Richard A. Isaacson Award in Gravitational-Wave Science

This award recognizes outstanding contributions in gravitational-wave physics, gravitational-wave astrophysics, and the technologies that enable this science.

The annual award consists of $5,000, a certificate, travel reimbursement and a registration waiver to attend the APS April Meeting to give an invited talk and accept the award.

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Space.com

NEWS RELEASE 7-APR-2022

AMERICAN PHYSICAL SOCIETY

In the last seven years, scientists at the LIGO-Virgo Collaboration (LVC) have detected 90 gravitational waves signals. Gravitational waves are perturbations in the fabric of spacetime that race outwards from cataclysmic events like the merger of binary black holes (BBH). In observations from the first half of the most recent experimental run, which continued for six months in 2019, the collaboration reported signals from 44 BBH events.

But outliers were hiding in the data. Expanding the search, an international group of astrophysicists re-examined the data and found 10 additional black hole mergers, all outside the detection threshold of the LVC’s original analysis. The new mergers hint at exotic astrophysical scenarios that, for now, are only possible to study using gravitational wave astronomy.

“With gravitational waves, we’re now starting to observe the wide variety of black holes that have merged over the last few billion years,” says Physicist Seth Olsen, a Ph.D. candidate at Princeton University who led the new analysis. Every observation contributes to our understanding of how black holes form and evolve, he says, and the key to recognizing them is to find efficient ways to separate the signals from the noise.

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14 April 2022

The Dutch government intends to conditionally allocate 42 million euros from the Dutch National Growth Fund to the Einstein Telescope, and is also reserving 870 million euros for a future Dutch contribution to the construction. This decision was taken by the Cabinet based on the advice of the Advisory Committee of the National Growth Fund. With this decision, the Cabinet gives an enormous boost to Dutch science and to the broad development of the South Limburg border region.

The intended investment of 42 million euros will go towards preparatory work such as innovation of the necessary technology, location research, building up a high-tech ecosystem and organisation. With the reservation of the 870 million, the Netherlands has an excellent basis to apply in the future, together with Belgium and Germany, for the realisation of the Einstein Telescope in the border region of South Limburg.

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Supermassive black holes orbiting each other very closely are expected to produce gravitational waves.Credit: NASA’s Goddard Space Flight Center/Science Photo Library

Davide Castelvecchi -  Nature

27.1.2022

Astronomers could be on the verge of detecting gravitational waves from distant supermassive black holes — millions or even billions of times larger than the black holes spotted so far — an international collaboration suggests. The latest results from several research teams suggest they are closing in on a discovery after two decades of efforts to sense the ripples in space-time through their effects on pulsars, rapidly spinning spent stars that are sprinkled across the Milky Way.

Gravitational-wave hunters are looking for fluctuations in the signals from pulsars that would reveal how Earth bobs in a sea of gravitational waves. Like chaotic ripples in water, these waves could be due to the combined effects of perhaps hundreds of pairs of black holes, each lying at the centre of a distant galaxy.

So far, the International Pulsar Timing Array (IPTA) collaboration has found no conclusive evidence of these gravitational waves. But its latest analysis — using pooled data from collaborations based in North America, Europe and Australia — reveals a form of ‘red noise’ that has the features researchers expected to see. The findings were published on 19 January in Monthly Notices of the Royal Astronomical Society [1].

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Credit RIT

Matt Williams  - Universe Today

3.2.2022

In February 2016, scientists with the Laser Interferometer Gravitational-Wave Observatory (LIGO) confirmed the first-ever detection of a gravitational wave event. Originally predicted by Einstein’s Theory of General Relativity, GWs result from mergers between massive objects – like black holes, neutron stars, and supermassive black holes (SMBHs). Since 2016, dozens of events have been confirmed, opening a new window to the Universe and leading to a revolution in astronomy and cosmology.

In another first, a team of scientists led by the Center for Computational Relativity and Gravitation (CCRG) announced that they may have detected a merger of two black holes with eccentric orbits for the first time. According to the team’s paper, which recently appeared in Nature Astronomy, this potential discovery could explain why some of the black hole mergers detected by the LIGO Scientific Collaboration and the Virgo Collaboration are much heavier than previously expected.

