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Full-Text Articles in Physical Sciences and Mathematics

Measurements And Mitigation Of Scattered Light Noise In Ligo, Corey Daniel Austin Nov 2020

Measurements And Mitigation Of Scattered Light Noise In Ligo, Corey Daniel Austin

LSU Doctoral Dissertations

The Advanced LIGO (aLIGO) detectors use 1064 nm lasers to measure the tiny fluctuations in spacetime that occur when gravitational waves pass through the earth. LIGO makes use of advanced coating methods and materials to limit the amount of light that scatters from the main beam, but some amount of light does scatter. This stray light can interact with surfaces inside the interferometer that are not seismically isolated and then recombine with the main beam, introducing excess noise into the gravitational wave channel. This thesis reviews the methods for modeling scattered light with ray tracing software and analytical models, for …


Improving The Robustness Of The Advanced Ligo Detectors To Earthquakes, Eyal Schwartz, A. Pele, J. Warner, B. Lantz, Joseph Betzwieser, K. L. Dooley, S. Biscans, K. E. Ramirez Nov 2020

Improving The Robustness Of The Advanced Ligo Detectors To Earthquakes, Eyal Schwartz, A. Pele, J. Warner, B. Lantz, Joseph Betzwieser, K. L. Dooley, S. Biscans, K. E. Ramirez

Physics and Astronomy Faculty Publications and Presentations

Teleseismic, or distant, earthquakes regularly disrupt the operation of ground–based gravitational wave detectors such as Advanced LIGO. Here, we present EQ mode, a new global control scheme, consisting of an automated sequence of optimized control filters that reduces and coordinates the motion of the seismic isolation platforms during earthquakes. This, in turn, suppresses the differential motion of the interferometer arms with respect to one another, resulting in a reduction of DARM signal at frequencies below 100 mHz. Our method greatly improved the interferometers' capability to remain operational during earthquakes, with ground velocities up to 3.9 μm s−1 rms …


Properties And Astrophysical Implications Of The 150 M ⊙ Binary Black Hole Merger Gw190521, R. Abbott, T. D. Abbott, A. Aich, G. Bissenbayeva, Teviet Creighton, Mario C. Diaz, S. Mukherjee, V. Quetschke, Malik Rakhmanov, K. E. Ramirez, P. K. Roy, W. H. Wang, A. K. Zadrozny Sep 2020

Properties And Astrophysical Implications Of The 150 M ⊙ Binary Black Hole Merger Gw190521, R. Abbott, T. D. Abbott, A. Aich, G. Bissenbayeva, Teviet Creighton, Mario C. Diaz, S. Mukherjee, V. Quetschke, Malik Rakhmanov, K. E. Ramirez, P. K. Roy, W. H. Wang, A. K. Zadrozny

Physics and Astronomy Faculty Publications and Presentations

The gravitational-wave signal GW190521 is consistent with a binary black hole (BBH) merger source at redshift 0.8 with unusually high component masses, M ⊙ and M ⊙, compared to previously reported events, and shows mild evidence for spin-induced orbital precession. The primary falls in the mass gap predicted by (pulsational) pair-instability supernova theory, in the approximate range 65–120 M ⊙. The probability that at least one of the black holes in GW190521 is in that range is 99.0%. The final mass of the merger ( M ⊙) classifies it as an intermediate-mass black hole. Under the assumption of a quasi-circular …


Calibration Transients In Ligo Detectors, Thomas Daniel Abbott Jan 2020

Calibration Transients In Ligo Detectors, Thomas Daniel Abbott

LSU Doctoral Dissertations

This dissertation describes a novel method of analyzing fluctuations in the time-dependent calibration models of the LIGO interferometers to estimate their effect on strain reconstruction for gravitational-wave detections. The time-dependence of the calibration model of each detector is tracked with a set of parameters which are continuously measured while the interferometers are operating. These parameters track slow variations in the sensing function of the detectors as well as the actuators that hold the detectors in an operational state. The time-dependent parameter data during the second observation run (O2 [November 30, 2016 16:00 UTC to August 25, 2017 22:00:00 UTC]) and …


Modeling The Galactic Compact Binary Neutron Star Population And Studying The Double Pulsar System, Nihan Pol Jan 2020

Modeling The Galactic Compact Binary Neutron Star Population And Studying The Double Pulsar System, Nihan Pol

Graduate Theses, Dissertations, and Problem Reports

Binary neutron star (BNS) systems consisting of at least one neutron star provide an avenue for testing a broad range of physical phenomena ranging from tests of General Relativity to probing magnetospheric physics to understanding the behavior of matter in the densest environments in the Universe. Ultra-compact BNS systems with orbital periods less than few tens of minutes emit gravitational waves with frequencies ~mHz and are detectable by the planned space-based Laser Interferometer Space Antenna (LISA), while merging BNS systems produce a chirping gravitational wave signal that can be detected by the ground-based Laser Interferometer Gravitational-Wave Observatory (LIGO). Thus, BNS …