Understanding the Spectra of Accreting Substellar Objects: Observation and Data Reduction using PypeIt

The empirical mass vs. mass accretion relationship has been studied in the stellar mass regime for decades. However, this relation is not well understood at substellar masses. By measuring mass accretion rates for brown dwarfs, we aim to fill the substellar accretion rate space and establish the relationship between mass and mass accretion rate for brown dwarfs. This relationship is important for determining the formation and accretion mechanisms of brown dwarfs, as it is unclear whether these mechanisms are similar to those of planets or stars. Having a better comprehension of accretion at substellar masses will create a bridge between the planetary and stellar regimes, advancing our understanding of planet formation. In June of 2021 and January of 2022, we observed remotely using the LRIS instrument at Keck I to obtain spectroscopic data of five different young brown dwarf targets in the Upper Centaurus Lupus, Upper Scorpius, and Taurus star-forming regions. The wide spectral coverage of 0.3-1 micron makes LRIS an ideal instrument to obtain an accretion rate estimate for brown dwarfs using near-ultraviolet accretion continuum excess spanning the Balmer jump at 3646 Å, one of the most reliable tracers of an object’s mass accretion rate. The new data reduction pipeline, PypeIt (Prochaska et. al 2020), is a semi-automated spectroscopic data reduction pipeline that has previously been used to reduce LRIS data. In this project, I discuss the process of using PypeIt for LRIS spectroscopic data reduction, and we present preliminary reduced spectra for our new accreting brown dwarf sample.