gas in the black holes’ surroundings seems to make them pause with just a few light-years between them, increasing the chance that a survey might detect them in this phase.


    “The Competing Effect of Gas and Stars in the Evolution of Massive Black Hole Binaries,” Elisa Bortolas et al 2021 ApJL 918 L15.


    See the full article here .


    Please help promote STEM in your local schools.

    Stem Education Coalition


    AAS Mission and Vision Statement

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

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

    Adopted June 7, 2009

    The society was founded in 1899 through the efforts of George Ellery Hale. The constitution of the group was written by Hale, George Comstock, Edward Morley, Simon Newcomb and Edward Charles Pickering. These men, plus four others, were the first Executive Council of the society; Newcomb was the first president. The initial membership was 114. The AAS name of the society was not finally decided until 1915, previously it was the “Astronomical and Astrophysical Society of America”. One proposed name that preceded this interim name was “American Astrophysical Society”.

    The AAS today has over 7,000 members and six divisions – the Division for Planetary Sciences (1968); the Division on Dynamical Astronomy (1969); the High Energy Astrophysics Division (1969); the Solar Physics Division (1969); the Historical Astronomy Division (1980); and the Laboratory Astrophysics Division (2012). The membership includes physicists, mathematicians, geologists, engineers and others whose research interests lie within the broad spectrum of subjects now comprising contemporary astronomy.

    In 2019 three AAS members were selected into the tenth anniversary class of TED Fellows.

    The AAS established the AAS Fellows program in 2019 to “confer recognition upon AAS members for achievement and extraordinary service to the field of astronomy and the American Astronomical Society.” The inaugural class was designated by the AAS Board of Trustees and includes an initial group of 232 Legacy Fellows.

  • richardmitnick 1:32 pm on September 14, 2021 Permalink | Reply
    Tags: "NASA Provides Laser for LISA Mission", , Gravitational wave astronomy, LISA: Laser Interferometer Space Antenna, ,   

    From NASA Goddard Space Flight Center (US) : “NASA Provides Laser for LISA Mission” 

    NASA Goddard Banner

    From NASA Goddard Space Flight Center (US)

    By Karl B. Hille
    NASA’s Goddard Space Flight Center in Greenbelt, Md.

    Media contact:
    Claire Andreoli
    (301) 286-1940

    Finding the biggest collisions in the universe takes time, patience, and super steady lasers.

    In May, NASA specialists working with industry partners delivered the first prototype laser for the The European Space Agency [Agence spatiale européenne][Europäische Weltraumorganisation](EU)-led Laser Interferometer Space Antenna, or LISA, mission.

    The first prototype of a laser sits on a testbed at the Swiss Center for Electronics and Microtechnology (CSEM), headquartered in Neuchâtel, Switzerland. CSEM will test and characterize the laser, which will be used to conduct gravitational wave experiments in space for the LISA mission.Credits: European Space Agency/CSEM

    This unique laser instrument is designed to detect the telltale ripples in gravitational fields caused by the mergers of neutron stars, black holes, and supermassive black holes in space.

    Anthony Yu at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, leads the laser transmitter development for LISA.

    “We’re developing a highly stable and robust laser for the LISA observatory,” Yu said. “We’ve leveraged lessons learned from previous missions and the latest technologies in photonics packaging and reliability engineering. Now, to meet the challenging LISA requirements, NASA has developed a system that produces a laser transmitter by using a low-power laser enhanced by a fiber-optic amplifier.”

    The team is building upon the laser technology used in NASA’s GRACE mission. “We developed a more compact version as a master oscillator,” Yu said. “It has much smaller size, weight, and power consumption to allow for a fully redundant master oscillator for long-duration lifetime requirements.”

    The LISA laser prototype is a 2-watt laser operating in the near-infrared part of the spectrum. “Our laser is about 400 times more powerful than the typical laser pointer that puts out about 5 milliwatts or less,” Yu said. “The laser module size, not including the electronics, is about half the volume of a typical shoe box.”

    The Swiss Center for Electronics and Microtechnology (CSEM), headquartered in Neuchâtel, Switzerland, confirmed receipt of the lasers and will begin testing them for stability.

    LISA will consist of three spacecraft following Earth in its orbit around the Sun and flying in a precision formation, with 1.5 million miles (2.5 million kilometers) separating each one. Each spacecraft will continuously point two lasers at its counterparts. The laser receiver must be sensitive to a few hundreds of picowatts of signal strength, as the laser beam will spread to about 12 miles (20 kilometers) by the time it reaches its target spacecraft. A time-code signal embedded in the beams allows LISA to measure the slightest interference in these transmissions.

    Ripples in the fabric of space-time as small as a picometer – 50 times smaller than a hydrogen atom – will produce a detectable change in the distances between the spacecraft. Measuring these changes will give scientists the general scale of what collided to produce these ripples and an idea of where in the sky to aim other observatories looking for secondary effects.

    These gravitational wave fluctuations are so small they would be obscured by external forces such as dust impacts and the radiation pressure of sunlight on the spacecraft. To mitigate this, the drag-free control concept – demonstrated on the LISA Pathfinder mission in 2015 – uses free-floating test masses sheltered inside each spacecraft as reference points for the measurement.

    LISA expands on work by the National Science Foundation’s (US)3 Laser Interferometer Gravitational-Wave Observatory (LIGO), which captured its first recording of gravitational waves in 2015.

    Since then, the pair of ground-based observatories in Hanford, Washington, and Livingston, Louisiana, have captured four dozen mergers.

    Thomas Hams, program scientist for LISA at NASA Headquarters in Washington, said the precision laser measurements will allow us to zoom in on the gravitational wave signatures of these mergers and enable other observatories to focus on the right part of the sky to capture these events in the electromagnetic spectrum.

    NASA’s Fermi Gamma-ray Space Telescope picked up the first such multimessenger observation just seconds after LIGO detected a merger of two neutron stars through gravitational waves.

