GENERAL
EP099B, 22 GHz experiment on 2016 November 6
Participating stations: Jb Ef Mc Nt O6 Ur Tr Ys Sv Zc Bd Sr Mh Kt Ky Ku
However note: no Nt, Kt, Ky
You can find information on individual stations at:
http://www.evlbi.org/user_guide/EVNstatus.txt.
The following are plots from the EVN pipeline analysis, in which the refant was: Ef
The EVN reliability indicator (ERI) for stations in this experiment were
Nt, Kt, Ky = 0, Zc 0.92, Rest=1
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POSSM_AUTOCORR
Auto-corr Amplitude vs frequency plots for each station showing all IFs and Pols.
RFI can easily be found by looking at the continuum source scans in this plot.
Overall, RFI does not look severe in this experiment.
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VPLOT_UNCAL
Amp and phase vs time, for the whole experiment. Shows visibilities on all baselines to the refant. All
IFs and Pols shown. This is a good place to look for stations that missed scans during the experiment.
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POSSM_UNCAL
Uncalibrated, vector averaged, cross power specra for baselines to the refant. No bandpass done yet.
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POSSM_CPOL
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TSYS
Plots of system temperature vs time for each station (and each IF). Flat-line plots indicate that this
information was not available for a given station, in which case we create a
generic tsys table scalled to the station's gain (Jy/K). In this case Ur did
not provide antab information so a nominal value was used.
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GAIN
Gain info in CL2, determined using tsys tables. Plot shows Gain vs time for each station, each IF and each Pol.
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FRING_DELAY
Plot of SN2. Shows delay vs time from FRING results (usually only calibrators and reference sources).
This is a good place to look for times where FRING failed to get solutions. Here FRING uses a signal to
noise cutoff of 5.
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FRING_RATE
SN2 as abover, but for rate.
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FRING_PHAS
Pot of CL3. This is the CL table generated using CL2 (amplitude cal) and SN2 (FRING solutions). Plot
shows phase calibration data vs time. Missing data indicate possible issues in those previous steps. If
the data are complete (all stations and most scans present) then use this table to phase-reference the
target.
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BANDPASS
Plot of BP1; the bandpass characteristic of each station, determined using the brightest source(s) in the experiment.
Look for small scatter in the phase data, this indicates a high signal to noise - which will lead to
better bandpass characterisation.
Bandpass calibrators used were 3C286, J0920+4441.
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VPLOT_CAL
Plot of visibilities vs time for all baselines to the refant, after applying CL3. This is a good place to look for quickly checking the success of the antab (CL2) and FRING (CL3) stages of the pipeline.
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POSSM_CAL
Amp and phas vs frequency plots for all baselines to refant, after applying CL3 and BP1. If CL3 and BP1
are good you will get flat phase and amplitude profiles, therefore this is a good place to check the
success of CL2 and particluarly BP1 for each scan/baseline/IF/Pol.
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IMAPN
Naturally-weighted dirty maps of phase-referenced targets.
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IMAPU
Uniformly-weighted dirty maps of phase-referenced targets.
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CALIB_PHAS1
Individual plots for each source that was used in FRING. Shows phase selfcal solutions (SN1 after SPLIT). This is particularly useful to check if the reference source could be self-calibrated, and to look for missing
scans/antennae.
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CALIB_AMP2
Individual plots for each source that was used in FRING. Shows amplitude selfcal solutions (SN2). This
table is important to properly calibrate amplitudes from stations that had to use generic tsys tables
(see TSYS, above).
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SENS
Plot of CL4 which shows amplitude calirations determined from CL3 and the amplitude selfcal solutions
from SN2 (from CALIB_AMP2, above). Comparison with GAIN plot (above) reveals the accuracy of the apriori
amplitude calibration derived from the TSYS tables - this is particularly important for stations that
have generic generated TSYS tables; Tsys may benefit from aditional scalling if there is a large differnce in SENS and GAIN plots.
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CLPHS
Closure phases for all triangles of antennae in the array. Individual plots for each source which was
used in FRING.
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VPLOT_MODEL
Similar to VPLOT_CAL for sources used in FRING, however each source has been individually SPLITed and modelled.
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UVCOV
Plot of the UV coverage for each source during the experiment.
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UVPLT
Plot of amplitude vs baseline lenght for each source. This can be useful to look for inications of
structure at different angular scales.
Several sources show spurious emission at longer wavelengths. This is probably what has lead to the streaks of
sidelobs in the final images. Additional careful flagging of suspect stations and IFs should be done until the
UVPLT is smoother.
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ICLN
CLEANed image of each source (FRINGed or phase-referened) after applying all relevant calibration by the
pipeline up to CL4; amplitude and phase selfcal calibrations.
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