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  • richardmitnick 11:12 am on August 2, 2017 Permalink | Reply
    Tags: , , , , , Gravitational waves,   

    From ScienceNews: “Virgo detector joins LIGO in the search for gravitational waves” 

    ScienceNews bloc

    ScienceNews

    August 1, 2017
    Emily Conover

    1
    THIRD WAVE The Virgo detector, shown above, has begun searching for gravitational waves. Located in Pisa, Italy, Virgo joins the two LIGO detectors in the quest.

    A third gravitational wave detector is now hunting for subtle ripples in the fabric of spacetime.

    The Virgo detector, located near Pisa, Italy, officially joined the two detectors of the Laser Interferometer Gravitational-Wave Observatory, LIGO, on August 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

    ESA/eLISA the future of gravitational wave research

    Together the three detectors will be able to better pinpoint the source of detected gravitational waves.

    LIGO has so far detected three sets of gravitational waves from colliding black holes. In the future, observations with all three detectors could allow telescopes to zero in on the sources and look for light from the cosmic cataclysms that generate the waves.

    The Virgo detector consists of two arms, each 3 kilometers long. Laser light bounces back and forth in the arms, acting like a measuring stick for distortions of spacetime. The design is similar to LIGO’s two detectors in Hanford, Wash., and Livingston, La., which each boast a pair of 4-kilometer-long arms.

    All three detectors will collect data until August 25, when scientists will shift to working on improving the trio’s detection capabilities. The next round of data-taking will begin in fall 2018.

    See the full article here .

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  • richardmitnick 3:06 pm on July 18, 2017 Permalink | Reply
    Tags: , , Gravitational waves,   

    From COSMOS: “How giant atoms may help catch gravitational waves from the Big Bang” 

    Cosmos Magazine bloc

    COSMOS

    7.18.17
    Diego A. Quiñones, U Leeds

    Huge, highly excited atoms may give off flashes of light when hit by a gravitational wave.

    1
    Some of the earliest known galaxies in the universe, seen by the Hubble Space Telescope. NASA/ESA

    NASA/ESA Hubble Telescope

    There was a lot of excitement last year when the LIGO collaboration detected gravitational waves, which are ripples in the fabric of space itself.


    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

    And it’s no wonder – it was one of the most important discoveries of the century. By measuring gravitational waves from intense astrophysical processes like merging black holes, the experiment opens up a completely new way of observing and understanding the universe.

    But there are limits to what LIGO can do. While gravitational waves exist with a big variety of frequencies, LIGO can only detect those within a certain range. In particular, there’s no way of measuring the type of high frequency gravitational waves that were generated in the Big Bang itself. Catching such waves would revolutionise cosmology, giving us crucial information about how the universe came to be. Our research presents a model that may one day enable this.

    In the theory of general relativity developed by Einstein, the mass of an object curves space and time – the more mass, the more curvature. This is similar to how a person stretches the fabric of a trampoline when stepping on it. If the person starts moving up and down, this would generate undulations in the fabric that will move outwards from the position of the person. The speed at which the person is jumping will determine the frequency of the generated ripples in the fabric.

    An important trace of the Big Bang is the Cosmic Microwave Background.

    CMB per ESA/Planck

    ESA/Planck

    This is the radiation left over from the birth of the universe, created about 300,000 years after the Big Bang. But the birth of our universe also created gravitational waves – and these would have originated just a fraction of a second after the event. Because these gravitational waves contain invaluable information about the origin of the universe, there is a lot of interest in detecting them. The waves with the highest frequencies may have originated during phase transitions of the primitive universe or by vibrations and snapping of cosmic strings.

    An instant flash of brightness

    Our research team, from the universities of Aberdeen and Leeds, think that atoms may have an edge in detecting elusive, high-frequency gravitational waves. We have calculated that a group of “highly excited” atoms (called Rydberg atoms – in which the electrons have been pushed out far away from the atom’s nucleus, making it huge – will emit a bright pulse of light when hit by a gravitational wave.

    To make the atoms excited, we shine a light on them. Each of these enlarged atoms is usually very fragile and the slightest perturbation will make them collapse, releasing the absorbed light. However, the interaction with a gravitational wave may be too weak, and its effect will be masked by the many interactions such as collisions with other atoms or particles.

    Rather than analysing the interaction with individual atoms, we model the collective behaviour of a big group of atoms packed together. If the group of atoms is exposed to a common field, like our oscillating gravitational field, this will induce the excited atoms to decay all at the same time. The atoms will then release a large number of photons (light particles), generating an intense pulse of light, dubbed “superradiance”.

    As Rydberg atoms subjected to a gravitational wave will superradiate as a result of the interaction, we can guess that a gravitational wave has passed through the atomic ensemble whenever we see a light pulse.

    By changing the size of the atoms, we can make them radiate to different frequencies of the gravitational wave. This can be this useful for detection in different ranges. Using the proper kind of atoms, and under ideal conditions, it could be possible to use this technique to measure relic gravitational waves from the birth of the universe. By analysing the signal of the atoms it is possible to determine the properties, and therefore the origin, of the gravitational waves.

    There may be some challenges for this experimental technique: the main one is getting the atoms in an highly excited state. Another one is to have enough atoms, as they are so big that they become very hard to contain.

    A theory of everything?

    Beyond the possibility of studying gravitational waves from the birth of the universe, the ultimate goal of the research is to detect gravitational fluctuations of empty space itself – the vacuum. These are extremely faint gravitational variations that occur spontaneously at the smallest scale, popping up out of

    Discovering such waves could lead to the unification of general relativity and quantum mechanics, one of the greatest challenges in modern physics. General relativity is unparalleled when it comes to describing the world on a large scale, such as planets and galaxies, while quantum mechanics perfectly describes physics on the smallest scale, such as the atom or even parts of the atom. But working out the gravitational impact of the tiniest of particles will therefore help bridge this divide.

    But discovering the waves associated with such quantum fluctuations would require a great number of atoms prepared with an enormous amount of energy, which may not be possible to do in the laboratory. Rather than doing this, it might be possible to use Rydberg atoms in outer space. Enormous clouds of these atoms exist around white dwarfs – stars which have run out of fuel – and inside nebulas with sizes more than four times larger than anything that can be created on Earth. Radiation coming from these sources could contain the signature of the vacuum gravitational fluctuations, waiting to be unveiled.

    See the full article here .

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  • richardmitnick 5:07 pm on July 7, 2017 Permalink | Reply
    Tags: , , , , GOTO telescope, Gravitational waves, ,   

    From Monash and Warwick: “New era for astrophysics with launch of telescope for detecting optical signals from gravitational waves” 

    U Warwick bloc

    University of Warwick

    Monash Univrsity bloc

    Monash University

    05 July 2017

    Silvia Dropulich
    T: +61 3 9902 4513 M: +61
    (0) 0435138743E
    silvia.dropulich@monash.edu

    Luke Walton, International Press Officer
    +44 (0) 7824 540 863
    +44 (0) 2476 150 868
    L.Walton.1@warwick.ac.uk

    1

    2

    A new telescope for detecting optical signatures of gravitational waves has officially launched in La Palma.