    “With LISA, the hope is you will be able to see these things develop before the merger actually happens,” Hams said. “There will be an indicator that something is coming.”

    Industry Partnership

    To achieve the required stability, the team brought Fibertek Inc. in Herndon, Virginia, and Avo Photonics Inc. in Horsham, Pennsylvania, to develop the laser, oscillator, and power amplifier, and an independent optical engineer in San Jose, California.

    Avo Photonics built the laser for the observatory.

    “Here you have the challenges of spaceborne ruggedness needs, on top of submicron-level optical alignment tolerance requirements. These really push your optical, thermal, and mechanical design chops,” Avo Photonics President Joseph L. Dallas said. “In addition, the narrow linewidth, low noise, and overall stability needed for this mission is unprecedented.”

    Photonics pioneer Tom Kane invented the monolithic laser oscillator technology that Goddard used to stabilize the frequency of the laser light. “Your average laser can be very messy,” Kane said. “They can wander all around their target frequency. You need a ‘quiet’ laser that’s exactly one wavelength and a perfect beam out to 15 decimal places of accuracy.”

    His oscillator technology uses feedback loops to keep the laser burning at such precision. “The wavelength ends up becoming the ruler for these incredible distances,” Kane said.

    The high-power, low-noise amplifier came from Fibertek.

    Fibertek also contributed to NASA’s Ice Cloud and Land Elevation Satellite (ICESat) 2 and the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO), which has been operating a laser pointed at Earth for 15 years.

    Including time for testing on the ground and potential mission extensions, LISA’s lasers must operate without skipping a hertz for up to 16 years, Goddard’s Yu said.

    “Once launched, they will need to be in 24/7 operation for five years for the initial mission, with a possible six to seven years of extended mission after that,” Yu explained. “We need them to be stable and quiet.”

    See the full article here.


    Please help promote STEM in your local schools.

    Stem Education Coalition

    NASA/Goddard Campus

    NASA’s Goddard Space Flight Center, Greenbelt, MD (US) is home to the nation’s largest organization of combined scientists, engineers and technologists that build spacecraft, instruments and new technology to study the Earth, the sun, our solar system, and the universe.

    Named for American rocketry pioneer Dr. Robert H. Goddard, the center was established in 1959 as NASA’s first space flight complex. Goddard and its several facilities are critical in carrying out NASA’s missions of space exploration and scientific discovery.

    GSFC also operates two spaceflight tracking and data acquisition networks (the NASA Deep Space Network(US) and the Near Earth Network); develops and maintains advanced space and Earth science data information systems, and develops satellite systems for the National Oceanic and Atmospheric Administration(US) .

    GSFC manages operations for many NASA and international missions including the NASA/ESA Hubble Space Telescope; the Explorers Program; the Discovery Program; the Earth Observing System; INTEGRAL; MAVEN; OSIRIS-REx; the Solar and Heliospheric Observatory ; the Solar Dynamics Observatory; Tracking and Data Relay Satellite System ; Fermi; and Swift. Past missions managed by GSFC include the Rossi X-ray Timing Explorer (RXTE), Compton Gamma Ray Observatory, SMM, COBE, IUE, and ROSAT. Typically, unmanned Earth observation missions and observatories in Earth orbit are managed by GSFC, while unmanned planetary missions are managed by the Jet Propulsion Laboratory (JPL) in Pasadena, California(US).

    Goddard is one of four centers built by NASA since its founding on July 29, 1958. It is NASA’s first, and oldest, space center. Its original charter was to perform five major functions on behalf of NASA: technology development and fabrication; planning; scientific research; technical operations; and project management. The center is organized into several directorates, each charged with one of these key functions.

    Until May 1, 1959, NASA’s presence in Greenbelt, MD was known as the Beltsville Space Center. It was then renamed the Goddard Space Flight Center (GSFC), after Robert H. Goddard. Its first 157 employees transferred from the United States Navy’s Project Vanguard missile program, but continued their work at the Naval Research Laboratory in Washington, D.C., while the center was under construction.

    Goddard Space Flight Center contributed to Project Mercury, America’s first manned space flight program. The Center assumed a lead role for the project in its early days and managed the first 250 employees involved in the effort, who were stationed at Langley Research Center in Hampton, Virginia. However, the size and scope of Project Mercury soon prompted NASA to build a new Manned Spacecraft Center, now the Johnson Space Center, in Houston, Texas. Project Mercury’s personnel and activities were transferred there in 1961.

    The Goddard network tracked many early manned and unmanned spacecraft.

    Goddard Space Flight Center remained involved in the manned space flight program, providing computer support and radar tracking of flights through a worldwide network of ground stations called the Spacecraft Tracking and Data Acquisition Network (STDN). However, the Center focused primarily on designing unmanned satellites and spacecraft for scientific research missions. Goddard pioneered several fields of spacecraft development, including modular spacecraft design, which reduced costs and made it possible to repair satellites in orbit. Goddard’s Solar Max satellite, launched in 1980, was repaired by astronauts on the Space Shuttle Challenger in 1984. The Hubble Space Telescope, launched in 1990, remains in service and continues to grow in capability thanks to its modular design and multiple servicing missions by the Space Shuttle.

    Today, the center remains involved in each of NASA’s key programs. Goddard has developed more instruments for planetary exploration than any other organization, among them scientific instruments sent to every planet in the Solar System. The center’s contribution to the Earth Science Enterprise includes several spacecraft in the Earth Observing System fleet as well as EOSDIS, a science data collection, processing, and distribution system. For the manned space flight program, Goddard develops tools for use by astronauts during extra-vehicular activity, and operates the Lunar Reconnaissance Orbiter, a spacecraft designed to study the Moon in preparation for future manned exploration.

