In the following, cloud unit refers to spatial coordinates in which the extent of the cloud is one unit.
The recognized key-words:
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
=== A ===
- read from the specified file the grid IDs for which ALI is enabled
- #=0: cell emission (with cellpackages<0) is weighted by the total emission from the cell. #=1: emission is weighted by the sqrt of the cell emission. Default=0.
=== B ===
=== C ===
- For the simulation of the emission from the medium, number of generated photon packages per cell. Positive numbers: the same given number of packages from every cell. Negative numbers: the number of packages is weighted by the total emission from the cell, with abs(#) packages per cell on average. See also autoweight.
- Calculate column density map. No emission map or radiation field simulation is performed. With the optional parameter, save a map of the optical depth at the given frequency (Hz) instead of the column density (assumes constant dust abundances).
- Only one in (refinement factor)^2 rays from a subgrid to the parent are retained (i.e. Russian roulette at borders with a probability of (1-rf^2)/rf^2 of terminating the path). Should be used with dividerays.
- Specifies the prefix in the name of the hierarchy files and the grid files.
=== D ===
- Density values in the grid files are multiplied with this value before calculations.
- Diffuse volume emission (photons/cm^3) is read from .diffuse files and included in the emission. The optional number can be used to multiply the emission by a constant factor.
- Specifies the number of ray directions used in the calculation of the internal radiation field. The number is the number of rays through each cell.
- Rays entering a subgrid are divided to (refinement factor)^2 packages to improves sampling. Should be used with combinerays.
- Temperature cubes are saved for each iteration. Note that the corresponding keyword must be set also in the A2E ini-file and the filenames must match.
- Adds another dust component to the model. Can appear several times in the ini-file.
=== E ===
- Calculate surface brightness map instead of simulating the radiation field inside the cloud.
- No dust emission from cells with a point source. May be useful in some cases of subgrid modelling.
=== F ===
- Specifies the name of an ascii file that lists the frequencies used in the calculation (and in output files). Note that if the keyword frequency is also used, that overrides this setting.
=== G ===
- The number of ghost cells in the input MHD model. Affects the reading of the hierarchy information.
- Sets the physical size of the model. The value is the extent of the full model in parsecs (i.e., the length corresponding to the length of one unit in the hierarchy file). Note that the rootgrid does not need to be a cube.
=== H ===
=== I ===
ifreq #1 #2
- Instead of going throug all frequencies listed in the frequency file, simulate only frequencies from #1 to #2 (inclusive, starting from 0).
- Adds an internal radiation source. For syntax, see corresponding keyword in CRT.
iterate AUTO iter.file | iteration.list [#iterations]
- Controls the subgrid iteration. With AUTO the grids included in each iteration are selected automatically. iter_file should contain the parameters controlling the iteration, e.g. the thresholds for including grids in the iteration and the stopping criteria. Alternatively, the list of grids can be given in iteration.list file. The file should list the ID#s of the rootgrids for the subtrees included in each (sub)iteration (one number per line, -1 as the last entry). The optional number of iterations can be used to set how many times the list given in iteration.list is processed through (default=1).
=== J ===
=== K ===
=== L ===
=== M ===
- Emission maps are calculated according to the instructions in the given ascii file. Each line of the file has 9 fields. These correspond to the arguments of the keyword mapsize followed by the arguments of the keyword mapdirection followed by the name of a binary file where the surface brightness values are written (binary file containing as many floats as there are pixels). Note that in this case the ascii file intensity.map is not produced.
mapdirection theta phi
- Specifies the direction towards the observer. Theta is angle from positive z-axis, phi is rotation around this axis.
mapsize Y X DX NPIX gridlines
- Specifies the size of the written emission maps. (X,Y) is the centre of the map (offsets in "cloud units" from the direction of the cloud centre), DX is the pixel size (in "cloud units"), NPIX is the number of pixels (map equals NPIX times NPIX pixels). If integer gridlines>0, the images include outlines of the grids.
=== N ===
- Peeloff extinction tables are calculated with the pixel size corresponding to the smallest cell size in the model. Accurate, but calculating and storing the extinction tables is expensive, if the hierarchy is very deep (=many levels).
- Tells AMR that the abundances of the dust components are not necessarily constant. This means that more memory is required to store component abundances. Doesn't actually seem to be implemented at the moment...
=== O ===
- Calculates only the scattered flux, abrsorptions are not saved.
- Defines the external radiation field (or an external source). For details, see the corresponding keyword in CRT.
=== P ===
- Upper limit for the number of photon packages that can exist at any given time.
peeloffdir theta phi
- Add a new direction towards the scattered light is calculated. Theta and phi are as with mapdirection. Several directions can be specified by repeated use of the keyword.
photonlimit #1 #2
- If the number of photons in a package drops below #1, Russian roulette is used to determine whether the package continues: the package has a one in #2 chance of not being terminated.
polychromatic #1 #2 #3...
- Uses polychromatic photon packages. The numbers denote how many frequencies are simulated at once: first set included #1 frequencies, the second #2 and so on. The last number of the list is repeated until all the frequncies have been simulated.
=== Q ===
=== R ===
=== S ===
sampledensityfield #res #lx #ly #lz #nx #ny #nz
- Writes a file density.sampling that contains a regular grid of #nx×#ny×#nz samples of the density field (#nx×#ny×#nz 4 byte floats). #res sets the resolution at which the sampling is done, #lx, #ly, and #lz indicate the lower left corner of the sampled region and #nx, #ny, and #nz set the size of the sampled region. Note that when this option is used, the programs only writes the density file and no simulation of the radiation field is performed.
- peeloff without using precalculated extinction tables at the subgrid boundaries. Slower especially if the number of photon packages is very high.
- includes embedded point sources (defined with inside) in the emission map.
- For discrete sources, the number of photon packages generated per source (and frequency).
=== T ===
- Dumps the mass-weighted temperature map and quits. .T temperature cubes must exist for this to work.
=== U ===
- Peel-off alhorithm is used to improve the calculation of images of scattered light.
=== V ===
=== X ===
=== Y ===
=== Z ===