    2
    Overview of some of the telescopes at the Roque de los Muchachos Observatory, in the municipality of Garafía on the island of La Palma in the Canary Islands

    The project, built and operated by international researchers, is partly funded through the Monash Warwick Alliance, an award-winning global partnership between Monash University and the University of Warwick.

    Detecting optical signatures of gravitational waves opens a new era in astrophysics, allowing astronomers to probe into the distant Universe and better understand the nature of gravity. The Gravitational-wave Optical Transient Observer (GOTO) was inaugurated at Warwick’s astronomical observing facility in La Palma, Canary Islands, on 3 July 2017.

    GOTO is an autonomous, intelligent telescope, which will search for unusual activity in the sky, following alerts from gravitational wave detectors – such as the Advanced Laser Interferometer Gravitational-Wave Observatory (Adv-LIGO), which recently secured the first direct detections of gravitational waves.


    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

    Gravitational waves are ripples in the fabric of space-time, created when massive bodies – particularly black holes and neutron stars – orbit each other and merge at very high speeds. These waves radiate through the Universe at the speed of light, and analysing them heralds a new era in astrophysics, giving astronomers vital clues about the bodies from which they originated – as well as long-awaited insight into the nature of gravity itself.

    First predicted over a century ago by Albert Einstein, they have only been directly detected in the last two years, and astronomers’ next challenge is to associate the signals from these waves with signatures in the electromagnetic spectrum, such as optical light. This is GOTO’s precise aim: to locate optical signatures associated with the gravitational waves as quickly as possible, so that astronomers can study these sources with a variety of telescopes and satellites before they fade away.

    Dr Duncan Galloway, from the School of Physics & Astronomy at Monash University, said the project is very significant for the Monash Centre for Astrophysics.

    “We’ve invested strongly in gravitational wave astronomy over the last few years, leading up to the first detection announced last year, and the telescope project represents a fundamentally new observational opportunity,” Dr Galloway said.

    “It’s really satisfying seeing a research collaboration that we’ve build over many years coming to fruition in such an exciting way, and we couldn’t have got here without the support of the Alliance and the participating universities.”

    Dr Danny Steeghs, from Warwick’s Astronomy and Astrophysics Group, who is leading the project said:

    “After all the hard work put in by everyone, I am delighted to see the GOTO telescopes in operational mode at the Roque de los Muchachos observatory. We are all excited about the scientific opportunities it will provide.”

    GOTO is the latest addition to the University of Warwick’s astronomical facility at La Palma, which includes the SuperWASP Exoplanet discovery camera – the most successful ground based exoplanet discovery project in existence.

    GOTO is operated on behalf of a consortium of institutions including the University of Warwick, Monash University, the Armagh Observatory, Leicester and Sheffield Universities, and the National Astronomical Research Institute of Thailand (NARIT). La Palma is one of the world’s premier astronomical observing sites, owing to the fact that it is the steepest island in the world and has very little pollution – giving researchers clear views of the sky.

    See the full Monash article here .
    See the full Warwick article here .
    My text is from Monash.

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    Monash U campus

    Monash University (/ˈmɒnæʃ/) is an Australian public research university based in Melbourne, Australia. Founded in 1958, it is the second oldest university in the State of Victoria. Monash is a member of Australia’s Group of Eight and the ASAIHL, and is the only Australian member of the influential M8 Alliance of Academic Health Centers, Universities and National Academies. Monash is one of two Australian universities to be ranked in the The École des Mines de Paris (Mines ParisTech) ranking on the basis of the number of alumni listed among CEOs in the 500 largest worldwide companies.[6] Monash is in the top 20% in teaching, top 10% in international outlook, top 20% in industry income and top 10% in research in the world in 2016.[7]

    Monash enrolls approximately 47,000 undergraduate and 20,000 graduate students,[8] It also has more applicants than any university in the state of Victoria.

    Monash is home to major research facilities, including the Australian Synchrotron, the Monash Science Technology Research and Innovation Precinct (STRIP), the Australian Stem Cell Centre, 100 research centres[9] and 17 co-operative research centres. In 2011, its total revenue was over $2.1 billion, with external research income around $282 million.[10]

    The university has a number of centres, five of which are in Victoria (Clayton, Caulfield, Berwick, Peninsula, and Parkville), one in Malaysia.[11] Monash also has a research and teaching centre in Prato, Italy,[12] a graduate research school in Mumbai, India[13] and a graduate school in Jiangsu Province, China.[14] Since December 2011, Monash has had a global alliance with the University of Warwick in the United Kingdom.[15] Monash University courses are also delivered at other locations, including South Africa.

    The Clayton campus contains the Robert Blackwood Hall, named after the university’s founding Chancellor Sir Robert Blackwood and designed by Sir Roy Grounds.[16]

    In 2014, the University ceded its Gippsland campus to Federation University.[17] On 7 March 2016, Monash announced that it would be closing the Berwick campus by 2018.

    U Warwick Campus

    Warwick is a world-leading university with the highest academic and research standards. But we’re not letting the story end there.

    That’s because we’re a place of possibility. We’re always looking for new ways to make things happen. Whether you’re a dedicated student, an innovative lecturer or an ambitious company, Warwick provides a tireless yet supportive environment in which you can make an impact.

    And our students, alumni and staff are consistently making an impact – the kind that changes lives, whether close to home or on a global scale.

    It’s the achievements of our people that help explain why our levels of research excellence and scholarship are recognised internationally.

    It’s a prime attraction for some of the biggest names in worldwide business and industry.

    It’s why we’re ranked highly in the lists of great UK and world universities.

    All of this contributes to a compelling story, one that’s little more than 50 years old. But who said youth should hold you back from changing the world?

     
  • richardmitnick 2:07 pm on June 27, 2017 Permalink | Reply
    Tags: , Gravitational waves, , , , ,   

    From Symmetry: “The rise of LIGO’s space-studying super-team” 

    Symmetry Mag

    Symmetry

    06/27/17
    Troy Rummler

    The era of multi-messenger astronomy promises rich rewards—and a steep learning curve.

    NASA/Fermi LAT

    Sometimes you need more than one perspective to get the full story.

    Scientists including astronomers working with the Fermi Large Area Telescope have recorded brief bursts of high-energy photons called gamma rays coming from distant reaches of space. They suspect such eruptions result from the merging of two neutron stars—the collapsed cores of dying stars—or from the collision of a neutron star and a black hole.

    But gamma rays alone can’t tell them that. The story of the dense, crashing cores would be more convincing if astronomers saw a second signal coming from the same event—for example, the release of ripples in space-time called gravitational waves.