  • richardmitnick 4:43 pm on January 19, 2021 Permalink | Reply
    Tags: , , Biomarkers left behind by tiny single-cell organisms called archaea in the distant past., Gravitational wave astronomy, , , , TEX86   

    From ARC Centres of Excellence for Gravitational Wave Discovery OzGrav (AU) via phys.org: “Using 100-million-year-old fossils and gravitational-wave science to predict Earth’s future climate” 


    From ARC Centres of Excellence for Gravitational Wave Discovery




    January 19, 2021

    A group of international scientists, including an Australian astrophysicist, has used findings from gravitational wave astronomy (used to find black holes in space) to study ancient marine fossils as a predictor of climate change.

    The research, published in the journal Climate of the Past, is a unique collaboration between palaeontologists, astrophysicists and mathematicians seeking to improve the accuracy of a palaeo-thermometer, which can use fossil evidence of climate change to predict what is likely to happen to the Earth in coming decades.

    Professor Ilya Mandel, from the ARC Centre of Excellence in Gravitational Wave Discovery (OzGrav), and colleagues, studied biomarkers left behind by tiny single-cell organisms called archaea in the distant past, including the Cretaceous period and the Eocene.

    Marine archaea in our modern oceans produce compounds called Glycerol Dialkyl Glycerol Tetraethers (GDGTs). The ratios of different types of GDGTs they produce depend on the local sea temperature at the site of formation.

    When preserved in ancient marine sediments, the measured abundances of GDGTs have the potential to provide a geological record of long-term planetary surface temperatures.

    To date, scientists have combined GDGT concentrations into a single parameter called TEX86, which can be used to make rough estimates of the surface temperature. However, this estimate is not very accurate when the values of TEX86 from recent sediments are compared to modern sea surface temperatures.

    Image of archaea. Credit: Steve Gschmeissner/Science Photo Library

    “After several decades of study, the best available models are only able to measure temperature from GDGT concentrations with an accuracy of around 6 degrees Celsius,” Professor Mandel said. Therefore, this approach cannot be relied on for high-precision measurements of ancient climates.

    Professor Mandel and his colleagues at the University of Birmingham in the UK have applied modern machine-learning tools—originally used in the context of gravitational-wave astrophysics to create predictive models of merging black holes and neutron stars—to improve temperature estimation based on GDGT measurements. This enabled them to take all observations into account for the first time rather than relying on one particular combination, TEX86. This produced a far more accurate palaeo-thermometer. Using these tools, the team extracted temperature from GDGT concentrations with an accuracy of just 3.6 degrees—a significant improvement, nearly twice the accuracy of previous models.

    According to Professor Mandel, determining how much the Earth will warm in coming decades relies on modelling, “so it is critically important to calibrate those models by utilizing literally hundreds of millions of years of climate history to predict what might happen to the Earth in the future,” he said.

    See the full article here .


    Please help promote STEM in your local schools.

    Stem Education Coalition

    OzGrav (AU)

    ARC Centres of Excellence for Gravitational Wave Discovery OzGrav (AU)
    A new window of discovery.
    A new age of gravitational wave astronomy.
    One hundred years ago, Albert Einstein produced one of the greatest intellectual achievements in physics, the theory of general relativity. In general relativity, spacetime is dynamic. It can be warped into a black hole. Accelerating masses create ripples in spacetime known as gravitational waves (GWs) that carry energy away from the source. Recent advances in detector sensitivity led to the first direct detection of gravitational waves in 2015. This was a landmark achievement in human discovery and heralded the birth of the new field of gravitational wave astronomy. This was followed in 2017 by the first observations of the collision of two neutron-stars. The accompanying explosion was subsequently seen in follow-up observations by telescopes across the globe, and ushered in a new era of multi-messenger astronomy.

    The mission of the ARC Centre of Excellence for Gravitational Wave Discovery (OzGrav) is to capitalise on the historic first detections of gravitational waves to understand the extreme physics of black holes and warped spacetime, and to inspire the next generation of Australian scientists and engineers through this new window on the Universe.

    OzGrav is funded by the Australian Government through the Australian Research Council Centres of Excellence funding scheme, and is a partnership between Swinburne University (host of OzGrav headquarters), the Australian National University, Monash University, University of Adelaide, University of Melbourne, and University of Western Australia, along with other collaborating organisations in Australia and overseas.


    The objectives for the ARC Centres of Excellence are to to:

    undertake highly innovative and potentially transformational research that aims to achieve international standing in the fields of research envisaged and leads to a significant advancement of capabilities and knowledge

    link existing Australian research strengths and build critical mass with new capacity for interdisciplinary, collaborative approaches to address the most challenging and significant research problems

    develope relationships and build new networks with major national and international centres and research programs to help strengthen research, achieve global competitiveness and gain recognition for Australian research

    build Australia’s human capacity in a range of research areas by attracting and retaining, from within Australia and abroad, researchers of high international standing as well as the most promising research students

    provide high-quality postgraduate and postdoctoral training environments for the next generation of researchers

    offer Australian researchers opportunities to work on large-scale problems over long periods of time

    establish Centres that have an impact on the wider community through interaction with higher education institutes, governments, industry and the private and non-profit sector.

  • richardmitnick 4:30 pm on August 18, 2020 Permalink | Reply
    Tags: , , , , , , Gravitational wave astronomy,   

    From Harvard-Smithsonian Center for Astrophysics: “Where Might Very Unequal Mass Black Hole Binaries Come From?” 

    Harvard Smithsonian Center for Astrophysics

    From Harvard-Smithsonian Center for Astrophysics

    A schematic showing two pathways (each one requiring two prior black hole binary merging events) to assemble a roughly 30 solar-mass black like the one detected in a recent black hole binary gravitational wave merger event. Astronomers trying to explain where the massive spinning black hole in the pair was formed conclude that in dense stellar clusters a three-step process is the most likely path. Rodriguez et al., 2020.

