We construct a model for the Milky Way where the interstellar Medium (ISM) is
equipped with self-consistent dynamics. Constructing models with
self-consistent dynamics is a challenging mathematical task and we developed a
new, fixed-point like algorithm to do so. In simulations a spiral structure
emerges from this model that is almost identical with the one in the Milky
Way’s ISM. Further, the Jeans instability offers an explanation for the
observed velocity dispersion of atomic hydrogen in the ISM; this instability
vanishes from our model if we choose a velocity dispersion just above the
observed one. Our model uses baryonic, dark matter, which resides in the disc
and is dynamically cold; it is a typical example for the Bosma effect.
