Alan Vasquez Soto

Zoom link: https://unc.zoom.us/j/98720473954

Title: 

Exploring the Fast Transient Optical Sky & Developing New Technologies for the Argus Array

Abstract:

Time-domain surveys like ZTF, ASAS-SN, and PanStarrs have discovered myriad phenomena, such as supernovae evolving on day-to-month timescales. These systems achieve nightly to weekly full-sky cadence by observing individual tiles and periodically revisiting previously observed areas, but they can miss transients evolving at faster rates or occurring outside their field of view (FoV). Reaching these rapid, rare transients requires surveying the entire sky simultaneously. The Evryscope follows this approach, with a northern and southern pair of telescopes surveying the sky above the horizon every two minutes. With the Evryscopes and the Evryscope Fast Transient Engine (EFTE), we characterized a category of rapid transients produced by glints from objects in Earth orbit; this foreground fog of flashes pollutes alerts from stellar flares, optical counterparts to gamma-ray bursts, and other fast optical signals. I present an analysis of orbital regions occupied by these impostors and a potential framework to discriminate them from astrophysical events with similar imprints in astronomical images. In over 2.4 × 106 EFTE detections between late 2019 and mid-2022, I found over 12,000 objects producing these glints. Over 90% reside in low Earth orbit (LEO) and medium Earth orbit (MEO) and form a foreground of false-positive detections in upcoming surveys searching for fast transients. Moving to the next generation of surveys, the Argus Array is an all-sky system that multiplexes 900 telescopes onto a single mount. With arcsecond-scale sampling, sCMOS detectors, and wide-field optics, Argus can reach extragalactic transients. However, with resolution nearing seeing-limited performance, Argus is physically orders of magnitude larger than Evryscope. This necessitates a custom mount capable of supporting and tracking 900 telescopes, while maintaining their optics presents a challenge equivalent to servicing every currently operational robotic telescope combined. I present solutions to these challenges, implemented in the Argus Pathfinder Array. This scaled prototype demonstrates how to construct and maintain an Argus Array. I detail our new pseudofocal telescope design, reducing the maintenance overheads when operating hundreds of individual telescopes to initial commissioning. I also present scalable motion control systems driving current designs for the Argus Array. This work concludes with early performance results from Argus Pathfinder.