 |
|
UO plays key role in LIGO's new view of a cosmic event
January 04, 2008Lack of gravitational wave prompts fresh look at gamma ray burst
An international team of physicists, including University of Oregon scientists, has concluded that last February's intense burst of gamma rays possibly coming from the Andromeda Galaxy lacked a gravitational wave. That absence, they say, rules out an initial interpretation that the burst came from merging neutron stars or black holes within Andromeda.
A revised interpretation, presented last month by the UO's Isabel Leonor at the 12th Gravitational Wave Data Analysis Workshop in Cambridge, Mass., suggests two possible origins: A merger event beyond Andromeda or a burst from an astronomical object known as a soft gamma-ray repeater within Andromeda. The latter, also called a magnetar, involves neutron stars with enormous magnetic fields that occasionally produce big outbursts of gamma rays.
The new findings are based on a collaborative analysis by the Laser Interferometer Gravitational-Wave Observatory (LIGO) Scientific Collaboration, a project funded by the National Science Foundation. LIGO was designed and is operated by the California Institute of Technology and the Massachusetts Institute of Technology for the detection of cosmic gravitational waves and for the development of gravitational wave observations as an astronomical tool.
Leonor, a research associate in the experimental relativity group of the UO's Center for High Energy Physics, and colleague Ray Frey, a professor of physics, initiated the during a discussion of the event, known as GRB070201, at a meeting in Louisiana in March. The UO's experimental relativity group is part of the LIGO Scientific Collaboration.
Gamma ray bursts are among the most violent and energetic events in the universe. Scientists have only recently begun to understand their origins. On Feb. 1, 2007, four gamma ray satellites measured a short but intense outburst of energetic gamma rays originating in the direction of the Andromeda galaxy 2.5 million light years from Earth. The majority of short (less than 2 seconds) gamma ray bursts (GRBs) are thought to come from the merger and coalescence of two massive but compact objects such as neutron stars or black hole systems. They also can come from less-common soft, gamma ray repeaters, which emit fewer intense gamma rays.
During February's blast of gamma rays, the four-kilometer and two-kilometer gravitational wave interferometers at LIGO's Hanford, Wash., facility were collecting data but did not detect any associated gravitational waves. That non-detection was significant, the scientists report.
The burst occurred along a line of sight that was consistent with it originating from one of Andromeda's spiral arms. Initially a binary coalescence event--the merger of two neutron stars or black holes, for example -- was considered the most likely explanation. Such a monumental cosmic event occurring in a nearby galaxy should have generated gravitational waves that would be easily measured by the ultra-sensitive LIGO detectors. The absence of a gravitational wave signal meant the burst could not have originated in this way in the Andromeda Galaxy.
"In general, our understanding of GRBs and soft gamma ray repeaters has increased dramatically in the past decade but is still in an early stage," Frey said. "So every piece of the puzzle that is put in place gives the overall picture more clarity."
The LIGO Scientific Collaboration includes 580 scientists at universities around the United States and 11 other countries. The collaboration interferometer network includes the GEO600 interferometer located in Hannover, Germany, which was designed and is operated by scientists from the Max Planck Institute for Gravitational Physics and partners in the United Kingdom.
Each of the L-shaped LIGO interferometers (including the detectors in Hanford and a four kilometer instrument in Livingston, La.), uses a laser split into two beams which travel back and forth down long arms in evacuated beam tubes. The beams are used to monitor the distance between precisely figured mirrors. According to Albert Einstein's 1916 theory of general relativity, the relative distance of the mirrors changes very slightly when a gravitational wave -- a distortion in space-time produced by massive accelerating objects that propagates outward through the universe -- passes by. An interferometer is constructed so that it can detect a change of less than a thousandth the diameter of an atomic nucleus in the lengths of the arms relative to each other.
LIGO's contribution to the study of GRB070201 marked a milestone for the project, said Caltech's Jay Marx, LIGO's executive director. "Having achieved its design goals two years ago, LIGO is now producing significant scientific results," he said in a Caltech news release. "The non-detection of a signal from GRB070201 is an important step towards a very productive synergy between gravitational wave and other astronomical communities that will contribute to our understanding of the most energetic events in the cosmos."
Until now, astronomers who have studied GRBs relied on data from telescopes conducting visible, infrared, radio, x-ray and gamma ray observations, said David Reitze, a professor of physics at the University of Florida and spokesperson for the LIGO Scientific Collaboration. Gravitational waves offer a new window into the nature of these events, he said in the Caltech release.
Even before the event of last February, the UO's experimental gravity group has been leading LIGO's effort in the scientific search for gravitational-wave bursts associated with the enigmatic astrophysical objects that are gamma-ray bursts. The UO team analyzed data from the second, third and fourth LIGO science runs. During the fifth LIGO science run, which lasted two years and during which the interferometers were at their design sensitivities, there were about 200 GRBs observed by gamma-ray satellite experiments.
