hfs_cube

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hfs_cube is a batch procedure for fitting simultaneously up to 9 velocity components of a spectral line with hyperfine structure to data from a 3-axes FITS data cube. The fit procedure is the same as that of hfs_fit, but it is not interactive.

Input

• <parfile>.par, parameter file with the following information:

  1. Transition name (e.g. "NH3(1,1)", "C18O(1-0)") or identification number (its position in the hfs_transitions.dat file).

  2. FITS data cube file to read. The file must have 3 non-degenerate axes, in this order: x position, y position, velocity channel.

  3. Rms of channels without emission, minimum SNR of spectra to be fitted. Components with a peak intensity below SNR times rms are not fitted.

  4. Number of velocity components to fit, Ncomp, between 1 and 9.

  5. 2×Ncomp values, with the first and last channel of the velocity range for each component. The channel ranges must be non overlapping. For the first component, 0 defaults to 1 (first), nchan (last).

  6. Hanning filter half-width (channels): 0= no smoothing; 1= standard 3-point Hanning smoothing, the resulting spectrum having half the initial number of channels. In general, Hanning smoothing of 2×HFHW+1 points, resulting in a final number of channels HFHW+1 times smaller.

  7. Boxcar smoothing radius (pixels): 0= no smoothing.

  8. First X pixel, last X pixel, X increment of the subimage to be fitted. 0 defaults to 1 (first), ndim1 (last), 1 (increment).

  9. First Y pixel, last Y pixel, Y increment of the subimage to be fitted. 0 defaults to 1 (first), ndim2 (last), 1 (increment).

  10. Iteration parameters: Nksample, Final_Range.

The file can be given as an argument to hfs_cube:

$ hfs_cube <parfile>.par

Example of parameter file:

Output

• log/<parfile>.log: log file in folder log with the details of the fitting process for all the pixels of the subimage.

• <parfile>_comp#.out: an ASCII file for each velocity component, with the values of the parameters fitted for each pixel of the subimage. The first lines beginning with "!" are the header and give information about the parameter file, FITS file, velocity component number, velocity range of the component, hanning filtering, boxcar radius, and column headers. The following lines have 13 columns: Δv, Error, vLSR, Error, Aτm, Error, τm, Error, Rms, Xoffset, Yoffset, Xpixel, Ypixel. The offsets are measured from the reference pixel of the FITS file, and given in arcsec. The file is used by hfs_view, and is readable by GREG.

• ps/<parfile>_<xoffset>.ps: PostScript files in folder ps, with plots of the data, the components fitted, and the residual for all pixels of the subimage with Xoffset = <xoffset> arcsec.

• maps/<parfile>_dvline_comp#.fits, maps/<parfile>_vlsr_comp#.fits, maps/<parfile>_ataum_comp#.fits, maps/<parfile>_taum_comp#.fits:  FITS files in folder maps, with maps, for each velocity component, of the parameters fitted and their uncertainty. Each FITS file has two planes, the first plane with the values of the parameter, and the second plane with the uncertainties.

• maps/<parfile>_rmsfit.fits, FITS file with the rms fit residual for every pixel.