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

    “The Fermi Large Area Telescope detects a few short gamma ray bursts per year already, but detecting one in correspondence to a gravitational-wave event would be the first direct confirmation of this scenario,” says postdoctoral researcher Giacomo Vianello of the Kavli Institute for Particle Astrophysics and Cosmology, a joint institution of SLAC National Accelerator Laboratory and Stanford University.

    Scientists discovered gravitational waves in 2015 (announced in 2016). Using the Laser Interferometer Gravitational-Wave Observatory, or LIGO, they detected the coalescence of two massive black holes.


    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

    LIGO scientists are now sharing their data with a network of fellow space watchers to see if any of their signals match up. Combining multiple signals to create a more complete picture of astronomical events is called multi-messenger astronomy.​

    Looking for a match

    “We had this dream of finding astronomical events to match up with our gravitational wave triggers,” says LIGO scientist Peter Shawhan of the University of Maryland. ​

    But LIGO can only narrow down the source of its signals to a region large enough to contain roughly 100,000 galaxies.

    Searching for contemporaneous signals within that gigantic volume of space is extremely challenging, especially since most telescopes only view a small part of the sky at a time. So Shawhan and his colleagues developed a plan to send out an automatic alert to other observatories whenever LIGO detected an interesting signal of its own. The alert would contain preliminary calculations and the estimated location of the source of the potential gravitational waves.

    “Our early efforts were pretty crude and only involved a small number of partners with telescopes, but it kind of got this idea started,” Shawhan says. The LIGO Collaboration and the Virgo Collaboration, its European partner, revamped and expanded the program while upgrading their detectors. Since 2014, 92 groups have signed up to receive alerts from LIGO, and the number is growing.

    LIGO is not alone in latching onto the promise of multi-messenger astronomy. The Supernova Early Warning System (SNEWS) also unites multiple experiments to look at the same event in different ways.

    Neutral, rarely interacting particles called neutrinos escape more quickly from collapsing stars than optical light, so a network of neutrino experiments is prepared to alert optical observatories as soon as they get the first warning of a nearby supernova in the form of a burst of neutrinos.

    National Science Foundation Director France Córdova has lauded multi-messenger astronomy, calling it in 2016 a bold research idea that would lead to transformative discoveries.​

    The learning curve

    Catching gamma ray bursts alongside gravitational waves is no simple feat.

    The Fermi Large Area Telescope orbits the earth as the primary instrument on the Fermi Gamma-ray Space Telescope.

    NASA/Fermi Telescope

    The telescope is constantly in motion and has a large field of view that surveys the entire sky multiple times per day.

    But a gamma-ray burst lasts just a few seconds, and it takes about three hours for LAT to complete its sweep. So even if an event that releases gravitational waves also produces a gamma-ray burst, LAT might not be looking in the right direction at the right time. It would need to catch the afterglow of the event.

    Fermi LAT scientist Nicola Omodei of Stanford University acknowledges another challenge: The window to see the burst alongside gravitational waves might not line up with the theoretical predictions. It’s never been done before, so the signal could look different or come at a different time than expected.

    That doesn’t stop him and his colleagues from trying, though. “We want to cover all bases, and we adopt different strategies,” he says. “To make sure we are not missing any preceding or delayed signal, we also look on much longer time scales, analyzing the days before and after the trigger.”

    Scientists using the second instrument on the Fermi Gamma-ray Space Telescope have already found an unconfirmed signal that aligned with the first gravitational waves LIGO detected, says scientist Valerie Connaughton of the Universities Space Research Association, who works on the Gamma-Ray Burst Monitor. “We were surprised to find a transient event 0.4 seconds after the first GW seen by LIGO.”

    While the event is theoretically unlikely to be connected to the gravitational wave, she says the timing and location “are enough for us to be interested and to challenge the theorists to explain how something that was not expected to produce gamma rays might have done so.”

    From the ground up

    It’s not just space-based experiments looking for signals that align with LIGO alerts. A working group called DESgw, members of the Dark Energy Survey with independent collaborators, have found a way to use the Dark Energy Camera, a 570-Megapixel digital camera mounted on a telescope in the Chilean Andes, to follow up on gravitational wave detections.​


    Dark Energy Camera [DECam], built at FNAL


    NOAO/CTIO Victor M Blanco 4m Telescope which houses the DECam at Cerro Tololo, Chile, housing DECam

    “We have developed a rapid response system to interrupt the planned observations when a trigger occurs,” says DES scientist Marcelle Soares-Santos of Fermi National Accelerator Laboratory. “The DES is a cosmological survey; following up gravitational wave sources was not originally part of the DES scientific program.”

    Once they receive a signal, the DESgw collaborators meet to evaluate the alert and weigh the cost of changing the planned telescope observations against what scientific data they could expect to see—most often how much of the LIGO source location could be covered by DECam observations.

    “We could, in principle, put the telescope onto the sky for every event as soon as night falls,” says DES scientist Jim Annis, also of Fermilab. “In practice, our telescope is large and the demand for its time is high, so we wait for the right events in the right part of the sky before we open up and start imaging.”

    At an even lower elevation, scientists at the IceCube neutrino experiment—made up of detectors drilled down into Antarctic ice—are following LIGO’s exploits as well.

    U Wisconsin ICECUBE neutrino detector at the South Pole

    Lunar Icecube

    IceCube DeepCore

    IceCube PINGU

    DM-Ice II at IceCube

    “The neutrinos IceCube is looking for originate from the most extreme environment in the cosmos,” says IceCube scientist Imre Bartos of Columbia University. “We don’t know what these environments are for sure, but we strongly suspect that they are related to black holes.”

    LIGO and IceCube are natural partners. Both gravitational waves and neutrinos travel for the most part unimpeded through space. Thus, they carry pure information about where they originate, and the two signals can be monitored together nearly in real time to help refine the calculated location of the source.

    The ability to do this is new, Bartos says. Neither gravitational waves nor high-energy neutrinos had been detected from the cosmos when he started working on IceCube in 2008. “During the past few years, both of them were discovered, putting the field on a whole new footing.”

    Shawhan and the LIGO collaboration are similarly optimistic about the future of their program and multi-messenger astronomy. More gravitational wave detectors are planned or under construction, including an upgrade to the European detector Virgo, the KAGRA detector in Japan, and a third LIGO detector in India, and that means scientists will home in closer and closer on their targets.​


    VIRGO Gravitational Wave interferometer, near Pisa, Italy

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

    IndIGO LIGO in India

    IndIGO in India

    See the full article here .

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    Symmetry is a joint Fermilab/SLAC publication.


     
  • richardmitnick 4:39 pm on June 23, 2017 Permalink | Reply
    Tags: , , Gravitational waves, , NASA/DLR Grace   

    From Goddard: “ESA to Develop Gravitational Wave Space Mission with NASA Support” 

    NASA Goddard Banner
    NASA Goddard Space Flight Center

    June 22, 2017
    Francis Reddy
    NASA’s Goddard Space Flight Center, Greenbelt, Md.

