[daip] [!10187]: AIPS - SAD; IM2PARM

[Robert Gray]

Robert Gray updated #10187
--------------------------

SAD; IM2PARM
------------

           Ticket ID: 10187
                 URL: https://help.nrao.edu/staff/index.php?/Tickets/Ticket/View/10187
           Full Name: Robert Gray
               Email: roberthansengray 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: 13 April 2017 03:31 PM
             Updated: 13 April 2017 03:31 PM
                 Due: 17 April 2017 03:31 PM (4d 0h 0m)
      Resolution Due: 21 April 2017 03:31 PM (8d 0h 0m)



Hi!

1.  I’m having a problem with SAD, where it fails to report an obvious source for ‘reasons 1’. 

This happens during feature finding for a 1024-cahnnel cube, with continuum source positions clboxed.   IMEAN reports Max=8.4 Jy, rms=0.76, for snr=11 in a channel with a feature (found in other work), but SAD does not report it - PRTLVL shows that it was found but rejected.  SAD does report a half-dozen weaker ‘sources’, which apparently are sidelobes of the rejected source.  After adding this feature to the clbox list, SAD reports it as peak=9.9 Jy, rms=0.66, for snr=15, and does not report any of the previous ‘sources’ (presumably all sidelobes that go away when the feature position is cleaned).  

Any idea why SAD is rejecting a feature with snr=11?  And how to prevent that?

2.  Since I’m looking for single-channel features in ~100k channels, and already have a list of clboxes for continuum sources, it would be good to automatically generate additional clboxes for any channel with an unexpected feature that should be cleaned – as in the situation above.  I once tried IM2PARM, and it missed some obvious continuum sources in a test so I didn’t continue with it, but maybe I failed to set it up right.  Is below an appropriate setup?

IM2PARM(1)=1;  	* add no more than one clbox to the current channel image
IM2PARM(2)=6;	* SNR threshold for creating a box (default 3 seems too low)
IM2PARM(7)=1;	* do not pass box onto next channel 

Any suggestions would much appreciated!  This is gonna take months, and I want to get it right...

Bob


------------------------------------------------------
Staff CP:  https://help.nrao.edu/staff