Gregory M. Harry

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We report on thermal noise from the internal friction of dielectric coatings made from alternating layers of Ta 2 O 5 and SiO 2 deposited on fused silica substrates. We present calculations of the thermal noise in gravitational wave interferometers due to optical coatings, when the material properties of the coating are different from those of the substrate(More)
Current interferometric gravitational wave detectors use test masses with mirror coatings formed from multiple layers of dielectric materials, most commonly alternating layers of SiO 2 (silica) and Ta 2 O 5 (tantala). However, mechanical loss in the Ta 2 O 5 /SiO 2 coatings may limit the design sensitivity for advanced detectors. We have investigated(More)
Gravitational waves are a prediction of Einstein's general theory of relativity. These waves are created by massive objects, like neutron stars or black holes, oscillating at speeds appreciable to the speed of light. The detectable effect on the Earth of these waves is extremely small, however, creating strains of the order of 10(-21). There are a number of(More)
Gamma-ray bursts are believed to originate in core-collapse of massive stars. This produces an active nucleus containing a rapidly rotating Kerr black hole of mass M H and angular velocity Ω H ≃ 1/2M H , surrounded by a uniformly magnetized torus of angular velocity Ω T = ηΩ H represented by two counter-oriented current rings. We quantify black hole-spin(More)
Second-generation interferometric gravitational-wave detectors will operate at temperatures noticeably above room temperature. Study was done to determine what effect elevated temperatures would have on the Q and coating thermal noise of the detector mirrors. Results show that increased temperature increases loss angle in a manner that is more significant(More)
The Big Bang Observer is a proposed space-based gravitational-wave detector intended as a follow on mission to the Laser Interferometer Space Antenna (LISA). It is designed to detect the stochastic background of gravitational waves from the early universe. We discuss how the interferometry can be arranged between three spacecraft for this mission and what(More)
We report on results of computer simulations of spherical resonant–mass gravitational wave antennas interacting with high–frequency radiation from astronomical sources. The antennas were simulated with three–mode induc-tive transducers placed on the faces of a truncated icosahedron. Overall, the spheres were modeled with a sensitivity of about three times(More)
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