Fermi National Accelerator Laboratory

Time-dependent star formation in ART
Blake Wetherton, University of Wisconsin-Madison
Practicum Year: 2017
Practicum Supervisor: Nickolay Gnedin, Scientist II, Particle Physics, Fermi National Accelerator Laboratory
For this project, a time-dependent phenomenological model of star formation was implemented in the ART code. The model is based on work by Lee et al (2016) in which the time dependent model is proposed to explain the broad spread in observed star formation efficiencies across molecular gas clouds. The algorithm implemented in ART treats molecular gas clouds (generally the breeding grounds for stars) and stars alike as particles, evolving both stellar and molecular masses via an explicitly time-dependent differential equation, and is eventually intended for cosmological simulations where stars and molecular gas clouds alike cannot be resolved in the simulation. The evolution of the differential equation continues for a specified period, after which the molecular gas cloud explodes by injecting its molecular mass back into the ambient medium at a higher temperature; the particle is treated as a normal star particle thereafter. The algorithm was implemented in ART and preliminary parameter sweeps were made to try to match observational distributions of star forming efficiency. Results so far are mixed, with hope that a suitable set of parameters will soon be identified to match several observational constraints.