EPoS Contribution
EPoS Contribution
Structure and Dynamics of Filaments and Clumps in Giant Molecular Clouds

Michael Butler
UZH, Zurich, CH
We present hydrodynamic simulations of self-gravitating dense gas in a galactic disk, exploring scales ranging from 1 kpc down to ~0.1 pc. Our primary goal is to understand how dense filaments, clumps and cores form in Giant Molecular Clouds (GMCs). These structures are thought to be the precursors to massive stars and star clusters, so their formation may be the rate limiting step controlling global star formation rates in galactic systems as described by the Kennicutt-Schmidt relation. Our study follows on from an earlier study, which carried out simulations to 0.5 pc resolution and examined global aspects of the formation of dense gas clumps and the resulting star formation rate. Here, using our higher resolution, we examine the detailed structure and kinematics of dense filaments and clumps within the GMCs. This includes examining the column density probability distribution functions of the regions containing the filaments, the separation of clumps along filaments and the velocity gradients of the filaments. We also consider the dynamical state of the filaments. These properties are then compared to observations of dense clumps and filaments within Galactic GMCs, in particular via studies of Infrared Dark Clouds (IRDCs). We find that while a number of the properties of the simulated clouds are similar to observed systems, the overall densities and star formation rates in the simulation are much higher. Also the kinematics of the simulated structures are much more disturbed, with large velocities and velocity gradients produced during global collapse. We expect that dynamically important magnetic fields are needed to bring the simulated structures into better agreement with observed clouds. Mechanical and radiative feedback is not likely to be that important for influencing IRDC structures, but may be needed to inhibit and regulate the global star formation rate.
Caption: Density projections, from top to bottom, along the x, y, and z axes of our sample of four simulated filaments. Each box is 50 pc3.
Collaborators:
J.C. Tan, UF, US
S. van Loo, Harvard CfA, US
R. Teyssier, UZH, Switzerland
Key publication

Suggested Sessions: Filaments