Abstract
We present a hydrodynamical simulation of a Milky Way-like galaxy, reaching
the resolution of 0.05 pc with a self-consistent description of the galaxy
comprising live stellar and dark matter dynamics. The model includes star
formation and a new implementation of stellar feedback through
photo-ionization, radiative pressure and supernova blasts. The resolution of
the simulation allows us to probe the structure of the interstellar medium down
to the formation sites of individual stars, at subparsec resolution for a few
cloud lifetimes, and at 0.05 pc for about a cloud crossing time. In the full
galactic context, turbulence cascade and gravitation from the kpc scales are de
facto included in smaller structures like molecular clouds, without having to
add them artificially. In this first paper of a series, we present the global
structures of the interstellar medium. In particular, the formation of a bar
influences the dynamics of the central \~ 100 pc by creating resonances that
regulate the fueling of the central black hole. At larger radii, the spiral
arms host the formation of regularly spaced clouds: beads on a string and spurs
form from gravitational and Kelvin-Helmholtz instabilities, respectively. These
instabilities pump turbulent energy in the gas, generally in the supersonic
regime. Because of asymmetric drift due to increased velocity dispersion of
young stars compared to gas, and to galactic rotation, the supernovae explode
outside of their dense gaseous nursery, which diminishes the effect of stellar
feedback on the structure of clouds. The evolution of gas clouds is thus mostly
due to fragmentation and gas consumption, regulated mainly by supersonic
turbulence, while feedback plays a less important role. abridged
Users
Please
log in to take part in the discussion (add own reviews or comments).