GALMOD task

GALMOD is the routine underlying the 3DFIT task. It builds a 3D simulated datacube of a disk galaxy starting from a set of concentric rings with given column density and kinematics. The routine is an updated version of the namesake routine in GIPSY (see also GIPSY GALMOD).

Parameters

Parameters for rings are the same of the 3DFIT task. Options are LTYPE, CDENS, NV and VELDEF (see 3DFIT options).

Additional GALMOD-specific parameters are:

  • GALMOD [false]. This flag enables the 3D disk modelling. Can be true or false.

  • VVERT [0]. Vertical velocity in km/s.

  • DVDZ [0]. Gradient of rotation velocity as we move away from the disk plane. This is in km/s/arcs.

  • ZCYL [0]. Height in arcsec from the disk plane where the gradient DVDZ begins.

  • SM [true]. Whether to smooth the model to the same spatial resolution of data.

Outputs

The task produces the following outputs. Here NAME is the name of the galaxy and NORM is the kind normalization used.

  • A FITS file NAMEmod_NORM.fits, containing the model datacube.

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

  • FITS files of position-velocity cuts taken along the average major and minor axes for the input datacube and the model. In particular:

    • NAME_pv_a.fits: P-V of the data along the major axis.

    • NAME_pv_b.fits: P-V of the data along the minor axis.

    • NAMEmod_pv_a_NORM.fits: P-V of the model along the major axis.

    • NAMEmod_pv_b_NORM.fits: P-V of the model along the minor axis.

  • FITS files of the moment maps for the input data and the model. These can be found in the maps subdirectory:

    • NAME_0mom.fits, NAME_1mom.fits, NAME_2mom.fits: 0th, 1st and 2nd moment maps of the data.

    • NAME_NORM_0mom.fits, NAME_NORM_1mom.fits, NAME_NORM_2mom.fits: 0th, 1st and 2nd moment maps of the model.

  • A text file densprof.txt, with the radial intensity profiles along the chosen rings.

Example

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

FITSFILE    ngc2403.fits

/////////// GALMOD parameters /////////////
GALMOD      true
// Input rings
NRADII      41
RADSEP      30     
VSYS        132.8
XPOS        77         
YPOS        77     
VROT        120  
VDISP       8          
INC         60
PA          123.7
Z0          10
DENS        1
VRAD        10
// Normalization type
NORM        NONE
// Mask
MASK        SMOOTH
///////////////////////////////////////////