Type: Talk
Session: Microlensing
Author: Natasha Abrams

Abstract: Microlensing events have historically been discovered throughout the Galactic bulge and plane by surveys designed solely for that purpose. We conducted a multi-year search for microlensing events on the Zwicky Transient Facility (ZTF), an all-sky optical synoptic survey that observes the entire visible Northern sky every few nights. We discovered 60 high quality microlensing events in the three years of ZTF-I using the bulk lightcurves in the ZTF Public Data Release 5. 19 of our events are found outside of the Galactic plane (|b| > 10°), nearly doubling the number of previously discovered events in the stellar halo from surveys pointed toward the Magellanic Clouds and the Andromeda Galaxy. We investigate why a high fraction of events were found outside of the Galactic plane including the following possible explanations: degraded photometry in crowded fields, airmass effects on photometry, systematic contamination in out-of-plane microlensing identification, or a true excess of out-of-plane microlensing. We will discuss the implications this has for Rubin crowded field photometry and microlensing identification pipelines.