    The direct detection of gravitational waves from at least eleven sources during the past five years has offered spectacular confirmation of Einstein’s model of gravity and space-time, while the modeling of these events has provided information on star formation, gamma-ray bursts,neutron stars, the age of the universe, and even verification of ideas about how very heavy elements are produced. The majority of these gravitational wave events arose from the merger of two black holes of comparable masses in an orbiting pair. Near-equal mass pairs are strongly preferred in models of binary black hole formation, whether they result from the evolution of isolated binary stars or from the dynamical pairing of two black holes. This year, however, the LIGO and Virgo gravitational wave observatories reported the first detection of a very unequal mass pair of black holes, GW190412, whose estimated masses are about 30 and 8 solar-masses. The question, then, is how were they formed?

    MIT /Caltech Advanced aLigo

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

    VIRGO Gravitational Wave interferometer, near Pisa, Italy

    VIRGO Gravitational Wave interferometer, near Pisa, Italy

    CfA astronomer Carl Rodriguez led a team of colleagues in a theoretical investigation of how such an unequal mass binary might form. The most obvious solution is look in a dense star cluster, where low-spin, comparable mass black hole pairs can naturally form, in part because massive black holes and stars tend to sink toward the center of the cluster and can more readily encounter each other. But even there those encounters are unlikely to produce an unequal mass pair. The spin of each black hole adds a further complicating factor. The spin is quantified by a number between zero and one. If each of the black holes in a merger has a low value of spin, as is expected, then their merger will normally produce a more massive black hole whose spin is large, perhaps around 0.7, but the inferred spin of the massive black hole in GW190412 is well determined to be about 0.43, suggesting that it did not arise from such a simple merger.

    The astronomers argue that the most likely way to produce this unlikely pair may be through two prior black hole pair mergers in the cluster, a process that can ultimately result in a black hole with the correct inferred spin. First, two black hole binary pairs each merge; each of these pairs has black holes of comparable moderate masses and each produces a more massive black hole. Next, these two new black holes themselves form a binary pair and then merge, producing the roughly 30 solar-mass, moderate spin black hole as seen. Then that blackhole pairs up with a low mass black hole to form the binary whose collapse produced the event seen as GW190412. (Similar multi-step variants are possible as well.) Although such a series of events are rare, the scientists show that known star clusters could provide the right environments for it to occur. The new result and analysis, as in the case of previous gravitational wave discoveries, have expanded our view of cosmic variety while tacking fundamental assumptions. One of those assumptions is that black holes are typically formed from stellar collapse with low spins. Future work will show whether a three-step merger process is needed to explain events like GW190412, or whether assumptions like this one about spin need to be challenged instead.

    Science paper:
    GW190412 as a Third-generation Black Hole Merger from a Super Star Cluster
    The Astrophysical Journal Letters

    See the full article here .

    Please help promote STEM in your local schools.

    Stem Education Coalition

    The Center for Astrophysics combines the resources and research facilities of the Harvard College Observatory and the Smithsonian Astrophysical Observatory under a single director to pursue studies of those basic physical processes that determine the nature and evolution of the universe. The Smithsonian Astrophysical Observatory (SAO) is a bureau of the Smithsonian Institution, founded in 1890. The Harvard College Observatory (HCO), founded in 1839, is a research institution of the Faculty of Arts and Sciences, Harvard University, and provides facilities and substantial other support for teaching activities of the Department of Astronomy.

  • richardmitnick 5:13 pm on August 3, 2020 Permalink | Reply
    Tags: "Unequal neutron-star mergers create unique 'bang' in simulations", , , , , Gravitational wave astronomy, , ,   

    From Pennsylvania State University: “Unequal neutron-star mergers create unique ‘bang’ in simulations” Updated to include the full list of supercomputers used in this project 

    Penn State Bloc

    From Pennsylvania State University

    David Radice

    Gail McCormick
    Work Phone: 814-863-0901

    Through a series of simulations, an international team of researchers has determined that some mergers of neutron stars produce radiation that should be detectible from Earth. When neutron stars of unequal mass merge, the smaller star is ripped apart by tidal forces from its massive companion (left). Most of the smaller partner’s mass falls onto the massive star, causing it to collapse and to form a black hole (middle). But some of the material is ejected into space; the rest falls back to form a massive accretion disk around the black hole (right). Image: Adapted from Bernuzzi et al. 2020, Monthly Notices of the Royal Astronomical Society.

    When two neutron stars slam together, the result is sometimes a black hole that swallows all but the gravitational evidence of the collision. However, in a series of simulations, an international team of researchers including a Penn State scientist determined that these typically quiet — at least in terms of radiation we can detect on Earth — collisions can sometimes be far noisier.

    “When two incredibly dense collapsed neutron stars combine to form a black hole, strong gravitational waves emerge from the impact,” said David Radice, assistant professor of physics and of astronomy and astrophysics at Penn State and a member of the research team. “We can now pick up these waves using detectors like LIGO in the United States and Virgo in Italy.

    MIT /Caltech Advanced aLigo

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

    VIRGO Gravitational Wave interferometer, near Pisa, Italy

    VIRGO Gravitational Wave interferometer, near Pisa, Italy

    A black hole typically swallows any other radiation that could have come out of the merger that we would be able to detect on Earth, but through our simulations, we found that this may not always be the case.”

    The research team found that when the masses of the two colliding neutron stars are different enough, the larger companion tears the smaller apart. This causes a slower merger that allows an electromagnetic “bang” to escape. Astronomers should be able to detect this electromagnetic signal, and the simulations provide signatures of these noisy collisions that astronomers could look for from Earth.

    The research team, which includes members of the international collaboration CoRe (Computational Relativity), describe their findings in a paper appearing online in the Monthly Notices of the Royal Astronomical Society.

    “Recently, LIGO announced the discovery of a merger event in which the two stars have possibly very different masses,” said Radice. “The main consequence in this scenario is that we expect this very characteristic electromagnetic counterpart to the gravititational wave signal.”

