Making electromagnetic follow up of gravitational waves even harder - data quality challenges in LIGO and LISA

Laura Nuttall (Portsmouth)

There have been ~200 candidate gravitational-wave events identified by LIGO, Virgo and KAGRA in the current observing run O4. We are seeing gravitational waves almost every day! Transient gravitational-wave detector noise can mask or mimic a real gravitational wave, and certain forms of noise can bias the estimation of key parameters of the gravitational wave signal, such as its sky localisation. With the increase in detectable gravitational waves comes the added challenge that more events are overlapping with instrumental noise. In fact around a quarter of gravitational wave events have some form of instrumental noise in their analysis window. In this talk, I will discuss some of the challenges and mitigation strategies LIGO uses to deal with bad data quality and how this can hamper efforts to find an electromagnetic counterpart. I will also discuss the challenges in the detection and inference of massive black hole binaries that we expect to detect with LISA, and what this means for finding the electromagnetic counterpart from the collision of two supermassive black holes.