The team consisted of astrophysicists from the CCRG Rochester Institute of Technology, the Institute of Computational and Experimental Research in Mathematics (ICERM) at Brown University, and the University of Florida. As they indicate in their paper, the team took a fresh look at previous findings made in 2020, where they were part of the team that observed the most massive GW binary detected to date (GW190521). This consisted of two black holes that were about 85 and 66 Solar masses, respectively. This resulted in the formation of a black hole remnant of 142 solar masses.

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Collisions of two neutron stars (illustrated) probably produce more of the universe’s heavy elements than similar collisions of a black hole and neutron star. A. SIMONNET/SONOMA STATE UNIV., LIGO, NSF (EDITED BY MIT NEWS)

By Emily Conover NOVEMBER 3, 2021 

The cosmic origins of elements heavier than iron are mysterious. One elemental birthplace came to light in 2017 when two neutron-rich dead stars collided and spewed out gold, platinum and other hefty elements (SN: 10/16/17). A few years later, a smashup of another neutron star and a black hole left scientists wondering which type of cosmic clash was the more prolific element foundry (SN: 6/29/21).

Now, they have an answer. Collisions of two neutron stars probably take the cake, scientists report October 25 in Astrophysical Journal Letters.

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A black hole (illustrated in black) and a neutron star (white) spiral inward before merging, producing ripples in spacetime (dark gray). MARK MYERS/OZGRAV/SWINBURNE UNIVERSITY

An elusive source of ripples in spacetime has finally been found

By Emily Conover JUNE 29, 2021

Caught in a fatal inward spiral, a neutron star met its end when a black hole swallowed it whole. Gravitational ripples from that collision spread outward through the cosmos, eventually reaching Earth. The detection of those waves marks the first reported sighting of a black hole engulfing the dense remnant of dead star. And in a surprise twist, scientists spotted a second such merger just days after the first.

Until now, all identified sources of gravitational waves were twos of a kind: either two black holes or two neutron stars, spiraling around one another before colliding and coalescing (SN: 1/21/21). The violent cosmic collisions create waves that stretch and squeeze the fabric of spacetime, undulations that can be sussed out by sensitive detectors.

The mismatched pairing of a black hole and neutron star was the final type of merger that scientists expected to find with current gravitational wave observatories. By pure coincidence, researchers spotted two of these events within 10 days of one another, the LIGO, Virgo and KAGRA collaborations report in the July 1 Astrophysical Journal Letters.

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September 29, 2021

New mirror coatings will increase the volume of space LIGO can probe in its next run

Since LIGO's groundbreaking detection, in 2015, of gravitational waves produced by a pair of colliding black holes, the observatory, together with its European partner facility Virgo, has detected dozens of similar cosmic rumblings that send ripples through space and time.

In the future, as more and more upgrades are made to the National Science Foundation-funded LIGO observatories—one in Hanford, Washington, and the other in Livingston, Louisiana—the facilities are expected to detect increasingly large numbers of these extreme cosmic events. These observations will help solve fundamental mysteries about our universe, such as how black holes form and how the ingredients of our universe are manufactured.

One important factor in increasing the sensitivity of the observatories involves the coatings on the glass mirrors that lie at the heart of the instruments. Each 40-kilogram (88-pound) mirror (there are four in each detector at the two LIGO observatories) is coated with reflective materials that essentially turn the glass into mirrors. The mirrors reflect laser beams that are sensitive to passing gravitational waves.

Generally, the more reflective the mirrors the more sensitive the instrument, but there is a catch: The coatings that make the mirrors reflective also can lead to background noise in the instrument—noise that masks gravitational-wave signals of interest.

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Image from a MAYA collaboration numerical relativity simulation of a neutron star-black hole (NSBH) binary merger, showing the disruption of the neutron star. Credit: Deborah Ferguson (UT Ausitn), Bhavesh Khamesra (Georgia Tech), and Karan Jani (Vanderbilt University).

News Release • June 29, 2021

For the first time, researchers have confirmed the detection of a collision between a black hole and a neutron star. In fact, the scientists detected not one but two such events occurring just 10 days apart in January 2020. The extreme events made splashes in space that sent gravitational waves rippling across at least 900 million light-years to reach Earth. In each case, the neutron star was likely swallowed whole by its black hole partner.

