UNC-CH Physics and Astronomy Thesis Proposal Presentation

Hank Corbett

“The Evryscope Fast Transient Engine: Real-Time Transient Discovery for the Evryscopes”

Astrophysical transients with rapid development on sub-hour times are both intrinsically rare and difficult to both identify and follow up spectroscopically on timescales comparable to their lifetime. Such events include superflares on cool stars, optical flashes from gamma-ray bursts, shockwave breakout in young supernovae, and potentially new-classes of exotic transients. I have developed the Evryscope Fast Transient Engine (EFTE), a data reduction pipeline designed to provide low-latency transient alerts from the Evryscopes, a north-south pair of of ultra-wide-field telescopes with an instantaneous footprint covering 38% of the sky. EFTE uses a simple, efficient image subtraction routine suited to continuously monitoring the transient sky at minute cadence. Candidates are reported within the base Evryscope two-minute cadence for 98.5% of images, and those that pass a series of automated vetting checks are reported to users for verification and optionally for delegation to followup resources. In work completed to-date, I have used EFTE to produce the first empirical measurements of the rate of sub-second, star-like reflections from objects in Earth orbit, which have historically caused false alarms for transient surveys. We measure a rate orders of magnitude higher than the combined rate of public alerts from all active all-sky fast-timescale transient searches, including neutrino, gravitational-wave, gamma-ray, and radio observatories. Going forward in my dissertation research, I will characterize early discoveries from EFTE using additional data from the Goodman High-Throughput Spectrograph on the SOAR 4.1-meter, and perform a joint search for sub-hour duration transients using simultaneous data from the NASA Transiting Exoplanet Survey Satellite (TESS).