    ESA (the European Space Agency) has selected the Laser Interferometer Space Antenna (LISA) for its third large-class mission in the agency’s Cosmic Vision science program. The three-spacecraft constellation is designed to study gravitational waves in space and is a concept long studied by both ESA and NASA.

    ESA’s Science Program Committee announced the selection at a meeting on June 20. The mission will now be designed, budgeted and proposed for adoption before construction begins. LISA is expected to launch in 2034. NASA will be a partner with ESA in the design, development, operations and data analysis of the mission.

    ESA/eLISA the future of gravitational wave research

    Gravitational radiation was predicted a century ago by Albert Einstein’s general theory of relativity. Massive accelerating objects such as merging black holes produce waves of energy that ripple through the fabric of space and time. Indirect proof of the existence of these waves came in 1978, when subtle changes observed in the motion of a pair of orbiting neutron stars showed energy was leaving the system in an amount matching predictions of energy carried away by gravitational waves.

    In September 2015, these waves were first directly detected by the National Science Foundation’s ground-based Laser Interferometer Gravitational-Wave Observatory (LIGO).


    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 signal arose from the merger of two stellar-mass black holes located some 1.3 billion light-years away. Similar signals from other black hole mergers have since been detected.

    Seismic, thermal and other noise sources limit LIGO to higher-frequency gravitational waves around 100 cycles per second (hertz). But finding signals from more powerful events, such as mergers of supermassive black holes in colliding galaxies, requires the ability to detect frequencies much lower than 1 hertz, a sensitivity level only possible from space.

    LISA consists of three spacecraft separated by 1.6 million miles (2.5 million kilometers) in a triangular formation that follows Earth in its orbit around the sun. Each spacecraft carries test masses that are shielded in such a way that the only force they respond to is gravity. Lasers measure the distances to test masses in all three spacecraft. Tiny changes in the lengths of each two-spacecraft arm signals the passage of gravitational waves through the formation.

    For example, LISA will be sensitive to gravitational waves produced by mergers of supermassive black holes, each with millions or more times the mass of the sun. It will also be able to detect gravitational waves emanating from binary systems containing neutron stars or black holes, causing their orbits to shrink. And LISA may detect a background of gravitational waves produced during the universe’s earliest moments.

    For decades, NASA has worked to develop many technologies needed for LISA, including measurement, micropropulsion and control systems, as well as support for the development of data analysis techniques.

    For instance, the GRACE Follow-On mission, a U.S. and German collaboration to replace the aging GRACE satellites scheduled for launch late this year, will carry a laser measuring system that inherits some of the technologies originally developed for LISA.

    NASA/DLR Grace

    The mission’s Laser Ranging Interferometer will track distance changes between the two satellites with unprecedented precision, providing the first demonstration of the technology in space.

    In 2016, ESA’s LISA Pathfinder successfully demonstrated key technologies needed to build LISA.

    ESA/LISA Pathfinder

    Each of LISA’s three spacecraft must gently fly around its test masses without disturbing them, a process called drag-free flight. In its first two months of operations, LISA Pathfinder demonstrated this process with a precision some five times better than its mission requirements and later reached the sensitivity needed for the full multi-spacecraft observatory. U.S. researchers collaborated on aspects of LISA Pathfinder for years, and the mission carries a NASA-supplied experiment called the ST7 Disturbance Reduction System, which is managed by NASA’s Jet Propulsion Laboratory in Pasadena, California.

    For more information about the LISA project, visit:

    https://lisa.nasa.gov

    See the full article here.

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    NASA’s Goddard Space Flight Center 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.


    NASA/Goddard Campus

     
  • richardmitnick 7:56 pm on June 9, 2017 Permalink | Reply
    Tags: , Gravitational waves, , SDSC- San Diego Supercomputer Center,   

    From Science Node: “XSEDE cuts through the noise” 

    Science Node bloc
    Science Node

    06 June, 2017
    Alisa Alering

    3
    Courtesy LIGO; Caltech; MIT; Sonoma State; Aurore Simonnet.

    Over two billion years ago, when multicellular life had only just begun to evolve on Earth, two black holes collided and merged to form a new black hole.

    With a mass 49 times that of our sun, the massive collision set off ripples in space-time that radiated from the event like waves from a stone thrown into a pond. Predicted by Albert Einstein in 1916 and known as gravitational waves, those ripples are still traveling.


    Surf’s up! The Extreme Science and Engineering Discovery Environment (XSEDE) provides the HPC resources required to pluck gravitational waves from the noise found on LIGO detectors. Courtesy XSEDE.

    Able to pass through dust, matter, or anything else without being distorted, gravitational waves carry unique information about cosmic events that can’t be obtained in any other way. When the waves reach Earth, they give astrophysicists a completely new way to explore the universe.

    The first such waves were detected on September 14, 2015 by the Laser Interferometer Gravitational-Wave Observatory (LIGO) Scientific Collaboration. In the months since, two more gravitational wave events have been confirmed, one in December 2015 and the most recent on January 4, 2017.


    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

    Signal from noise

    When gravitational waves pass by, they change the distance between objects. The change is so infinitesimal that it can’t be felt, or seen with a microscope. But incredibly sensitive scientific instruments—interferometers—can detect a change that is a thousand times smaller than a proton.

    The LIGO Scientific Collaboration, a body of more than 1,000 international scientists who collectively perform LIGO research, operates two interferometers located over 2000 miles apart in Washington and Louisiana, USA.

    Despite the sensitivity of the instruments, it’s not easy to detect a gravitational wave. When a signal is received, scientists must determine what it means and how likely it is to be noise or a real gravitational wave. Making that determination requires high-performance computing.

    Since 2013, LIGO has collaborated with the Extreme Science and Engineering Discovery Environment (XSEDE), a National Science Foundation (NSF)-funded cyberinfrastructure network that includes not just high-performance computing systems but also experts who help researchers move projects forward.

    Better, faster, cheaper

    In order to validate the discovery of a gravitational wave, researchers measure the significance of the signal by calculating a false alarm rate for the event.


    Making waves, taking names. The top part of the animation shows two black holes orbiting each other until they merge, and the lower part shows the two distinct gravitational waves emitted. Thanks to supercomputers at TACC and SDSC, researchers can pick out these waves from other detector noise. Courtesy Simulating eXtreme Spacetimes collaboration.

    TACC Maverick HP NVIDIA supercomputer

    TACC Lonestar Cray XC40 supercomputer

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

    TACC HPE Apollo 8000 Hikari supercomputer

    TACC Maverick HP NVIDIA supercomputer

    SDSC Triton HP supercomputer

    SDSC Gordon-Simons supercomputer

    SDSC Dell Comet supercomputer

    Once confirmed, further supercomputer analysis is used to extract precise estimates of the physical properties of the event, including the masses of the colliding objects, position, orientation, and distance from the Earth, carefully checking millions of combinations of these characteristics and testing how well the predicted waveform matches the signal detected by LIGO.