"It gives me a very satisfying feeling to contribute in a meaningful way to the science of astrophysics in collaboration with world-class scientists," Leonor said. "My fascination with understanding the universe was, after all, why I became a scientist."
Frey noted that the sensitivity of LIGO is improving dramatically, "so it is exciting for us to begin making astrophysically interesting statements with gravitational waves, a new way of observing the universe. So while the GRB070201 result is a kind of dog-that-did-not-bark statement, we expect to be eventually hearing a canine chorus of gravitational waves."
The Oregon group also has played a key role in the commissioning of the LIGO instruments at the Hanford and Livingston sites. This effort has been led by Robert Schofield, a senior research associate. The UO group is made up of three faculty members, three research associates, one graduate student and undergraduate research assistants.
The next major construction milestone for LIGO will be the Advanced LIGO Project. Work is expected to start this year. Advanced LIGO will utilize the infrastructure of LIGO, but will be 10 times more sensitive, allowing scientists to detect cataclysmic events such as black-hole and neutron-star collisions at 10-times-greater distances.
University of Oregon
The new findings are based on a collaborative analysis by the Laser Interferometer Gravitational-Wave Observatory (LIGO) Scientific Collaboration, a project funded by the National Science Foundation. LIGO was designed and is operated by the California Institute of Technology and the Massachusetts Institute of Technology for the detection of cosmic gravitational waves and for the development of gravitational wave observations as an astronomical tool.
Leonor, a research associate in the experimental relativity group of the UO's Center for High Energy Physics, and colleague Ray Frey, a professor of physics, initiated the during a discussion of the event, known as GRB070201, at a meeting in Louisiana in March. The UO's experimental relativity group is part of the LIGO Scientific Collaboration.
Gamma ray bursts are among the most violent and energetic events in the universe. Scientists have only recently begun to understand their origins. On Feb. 1, 2007, four gamma ray satellites measured a short but intense outburst of energetic gamma rays originating in the direction of the Andromeda galaxy 2.5 million light years from Earth. The majority of short (less than 2 seconds) gamma ray bursts (GRBs) are thought to come from the merger and coalescence of two massive but compact objects such as neutron stars or black hole systems. They also can come from less-common soft, gamma ray repeaters, which emit fewer intense gamma rays.
During February's blast of gamma rays, the four-kilometer and two-kilometer gravitational wave interferometers at LIGO's Hanford, Wash., facility were collecting data but did not detect any associated gravitational waves. That non-detection was significant, the scientists report.
The burst occurred along a line of sight that was consistent with it originating from one of Andromeda's spiral arms. Initially a binary coalescence event--the merger of two neutron stars or black holes, for example -- was considered the most likely explanation. Such a monumental cosmic event occurring in a nearby galaxy should have generated gravitational waves that would be easily measured by the ultra-sensitive LIGO detectors. The absence of a gravitational wave signal meant the burst could not have originated in this way in the Andromeda Galaxy.
"In general, our understanding of GRBs and soft gamma ray repeaters has increased dramatically in the past decade but is still in an early stage," Frey said. "So every piece of the puzzle that is put in place gives the overall picture more clarity."
The LIGO Scientific Collaboration includes 580 scientists at universities around the United States and 11 other countries. The collaboration interferometer network includes the GEO600 interferometer located in Hannover, Germany, which was designed and is operated by scientists from the Max Planck Institute for Gravitational Physics and partners in the United Kingdom.
Each of the L-shaped LIGO interferometers (including the detectors in Hanford and a four kilometer instrument in Livingston, La.), uses a laser split into two beams which travel back and forth down long arms in evacuated beam tubes. The beams are used to monitor the distance between precisely figured mirrors. According to Albert Einstein's 1916 theory of general relativity, the relative distance of the mirrors changes very slightly when a gravitational wave -- a distortion in space-time produced by massive accelerating objects that propagates outward through the universe -- passes by. An interferometer is constructed so that it can detect a change of less than a thousandth the diameter of an atomic nucleus in the lengths of the arms relative to each other.
LIGO's contribution to the study of GRB070201 marked a milestone for the project, said Caltech's Jay Marx, LIGO's executive director. "Having achieved its design goals two years ago, LIGO is now producing significant scientific results," he said in a Caltech news release. "The non-detection of a signal from GRB070201 is an important step towards a very productive synergy between gravitational wave and other astronomical communities that will contribute to our understanding of the most energetic events in the cosmos."
Until now, astronomers who have studied GRBs relied on data from telescopes conducting visible, infrared, radio, x-ray and gamma ray observations, said David Reitze, a professor of physics at the University of Florida and spokesperson for the LIGO Scientific Collaboration. Gravitational waves offer a new window into the nature of these events, he said in the Caltech release.
