Fermi Gamma-ray Space Telescope

Seeking Multimessenger Transients: Archival Searches and Prompt Alerts for Cosmic Fermi LAT Photon + High-Energy Neutrino Emitting Sources

Colin Turley
(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.