    To draw larger conclusions about the nature of black holes requires careful modeling based on the received data. Each simulation can take from a week to one month to complete, depending upon the complexity.

    Such intensive data analysis requires large scale high-throughput computing with parallel workflows at the scale of tens of thousands of cores for long periods of time. LIGO has been allocated millions of hours on XSEDE’s high-performance computers, including Stampede at the Texas Advanced Computing Center (TACC) and Comet at the San Diego Supercomputer Center (SDSC).

    Over the first year of XSEDE’s collaboration with LIGO, XSEDE worked to increase the speed of the applications, making them 8-10x faster on average.

    “The strategic collaboration between the two NSF-funded projects allows for accelerated scientific discovery which also translates into cost-savings for LIGO on the order of tens of millions of dollars so far,” says Pedro Marronetti, Gravitational Physics program director at the NSF.

    Waves of the future

    LIGO plans to upgrade its observatories and improve the sensitivity of its detectors before the next observational period begins in late 2018. LIGO predicts that once its observatories reach their most sensitive state, they may able to detect as many as 40 gravitational waves per year.

    3

    More instruments like LIGO will soon be listening for waves around the world in Italy, Japan, and India. Scientists also hope to place interferometers in orbit in order to avoid interference from Earth noise.

    And that means much more computing power will be required to verify the signals and extract information about the nature and origins of our universe.

    See the full article here .

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    Science Node is an international weekly online publication that covers distributed computing and the research it enables.

    “We report on all aspects of distributed computing technology, such as grids and clouds. We also regularly feature articles on distributed computing-enabled research in a large variety of disciplines, including physics, biology, sociology, earth sciences, archaeology, medicine, disaster management, crime, and art. (Note that we do not cover stories that are purely about commercial technology.)

    In its current incarnation, Science Node is also an online destination where you can host a profile and blog, and find and disseminate announcements and information about events, deadlines, and jobs. In the near future it will also be a place where you can network with colleagues.

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  • richardmitnick 12:07 pm on June 1, 2017 Permalink | Reply
    Tags: , , , , , Gravitational waves, LIGO snags another set of gravitational waves   

    From ScienceNews: “LIGO snags another set of gravitational waves” 

    ScienceNews bloc

    ScienceNews

    June 1, 2017
    Emily Conover

    Spacetime vibrations arrive from black hole collision 3 billion light-years away.

    1
    THREE OF A KIND Scientists have made a third detection of gravitational waves. A pair of black holes, shown above, fused into one, in a powerful collision about 3 billion light-years from Earth. That smashup churned up ripples in spacetime that were detected by the LIGO experiment.

    For a third time, scientists have detected the infinitesimal reverberations of spacetime: gravitational waves.

    Two black holes stirred up the spacetime wiggles, orbiting one another and spiraling inward until they fused into one jumbo black hole with a mass about 49 times that of the sun. Ripples from that union, which took place about 3 billion light-years from Earth, zoomed across the cosmos at the speed of light, eventually reaching the Advanced Laser Interferometer Gravitational-Wave Observatory, LIGO, which detected them on January 4.

    “These are the most powerful astronomical events witnessed by human beings,” Michael Landry, head of LIGO’s Hanford, Wash., observatory, said during a news conference May 31 announcing the discovery. As the black holes merged, they converted about two suns’ worth of mass into energy, radiated as gravitational waves.

    ________________________________________________________________________________
    Place in space

    Based on the time that signals arrived at each of LIGO’s two detectors, scientists were able to determine regions on the sky from which the gravitational waves came. LIGO’s three detections are shown, plus a fourth possible detection that was not strong enough to confirm. Lines indicate probabilities that the signal originated within each region. Outermost curves indicate 90 percent, while inner curves indicate 10 percent.

    2
    Leo Singer/LIGO, Caltech, MIT; Axel Mellinger (Milky Way image)

    ________________________________________________________________________________

    LIGO’s two detectors, located in Hanford and Livingston, La., each consist of a pair of 4-kilometer-long arms. They act as outrageously oversized rulers to measure the stretching of spacetime caused by gravitational waves.


    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

    According to Einstein’s theory of gravity, the general theory of relativity, massive objects bend the fabric of space and create ripples when they accelerate — for example, when two objects orbit one another. Gravitational ripples are tiny: LIGO is tuned to detect waves that stretch and squeeze the arms by a thousandth of the diameter of a proton. Black hole collisions are one of the few events in the universe that are catastrophic enough to produce spacetime gyrations big enough to detect.

    The two black holes that spawned the latest waves were particularly hefty [Physical Review Letters], with masses about 31 and 19 times that of the sun, scientists report June 1 in Physical Review Letters. LIGO’s first detection, announced in February 2016, came from an even bigger duo: 36 and 29 times the mass of the sun (SN: 3/5/16, p. 6). Astrophysicists don’t fully understand how such big black holes could have formed. But now, “it seems that these are not so uncommon, so clearly there’s a way to produce these massive black holes,” says physicist Clifford Will of the University of Florida in Gainesville. LIGO’s second detection featured two smaller black holes, 14 and eight times the mass of the sun (SN: 7/9/16, p. 8).

    _________________________________________________________________________________

    Sizing up gravitational waves

    LIGO’s three gravitational wave sightings all came from merging black holes. But those mergers varied in mass, distance and the amount of energy radiated in gravitational waves.
    First detection

    Date: September 14, 2015
    Mass of first black hole: 36.2 solar masses
    Mass of second black hole: 29.1 solar masses
    Merged mass: 62.3 solar masses
    Energy radiated as gravitational waves: 3 solar masses
    Distance from Earth: 1.4 billion light-years
    Second detection

    Date: December 26, 2015
    Mass of first black hole: 14.2 solar masses
    Mass of second black hole: 7.5 solar masses
    Merged mass: 20.8 solar masses
    Energy radiated as gravitational waves: 1 solar mass
    Distance from Earth: 1.4 billion light-years
    Third detection

    Date: January 4, 2017
    Mass of first black hole: 31.2 solar masses
    Mass of second black hole: 19.4 solar masses
    Merged mass: 48.7 solar masses
    Energy radiated as gravitational waves: 2 solar masses
    Distance from Earth: 2.9 billion light-years

    _________________________________________________________________________________

    Weighty black holes are difficult to explain, because the stars that collapsed to form them must have been even more massive. Typically, stellar winds steadily blow away mass as a star ages, leading to a smaller black hole. But under certain conditions, those winds might be weak — for example, if the stars contain few elements heavier than helium or have intense magnetic fields (SN Online: 12/12/16). The large masses of LIGO’s black holes suggest that they formed in such environments.

