Sarah obtained her Bachelor’s degree in Physics from the University of Copenhagen in 2012, after which she acquired her Master’s and PhD degrees in Astronomy from Columbia University in 2015 and 2018, respectively. Currently, she holds a NASA Hubble Fellowship at New York University, where she studies galactic dynamics, dark matter and the Galactic bar.
Stellar streams emerge, in part, from disrupting clusters of stars. Sarah showed that the shape of the dark matter mass distribution in the Milky Way can be distinguished based on the morphology of stellar streams. Streams spread much further in space on mildly chaotic orbits. Sarah dubbed this mechanism stream-fanning in her Pearson et al. 2015 article in the Astrophysical Journal. In Pearson et al. 2019, Sarah and her collaborators recently demonstrated that thin stellar streams from globular cluster will be observable in at least 200 nearby galaxies with NASA's Nancy Grace Roman Space Telescope.
Sarah has been involved in observational (Pearson et al. 2016, Privon, Pearson+ 2017, Luber, Pearson+ 2021) and theoretical (Pearson et al. 2018, Besla, Pearson+ 2018) studies on the nature of collisions between dwarf galaxies. The motivation for investigating this population of galaxies, is to better understand how galaxies build up their mass in the early Universe, and how they cycle through their matter today.
The Galactic Bar
In recent years, Sarah has become interested in galactic bars. In her Pearson et al. 2017 publication in Nature Astronomy, she showed that bars can punch holes in stellar streams. The signature of those events, is similar to the signature predicted from dark matter subhalos passing close by stellar streams. She is now working on several projects related to understanding the formation and evolution of galactic bars (see e.g. Bonaca, Pearson et al. 2019).