Even before the event of last February, the UO's experimental gravity group has been leading LIGO's effort in the scientific search for gravitational-wave bursts associated with the enigmatic astrophysical objects that are gamma-ray bursts. The UO team analyzed data from the second, third and fourth LIGO science runs. During the fifth LIGO science run, which lasted two years and during which the interferometers were at their design sensitivities, there were about 200 GRBs observed by gamma-ray satellite experiments.
"It gives me a very satisfying feeling to contribute in a meaningful way to the science of astrophysics in collaboration with world-class scientists," Leonor said. "My fascination with understanding the universe was, after all, why I became a scientist."
Frey noted that the sensitivity of LIGO is improving dramatically, "so it is exciting for us to begin making astrophysically interesting statements with gravitational waves, a new way of observing the universe. So while the GRB070201 result is a kind of dog-that-did-not-bark statement, we expect to be eventually hearing a canine chorus of gravitational waves."
The Oregon group also has played a key role in the commissioning of the LIGO instruments at the Hanford and Livingston sites. This effort has been led by Robert Schofield, a senior research associate. The UO group is made up of three faculty members, three research associates, one graduate student and undergraduate research assistants.
The next major construction milestone for LIGO will be the Advanced LIGO Project. Work is expected to start this year. Advanced LIGO will utilize the infrastructure of LIGO, but will be 10 times more sensitive, allowing scientists to detect cataclysmic events such as black-hole and neutron-star collisions at 10-times-greater distances.
University of Oregon
Gravitational Wave Current Events and Gravitational Wave News RSSQuantum goes massive
An astrophysics experiment in America has demonstrated how fundamental research in one subject area can have a profound effect on work in another as the instruments used for the Laser Interferometer Gravitational-Wave Observatory (LIGO) pave the way for quantum experiments on a macroscopic scale.
Simulations Illuminate Universe's First Twin Stars
The earliest stars in the universe formed not only as individuals, but sometimes also as twins, according to a paper published today in Science Express.
Cardiff researchers could herald a new era in fundamental physics
Cardiff University researchers who are part of a British-German team searching the depths of space to study gravitational waves, may have stumbled on one of the most important discoveries in physics according to an American physicist.
Supernova birth seen for first time
Astronomers have seen the aftermath of spectacular stellar explosions known as supernovae before, but until now no one has witnessed a star dying in real time.
RIT Team Simulates First Merger of Three Black Holes on a Supercomputer
The same team of astrophysicists that cracked the computer code simulating two black holes crashing and merging together has now, for the first time, caused a three-black-hole collision.
Listening for the cosmic symphony: New SU supercomputer will help scientists listen for black holes
Scientists hope that a new supercomputer being built by Syracuse University's Department of Physics may help them identify the sound of a celestial black hole. The supercomputer, dubbed SUGAR (SU Gravitational and Relativity Cluster), will soon receive massive amounts of data from the California Institute of Technology (Caltech) that was collected over a two-year period at the Laser Interferometer Gravitational-Wave Observatory (LIGO).
A new window on the universe
Using new tools to look at the universe, says Patrick Brady, often has led to discoveries that change the course of science. History is full of examples.
Superstrings could add gravitational cacophony to universe's chorus
Albert Einstein theorized long ago that moving matter would warp the fabric of four-dimensional space-time, sending out ripples of gravity called gravitational waves. No one has observed such a phenomenon so far, but University of Washington researchers believe it is possible to detect such waves coming from strange wispy structures called cosmic superstrings.
The day LISA Pathfinder hung in the balance
At the core of ESA's LISA Pathfinder mission sit two small hearts. Each is a cube, just 5 centimetres across. Together they will allow LISA Pathfinder to lay the foundations for future space-based measurements that investigate the very core of Einstein's General Relativity.
GEO600 starts continuous search for Gravitational Waves
The joint German-British Gravitational Wave Detector GEO600 has now entered an 18-month run of continuous measurement.