    After reporting the first detection of a neutron-star merger in 2017, in 2019 the LIGO team reported the second, which they named GW190425. The result of the 2017 collision was about what astronomers expected, with a total mass of about 2.7 times the mass of our sun and each of the two neutron stars about equal in mass. But GW190425 was much heavier, with a combined mass of around 3.5 solar masses and the ratio of the two participants more unequal — possibly as high as 2 to 1.

    “While a 2 to 1 difference in mass may not seem like a large difference, only a small range of masses is possible for neutron stars,” said Radice.

    Neutron stars can exist only in a narrow range of masses between about 1.2 and 3 times the mass of our sun. Lighter stellar remnants don’t collapse to form neutron stars and instead form white dwarfs, while heavier objects collapse directly to form black holes. When the difference between the merging stars gets as large as in GW190425, scientists suspected that the merger could be messier — and louder in electromagnetic radiation. Astronomers had detected no such signal from GW190425’s location, but coverage of that area of the sky by conventional telescopes that day wasn’t good enough to rule it out.

    To understand the phenomenon of unequal neutron stars colliding, and to predict signatures of such collisions that astronomers could look for, the research team ran a series of simulations using Pittsburgh Supercomputing Center’s Bridges platform and the San Diego Supercomputer Center’s Comet platform — both in the National Science Foundation’s XSEDE network of supercomputing centers and computers — and other supercomputers.

    Bridges HPE Apollo 2000 XSEDE-allocated supercomputer at Pittsburgh Supercomputing Center

    SDSC Dell Comet supercomputer at San Diego Supercomputer Center (SDSC)

    The supercomputer Lenovo SuperMUC at at Leibniz Supercomputing Centre, Munich

    MARCONI, CINECA, Lenovo NeXtScale supercomputer Italy

    Dell Poweredge U Texas Austin Stampede Supercomputer. Texas Advanced Computer Center 9.6 PF

    NCSA U Illinois Urbana-Champaign Blue Waters Cray Linux XE/XK hybrid machine supercomputer,
    at the National Center for Supercomputing Applications

    Resources of the National Energy Re-search Scientific Computing Center, a DOE Office of Science User Facility supported by the Office of Science of the U.S. Department of Energy, used in this workspecific assets not named:


    NERSC Cray Cori II supercomputer, named after Gerty Cori, the first American woman to win a Nobel Prize in science

    NERSC Hopper Cray XE6 supercomputer, named after Grace Hopper, One of the first programmers of the Harvard Mark I computer

    NERSC Cray XC30 Edison supercomputer

    NERSC GPFS for Life Sciences

    The Genepool system is a cluster dedicated to the DOE Joint Genome Institute’s computing needs. Denovo is a smaller test system for Genepool that is primarily used by NERSC staff to test new system configurations and software.

    NERSC PDSF computer cluster in 2003.

    PDSF is a networked distributed computing cluster designed primarily to meet the detector simulation and data analysis requirements of physics, astrophysics and nuclear science collaborations.


    Cray Shasta Perlmutter SC18 AMD Epyc Nvidia pre-exascale supeercomputer

    NERSC is a DOE Office of Science User Facility.

    The researchers found that as the two simulated neutron stars spiraled in toward each other, the gravity of the larger star tore its partner apart. That meant that the smaller neutron star didn’t hit its more massive companion all at once. The initial dump of the smaller star’s matter turned the larger into a black hole. But the rest of its matter was too far away for the black hole to capture immediately. Instead, the slower rain of matter into the black hole created a flash of electromagnetic radiation.

    The research team hopes that the simulated signature they found can help astronomers using a combination of gravitational-wave detectors and conventional telescopes to detect the paired signals that would herald the breakup of a smaller neutron star merging with a larger.

    The simulations required an unusual combination of computing speed, massive amounts of memory, and flexibility in moving data between memory and computation. The team used about 500 computing cores, running for weeks at a time, over about 20 separate instances. The many physical quantities that had to be accounted for in each calculation required about 100 times as much memory as a typical astrophysical simulation.

    “There is a lot of uncertainty surrounding the properties of neutron stars,” said Radice. “In order to understand them, we have to simulate many possible models to see which ones are compatible with astronomical observations. A single simulation of one model would not tell us much; we need to perform a large number of fairly computationally intensive simulations. We need a combination of high capacity and high capability that only machines like Bridges can offer. This work would not have been possible without access to such national supercomputing resources.”

    See the full article here .


    Please help promote STEM in your local schools.

    Stem Education Coalition

    Penn State Campus

    About Penn State


    We teach students that the real measure of success is what you do to improve the lives of others, and they learn to be hard-working leaders with a global perspective. We conduct research to improve lives. We add millions to the economy through projects in our state and beyond. We help communities by sharing our faculty expertise and research.

    Penn State lives close by no matter where you are. Our campuses are located from one side of Pennsylvania to the other. Through Penn State World Campus, students can take courses and work toward degrees online from anywhere on the globe that has Internet service.

    We support students in many ways, including advising and counseling services for school and life; diversity and inclusion services; social media sites; safety services; and emergency assistance.

    Our network of more than a half-million alumni is accessible to students when they want advice and to learn about job networking and mentor opportunities as well as what to expect in the future. Through our alumni, Penn State lives all over the world.

    The best part of Penn State is our people. Our students, faculty, staff, alumni, and friends in communities near our campuses and across the globe are dedicated to education and fostering a diverse and inclusive environment.

