(D. B. Fox, A. Keivani, D. F. Cowen, K. Murase, M. Mostafa, J. J. DeLaunay, H. A. Alaya Solares)
We have been seeking to identify individual sources or subthreshold source populations of high-energy neutrino + gamma-ray ("nu+gamma") emitting transients by coincidence analysis of Fermi LAT gamma-ray and high-energy neutrino datasets. I will present our published analysis of public IceCube + Fermi LAT data which has demonstrated our approach and provided our first results. Although we identify no single high-confidence transients nor evidence of a subthreshold source population, we do find a possible (p=7.0%) correlation between IceCube (59-string) neutrino positions and persistently bright portions of the Fermi LAT sky; we plan to explore this possible correlation in future work. We have since extended and applied our approach to the full 8-year ANTARES neutrino dataset, and have begun implementation and deployment of the first real-time nu+gamma (candidate) transient alerts via the Astrophysical Multimessenger Observatory Network (AMON). Monte Carlo simulations confirm that our alerts are capable of triggering on single-neutrino (ANTARES or IceCube) coincidences with high-multiplicity Fermi LAT sources, including LAT-detected gamma-ray bursts. I will present the latest results of these archival and real-time multimessenger transient searches.