More Gravitational Wave Current Events and Gravitational Wave News Articles
 |
Traveling at the Speed of Thought: Einstein and the Quest for Gravitational Waves by Daniel Kennefick (Author) Since Einstein first described them nearly a century ago, gravitational waves have been the subject of more sustained controversy than perhaps any other phenomenon in physics. These as yet undetected fluctuations in the shape of space-time were first predicted by Einstein's general theory of relativity, but only now, at the dawn of the twenty-first century, are we on the brink of finally observing them. Daniel Kennefick's landmark book takes readers through the theoretical controversies and thorny debates that raged around the subject of gravitational waves after the publication of Einstein's theory. The previously untold story of how we arrived at a settled theory of gravitational waves includes a stellar cast from the front ranks of twentieth-century physics, including Richard... |
 |
Stitch in Time Also With: Egami Media (Producer) |
 |
Gravitational Waves: Volume 1: Theory and Experiments by Michele Maggiore (Author) The aim of this book is to become THE reference text for gravitational-wave physics, covering in detail both the experimental and the theoretical aspects. It is he only existing book on gravitational waves, and it will likely remain unique for its broadeness and scope. It brings the reader to the forefront of present-day research, both theoretical and experimental, assuming no previous knowledge of gravitational-wave physics. Part I of this volume is devoted to the theory of gravitational waves. Here we have rederived - in a coherent way - most of the results that we present, clarifying or streamlining existing derivations. Part II is devoted to a description of experimental GW physics. We discuss in great detail exisiting and planned experiments, as well as data... |
|
Thoughts of an Untamed Mind by Aaron D. Spears | |
 |
Analysis of Gravitational-Wave Data (Cambridge Monographs on Particle Physics, Nuclear Physics and Cosmology) by Piotr Jaranowski (Author), Andrzej Krolak (Author) Research in this field has grown considerably in recent years due to the commissioning of a world-wide network of large-scale detectors. This network collects a very large amount of data that is currently being analyzed and interpreted. This book introduces researchers entering the field, and researchers currently analyzing the data, to the field of gravitational-wave data analysis. An ideal starting point for studying the issues related to current gravitational-wave research, the book contains detailed derivations of the basic formula related to the detectors' responses and maximum-likelihood detection. These derivations are much more complete and more pedagogical than those found in current research papers, and will enable readers to apply general statistical concepts to the analysis of... |
 |
Gravity's Shadow: The Search for Gravitational Waves by Harry Collins (Author) According to the theory of relativity, we are constantly bathed in gravitational radiation. When stars explode or collide, a portion of their mass becomes energy that disturbs the very fabric of the space-time continuum like ripples in a pond. But proving the existence of these waves has been difficult; the cosmic shudders are so weak that only the most sensitive instruments can be expected to observe them directly. Fifteen times during the last thirty years scientists have claimed to have detected gravitational waves, but so far none of those claims have survived the scrutiny of the scientific community. Gravity's Shadow chronicles the forty-year effort to detect gravitational waves, while exploring the meaning of scientific knowledge and the nature of expertise. Gravitational... |
 |
General Relativity and Gravitational Waves by J. Weber (Author) Upper-level undergraduates and graduate students receive a brief but thorough introduction to the foundations of general relativity from a pioneer in the investigation of gravitational waves, who introduces the related Riemannian geometry and tensor calculus, conservation laws, and classic experiments. 1961 edition. |
|
Fundamentals of Interferometric Gravitational Wave Detectors by Peter R. Saulson (Author) Gravitational waves were predicted by Einstein many years ago but have not yet been seen. This book is about the technology of the new generation of interferometric gravitational wave detectors now being built, such as the US LIGO (Laser Interferometric Gravitational-Wave Observatory) project. The book aims to make plain how these detectors function, and why it is reasonable to think that gravitational waves may be successfully detected. After an introduction to the physical and astronomical aspects of gravitational waves, the book concentrates on explaining the basic principles behind the detectors and discusses the strategies for utilizing them. All the required background in relativity, astronomy, optics and experimental physics techniques is developed within the text and anyone with... | |
 |
Gravitational Waves (Studies in High Energy Physics, Cosmology and Gravitation) by I. Ciufolini (Editor), V. Gorini (Editor), U. Moschella (Editor), P Fre (Editor) Gravitational waves represent today a hot topic, which promises to play a central role in astrophysics, cosmology and theoretical physics. Technological developments have led us to the brink of their direct observation, which could become a reality in the coming years. The direct observation of gravitational waves will open an entirely new field: gravitational wave astronomy. This is expected to bring a revolution in our knowledge of the universe by allowing the observation of hitherto unseen phenomena such as coalescence of compact objects (neutron stars and black holes), fall of stars into supermassive black holes, stellar core collapses, big-bang relics and the new and unexpected. This book provides a comprehensive review of gravitational... |
 |
Gravitational Wave and Time by J.A. Freire (Author) Albert Einstein predicted the existence of gravitational waves in 1916 as part of the theory of general relativity. Einstein described space and time as different aspects of our reality, in which matter and energy are ultimately the same thing. Space-time can be thought of as a ''fabric'' defined by the measuring of distances by rulers and the measuring of time by clocks. The presence of large amounts of mass or energy distort space-time-into essence causing the fabric to become curved, or ''warped'' -and we observe this as gravity. LIGO is a scientific collaboration of the California Institute of Technology (Caltech) and Massachusetts Institution of Technology (MIT), funded by the National Science Foundation. In this book, J. A. Freire outlines a mathematical development in two... |
| © 2009 BrightSurf.com |