# Nuclear Spirals in the inner Milky Way

## TL;DR

This paper uses hydrodynamical simulations to model the gas flow in the Milky Way's Central Molecular Zone, revealing nuclear spiral arms and their relation to observed molecular structures, consistent with larger scale galactic flow.

## Contribution

It presents a new hydrodynamical simulation-based model linking observed molecular structures to nuclear spiral arms in the Milky Way's center.

## Key findings

- Identification of nuclear spiral arms in the CMZ.
- Consistency of the model with observed molecular clouds.
- Alignment of the model with large-scale galactic gas flow.

## Abstract

We use hydrodynamical simulations to construct a new coherent picture for the gas flow in the Central Molecular Zone (CMZ), the region of our Galaxy within $R\leq 500\, \mathrm{pc}$. We relate connected structures observed in $(l,b,v)$ data cubes of molecular tracers to nuclear spiral arms. These arise naturally in hydrodynamical simulations of barred galaxies, and are similar to those that can be seen in external galaxies such as NGC4303 or NGC1097. We discuss a face-on view of the CMZ including the position of several prominent molecular clouds, such as Sgr B2, the $20\,{\rm km\, s^{-1}}$ and $50\,{\rm km\, s^{-1}}$ clouds, the polar arc, Bania Clump 2 and Sgr C. Our model is also consistent with the larger scale gas flow, up to $R\simeq 3\,\rm kpc$, thus providing a consistent picture of the entire Galactic bar region.