AEI: Gravitational-Wave Detectors Begin Third Observation Run

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AEI: Gravitational-Wave Detectors Begin Third Observation Run

Post by bystander » Tue Mar 26, 2019 9:38 pm

Gravitational-Wave Detectors Begin Third Observation Run
Albert Einstein Institute | Max Planck Institute for Gravitational Physics | 2019 Mar 26

On 1st of April 2019, the twin LIGO instruments, the Virgo detector, and the GEO600 instrument start their third observation run “O3”, which is scheduled to last for one year. The detectors’ sensitivities have been further increased in the past months and previous engineering runs. AEI scientists expect to detect up to dozens of mergers of black holes and further neutron star collisions. LIGO Scientific Collaboration researchers at the Max Planck Institute for Gravitational Physics (Albert Einstein Institute; AEI) in Potsdam and Hannover and at the Leibniz Universität Hannover (LUH) are leading partners in the international gravitational-wave community. They have continued to improve the source modeling, follow-up analyses and the detector technology. ...

The estimated rates of binary black hole mergers range from a few events per month to a few events per week. Mergers of neutron stars could be seen as often as once per year and up to once per month. Whether a hitherto undetected merger of a neutron star with a black hole will be observed in O3 is uncertain.

The LIGO detectors transitioned into O3 directly from the 14th engineering run, which began on March 4th. Compared to the best sensitivities reached in O2, their detection horizons for binary neutron star mergers have increased by about 60 Mpc (190 million light-years) to 170 Mpc (550 million light-years) for LIGO, increasing the detection rate by roughly a factor of three to four compared to O2.

O3 will last for an entire year. The Japanese KAGRA detector is expected to join the observation run in late 2019, extending the network by another large detector. ...

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Last edited by bystander on Thu Mar 28, 2019 2:08 am, edited 2 times in total.
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LSU: Listening to the Quantum Vacuum to Catch Gravitational Waves

Post by bystander » Tue Mar 26, 2019 9:49 pm

Hello, Quantum Vacuum, Nice to See You
Louisiana State University | 2019 Mar 26

Thomas Corbitt ... and his team of researchers measure quantum behavior at room temperature, visible to the naked eye, as reported today in the journal Nature.

Since the historic finding of gravitational waves from two black holes colliding over a billion light years away was made in 2015, physicists are advancing knowledge about the limits on the precision of the measurements that will help improve the next generation of tools and technology used by gravitational wave scientists.

LSU Department of Physics & Astronomy Associate Professor Thomas Corbitt and his team of researchers now present the first broadband, off-resonance measurement of quantum radiation pressure noise in the audio band, at frequencies relevant to gravitational wave detectors, as reported today in the scientific journal Nature. The research was supported by the National Science Foundation, or NSF, and the results hint at methods to improve the sensitivity of gravitational-wave detectors by developing techniques to mitigate the imprecision in measurements called “back action,” thus increasing the chances of detecting gravitational waves.

Corbitt and researchers have developed physical devices that make it possible to observe—and hear—quantum effects at room temperature. It is often easier to measure quantum effects at very cold temperatures, while this approach brings them closer to human experience. Housed in miniature models of detectors like LIGO (the Laser Interferometer Gravitational-Wave Observatory, one located in Livingston, La., and the other in Hanford, Wash.), these devices consist of low-loss, single-crystal micro-resonators—each a tiny mirror pad the size of a pin prick, suspended from a cantilever. A laser beam is directed at one of these mirrors, and as the beam is reflected, the fluctuating radiation pressure is enough to bend the cantilever structure, causing the mirror pad to vibrate, which creates noise.

Gravitational wave interferometers use as much laser power as possible in order to minimize the uncertainty caused by the measurement of discrete photons and to maximize the signal-to-noise ratio. These higher power beams increase position accuracy but also increase back action, which is the uncertainty in the number of photons reflecting from a mirror that corresponds to a fluctuating force due to radiation pressure on the mirror, causing mechanical motion. Other types of noise, such as thermal noise, usually dominate over quantum radiation pressure noise, but Corbitt and his team, including collaborators at MIT, have sorted through them. Advanced LIGO and other second and third generation interferometers will be limited by quantum radiation pressure noise at low frequencies when running at their full laser power. Corbitt’s paper in Nature offers clues as to how researchers can work around this when measuring gravitational waves. ...

Measurement of Quantum Back Action in the Audio Band at Room Temperature ~ Jonathan Cripe et al
Know the quiet place within your heart and touch the rainbow of possibility; be
alive to the gentle breeze of communication, and please stop being such a jerk.
— Garrison Keillor