The Discovery, Follow-up, and Implications of Electromagnetic Counterparts to BNS Mergers

On August 17th, 2017, the field of multi-messenger, gravitational-wave, astronomy was born. On this date, Advanced LIGO and Advanced Virgo observed gravitational waves from the coalescence of a neutron star binary with a false alarm probability of 1 per 10000 years and counterparts were subsequently identified across the entire electromagnetic spectrum. Now, in April 2019, LIGO/Virgo Observing Run 3 will commence, with the expectation of many more multi-messenger detections. In this talk, I will give a broad review of the electromagnetic emission associated with the the binary neutron star (BNS) merger, GW170817. I will describe the process of the discovery and localization of the counterparts, review the extensive follow-up observations obtained, and place these observations in context. I will discuss the implications of these observations on our understanding of topics ranging from the ejecta from neutron star mergers and the origin of r-process elements to the nature of gamma-ray bursts. Finally, I will give prospects for LIGO/Virgo O3 and describe how the identification of populations of electromagnetic counterparts to BNS mergers will allow us constrain the neutron star equation of state and the expansion of the universe.