[daip] [!7191]: AIPS - CALIB variable gains for 3C286

[Wen-fai Fong]

Wen-fai Fong updated #7191
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CALIB variable gains for 3C286
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           Ticket ID: 7191
                 URL: https://help.nrao.edu/staff/index.php?/Tickets/Ticket/View/7191
           Full Name: Wen-fai Fong
               Email: wfong at cfa.harvard.edu
             Creator: User
          Department: AIPS Data Reduction
       Staff (Owner): -- Unassigned --
                Type: Issue
              Status: Open
            Priority: Default
                 SLA: NRAO E2E
      Template Group: Default
             Created: 01 September 2015 11:20 PM
             Updated: 01 September 2015 11:20 PM
                 Due: 04 September 2015 11:20 PM (3d 0h 0m)
      Resolution Due: 10 September 2015 11:20 PM (9d 0h 0m)



Hi,

I'm reducing a data set acquired yesterday (8/31/2015) - a 1 hr observation in X-band. The data set uses flux calibrator 3C286. My reduction runs normally, and the flux of 3C286 is as expected when I run SETJY. But when I run CALIB on 3C286 using a 3C286_X model (created with CALRD), the gains across the IFs are abnormally high for most of the IFs:

CFA-PI> CALIB1: RPOL, IF= 1 The average gain over these antennas is  7.600E+00
CFA-PI> CALIB1: RPOL, IF= 2 The average gain over these antennas is  7.580E+00
CFA-PI> CALIB1: RPOL, IF= 3 The average gain over these antennas is  7.615E+00
CFA-PI> CALIB1: RPOL, IF= 4 The average gain over these antennas is  7.752E+00
CFA-PI> CALIB1: RPOL, IF= 5 The average gain over these antennas is  6.621E+00
CFA-PI> CALIB1: RPOL, IF= 6 The average gain over these antennas is  7.238E+00
CFA-PI> CALIB1: RPOL, IF= 7 The average gain over these antennas is  8.077E+00
CFA-PI> CALIB1: RPOL, IF= 8 The average gain over these antennas is  1.231E+01
CFA-PI> CALIB1: RPOL, IF= 9 The average gain over these antennas is  7.199E+00
CFA-PI> CALIB1: RPOL, IF=10 The average gain over these antennas is  7.207E+00
CFA-PI> CALIB1: RPOL, IF=11 The average gain over these antennas is  6.953E+00
CFA-PI> CALIB1: RPOL, IF=12 The average gain over these antennas is  7.181E+00
CFA-PI> CALIB1: RPOL, IF=13 The average gain over these antennas is  6.903E+00
CFA-PI> CALIB1: RPOL, IF=14 The average gain over these antennas is  8.874E+00
CFA-PI> CALIB1: RPOL, IF=15 The average gain over these antennas is  1.120E+01
CFA-PI> CALIB1: RPOL, IF=16 The average gain over these antennas is  2.039E+01
CFA-PI> CALIB1: LPOL, IF= 1 The average gain over these antennas is  7.388E+00
CFA-PI> CALIB1: LPOL, IF= 2 The average gain over these antennas is  7.378E+00
CFA-PI> CALIB1: LPOL, IF= 3 The average gain over these antennas is  7.344E+00
CFA-PI> CALIB1: LPOL, IF= 4 The average gain over these antennas is  7.320E+00
CFA-PI> CALIB1: LPOL, IF= 5 The average gain over these antennas is  6.245E+00
CFA-PI> CALIB1: LPOL, IF= 6 The average gain over these antennas is  6.567E+00
CFA-PI> CALIB1: LPOL, IF= 7 The average gain over these antennas is  7.394E+00
CFA-PI> CALIB1: LPOL, IF= 8 The average gain over these antennas is  1.146E+01
CFA-PI> CALIB1: LPOL, IF= 9 The average gain over these antennas is  6.856E+00
CFA-PI> CALIB1: LPOL, IF=10 The average gain over these antennas is  6.949E+00
CFA-PI> CALIB1: LPOL, IF=11 The average gain over these antennas is  6.718E+00
CFA-PI> CALIB1: LPOL, IF=12 The average gain over these antennas is  6.962E+00
CFA-PI> CALIB1: LPOL, IF=13 The average gain over these antennas is  6.546E+00
CFA-PI> CALIB1: LPOL, IF=14 The average gain over these antennas is  8.224E+00
CFA-PI> CALIB1: LPOL, IF=15 The average gain over these antennas is  1.049E+01
CFA-PI> CALIB1: LPOL, IF=16 The average gain over these antennas is  2.120E+01

And if I try to continue the reduction and run CALIB on the phase calibrator, no valid solutions are found and the routine crashes.

I have tried re-running from the task FRING, using different reference antennas and time ranges but nothing works. I thought this might be specific to this observations, but this happened the last time I tried to reduce data using 3C286, on July 28, 2015 - where the gains were also abnormally high for the same IFs.

Please let me know if you have any suggestions to solve this issue or know what could be going on. Thanks!

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