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Abstract: Supernova explosions drive shocks into the surrounding interstellar medium (ISM) heating it to high temperatures. Centuries to millennia after the explosion, the shock-excited gas emits copiously at optical wavelengths, and it is these emitting nebulae that we know as supernova remnants (SNRs). One of the best known and best studied SNRs, which often serves as a textbook example, is the Cygnus Loop. In this talk I will present the results of a temporal study based on HST narrowband images, obtained about two decades apart, of a faint shock front that lies along the north-east limb of the Cygnus Loop. I will describe the background and context for our study and highlight how HST and other telescopes have opened up new vistas for the exploration of SNR shocks and their impact on the ISM.

Bio: Ravi Sankrit obtained his PhD from Arizona State University, working on some of the early narrowband images obtained with HST/WFPC2, including those of the Crab Nebula and the Eagle Nebula (the original "Pillars of Creation" image). He then moved to the Johns Hopkins University as a post-doctoral fellow, and stayed on for several years as part of the Far-Ultraviolet Spectroscopic Explorer (FUSE) science team. After FUSE, Ravi moved across the country to work at the Space Sciences Laboratory (UC Berkeley) and then at the SOFIA Science Center in Moffett Field, California. He came back to Baltimore in 2017 and has since been an Instrument Scientist on the Cosmic Origins Spectrograph (COS) team. He studies emission line nebulae - from the compact regions around symbiotic stars to large-scale superbubbles, with a particular focus on supernova remnants.

We Need You - to attend our Jan. 16th General Meeting (in person or via Zoom) to vote for HAL officers. Better yet, consider running for a HAL leadership position.

Abstract: Producing optimized and accurate transmission spectra from telescope data is a manual and labor-intensive process. Using artificial-intelligence-based processing, we automate and optimize the data reduction and model-fitting required for processing light curves and spectroscopic data from exoplanet transits with the Eureka! pipeline for Hubble Space Telescope (HST) observations.

Using AI-based processing of HST transit observations, we present a standardized, homogeneous survey of exoplanet atmospheres. Spanning a range of exoplanet-types from hot Jupiters to sub-Neptunes, this AI-enabled science provides one of the most comprehensive surveys of exoplanet atmospheres to date. Using this tool to perform large-scale, data-driven comparative exoplanetology, we have identified long-sought after trends in cloud-formation for both the Jovian and Neptune/sub-Neptune regimes of exoplanets.

Bio: Reza is an exoplanet astronomer at The Johns Hopkins University Applied Physics Laboratory. He received his PhD in Electromagnetics from Auburn University in 2016 and has served various science and engineering roles since starting at APL in 2016. His work focuses on exoplanet atmospheres & magnetic fields using ground and space-based telescopes (from optical to radio), technosignatures, and extending NASA's Deep Space Network capability. He has served various roles on NASA’s New Horizons, Dragonfly and Interstellar Probe missions.