SimLine

SimLine - Radiative transfer in molecular lines

SimLine is a FORTRAN code to compute the profiles of molecular rotational transitions and atomic fine structure lines in spherically symmetric clouds with arbitrary density, temperature and velocity structure. The radiative transfer code is described in detail in Ossenkopf, Trojan & Stutzki (2001). It participated in the radiative transfer comparison benchmark described by van Zadelhoff et al. (2002).

The code is designed towards a maximum flexibility and very high accuracy based on a completely adaptive discretization of all quantities. The code can treat arbitrary species in spherically symmetric configurations with arbitrary velocity structures and optical depths between about -5 and 5000. Moreover, SimLine includes the treatment of turbulence and clumping effects in a local statistical approximation combined with a radial dependence of the correlation parameters.

In the adaptive numerical discretizations the user has full error control and the line profiles may be computed in almost arbitrary accuracy. An accelerated lambda iteration is used to solve the equation system. The input of physical cloud parameters, telescope parameters, and numerical control parameters may be done either interactively or as file input. Molecular data are read from table files.

The code consists of two parts: the self-consistent solution of the balance equations for all level populations and energy densities at all radial points and the computation of the emergent line profiles observed from a telescope with finite beam width and arbitrary offset.

The latest source of the code can be found at the FTP directory A detailed manual describing the interfaces and program structure is available as PDF file. If you have used an earlier version of SimLine, have a look at the list of recent changes.

Created: Dr. V. Ossenkopf
Last change: 03/13/2012

SimLine - Radiative transfer in molecular lines