Modelling CO freeze-out and its impact on observational properties of star forming filaments
U Cologne, Cologne, DE
In the past decades more and more elaborated chemical networks have been developed to describe the chemical conditions of star forming regions under various conditions. However, due to their complexity and high computational demands, they have mainly been applied to time-independent configurations. In contrast, the application to time-dependent, magentohydrodynamical (MHD) simulations has been rather limited.
Here, we present simulations of star forming filaments including one of the largest chemical networks ever used in a fully self-consistent, 3-dimensional, MHD simulation. The simulations are performed with the chemistry package
KROME, for which we have contributed in its development. The KROME package is a highly flexible chemistry solver, which can be adapted to a wide range of astrophysical applications. The network used in our simulations accounts for all relevant cooling and heating processes in the ISM and uses 40 thoroughly selected species and about 300 reaction rates. This allows us to described the detailed evolution of various important gas tracers like e.g. CO or HCO+ as well as the evolution of dust. The chemical network is coupled to a simplified radiation transport scheme allowing us to include photochemical reactions as well.
In our presentation we will in particular focus on the effect of CO freeze-out on the thermodynamical properties of star forming filaments. We will discuss how the inclusion of CO freeze-out influences observational properties like filament widths and masses. In this context we will present synthetic observations of several line transitions and continuum emission produced from our simulation data. We will compare them with actual observations, draw some basic conclusions how to interpret modern observations, and present predictions for future observations. We will also briefly discuss the applicability of such large networks in 3D-MHD simulations, in particular with respect to their computational demands as well as the usage on modern supercomputers.
|Caption: Spatial distribution of the abundance of H_2, H, CO, and C for one of the simulated filaments.
S. Walch, U Cologne, DE
A. Sanchez-Monge, U Cologne, DE
T. Grassi, StarPlan, DK
Suggested Session: Filaments