  • richardmitnick 5:46 pm on July 20, 2020 Permalink | Reply
    Tags: "A High-Energy Take on Black Hole Encounters", Accuracy is necessary for improved LIGO; Virgo; KAGRA and future instruments (LISA; Cosmic Explorer; and the Einstein Telescope), Accurate theoretical models used as templates in the data analysis, Accurate theoretical predictions for the observed waveforms obtained through the notoriously difficult task of solving Einstein’s field equations., , , , Both sophisticated numerical simulations and perturbative analytic calculations are necessary for this purpose., Gravitational wave astronomy, , , Inspired by particle physics where everything is conceptually reduced to scattering processes between point particles., , , , Quantum scattering amplitudes, The binary black hole problem   

    From “Physics”: “A High-Energy Take on Black Hole Encounters” 

    About Physics

    From “Physics”

    July 20, 2020

    A particle physics approach to describing black hole interactions opens up new avenues for understanding gravitational-wave observations.

    APS/Alan Stonebraker.
    Figure 1: Black hole scattering can be treated as a particle-like interaction, in which the black holes exchange gravitons. By calculating the quantum scattering amplitudes, researchers can obtain important information about merging black hole binaries that emit gravitational waves. New work has demonstrated a theoretical shortcut that improves the accuracy of these calculations.

    Gravitational-wave astronomy sounds like science fiction: two massive black holes swirl toward each other at a substantial fraction of the speed of light, radiating a burst of energy that outweighs the Sun in the form of gravitational waves. Millions of light years away, on Earth, we observe these ripples in the geometry of spacetime through the tiny deformations they produce in kilometers-long arms of laser interferometers [1].

    Caltech/MIT Advanced aLigo Hanford, WA, USA installation

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

    Cornell SXS, the Simulating eXtreme Spacetimes (SXS) project

    Gravitational waves. Credit: MPI for Gravitational Physics/W.Benger-Zib

    One crucial ingredient in interpreting these gravitational-wave signals is having accurate theoretical predictions for the observed waveforms, obtained through the notoriously difficult task of solving Einstein’s field equations. Future progress depends upon significantly improving these theoretical calculations, as current predictions may not be accurate enough for upgraded detectors coming online in 2022 [2]. Inspired by particle physics, where everything is conceptually reduced to scattering processes between point particles, some theorists have begun to attack the binary black hole problem by studying a related problem in which two black holes fly near each other and are deflected (scattered) by their gravitational interaction. Within this framework, Thibault Damour from the Institute of Advanced Scientific Studies (IHÉS) in France and colleagues have sparked unanticipated progress in theoretical gravitational-wave predictions [3–5]. Their latest work shows that there exists a computational shortcut for the generic scattering problem by considering a special limit where one black hole weighs much less than the other.

    The detection of gravitational waves—as well as the extraction of source information (such as mass, spin, and location) and the testing of fundamental physics—relies heavily on accurate theoretical models used as templates in the data analysis. Both sophisticated numerical simulations and perturbative analytic calculations are necessary for this purpose, and both need to improve in accuracy in order to analyze the data that will come from recently enhanced observatories (LIGO, Virgo, and KAGRA) and future instruments (LISA, Cosmic Explorer, and the Einstein Telescope) [2].

    KAGRA gravitational wave detector, Kamioka mine in Kamioka-cho, Hida-city, Gifu-prefecture, Japan

    VIRGO Gravitational Wave interferometer, near Pisa, Italy

    Gravity is talking. Lisa will listen. Dialogos of Eide

    ESA/eLISA the future of gravitational wave research

    Cosmic Explorer. Location in USA undetermined or at least unstated anywhere.

    Depiction of the ASPERA Albert Einstein Telescope, Albert Einstein Institute Hannover and Max Planck Institute for Gravitational Physics and Leibniz Universität Hannover

    In perturbation theory, the equations of motion are written as a series of terms that contain some small quantity ϵ taken to increasing powers: first order ϵ, second order ϵ^2, third order ϵ^3, etc. The landscape of perturbative analytic methods can be charted according to the quantity that is small: a weak gravitational field (the post-Minkowskian expansion), a weak field and slow-moving black holes (the post-Newtonian expansion), or a small mass ratio between the black holes (as in the gravitational self-force program). In the past, the post-Minkowskian approximation has received the least attention since it is most useful for the scattering of black holes—an event that would normally produce too little gravitational radiation to be observed. However, theorists recently realized that calculations made for scattering (unbound) black holes can reveal important elements, such as the gravitational potential, for merging (bound) systems. This connection has brought together researchers from the classical and quantum gravity communities, with a continuing interchange of fruitful ideas.

    The basic idea in this scattering approach is to treat black holes as quantum particles that interact through the exchange of gravitons, in the same way that electrons interact through the exchange of photons (Fig. 1). By combining all the different ways that particles interact, researchers can achieve extremely precise predictions—as evidenced by the experimental confirmation of up to 12 digits of the predicted anomalous magnetic dipole moment of the electron [6]. A seminal quantum idea is that scattering amplitudes, which give the probability for particular scattering processes, are strongly constrained from general principles (symmetries, locality, conservation of probability). Several groups are currently applying these and other powerful techniques from quantum field theory to determine gravitational scattering amplitudes between “black hole particles.” The amplitudes are quantum observables, but researchers can extract a classical part, which can be used to construct templates for gravitational-wave analysis [7].

    Damour has discovered a simple yet far-reaching connection between different perturbative approaches to classical black hole scattering calculations [3]. He has shown that the mass dependence of the classical scattering-angle function is such that the function can be completely fixed at a certain order in the post-Minkowskian approximation from lower orders in the self-force (small-mass-ratio) approximation. This finding is powerful since the latter approximation makes full use of the exact (nonlinear) black hole solutions in Einstein’s classical gravity. For instance, according to Damour’s findings, the fourth order in the post-Minkowskian approximation—one order above the state-of-the-art quantum amplitude calculation achieved by Zvi Bern and collaborators [7]—could be determined from only the first-order self-force calculations. This shortcut could accelerate efforts to reach higher-order (more accurate) predictions in the future. Already, Damour and his colleagues have used first-order self-force calculations to determine large parts of the fifth- to sixth-order post-Newtonian conservative dynamics, which are needed to pin down the gravitational potential in bound systems [4, 5, 8]. Some of the terms in these calculations have been fiercely debated and were the subject of a friendly wager between Bern and Damour [9], recently conceded by Damour [5].

