FLiTs ray-tracer

ProDiMo can perform line radiative transfer when the line emissions do not overlap in wavelength. The computation is carried-out line by line. In the mid-IR, molecular line emissions can overlap. Therefore, another code is needed to compute the spectra.

FLiTs is a code written by Michiel Min [http://www.michielmin.nl] and is described in Woitke et al. 2018. The code generates a spectrum within a requested wavelength range accounting for the transitions that are present within the range, especially, line overlaps are computed.

If you want to use his code together with ProDiMo, the code is available at https://github.com/michielmin/FLiTs

In Makefile, you need to set the path to your local cfitsio library (the same than for ProDiMo). For example: LIBS = -L\path_to_cfitsio\lib\ -lcfitsio

The command at the prompt

> make multi=true

will compile the code in parallel (openmp) mode.

In the "Parameter.in" file, we can add the switch:

.true. ! FLiTs

ProDiMo will write to the current location all the spectroscopic and collisional data need to run FLiTs''. All the level populations are written onto ProDiMoforFLiTs.fits.gz.

Once you have this file, you can restart a larger grid using the smaller grid population:

.true. ! population_restart

If you have a model ready and want to use FLiTs:

.true. ! immediate_FLiTs

The disk model (gas temperature, dust temperature, chemical abundances) is frozen. Just the level populations are recomputed and the files needed to run (FLiTs) are generated.

FLiTs comes with it own manual. The simplest way to run at the prompt is 

> path_to_FLiTs\FLiTs inputFLiTs.dat

The path is not needed if the path is in the bash/csh/tcsh file.

ProDiMo will quickly go through the disk and calculate all the level populations required.

One can also modify the inputFLiTs.dat file to remove transitions from species since each transition is treated individually by the code so the runtime depends a lot on the number of transitions requested.

Prodimopy will read the FliTs output spectrum if present when a ProDiMo model is read. Prodimopy also provides tools to convolve the spectrum to the desired spectral resolution (R)

Here is an example in the Woitke et al. 2018 paper:

FLiTs_paper_fig2

Reference - Woitke, P. et al. 2018 A&A, 618, 18