[daip] [!8690]: AIPS - Factor in CONVL

[Hansung Gim]

Hansung Gim updated #8690
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              Status: Open (was: Closed)

Factor in CONVL
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           Ticket ID: 8690
                 URL: https://help.nrao.edu/staff/index.php?/Tickets/Ticket/View/8690
           Full Name: Hansung Gim
               Email: hgim at astro.umass.edu
             Creator: User
          Department: AIPS Data Reduction
       Staff (Owner): Eric Greisen
                Type: Issue
              Status: Open
            Priority: Default
      Template Group: Default
             Created: 18 July 2016 06:41 PM
             Updated: 18 July 2016 08:18 PM



Dear Eric

  Thanks for your quick response. 
  However, I am still confusing with this issue. Is it right that the factor is set to be the ratio of new beam area to the old beam area ? 

  When I run the SAD to measure the flux densities of sources, it does not look that the signal in large beam is 3 times larger than that in small beam. For example, I have gotten

  In the beam size of 1.47"x1.42", 
                Peak     :     148.007 (3.561)       

   in the beam size of 6.0"x6.0" (which is convolved with the factor of 17.2463)
                Peak     :     140.490 (11.169)

, where the unit is microJy/beam. The flux density is similar unlike the noise. The noise of the peak flux density is ~3 times larger in the large beam size map. 

  Again, here is my question. As I know, the convolution with the larger beam reduces the noise. Could you let me know what I should do to reduce the RMS noise with convolution ? 


All the best,
Hansung






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