SPACEPAR task

SPACEPAR allows the user to explore the full parameter space for any pair of 3DFIT parameters in a given range. It is useful to check that 3DFIT is converging to a good enough minimum of the parameter space. It can be very slow to run, but it is particularly recommended for low quality observations and small data-cubes.

Parameters

Basic parameters for SPACEPAR are the same of the 3DFIT task. Additional specific parameters are:

  • SPACEPAR [false]. This flag enables the SPACEPAR task. Can be true or false.

  • P1 [none]. First parameter to explore. Can be any of the 3DFIT FREE parameters.

  • P1PAR [none]. A list of three numbers: the minimum value, the maximum value and the step size of the parameter space sampling for P1. For example, ‘0 100 1’ samples between 0 and 100 with step size 1.

  • P2 [none]. Second parameter to explore. Can be any of the 3DFIT FREE parameters.

  • P2PAR [none]. A list of three numbers: the minimum value, the maximum value and the step size of the parameter space sampling for P2. For example, ‘1 50 0.5’ samples between 1 and 50 with step size 0.5.

Outputs

The task produces the following outputs:

  • A FITS file NAME_spacepar.fits, containing the full parameter space for each ring.

  • A FITS file mask.fits, containing the mask used.

  • A Python script spacepar.py to conveniently plot parameter spaces.

  • A PDF file NAME_spacepar.pdf with the plots of parameter spaces for each ring (Python required), produced through the spacepar.py script. Example below.

Spacepar plot

Example

Above outputs can be obtained with the following parameter file and the usual example datacube.

FITSFILE    ngc2403.fits
THREADS     1

/////////// SPACEPAR-specific /////////////
SPACEPAR    true
//First parameter
P1          VROT
//Second parameter
P2          VDISP  
//First parameter range 
P1PAR       0 150 2
//Second parameter range
P2PAR       0 30 1 
///////////////////////////////////////////

// OTHER PARAMETERS IN COMMON WITH 3DFIT
NRADII      8
RADSEP      30     
VSYS        132.8
XPOS        77         
YPOS        77     
VROT        120  
VDISP       8          
INC         60
PA          123.7
Z0          10
FREE        VROT VDISP
LTYPE       2
FTYPE       2
DISTANCE    3.2
MASK        SEARCH
WFUNC       2