Presentation #241.35 in the session Evolution of Galaxies — iPoster Session.
In the hierarchical paradigm of galaxy formation, massive galaxies like the Milky Way (MW) and Andromeda (M31) are built up over time partially through the accretion of smaller galaxies. By studying the remnants of these accreted galaxies, we can not only learn both about the mass assembly of the main host galaxy, but also about the properties of the accreted galaxies. Tidal streams are formed when an accreted galaxy is tidally disrupted, and one way we can constrain the mass of the tidal stream progenitor is to measure the metallicities of its stars. However, some streams have been observed to have metallicity gradients such as the Giant Stellar Stream (GSS) in M31 (Escala et al. 2021) as well as in the Sagittarius Stream (Sgr) in the MW (Hayes et al. 2020). If a stream has a metallicity gradient, the mean metallicity we measure will be dependent on what portion of the stream is observable. For example, much of the GSS is obscured by the disk of M31. We are using simulated MW-mass galaxies from the FIRE-2 suite to quantify the relationship between observed metallicity gradients in streams at present day and the metallicity gradients and total masses of their progenitors.