[daip] [!9045]: AIPS - FLUX cutoff in task MOMNT

[Yogesh Chandola]

Yogesh Chandola updated #9045
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FLUX cutoff in task MOMNT 
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           Ticket ID: 9045
                 URL: https://help.nrao.edu/staff/index.php?/Tickets/Ticket/View/9045
           Full Name: Yogesh Chandola
               Email: yogesh.chandola at gmail.com
             Creator: User
          Department: AIPS Data Reduction
       Staff (Owner): -- Unassigned --
                Type: Issue
              Status: Open
            Priority: Default
                 SLA: NRAO E2E
      Template Group: Default
             Created: 28 September 2016 07:23 AM
             Updated: 28 September 2016 07:23 AM
                 Due: 30 September 2016 07:23 AM (2d 0h 0m)
      Resolution Due: 06 October 2016 07:23 AM (8d 0h 0m)



Hi,

 I have a query about determining the FLUX cut off for creating the mask using task MOMNT. I am using Hanning smoothing in velocity and Gaussian smoothing in spatial coordinates. To determine the FLUX cutoff, I am using the equation given in HELP/EXPLAIN for the task MOMNT, 

      "For FLUX
      try a value in the range
         1.5 to 4 * RMS / SQRT (A * B)
      where:
         A   = CELLSIZE(1)                 for velocity Boxcar
             = (CELLSIZE(1)+1)/2           for velocity Hanning ................... (1)
         B   = CELLSIZE(2)**2/(B1*B2)      for spatial Boxcar
             = CELLSIZE(2)**2/(B1*B2) + 1  for spatial Gaussian ................. (2)
         B1  = major axis FWHM of input map beam (in pixels)
         B2  = minor axis FWHM of input map beam (in pixels)
         RMS = r.m.s. noise in input map
     "
    In above equation, I am puzzled about the how cellsizes relate to A and B, in case of Hanning and Gaussian smoothing. Is there any proper reference, how these equations (1) and (2) have been derived ?

Best regards,
Yogesh  

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