Galactic Scale Flows and the Formatio of Molecular Clouds
Gerardo Ramon Fox
Poster -- Galactic scale ISM and star formation, Molecular clouds and filaments, Star-forming regions
The star formation process is initiated in the large-scale dynamics of a galaxy, with individual star forming events taking place on sub-parsec scales. Gas flows into a spiral arm where shocks are formed. The increase in density, coupled to self-gravity and thermal instabilities, leads to conditions for the formation of molecular clouds. Their internal dynamics drives self-gravitating clumps where star formation occurs on dynamical timescales and the star formation efficiency increases with the density. We present results of high-resolution smoothed particle hydrodynamics and N-body simulations of a model spiral galaxy. The model has a resolution down to 45 solar masses per gas particle and includes a scheme for supernovae feedback. These simulations allow us to study galactic scale flows in a spiral structure that forms self-consistently in a live disc rather than using an imposed potential. We identify the clouds in the simulation and trace their evolution and dynamics. The Lagrangian nature of the code allows us to trace the origin of the gas forming the clouds. We study the cloud’s physical parameters (e. g. mass, radius, velocity dispersion) and the relations between these parameters. We also explore how molecular clouds and star-forming regions relate to the spiral structure of a galaxy. The large-scale galactic structure determines the flows feeding star-forming regions. Understanding this connection will improve our knowledge of the global conditions for star formation.