    Scientists also disagree about how black holes partner up. One theory is that two neighboring stars each explode and produce two black holes, which then spiral inward. Another is that black holes find one another within a dense cluster of stars, as massive black holes sink to the center of the clump (SN Online: 6/19/16).

    The new detection provides some support for the star cluster theory: The pattern of gravitational waves LIGO observed hints that one of the black holes might be spinning in the opposite direction from its orbit. Like a cosmic do-si-do, each black hole in a pair twirls on its own axis as it spirals inward. Black holes that pair up as stars are likely to have their spins aligned with their orbits. But if the black holes instead find one another in the chaos of a star cluster, they could spin any which way. The potentially misaligned black hole LIGO observed somewhat favors the star cluster scenario. The measurement is “suggestive, but it’s not definite,” says astrophysicist Avi Loeb of Harvard University.

    Scientists will need more data to sort out how the black hole duos form, says physicist Emanuele Berti of the University of Mississippi in Oxford. “Probably the truth is somewhere in between.” Various processes could contribute to the formation of black hole pairs, Berti says.

    As with previous detections of gravitational waves, the scientists used their measurements to test general relativity. For example, while general relativity predicts that gravitational waves travel at the speed of light, some alternative theories of gravity predict that gravitational waves of different energies travel at different speeds. LIGO scientists found no evidence of such an effect, vindicating Einstein once again.

    Now, with three black hole mergers under their belts, scientists are looking forward to a future in which gravitational wave detections become routine. The more gravitational waves scientists detect, the better they can test their theories. “There are already surprises that make people stop and revisit some old ideas,” Will says. “To me that’s very exciting.”

    See the full article here .

    Science News offers readers a concise, current and comprehensive overview of the latest scientific research in all fields and applications of science and technology.

    Science News is edited for an educated readership of professionals, scientists and other science enthusiasts. Written by a staff of experienced science journalists, it treats science as news, reporting accurately and placing findings in perspective. Science News and its writers have won many awards for their work; here’s a list of many of them.

    Published since 1922, the biweekly print publication reaches about 90,000 dedicated subscribers and is available via the Science News app on Android, Apple and Kindle Fire devices. Updated continuously online, the Science News website attracted over 12 million unique online viewers in 2016.

    Science News is published by the Society for Science & the Public, a nonprofit 501(c) (3) organization dedicated to the public engagement in scientific research and education.

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  • richardmitnick 9:41 am on May 29, 2017 Permalink | Reply
    Tags: , , , Background of gravitational waves expected from binary black hole events like GW150914, , , , Gravitational waves   

    From LIGO: “Background of gravitational waves expected from binary black hole events like GW150914” 

    LSC LIGO Scientific Collaboration

    LIGO Scientific Collaboration

    5.29.17 Presentation
    No writer credit found


    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

    Introduction
    It is an amazing time in the field of gravitational-wave astronomy—the observation of gravitational waves by the Advanced LIGO detectors from a binary black hole merger is an event of tremendous scientific significance. A century ago, Einstein developed general relativity and predicted the existence of gravitational waves. This first direct detection of gravitational waves, the so-called “GW150914” event, is a confirmation of Einstein’s theory and is the first direct observation of a pair of black holes merging to form a single black hole. The observation of GW150914, and future observations of binary black hole mergers, will provide new insights about massive black holes in the relatively nearby part of our Universe.

    GW150914 will not be the only event of its type in the Universe. It can be expected that, on average, binary black hole mergers occur at some rate. When these mergers happen within a couple of billion light-years from the Earth, they will likely be directly observed by Advanced LIGO (and soon to come, Advanced Virgo, and ESA eLISA). Events that are further than this will just appear as random noise in the gravitational-wave detectors (like static on an old-fashioned TV), too small to be individually directly measured. However, it will be possible to observe the sum of binary black hole mergers that have happened throughout the history of our observable Universe.

    What is a gravitational-wave background?
    Gravitational waves are ripples in spacetime predicted by Einstein’s theory of general relativity. Gravitational waves are produced by accelerating objects of any size, including us humans. Most of these waves, however, are far too weak to experimentally detect. In general, we can only hope to observe gravitational waves produced by the most massive objects moving close to the speed of light, such as the binary black holes that produced GW150914.

    For every nearby, loud event like GW150914, there are many more that are too far away to be individually detected by Advanced LIGO. The gravitational waves from these distant binary black holes instead combine to create a relatively quiet “popcorn” background of gravitational waves. As a pair of black holes merges, it produces a short burst of gravitational waves lasting just a few tenths of a second. These mostly-quiet individual bursts are separated in time, and arrive at Earth at an average rate of about one every 15 minutes. Their exact arrival times, though, are randomly distributed, just like the random popping of individual kernels of popcorn.

    A popcorn background is an example of a broader category of gravitational-wave signal called a stochastic background. In general, stochastic backgrounds are formed by the combination of many unresolvable sources. Unresolvable sources are those which we cannot distinguish individually, either because they are too quiet (as in the case of a popcorn background described above) or because there are simply too many occurring at once. Detecting a stochastic background is something like listening to voices in a crowded room. Aside from the loudest people and those standing nearest to you, you can hear the remaining conversations blend together into a continuous hum.

    What can it tell us?
    Gravitational waves are expected to have been created throughout the history of the Universe. Depending on when they were produced, gravitational-wave backgrounds can be classified into two basic categories: cosmological and astrophysical. Cosmological backgrounds are predicted to have been produced by sources that existed in the very early Universe just a few seconds after the Big Bang, while astrophysical backgrounds are predicted to have been produced by systems of massive stars such as the neutron stars and black holes that we see today. Most likely, contributions to the gravitational-wave background from astrophysical sources will dominate cosmological ones. The gravitational-wave signal produced by a population of binary black holes like GW150914 is an example of an astrophysical background.

    The strength of the gravitational-wave background at different frequencies strongly depends on the type of sources that produce them. Thus, depending on the type of gravitational-wave background we detect, we may learn about the state of the Universe just a few moments after the Big Bang or how the Universe is evolving in more recent times. In addition, looking at whether the signal is stronger from certain directions on the sky or is uniformly spread out will give us information about the distribution of the sources that produced the background.

    What does GW150914 mean for a gravitational-wave background? Why is this interesting?
    GW150914 was a single event. Its gravitational waves were from the merger of two black holes, having masses of about 29 times and 36 times the mass of the Sun, forming a single black hole with a mass of about 62 times the Sun’s mass. The large component masses of the black holes making up GW150914 suggest that the unresolved popcorn signal from the population of binary black holes is probably stronger than most astrophysicists originally thought. This means we have a better chance of measuring this background with the Advanced LIGO and Virgo detectors. We will have to analyze the data for several years, but it may be possible to eventually measure the signal.