Gravitational waves are disturbances in the curvature of space-time created by massive objects in motion. During the five years since the waves were first measured, a finding that led to the 2017 Nobel Prize in Physics, researchers have identified more than 50 gravitational-wave signals from the merging of pairs of black holes and of pairs of neutron stars. Both black holes and neutron stars are the corpses of massive stars, with black holes being even more massive than neutron stars.

Now, in a new study, scientists have announced the detection of gravitational waves from two rare events, each involving the collision of a black hole and a neutron star. The gravitational waves were detected by the National Science Foundation's (NSF's) Laser Interferometer Gravitational-Wave Observatory (LIGO) in the United States and by the Virgo detector in Italy. The KAGRA detector in Japan, joined the LIGO-Virgo network in 2020, but was not online during these detections.

The first merger, detected on January 5, 2020, involved a black hole about 9 times the mass of our sun, or 9 solar masses, and a 1.9-solar-mass neutron star. The second merger was detected on January 15, and involved a 6-solar-mass black hole and a 1.5-solar-mass neutron star. The results were published today, June 29, in The Astrophysical Journal Letters.

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Link to ApJ publication

F. Elavsky and A. Geller/Northwestern Univ./LIGO-Virgo Collaboration

May 7, 2021• Physics 14, 67

The latest dataset from gravitational-wave observatories has enough events to allow researchers to study properties of the whole population of black holes.

Black holes (blue), neutron stars (orange), and compact objects of uncertain nature (gray) detected via gravitational waves through September 2019. Each binary merger involves three compact objects: the two coalescing objects and the final remnant. The vertical scale is in solar masses.

Less than six years after the first detection of gravitational waves, observations are becoming routine, with LIGO and Virgo logging black hole mergers more than once per week. At the APS April meeting, the LIGO-Virgo Collaboration (LVC) reported using their catalog of nearly 50 events to estimate the typical properties and histories of black holes. Measurements of black hole spins, for example, suggest that at least two different formation mechanisms are common for black hole binaries. These black hole “population” studies—akin to astronomers’ star surveys—are becoming a prized tool for gravitational-wave scientists, in addition to studies of individual events.

The black holes in the LVC catalog are stellar-mass black holes—the remnants of giant stars after they explode as supernovae. In the past, astronomers could spot these black holes only when they were in a binary orbit with a normal star, but the LIGO and Virgo observatories have revolutionized the field since 2015. “The vast majority of the stellar-mass black holes that we know about in the Universe [were detected via] gravitational waves,” said Carl Rodriguez of Carnegie Mellon University, Pennsylvania, in his presentation at the conference. So gravitational waves are now the main source of data from which astrophysicists will learn about these objects. “For the first time, we’re able to do astronomy” using gravitational waves, said Maya Fishbach of Northwestern University, Illinois, a member of the LVC. “We’re really going to learn more about star formation in general.”

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Europe’s proposed Einstein Telescope, an early design of which is shown here in an artist’s conception (not to scale), would comprise six detectors in a triangular arrangement of tunnels. ET CONCEPTUAL DESIGN TEAM

By Adrian Cho   Mar. 10, 2021

Just 5 years ago, physicists opened a new window on the universe when they first detected gravitational waves, ripples in space itself set off when massive black holes or neutron stars collide. Even as discoveries pour in, researchers are already planning bigger, more sensitive detectors. And a Ford versus Ferrari kind of rivalry has emerged, with scientists in the United States simply proposing bigger detectors, and researchers in Europe pursuing a more radical design.

“Right now, we’re only catching the rarest, loudest events, but there’s a whole lot more, murmuring through the universe,” says Jocelyn Read, an astrophysicist at California State University, Fullerton, who’s working on the U.S. effort. Physicists hope to have the new detectors running in the 2030s, which means they have to start planning now, says David Reitze, a physicist at the California Institute of Technology (Caltech). “Gravitational wave discoveries have captivated the world, so now is a great time to be thinking about what comes next.”

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Gravitational waves, produced when behemoths like black holes and neutron stars spiral inward and merge, have been spotted 50 times (each event represented with a large circle above). NADIEH BREMER/VISUALCINNAMON.COM

By Emily Conover and Nadieh Bremer

Fifty events reveal the similarities and differences in these cosmic smashups

Throughout the universe, violent collisions of cosmic beasts such as black holes wrench the fabric of spacetime, producing ripples called gravitational waves. For most of history, humans have been oblivious to those celestial rumbles. Today, we’ve detected scores of them.

