The SILCC (SImulating the LifeCycle of molecular Clouds) project – I. Chemical evolution of the supernova-driven ISM

• Published in: Monthly notices of the Royal Astronomical Society 2015-11, Vol.454 (1), p.238-268
• Main Authors: Walch, S., Girichidis, P., Naab, T., Gatto, A., Glover, S. C. O., Wünsch, R., Klessen, R. S., Clark, P. C., Peters, T., Derigs, D., Baczynski, C.
• Format: Article
• Language: English
• Subjects: Clouds; Discs; Explosions; Formations; Gravity; Magnetic fields; Molecular clouds; Phases; Simulation; Star & galaxy formation; Supernovae; Supernovas
• ISSN: 0035-8711; 1365-2966
• DOI: 10.1093/mnras/stv1975

The SILCC (SImulating the Life-Cycle of molecular Clouds) project aims to self-consistently understand the small-scale structure of the interstellar medium (ISM) and its link to galaxy evolution. We simulate the evolution of the multiphase ISM in a (500 pc)2 × ±5 kpc region of a galactic disc, with a gas surface density of $\Sigma _{_{\rm GAS}} = 10 \;{\rm M}_{\odot }\,{\rm pc}^{-2}$ . The flash 4 simulations include an external potential, self-gravity, magnetic fields, heating and radiative cooling, time-dependent chemistry of H2 and CO considering (self-) shielding, and supernova (SN) feedback but omit shear due to galactic rotation. We explore SN explosions at different rates in high-density regions (peak), in random locations with a Gaussian distribution in the vertical direction (random), in a combination of both (mixed), or clustered in space and time (clus/clus2). Only models with self-gravity and a significant fraction of SNe that explode in low-density gas are in agreement with observations. Without self-gravity and in models with peak driving the formation of H2 is strongly suppressed. For decreasing SN rates, the H2 mass fraction increases significantly from