    How do we detect these gravitational waves?
    Although the individual signals from the binary black hole mergers have a characteristic shape, the signals from distant sources will be too weak to be individually detected and the arrival times of the popcorn-like bursts will be random. This means that the standard searches that look for single events like GW150914 won’t work for detecting the relatively quiet popcorn signal from the population of binary black hole mergers throughout the Universe. So we need to take a different approach (described below) to detect the waves from these unresolvable sources.

    It is hard to search for a weak random signal using data from a single detector because the detector noise itself is also random. So instead we compare (“correlate”) data from pairs of detectors, e.g., the two LIGO detectors in Hanford, WA and Livingston, LA. The random gravitational-wave signal will be the same (“correlated”) in both detectors, while the detector noise will not (since the detectors are widely separated and most noise sources due to the environment are local to the detectors). Thus we can use this similarity (“correlation”) to distinguish the gravitational-wave signal from unwanted detector noise.

    Moreover, by performing this correlation over the whole duration of the run (which could be months or years), we build up the signal relative to the noise by including the contribution of the events that occur (on average) once every 15 minutes. The more data we have to analyze, the better it is for this type of search.

    Estimating the gravitational-wave background based on what we’ve learned from GW150914
    A number of factors contribute to how many binary black hole systems will form in the Universe. An important long-term research question will be to try and describe how systems like GW150914 were created. For example, maybe the two original black holes in GW150914 evolved from a binary star system, where the two stars orbiting one another were very massive. Or perhaps the system was created in a globular cluster (a group of stars tightly bound together by gravity) where one could imagine many interactions taking place that would make initially small black holes evolve into larger ones. The most massive stars are short-lived and often produce black holes upon their death, so knowing the birth rate of massive stars is important. Star formation rates depend on the amount of matter present, and its constituents; was there just hydrogen and helium present when the star was formed, or were there other elements as well? Also, how long did the two black holes take to get close enough to collide? All of these ingredients contribute to the different binary black hole formation models that we considered.

    If we detect a stochastic gravitational-wave background in the future, we will not be able to distinguish between different models describing how these binary black hole systems were created. We will, however, be able to contribute to understanding how often these mergers happen in the far away Universe. Future measurements of individual mergering black holes will provide a better estimate of how often these types of events take place in the nearby Universe and more information on the masses of the black holes. Combining what we learn from a stochastic background with measurements from individual events may help distinguish between different formation pathways for binary black holes.

    Implications for the future
    The GW150914 event suggests that merger rates and masses of binary black holes are on the high end of the range of earlier predictions. This means that a gravitational-wave background due to merging black holes is expected to be larger as well. There are sizable uncertainties associated with the strength of this background, but detecting it may be within reach of the advanced detectors at their peak sensitivity. Looking to the future, the next generation of gravitational-wave detectors might be able combine measurements of a gravitational-wave background with measurements of individual black hole mergers to distinguish how black holes may come to orbit one another.

    Glossary

    Astrophysical background A stochastic background of gravitational waves produced by sources such as neutron stars and black holes.
    Black hole A region of space-time caused by an extremely compact mass where the gravity is so intense it prevents anything, including light, from leaving.
    Correlation The amount of similarity between two sets of data. For example, the comparison of data from pairs of gravitational-wave detectors in order to search for weak signals (like a stochastic background) that are shared (“correlated”) between the two instruments.
    Cosmological background A stochastic background of gravitational waves produced by sources such as those in the very early Universe in the instant after the Big Bang.
    Globular cluster A very dense group of stars bound together by gravity.
    Neutron star An extremely dense object which remains after the collapse of a massive star.
    Popcorn background The combination effects of bursts of gravitational waves from all binary black holes too distant to be directly observed. These bursts arrive at Earth at random times, like the popping of individual kernels of corn.
    Spacetime An interwoven continuum of space and time.
    Stochastic background A gravitational-wave signal formed from the combination of many individually unresolvable sources. Sources are unresolvable if they are too weak to be directly observed or if too many overlap at once, like conversations in a loud, crowded room.
    Stochastic Randomly determined; having a random pattern that may be analyzed statistically but may not be predicted precisely.

    Read more:

    Freely readable preprint of the publication describing the analysis
    Data used for this analysis
    Advanced LIGO
    Advanced Virgo

    See the full article here .

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    About the LSC

    The LIGO Scientific Collaboration (LSC) is a group of scientists seeking to make the first direct detection of gravitational waves, use them to explore the fundamental physics of gravity, and develop the emerging field of gravitational wave science as a tool of astronomical discovery. The LSC works toward this goal through research on, and development of techniques for, gravitational wave detection; and the development, commissioning and exploitation of gravitational wave detectors.

    The LSC carries out the science of the LIGO Observatories, located in Hanford, Washington and Livingston, Louisiana as well as that of the GEO600 detector in Hannover, Germany. Our collaboration is organized around three general areas of research: analysis of LIGO and GEO data searching for gravitational waves from astrophysical sources, detector operations and characterization, and development of future large scale gravitational wave detectors.

    Founded in 1997, the LSC is currently made up of more than 1000 scientists from dozens of institutions and 15 countries worldwide. A list of the participating universities.

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

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

    VIRGO Gravitational Wave interferometer, near Pisa, Italy
    VIRGO Gravitational Wave interferometer, near Pisa, Italy

     
  • richardmitnick 4:40 pm on May 28, 2017 Permalink | Reply
    Tags: , , , , , , Gravitational waves,   

    From Monash: “Monash University researchers uncover new Gravitational Waves characteristics” 

    Monash Univrsity bloc

    Monash University

    23 May 2017

    1
    A visualization of a supercomputer simulation of merging black holes sending out gravitational waves. Credit: NASA/C. Henze/phys.org

    Monash University researchers have identified a new concept – ‘orphan memory’ – which changes the current thinking around gravitational waves.

    The research, by the Monash Centre for Astrophysics, was published recently in Physical Review Letters.

    Einstein’s theory of general relativity predicts that cataclysmic cosmic explosions stretch the fabric of spacetime.

    The stretching of spacetime is called ‘gravitational waves.’ After such an event, spacetime does not return to its original state. It stays stretched out. This effect is called ‘memory.’

    The term ‘orphan’ alludes to the fact that the parent wave is not directly detectable.

    “These waves could open the way for studying physics currently inaccessible to our technology,” said Monash School of Physics and Astronomy Lecturer, Dr Eric Thrane, one of the authors of the study, together with Lucy McNeill and Dr Paul Lasky.

    “This effect, called ‘memory’ has yet to be observed,” said Dr Thrane.

    Gravitational-wave detectors such as LIGO only ‘hear’’ gravitational waves at certain frequencies, explains lead author Lucy McNeill.


    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

    “If there are exotic sources of gravitational waves out there, for example, from micro black holes, LIGO would not hear them because they are too high-frequency,” she said.

    “But this study shows LIGO can be used to probe the universe for gravitational waves that were once thought to be invisible to it.”

