EVN User Experiment Pipeline Feedback
Pipeline feedback for experiment ER012C.
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the
address below.
Last updated: Thu May 30 12:08:30 CEST 2002
reynolds@jive.nl
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General Comments.
This project consisted of 8 stations. Urumqi wasn't included in the schedule by the user and Cambridge was unable to observe. On ceased observing half-way through the experiment. There are 2 IFs with both LCP and RCP. RFI is bad at all stations apart from Ef, Wb and Tr. Wb is the reference antenna for fringe-fitting. ERI=0.54 (Eb=0.92, Wb=0.98, On=0.5, Mc=0.99, Jb=0.92, Tr=1.0, Cm=0.0), ERI*=0.54 (artificial errors only).
IMPORTANT NOTE: This project lost a significant amount of data due to
blanking in the ANTAB file. Amplitude calibration should be repeated with the
new ANTAB file on VLBEER, and not the CL table provided by the pipeline.
Plots of the autocorrelations.
Comments.
RFI clearly visible - particularly bad at Mc.
Plots of the uncalibrated amplitude and phase against time.
Comments.
Ef: Some dead data is visible at 1/00:00 - 1/01:00
Wb: Dead or no data from 1/07:48 to end of expt.
On: No data from 1/02:00 to end of expt.
Plots of the uncalibrated amplitude and phase against frequency
channel.
Comments.
Eb: Fringes disappear during 1/00:00 - 1/01:00
Wb: Dead or no data from 1/07:48 to end of experiment.
Mc: Large and variable RFI in both IFs (LL and RR). Dead data 1/03:09 - 1/03:20.
Jb: RFI in IF2, Stokes LL only. Tr: RFI in both IFs - Stokes RR.
The uncalibrated amplitude and phase of the crosshand
correlations against frequency channel.
Comments.
No data.
TSYS against time.
Comments.
Effects of RFI is obvious in those channels that have been identified above. Jodrell has very few Tsys measurements.
Telescope sensitivities from the a priori TSYS and Gain
curves (the square of this number gives the antenna noise (SEFD) in Jy - the smaller the better).
Comments.
Due to the RFI the apparent gain on Mc changes rapidly and so choosing a representative gain is difficult. I have assumed 30(**2) as an average value. Sensitivities for Eb, Wb and Tr agree well with the status table values.
On: Gain is 65% of that on status table.
Mc: Gain is 300% of that on status table.
Jb: Gain is 200% of that on status table.
Fringe-fit phase solutions.
Comments.
Note that Wb is the reference antenna. Generally low phase rates until end of experiment.
Fringe-fit delay solutions.
Comments.
No comments.
Fringe-fit rate solutions.
Comments.
No comments.
Telescope bandpasses.
Comments.
Note that the pipeline was unable to solve for a full bandpass calibration using the cross-correlation spectra. Therefore I ran a manual, auto-correlation-only solution.
Mc: Effects of RFI are obvious.
Calibrated amplitude and phase against time
(a priori amplitude calibration and fringe-fit solutions applied).
Comments.
Eb: The dead data during 1/00:00 - 1/01:00 has been flagged automatically.
Calibrated amplitude and phase against frequency channel.
Comments.
Clearly the bandpass calibration has not worked entirely as expected.
Mc: Spikes in bandpass.
Jb: Over-correction in IF2, LL.
Tr: Over-correction in both IFs.
Phase corrections applied to a priori calibrated and fringe-fitted data by self-calibration.
Comments.
No comments.
Amplitude corrections applied to a priori calibrated and fringe-fitted data by self-calibration.
Also available as a text file.
Comments.
Ef: Occasional very high (>5) corrections.
On: Occasional very high (>5) corrections.
Mc: Occasional very high (>5) corrections.
Telescope sensitivities (the total AMP gain applied during
both a priori and self calibration; the square of this number gives the antenna
noise (SEFD) in Jy).
Comments.
Eb: Agrees with status table.
Wb: Agrees with status table.
On: Agrees with status table.
Mc: Not visible here due to the high points, but the average for each antenna is about 20 which agrees with the status table.
Jb: Variable, but the lowest values agree with status table.
Tr: 50% higher than on status table.
Residual closure phase (visibility closure phase with
model closure phase subtracted) for 1613+341.
Residual closure phase (visibility closure phase with
model closure phase subtracted) for J1157+1638.
Residual closure phase (visibility closure phase with
model closure phase subtracted) for J0657.
Comments.
For 1613+341:
Phase at 0 is rare on any baseline. Often at +/- 180 deg.
For J1157+1638:
Good/better closure phases, especially on Ef-Wb-Jb triangle.
For J0657:
Good/better closure phases, especially on Ef-Wb-Jb triangle.
Calibrated visibilities and the source model of
1613+341.
Calibrated visibilities and the source model of
J1157+1638.
Calibrated visibilities and the source model of
J0657.
Comments.
For 1613+341:
Good agreement in phases, poor in amplitude.
For J1157+1638:
Good agreement.
For J0657:
Good agreement.
Crude map of 1613+341 from the pipeline.
Crude map of J1157+1638 from the pipeline.
Crude map of J0657 from the pipeline.
Comments.
All sources appear unresolved although sidelobes are high.