The Radcliffe Wave on FIRE: Hunting for Sinusoidal ISM Gas Structures in Simulated Milky Way Disks

The distribution of gas and young stars near the Sun can tell us important information about the formation of molecular clouds and stars in the Milky Way. However, this distribution has been difficult to constrain observationally due to poor distance estimates. Thanks to recent 3D dust mapping, which leverages Gaia and other extensive photometric surveys, we can now map the distances and 3D distribution of molecular clouds more precisely than ever before. Recently, it was discovered that most of the star-forming regions are part of a large sinusoidal structure of gas and young stars, called the Radcliffe Wave, that extends ~2.7 kpc and oscillates above and below the midplane of the Milky Way disk. Observations of the Gould Belt - a partial ring of young stars surrounding the Sun, thought to be ~1 kpc in diameter and tilted ~20⁰ to the Galactic plane - previously had been assumed to be a coherent arrangement of young stars of a common origin and distance. However, the recent discovery of the Radcliffe Wave challenges the Gould Belt as it proposes the idea of a projection effect of the sinusoidal wave appearing like a partial ring. In this work, we use Milky Way-like galaxy simulations drawn from the Latte suite of FIRE-2 disks to hunt for similar structures and investigate their origins. In an initial analysis, we uncover analogous sinusoidal gas structures of similar amplitude and length as the Radcliffe Wave. In particular, we consider how an infalling satellite galaxy into a Milky Way-like halo can modify gas distribution through gravitational interactions with the disk. We discuss the frequency of finding Radcliffe Wave-like structures across all 15 FIRE-2 Latte simulations.