    While pushing forward on high-order perturbative predictions is certainly important, Damour has also challenged the community by raising issues over the fundamental aspects of quantum gravitational scattering research [3]. He has posed several subtle questions: Does it make sense to identify a classical part of a scattering amplitude, which is normally a probabilistic quantum observable with no direct classical analog? How precisely does the exchange of gravitons add up to large classical deflection angles? How does classical black hole scattering in the high-energy limit relate to quantum results for scattering of massless particles [10, 11]? Resolving these issues could help researchers map out future avenues to take toward more accurate predictions.

    The study of scattering black holes has become a promising research direction, attracting diverse groups working within a vast range of methodologies. The latest efforts [3–5, 7, 8, 12] demonstrate the potential of this approach for gravitational-wave science: More accurate predictions at high orders in perturbation theory are coming within reach, and further progress in this area can greatly enhance the science capability of near-future gravitational-wave observatories. Furthermore, the confrontation of different communities and their ways of thinking bears unforeseeable opportunities for theoretical discoveries, even beyond gravitational waves. The time has come to pass this horizon.

    This research is published in Physical Review D.

    A High-Energy Take on Black Hole EncountersJuly 20, 2020

    A particle physics approach to describing black hole interactions opens up new avenues for understanding gravitational-wave observations.

    Viewpoint on:
    Donato Bini, Thibault Damour, and Andrea Geralico
    Phys. Rev. D 102, 024061 (2020)

    Thibault Damour
    Phys. Rev. D 102, 024060 (2020)

    Donato Bini, Thibault Damour, and Andrea Geralico
    Phys. Rev. D 102, 024062 (2020)


    B. P. Abbott et al. (LIGO Scientific and Virgo Collaborations), “Observation of gravitational waves from a binary black hole merger,” Phys. Rev. Lett. 116, 061102 (2016).
    M. Pürrer and C.-J. Haster, “Gravitational waveform accuracy requirements for future ground-based detectors,” Phys. Rev. Research 2, 023151 (2020).
    T. Damour, “Classical and quantum scattering in post-Minkowskian gravity,” Phys. Rev. D 102, 024060 (2020).
    D. Bini et al., “Binary dynamics at the fifth and fifth-and-a-half post-Newtonian orders,” Phys. Rev. D 102, 024062 (2020).
    D. Bini et al., “Sixth post-Newtonian local-in-time dynamics of binary systems,” Phys. Rev. D 102, 024061 (2020).
    T. Aoyama et al., “Tenth-order QED contribution to the electron g−2 and an improved value of the fine structure constant,” Phys. Rev. Lett. 109, 111807 (2012).
    Z. Bern et al., “Scattering amplitudes and the conservative Hamiltonian for binary systems at third post-Minkowskian order,” Phys. Rev. Lett. 122, 201603 (2019).
    D. Bini et al., “Novel approach to binary dynamics: Application to the fifth post-Newtonian level,” Phys. Rev. Lett. 123, 231104 (2019).
    Z. Bern, QCD Meets Gravity 2019 conference, introductory slides.
    D. Amati et al., “Higher-order gravitational deflection and soft bremsstrahlung in planckian energy superstring collisions,” Nucl. Phys. B 347, 550 (1990).
    Z. Bern et al., “Universality in the classical limit of massless gravitational scattering,” arXiv:2002.02459.
    A. Antonelli et al., “Gravitational spin-orbit coupling through third-subleading post-Newtonian order: From first-order self-force to arbitrary mass ratios,” Phys. Rev. Lett. 125, 011103 (2020).

    See the full article here .


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

  • richardmitnick 12:17 pm on July 14, 2020 Permalink | Reply
    Tags: "Gravitational wave researchers go beyond the quantum limit", , , , , , Gravitational wave astronomy, ,   

    From University of Birmingham UK: “Gravitational wave researchers go beyond the quantum limit” 

    From University of Birmingham UK

    14 Jul 2020

    Scientists working at the LIGO facility in the United States, including a team from the University of Birmingham, have demonstrated how the ultra-fine tuning of the instruments enable it to push the boundaries of fundamental laws of physics.

    Caltech/MIT Advanced aLigo Hanford, WA, USA installation

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

    Cornell SXS, the Simulating eXtreme Spacetimes (SXS) project

    Gravitational waves. Credit: MPI for Gravitational Physics/W.Benger-Zib

    ESA/eLISA the future of gravitational wave research

    The US-based Laser Interferometer Gravitational-wave Observatory detects gravitational waves produced by catastrophic events in the universe, such as mergers of neutron stars and black holes. These space-time ripples are enabling scientists to observe gravitational effects in extreme conditions and probe fundamental questions about the universe and its history.

    In the core of the LIGO detectors are km-scale laser interferometers that measure the distance between 40 kg suspended mirrors with the best precision ever achieved. Typical LIGO sources – the gravitational waves – modulate the distance between the mirrors by 1/1000 of a nucleus size but are still observed with high fidelity. The unprecedented level of the LIGO sensitivity is achieved by the state-of-the-art engineering required to suppress vibrational and thermal noises in the detectors.

    At these levels of sensitivity, quantum mechanics starts to play an important role. The revolutionary and counter-intuitive theories developed in the 20th century typically describe the microscopic world, such as atoms and molecules, but also puts stringent constraints on the continuous measurement of the giant LIGO mirrors.

    Scientists at the LIGO site have now succeeded in looking below the so-called standard quantum limit – the limit when only natural quantum states are utilised in the measurement. Their results are published in Nature.

