SH048-0010
New Methods for Solar Hard X-ray Imaging Analysis with the FOXSI Sounding Rocket Experiment

Wednesday, 16 December 2020
Poster
Juliana Therese Vievering1, Lindsay Glesener2, P. S. Athiray3, Juan Camilo Buitrago-Casas4, Sophie Musset5, Daniel Ryan6, Shin-nosuke Ishikawa7, Shin Watanabe8, Tadayuki Takahashi9, Jessie McBrayer Duncan10, Steven Christe6 and Sam Krucker11,12, (1)University of Minnesota, Minneapolis, MN, United States, (2)University of Minnesota, Twin Cities, MN, United States, (3)Universities Space Research Association Huntsville, Huntsville, AL, United States, (4)Space Sciences Laboratory, Berkeley, CA, United States, (5)University of Glasgow, Glasgow, G12, United Kingdom, (6)NASA GSFC, Solar Physics Lab, Greenbelt, MD, United States, (7)Rikkyo University, Graduate School of Artificial Intelligence and Science, Tokyo, Japan, (8)ISAS Institute of Space and Astronautical Science, Kanagawa, Japan, (9)University of Tokyo, Kavli IPMU, Kashiwa, Japan, (10)University of Minnesota Twin Cities, Minneapolis, MN, United States, (11)UC Berkeley, Space Science Lab, Berkeley, CA, United States, (12)University of Applied Sciences and Arts Northwestern Switzerland, Windisch, Switzerland
Abstract:
Spectroscopic imaging in the hard X-ray (HXR) regime is essential for investigating the sites of energy release and transfer in solar flares, as HXRs provide insight into the acceleration of electrons and plasma heating. The Focusing Optics X-ray Solar Imager (FOXSI) sounding rocket experiment is the first solar-dedicated direct imager for HXRs and offers unprecedented capabilities for high-energy imaging spectroscopy of flares. Through use of grazing incidence optics, FOXSI achieves greater sensitivity and imaging dynamic range than its esteemed predecessor, the Reuven Ramaty High-Energy Solar Spectroscopic Imager (RHESSI), which was limited by the high background inherent to its indirect imaging technique. Additionally, FOXSI improves upon the Nuclear Spectroscopic Telescope Array (NuSTAR) with an angular resolution at scales relevant for studying flares and a higher detector throughput for measuring solar sources. Here we demonstrate the power of these enhanced capabilities through imaging analyses of two sub-A class microflares observed by the second FOXSI sounding rocket (FOXSI-2) on December 11, 2014. We apply a custom FOXSI image deconvolution method using a maximum likelihood procedure to explore the changing morphology of these small scale-events and compare the results to features observed in contemporaneous data from the Solar Dynamics Observatory Atmospheric Imaging Assembly (SDO/AIA). Additionally, we perform imaging spectroscopy to study the spatial complexity of energy release in these microflares and assess whether they are more similar in evolution to large flares or nanoflares.
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