beecee Posted April 5, 2019 Share Posted April 5, 2019 (edited) https://phys.org/news/2019-04-gravitational-expose-black-holes-dark.html Gravitational waves helping to expose black holes, dark matter and theoretical particles: extracts: Some gravitational observations can only be explained either by the presence of dark matter, which we cannot see, or by changing our laws of gravity. Professor Ulrich Sperhake, a theoretical physicist at the University of Cambridge, UK, and lead scientist in the StronGrHEPproject, described gravitational waves as a 'new window onto the universe' that could help us unravel these mysteries An idea Prof. Sperhake is investigating is to extend Einstein's general relativity with a new theory, dubbed scalar tensor gravity. This suggests that the universe is filled with an extra field – similar to a magnetic or electrical field – that has yet to be detected. It would mean that the supernova explosion of a dying star would not only be visible as a burst of gravitational waves, but there would be an afterglow of gravitational waves that we might detect. We could direct LIGO to regions of the sky where stars have exploded – known as supernovae – to try to detect such an afterglow from the scalar field that may persist centuries after the actual explosion. Separately, Prof. Sperhake is investigating if dark matter could be explained by theoretical subatomic particles called axions. He is trying to model what the echoes of gravitational waves from black holes might look like if these particles are present. "I would say axions are one of the best candidates for dark matter," he said. The next step is to apply his models to the data that LIGO gathers to see if theory and observation are a match more at link....... ::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: Just more examples of the everyday methodology of science and scientists, working, researching, and testing to the limits our current theories including GR. The often made accusations of recalcitrance, stubbornness and refusal to progress as new data comes to light is again shown to be agenda driven fairy tales. Latest news in the search for GW's is that aLIGO and Virgo is commencing their third run in the search....... https://www.ligo.caltech.edu/news/ligo20190326 LIGO and Virgo Resume Search for Ripples in Space and Time News Release • March 26, 2019 The National Science Foundation's LIGO (Laser Interferometer Gravitational-Wave Observatory) is set to resume its hunt for gravitational waves—ripples in space and time—on April 1, after receiving a series of upgrades to its lasers, mirrors, and other components. LIGO—which consists of twin detectors located in Washington and Louisiana—now has a combined increase in sensitivity of about 40 percent over its last run, which means that it can survey an even larger volume of space than before for powerful, wave-making events, such as the collisions of black holes. Joining the search will be Virgo, the European-based gravitational-wave detector, located at the European Gravitational Observatory (EGO) in Italy, which has almost doubled its sensitivity since its last run and is also starting up April 1. "For this third observational run, we achieved significantly greater improvements to the detectors' sensitivity than we did for the last run," says Peter Fritschel, LIGO's chief detector scientist at MIT. "And with LIGO and Virgo observing together for the next year, we will surely detect many more gravitational waves from the types of sources we've seen so far. We're eager to see new events too, such as a merger of a black hole and a neutron star." more news at link....... Edited April 5, 2019 by beecee Link to comment Share on other sites More sharing options...
beecee Posted April 11, 2019 Author Share Posted April 11, 2019 (edited) Up date of News from aLIGO/CalTech... https://www.ligo.caltech.edu/news/ligo20190411 First Public Gravitational Wave Alert Issued! News Release • April 11, 2019 The LIGO Scientific and Virgo Collaborations are excited to announce that they have sent out their first ever “public alert”, informing the world at large of a possible gravitational wave detection. Beginning with this current observing run (dubbed O3 for the third observing run with advanced detectors), LIGO and Virgo will publicly announce candidate gravitational wave triggers with a high likelihood of astrophysical origin within minutes of the waves arriving in the three detectors (LIGO Hanford, LIGO Livingston, and Virgo). LIGO Laboratory director, Dr. David Reitze, explained the reason for this new approach: "In O3 we transitioned to a system whereby LIGO and Virgo alert the electromagmetic (EM) astronomy community almost immediately that we have a statistically significant trigger; that is, a potential gravitational wave (GW) detection. The rationale for this is simple: The sooner we reveal a GW source, the sooner EM telescopes (X-ray, UV, optical, radio) can search for and hopefully find an electromagnetic signal from the same source. Capturing the EM signal as soon as possible is, in many cases, the key to understanding the dynamics of the event, revealing its true nature." Dr. Jonah Kanner, a senior scientist at LIGO Laboratory, added: "Public alerts will allow astronomers around the world to react quickly to gravitational-wave events, and find counterparts across the electromagnetic spectrum. Gravitational-wave astronomy is still very new, and has a huge potential for discovery.” This first public gravitational wave alert, sent out April 8, 2019, describes what is believed to be a binary black-hole merger that occurred some 4-billion light years away (1473 +/- 358 Mpc). LIGO’s Hanford and Livingston observatories and the Virgo detector in Italy were all in observation mode at the time and contributed to the detection. Combining the data obtained by each site yielded the sky-map seen below. The region of sky believed to contain the source of the gravitational wave detected on April 8, 2019. The area spans 387 square degrees, equivalent to nearly 2000 full-Moons, roughly meandering through the constellations Cassiopeia, Lacerta, Andromeda, and Cepheus in the northern hemisphere. Credit: LIGO/Caltech/MIT Gravitational wave public alerts will include a sky-map showing the possible location of the source on the sky, the time of the event, and what kind of event it is believed to be (e.g., binary black hole merger, black hole/neutron star merger, or binary neutron star merger). More detailed information about candidate events will be published at a later date after each one has been properly vetted and studied. The public can keep track of public alerts at https://gracedb.ligo.org/latest/, and iPhone users can even get an app to receive alerts as they happen! Find it here: Gravitational Wave Events iPhone App LIGO and Virgo anticipate that this is just the first of many public alerts yet to be distributed in the coming year. O3 began April 1, 2019 and is expected to last at least 12 months Edited April 12, 2019 by beecee Link to comment Share on other sites More sharing options...
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