Simulating Star Formation on Small and Large Scales: the Prestellar Core Mass Function and Chemistry in Molecular Clouds

Munan Gong (Princeton) - May 8 at 12:10 pm (Room 121)

Numerical simulation is a powerful tool for studying star formation, where the interplay of many processes, such as turbulence, gravity and chemistry takes place. In this presentation, I will discuss two topics in star formation simulation. First, I will present our study on the relation between the core mass function (CMF) and the initial mass function (IMF). We investigated the collapse of prestellar cores from gravitational fragmentation of turbulent converging flows, using three dimensional hydrodynamic simulations. We reproduced the CMF inferred from Herschel observations. However, the CMF can not simply be translated to the IMF: A significant fraction of low mass cores are gravitationally stable and will not collapse to form protostars; and moreover, without feedback, protostars in our simulations accrete many times the initial core mass from the surrounding dense filaments. Second, I will discuss the role of chemistry in molecular clouds. Although solving the time-dependent chemistry is necessary for accurate abundances and temperature in the dynamic interstellar medium (ISM), a full chemical network is too computationally expensive to incorporate in numerical simulations. To solve this problem, we have developed and tested a new simplified chemical network suitable for simulations of atomic and molecular ISM. Applying this network to large scale ISM simulations, we produced synthetic CO maps, and investigated the X_CO conversion factor in molecular clouds.

The seminar will be held in 131A Campbell Hall.

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