Spiral Structure on FIRE

The structure of spiral galaxies plays an integral role in understanding galactic dynamics and evolution; however, the precise nature of spiral arms still remains uncertain. We face two significant obstacles when attempting to characterize spiral structure: understanding the interconnectedness between spiral arms and the larger galactic environment and constraining the time-evolution. We address these problems by studying spiral arms using the Latte suite of FIRE-2 (Feedback in Realistic Environments) simulations. The Latte suite of Milky Way-mass galaxies have high spatial resolution (2 pc) over a large dynamic range (Mpc) which allows us to bridge interactions between small scale components, such as star clusters and giant molecular clouds, with large scale components, such as spiral arms, bars, warps, and infalling satellites. In this work, we present a first analysis characterization of the spiral structure in Latte. We classify the dominant modes in 3 Latte disks (m12i, m12f, and m12m) using Windowed Fast Fourier Transform (WFFT) spectral analysis. Our initial results consider how the strength, speed, and persistence of spiral arms vary across these systems over 8 Gyr in each simulation. This work provides a basis for understanding the impact that infalling satellites have on the formation of spiral arms and the influence that transient spiral arms have on stellar radial migration.