The first came in 2015, when scientists with the Advanced Laser Interferometer Gravitational-Wave Observatory, or LIGO, spotted gravitational waves spawned from the merger of two black holes. That event rattled the bones of the cosmos — shaking the underlying structure of space and time. The detection also stirred up astronomy, providing a new way to observe the universe, and verified a prediction of Albert Einstein’s general theory of relativity (SN: 2/11/16).

The first came in 2015, when scientists with the Advanced Laser Interferometer Gravitational-Wave Observatory, or LIGO, spotted gravitational waves spawned from the merger of two black holes. That event rattled the bones of the cosmos — shaking the underlying structure of space and time. The detection also stirred up astronomy, providing a new way to observe the universe, and verified a prediction of Albert Einstein’s general theory of relativity (SN: 2/11/16).

But like a lone ripple in a vast sea, a single detection can tell scientists only so much. Now, LIGO and its partner observatory Advanced Virgo have collected 50 sets of gravitational waves. Most of these spacetime ripples resulted from two black holes spiraling inward before colliding. Some arose from collisions of dense stellar corpses called neutron stars. Two collisions involve celestial bodies that can’t be confidently identified, hinting that scientists may have spotted the first merger of a neutron star with a black hole (SN: 6/23/20).

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This illustration generated by a computer model shows multiple black holes found within the heart of a dense globular star cluster. Credit: Aaron M. Geller, Northwestern University/CIERA

New analysis of gravitational-wave data leads to wealth of discoveries.

An international research collaboration including Northwestern University astronomers has produced the most detailed family portrait of black holes to date, offering new clues as to how black holes form. An intense analysis of the most recent gravitational-wave data available led to the rich portrait as well as multiple tests of Einstein’s theory of general relativity. (The theory passed each test.)

The team of scientists who make up the LIGO Scientific Collaboration (LSC) and the Virgo Collaboration is now sharing the full details of its discoveries. This includes new gravitational-wave detection candidates which held up to scrutiny — a whopping total of 39, representing a variety of black holes and neutron stars — and new discoveries as a result of combining all the observations. The 39 events averaged more than one per week of observing.

The observations could be a key piece in solving the many mysteries of exactly how binary stars interact. A better understanding of how binary stars evolve has consequences across astronomy, from exoplanets to galaxy formation.

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Scientists have now detected 50 sets of gravitational waves, many produced when two black holes (illustrated) spiral around one another before colliding and merging into one.
© N. FISCHER, S. OSSOKINE, H. PFEIFFER, A. BUONANNO/MAX PLANCK INSTITUTE FOR GRAVITATIONAL PHYSICS, SIMULATING EXTREME SPACETIMES (SXS) COLLABORATION

By Emily Conover OCTOBER 28, 2020 

Earth is awash in gravitational waves.

Over a six-month period, scientists captured a bounty of 39 sets of gravitational waves. The waves, which stretch and squeeze the fabric of spacetime, were caused by violent events such as the melding of two black holes into one.

The haul was reported by scientists with the LIGO and Virgo experiments in several studies posted October 28 on a collaboration website and at arXiv.org. The addition brings the tally of known gravitational wave events to 50.

The bevy of data, which includes sightings from April to October 2019, suggests that scientists’ gravitational wave–spotting skills have leveled up. Before this round of searching, only 11 events had been detected in the years since the effort began in 2015. Improvements to the detectors — two that make up the Advanced Laser Interferometer Gravitational-Wave Observatory, or LIGO, in the United States, and another, Virgo, in Italy — have dramatically boosted the rate of gravitational wave sightings.

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Impression of the Einstein Telescope, a large underground gravitational wave detector. As possible locations the Euro Region near Vaals and Sardinia are considered. IMAGE Nikhef / Thijs Balder

10 September 2020

Supported by the Netherlands, Belgium, Poland and Spain, the Italian government submitted an application on Wednesday to include the Einstein Telescope in a European roadmap for major research infrastructures. The inclusion of the Einstein Telescope in this ESFRI roadmap will be a recognition of the importance of the Einstein Telescope for Europe.

According to advanced plans, the Einstein Telescope will be the largest ever observatory for observing gravitational waves coming from colliding stars and black holes in the Universe. Such observations offer a new window on the cosmos and its history.

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