Michal Was – HDR’s defense – Nov. 23, 2023 – 10AM

Gamma-ray bursts and gravitational waves at audio frequencies have long been thought to have common astrophysical origins. This has been confirmed with the joint observation of GW170817 and GRB 170817A due to the merger of two neutron stars. This exceptional event has confirmed expectations, but also proved to be an extremely powerful and precise test of general relativity. It was at the origin of observation of afterglow emission at all electromagnetic wavelength with time evolution observed at the second, hours, days and months time scales. To make this and future observation possible, gravitational wave detector noise instrumental noise needs to be understood. There are many source, in particular I describe in more detail the noise of monolithic optical filter cavities, radio-frequency modulation sideband amplitude, radio-frequency digital demodulation, laser frequency and light back-scatter. The last one is often considered unpredictable, but with a detailed study it can be in fact precisely modeled and even used to calibrate gravitational wave detectors.