4-8 October 2015
Hans Harnack Haus
Europe/Berlin timezone
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Contribution Contributed Talk

Hans Harnack Haus -
FROM CLOUDS TO DENSE CORES 1

Modelling the detailed chemical evolution in 3-dimensional, simulations of star forming filaments

Speakers

  • Dr. Daniel SEIFRIED

Primary authors

Co-authors

Content

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 one-zone models or static 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 (www.kromepackage.org), 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. Moreover, using 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 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.

Furthermore, we will present which impact the interstellar radiation field as well as cosmic rays have on the detailed chemical composition during the collapse of filaments. We will also describe the thermal evolution of gas and dust in an unprecedented manner. Both, the chemical evolution as well as the thermodynamical evolution are necessary for producing reliable predictions for modern observations. 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.

Spatial distribution of H, H_2, C, and CO in a star forming filament