The IMACS Occultation Survey: II. An Extended Campaign

We report the results of our extended campaign to search for occultations of background stars by small (sub-km) Kuiper belt objects (KBOs) using the IMACS instrument on the Magellan Telescope. Previously, we implemented a novel shutterless continuous readout mode on the IMACS instrument, able to obtain high-speed photometry on multiple stars, simultaneously generating light curves for all targets with a 36 Hz cadence. Following our pilot study, we extended our observational campaign, improving our target selection methodology such that we can now simultaneously monitor thousands of stars in a crowded field-of-view. We were granted approximately 60 hrs observing time on Magellan in 2014, allowing us to increase our observational data set by almost an order of magnitude, giving us an inticipated 100,000 star-hours of light curves with per-point SNR > 10. We expect that these observation will result in the first ground-based detections of occultations by sub-km objects in the Kuiper-Belt, allowing us to verify and improve upon the sky plane density of sub-km diameter KBOs implied by the HST FGS detections reported by Schlichting et al. (2009, 2012).