    The experiment the LIGO team carried out used non-classical ‘squeezed light’ which reduces quantum fluctuations of the laser field. Denis Martynov, one of the Birmingham scientists who contributed to the research, says: “Just a few years ago, this type of quantum behaviour would have been too weak to be observed. But new measurement techniques are now enabling us to go beyond these limits. Not only that, but the approach taken by LIGO scientists in these experiments means that future improvements and upgrades to the instruments can be made with increased confidence that they will yield the improved sensitivity that we are looking for.”

    The ability to make these measurements, opens up the possibility of reducing the effects of quantum mechanics and improving overall the sensitivity of the instruments. The research marks an important step towards making further improvements in the sensitivity of gravitational wave technologies, enabling instruments in the future to reach even further through space and time to detect the echoes of these massive collisions.

    See the full article here .


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    Birmingham has been challenging and developing great minds for more than a century. Characterised by a tradition of innovation, research at the University has broken new ground, pushed forward the boundaries of knowledge and made an impact on people’s lives. We continue this tradition today and have ambitions for a future that will embed our work and recognition of the Birmingham name on the international stage.

  • richardmitnick 10:34 am on July 11, 2020 Permalink | Reply
    Tags: "Milky Way neutron star pair illuminates cosmic cataclysms", , , , , , Gravitational wave astronomy, , , , The binary neutron star named PSR J1913+1102, The fast-spinning binary neutron star was discovered in 2012 by the Pulsar Arecibo L-band Feed Array (PALFA) survey at the radio telescope at Arecibo Observatory Puerto Rico.   

    From Cornell Chronicle: “Milky Way neutron star pair illuminates cosmic cataclysms” 

    From Cornell Chronicle

    July 10, 2020
    Blaine Friedlander

    A pair of binary neutron stars in the Milky Way galaxy in this illustration may give researchers insight into cataclysmic mergers. William Gonzalez/Arecibo Observatory

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

    A pair of binary neutron stars in the Milky Way galaxy – discovered eight years ago by a pulsar survey developed at Cornell – is giving researchers a front-row seat at what they believe will be the stars’ eventual cataclysmic merger.

    Two Cornell astronomers with an international team of scientists have found that the masses of the neutron stars orbiting each other are strikingly different – so that when they eventually merge, their two masses will produce more ejecta than otherwise expected.

    The merger will be similar to the famous 2017 neutron star event, named GW170817, that produced the first observed gravitational waves and light – and featured a flurry of electromagnetic phenomena.

    MIT /Caltech Advanced aLigo

    VIRGO Gravitational Wave interferometer, near Pisa, Italy

    “The connection is that we’re getting a chance to see this kind of binary in its baby stages,” said James Cordes, the George Feldstein Professor of Astronomy in the College of Arts and Sciences and co-author of a study on the discovery. “Observe locally and understand from afar.”

    The team’s work was published July 8 in Nature.

    In the study, radio astronomers measured the masses of the two neutron stars in the binary neutron star, named PSR J1913+1102, and concluded that they were asymmetric, Cordes said.

    As a result, the astronomers believe that when this binary neutron star merges in about a half-billion years, violent tidal forces will shred the neutron stars and eject a lot of material as it emits gravitational waves.

    They’re basing that hypothesis on the August 2017 event, when the LIGO and Virgo detectors observed gravitational waves visually and by radio telescope that were 130 million light-years away. In the final throes of merging, two neutron stars had emitted copious gravitation waves.

    “That merger event detected in 2017 was a Rosetta stone for ‘multi-messenger’ astronomy, which includes standard observations in the gamma rays, X-rays, and optical and radio bands combined with gravitational waves,” said Cordes. “The cataclysmic event featured more ejecta than expected, allowing the detailed study.”

    For radio astronomers, examining the binary neutron star is a professional treat.

    “We’re watching the whole binary evolution process long before the merger happens,” said co-author Shami Chatterjee, senior research associate in astronomy. “This gives us a front-row seat right in our own Milky Way neighborhood.”

    The fast-spinning binary neutron star was discovered in 2012 by the Pulsar Arecibo L-band Feed Array (PALFA), survey at the radio telescope at Arecibo Observatory, Puerto Rico. Cordes started PALFA in 2004, and Cornell manages the PALFA data through the university’s Center for Advanced Computing.

    The larger neutron star is 1.62 times the mass of our own sun, but all that mass fits tightly into a ball the size of a city, according to the astronomers. The smaller star is about 1.27 times the mass of the sun.

    “Seeing PSR J1913+1102 allows astronomers to calculate what neutron star mergers should look like if the masses are asymmetrical,” Chatterjee said. “We can detect the gravitational waves, spot the neutron stars and know what we’re looking for in other galaxies.”

    The lead authors of the paper, “Asymmetric Mass Ratios for Bright Double Neutron-Star Mergers,” are Robert. D. Ferdman, University of East Anglia, Norwich, England; Paulo Freire, Max Planck Institute for Radio Astronomy, Bonn, Germany; Benetge Perera, Arecibo Observatory; and Nihan Pol from West Virginia University.

    The National Science Foundation funded the Cornell portion of the research.

    See the full article here .


    Please help promote STEM in your local schools.

    Stem Education Coalition

    Once called “the first American university” by educational historian Frederick Rudolph, Cornell University represents a distinctive mix of eminent scholarship and democratic ideals. Adding practical subjects to the classics and admitting qualified students regardless of nationality, race, social circumstance, gender, or religion was quite a departure when Cornell was founded in 1865.

    Today’s Cornell reflects this heritage of egalitarian excellence. It is home to the nation’s first colleges devoted to hotel administration, industrial and labor relations, and veterinary medicine. Both a private university and the land-grant institution of New York State, Cornell University is the most educationally diverse member of the Ivy League.

    On the Ithaca campus alone nearly 20,000 students representing every state and 120 countries choose from among 4,000 courses in 11 undergraduate, graduate, and professional schools. Many undergraduates participate in a wide range of interdisciplinary programs, play meaningful roles in original research, and study in Cornell programs in Washington, New York City, and the world over.

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