Primary Beam Correction and Mosaicing Multiple Fields

For mosaicing multiple fields, one might first read the ATNF user's Guide on Mosaicing Observing Strategies. After construction of the clean images for the individual fields, Miriad task linmos performs a simple linear mosaicing of input image (cubes) to produce a single output image (cube), correcting for the primary beam. Before running linmos, one needs to check up the header parameter Telescope of the images. If the header parameter Telescope is not specified, one needs to specify the primary beam type pbtype of the images (see previous section). Then, with linmos, one can perform mosaicing of the input images. Here is a usage:

  in       = sgrb2_1,sgrb2_2               %the input clean images for the
                                           %field 1 and field 2.
  out      = sgrb2.tpbcor                  %output image with bp correction.
  options  = taper                         %for uniform noise distribution.

The options= taper gives approximately uniform noise across the image. Fig. 6.1. shows a mosaicing image from the ${\rm H_2CO}$ line observations of the field 1 (sgrb2_1 for SgrB2(M)) and the field 2 (sgrb2_2 for SgrB2(N)).

Figure: The mosaicing image of SgrB2 for one of the channels produced from the ${\rm H_2CO}$ absorption line observations of field 1 (SgrB2(N)) and field 2 (SgrB2(M)).