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AR 15060 (Archival Research)

Sun Jul 14 04:08:41 GMT 2024

Principal Investigator: Yifan Zhou
PI Institution: The University of Virginia
Investigators (xml)

Title: Unleashing the Charges: An Improved Reduction of Key Exoplanet Datasets and a Tool for Ramp Effect Correction
Cycle: 25

Abstract
Among HST's most lasting and iconic results are WFC3/IR observations of transiting exoplanets that provided exciting insights into atmospheres of planets ranging from super-earths to hot-Jupiters. However, all time-resolved WFC3/IR observations suffer from an often-limiting detector systematic: the "ramp effect." Current efforts are forced to discard orbits most affected and to apply an empirical procedure to minimize the amplitude. We developed and demonstrated a powerful new, solid state physics-motivated detector model that accurately corrects for the ramp effect and reaches essentially photon-noise limited performance for even the most affected orbits. We propose here to apply our RECTE ramp charge trap correction to key archival datasets for which significant improvements are expected. We will also use these datasets to further test and document the RECTE correction on data acquired in different observing modes and to seek further improvements in RECTE's detector parameters. We will document and release RECTE, along with a data reduction cookbook, to the community. We also expect important improvements in the science results from the four key HST datasets. Our charge trap correction will help increasing HST's efficiency for infrared transit spectroscopy by about 20-25% (no more need to discard first orbits), saving dozens of orbits in the future, and will also improve the reliability and reproducibility of infrared time-domain observations. Our work is especially important for the most challenging transit and phase curve observations and will likely provide an example for an approach that can be utilized for JWST instruments with architectures similar to WFC3.