This book employs sophisticated statistical and computational techniques, including machine learning, to characterize the spectra of electromagnetic counterparts to gravitational wave sources. Specifically, the author studies the explosions associated with neutron star collisions called kilonovae, developing the SPARK tool to infer rapid neutron capture (r-process) abundance patterns and offer insight into the production of heavy elements in the Universe. The innovative methods implemented by the author in SPARK are insightful for characterizing spectra from the first neutron star merger, GW170817, and will be essential for understanding the properties of the broader population of kilonova explosions. SPARK is thus poised to become a high impact, open-source tool, making this thesis essential reading for the astrophysics research community.

Dr. Nicholas Vieira is an astrophysicist studying energetic explosions in space. He is particularly interested in the mergers of binary neutron star systems, which emit gravitational waves and produce kilonovae: optical transients marked by the nucleosynthesis of the heaviest elements. 

Vieira was born and raised in Montréal, Québec, Canada. He first pursued research in 2018, as an undergraduate at McGill University, with two projects: searching for interesting behavior in the optical light curves of X-ray binary systems of black holes and stars, under the supervision of Dr. Daryl Haggard, and attempting to infer the surface albedo of exoplanets, under Dr. Nicolas Cowan. He started graduate studies at McGill under the supervision of Dr. Daryl Haggard and Dr. John Ruan in 2019. In August 2019, he led a campaign searching for a kilonova counterpart to the first neutron star - black hole merger, GW190814. Continuing graduate school, he developed the tool Spectroscopic r-Process Abundance Retrieval for Kilonovae (SPARK) for inferring the abundances of heavy elements synthesized by rapid neutron capture (the r-process) in kilonovae. He published three papers on SPARK throughout his graduate studies, inferring for the first time the element-by-element composition of the GW170817 kilonova. 

Vieira is currently a Natural Sciences and Engineering Research Council of Canada (NSERC) Postdoctoral Scholar working at the Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA) at Northwestern University in Evanston, Illinois. He works on the Tool for Rapid Object Vetting and Examination (TROVE): a critical piece of software infrastructure which will enable future multi-messenger detections of binary neutron star mergers in both gravitational waves and light.