    Study co-author Dr Lasky said LIGO won’t be able to see the oscillatory stretching and contracting, but it will be able to detect the memory signature if such objects exist.

    The researchers were able to show that high-frequency gravitational waves leave behind a memory that LIGO can detect.

    “This realisation means that LIGO [or e/Lisa] may be able to detect sources of gravitational waves that no one thought it could,” said Dr Lasky.

    See the full article here .

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    Monash U campus

    Monash University (/ˈmɒnæʃ/) is an Australian public research university based in Melbourne, Australia. Founded in 1958, it is the second oldest university in the State of Victoria. Monash is a member of Australia’s Group of Eight and the ASAIHL, and is the only Australian member of the influential M8 Alliance of Academic Health Centers, Universities and National Academies. Monash is one of two Australian universities to be ranked in the The École des Mines de Paris (Mines ParisTech) ranking on the basis of the number of alumni listed among CEOs in the 500 largest worldwide companies.[6] Monash is in the top 20% in teaching, top 10% in international outlook, top 20% in industry income and top 10% in research in the world in 2016.[7]

    Monash enrolls approximately 47,000 undergraduate and 20,000 graduate students,[8] It also has more applicants than any university in the state of Victoria.

    Monash is home to major research facilities, including the Australian Synchrotron, the Monash Science Technology Research and Innovation Precinct (STRIP), the Australian Stem Cell Centre, 100 research centres[9] and 17 co-operative research centres. In 2011, its total revenue was over $2.1 billion, with external research income around $282 million.[10]

    The university has a number of centres, five of which are in Victoria (Clayton, Caulfield, Berwick, Peninsula, and Parkville), one in Malaysia.[11] Monash also has a research and teaching centre in Prato, Italy,[12] a graduate research school in Mumbai, India[13] and a graduate school in Jiangsu Province, China.[14] Since December 2011, Monash has had a global alliance with the University of Warwick in the United Kingdom.[15] Monash University courses are also delivered at other locations, including South Africa.

    The Clayton campus contains the Robert Blackwood Hall, named after the university’s founding Chancellor Sir Robert Blackwood and designed by Sir Roy Grounds.[16]

    In 2014, the University ceded its Gippsland campus to Federation University.[17] On 7 March 2016, Monash announced that it would be closing the Berwick campus by 2018.

     
  • richardmitnick 9:26 am on May 21, 2017 Permalink | Reply
    Tags: , , , , , Gravitational waves,   

    From Manu Garcia: ” LIGO, Boxing Day” 


    Manu Garcia, a friend from IAC.

    The universe around us.
    Astronomy, everything you wanted to know about our local universe and never dared to ask.

    Author: Manu Astrologus – Update: 21/5/17
    Second detection of gravitational waves.

    1
    Artist illustration represents two binary black hole systems for molten GW150914 (left) and GW151226 (right). Pair of black holes are shown together in this illustration but actually detected at different times and in different parts of the sky. The images have been scaled to show the difference in the masses of black holes. In the event GW150914 , black holes were 29 and 36 times the mass of the sun, while GW151226 , the two black holes weighing between 14 and 8 solar masses. Image Credit: LIGO / A. Simonnet.


    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 two gravitational wave detectors LIGO Hanford Washington and Livingston Louisiana have captured a second robust signal of two black holes in their final orbits then coalescence, fusion <>, in a single black hole. This event, called GW151226 , was seen on 26 December at 3:38:53 (coordinated universal time, also known as Greenwich Mean Time) near the end of the first LIGO observation period ( “O1”), and it was immediately nicknamed “the boxing day event”.

    As the first detection LIGO , this event was identified few minutes after passage of the gravitational wave. Subsequently, careful studies of tools and environments around the observatories showed that observed in the two detectors signal was truly distant black holes, about 1,400 million light years away, coinciding with the same distance as the first detected signal. However, the Boxing Day event differed from the first observation of gravitational waves LIGO in some important ways.

    The gravitational wave detectors came to the two almost simultaneously, indicating that the source is somewhere in heaven ring halfway between the two detectors. Knowing our pattern detector sensitivity, we can add that was a little more likely overhead or underfoot instead of west or east. With only two detectors, however, we can not reduce it much more than that. This differs from the first detected signal LIGO ( GW150914 , from 14 September 2015), which came from the southeast, hitting the detector Louisiana before Washington.
    The two black holes merged in the event of Boxing Day were less massive (14 and 8 times the mass of our sun) than those observed in the first detection GW150914 (36 and 29 times the mass of our sun). While this made the weakest signal that GW150914 , when these lighter black holes were combined, changed its signal at higher frequencies that bring in the sensitive band LIGO before the fusion event observed in September. This allowed us to observe more orbits that the first detection-orbits about 27 in about one second (this compares with only two tenths of observation in the first detection). Combined, these two factors (smaller and observed masses orbits) were keys to allow LIGO detect a weaker signal. They also allowed us to make more accurate comparisons with General Relativity. Note: the signal again coincides with Einstein’s theory.
    Last but not least, the event Boxing Day revealed that one of the first black holes was spinning like a top – and this is a first opportunity for LIGO can state this with confidence. A rotating black hole suggests that this object has a different story – p. Maybe “he sucked” the mass of a companion star before or after a star collapsing to form a black hole, achieving rotated in the process.

    With these two detections confirmed, along with a third probable detection made in October 2015 (believed to also could be caused by a pair of coalescing black holes) we can now begin to estimate the rate of coalescence of black hole in the universe based not in theory, but in actual observations. Of course, with only a few signs, our estimate is large uncertainties, but maybe now is between 9 and 240 binary coalescence of black hole Gigaparsec cubic per year, or about one every 10 years in a volume a trillion times the volume galaxy of the Milky Way. Happily, in its first months of operation, they advanced LIGO detectors were sensitive enough to dig deep enough into space to see about an event every two months.

    Our next observation interval – Watching Round # 2, or “O2” – will begin in the fall of 2016. With improved sensitivity, we expect to see more coalescence of black holes and possibly detect gravitational waves from other sources, such as mergers of binary star neutrons. We also expect the Virgo detector will join us later in the race O2. Virgo will be enormously useful for locating sources in the sky, collapsing the ring until a patch, but also helping us to understand the sources of gravitational waves.

    LIGO releases its data to the public. This policy of open data allows others to analyze our data, ensuring that LIGO and Virgo collaborations do not lose anything in their analyzes, and hoping that others might be even more interesting events. Our data are shared in the Open LIGO Science Center. GW151226 has its own page there.

    We invite you to stroll the LIGO Laboratory website where you will find charts to help you understand the observation of Boxing Day, links to the press release and suggestions for scientific papers if you want to deepen further. There you will also find links to the website of LIGO Scientific Collaboration, and our collaboration sister, Virgo, which are essential for these scientific results.

    Credit:
    LIGO.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

     
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