[daip] [!16519]: AIPS - Issues with UF002BC & UF002BD

[Luis Fernandez]

Luis Fernandez updated #16519
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Issues with UF002BC & UF002BD
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           Ticket ID: 16519
                 URL: https://help.nrao.edu/staff/index.php?/Tickets/Ticket/View/16519
                Name: Luis Fernandez
       Email address: lfernan at gmu.edu
             Creator: User
          Department: AIPS Data Reduction
       Staff (Owner): Eric Greisen
                Type: Issue
              Status: Open
            Priority: Default
                 SLA: NRAO E2E
      Template group: Default
             Created: 10 July 2020 02:50 PM
             Updated: 20 July 2020 12:54 PM
      Resolution due: 12 April 2023 12:00 AM (995d 11h 6m)

Hello Eric Greisen,
I took screen shots comparing two different datasets UF002BC (One of the problem data sets) and UF002BF (One of the best data sets) for both the SN table after running the task VLBACCOR as well as the TY table. I have attached them and only included 4 out of the 10 antennas for reference. They do seem to have similarities.
I also tried to rework fresh data from UF002BC by flagging out any bad data points using the task SNEDT for the TY table, Flagging any data under an elevation of 10 degrees as well as IF 4 (since this has an issue with phase) using the task UVFLG, and flagging out any frequencies that have RFI at different baselines before performing any calibrations using the task WIPER. There is an increase in the Integrated flux, but not significantly. For NGC 3079, this increased the Integrated Flux from originally 13.6 mJy to 14.4 mJy, but the uncertainty is 1 mJy for both. The Peak also increases from 3.01 +/- 0.18 mJy/beam to 3.78 +/- 0.22 mJy/beam. As for its phase calibrator J0956+5753, the Integrated Flux increases from 40.4 +/- 3 mJy to 42.2 +/- 1.9 mJy with a Peak increase from 26.6 +/- 1.2 mJy/beam to 31.0 =/- 0.91 mJy/beam. Which are both close to each other and not much of an increase, although the phases look much better than before and the RMS values did improve as well. It is still not accounting for the large difference in amplitude compared to the other data sets.
Could issues with the data in IF 4 cause this much of a drop in overall intensity or propagate errors to the other IF windows?
Thank you again for your help,
Luis Fernandez

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