EVN User Experiment Pipeline Feedback


Pipeline feedback for experiment GJ010A_3. If you have any comments on this experiment please email the address below.
A detailed description of the pipeline output is available.

Last updated: Tue Jun 29 16:02:19 CEST 2004 biggs@jive.nl

General Comments. ( Brief data summary and scan listing )
This is a global VLBI imaging experiment at 6cm (LCP only, 4 IFs). Scheduled stations were Ef, Mc, Nt, On, Jb (Mark2), Wb (tied array) and Tr. Non-EVN stations were the ten antennas of the VLBA plus a single antenna of the VLA. No stations failed outright. The reference antennas for calibration were Ef and NL with Ef used for the plotting reference. Data that does not include Ef will not be plotted! This pass of the pipeline corresponds to source B1152+199! The EVN reliability indicator was ERI=0.98 (Ef=0.97,Mc=1.0,Nt=1.0,On=0.99,Jb=0.98,Wb=0.99,Tr=0.99). ERI gives you an estimate of the ratio of the observed/good visibilities to the expected number. ERI* is the same, but excludes data lost due to circumstances out of the EVN's control e.g. bad weather (ERI*=0.98).

Plots of the autocorrelations .
Comments.
No signs of rfi in any channels.

Plots of the uncalibrated amplitude and phase against time .
Comments.
Data is present for every antenna in every channel.
Fd: drops out of the array at 0/22:30. Autocorrelations (above) show that it returns again (when Ef is not observing).

Plots of the uncalibrated amplitude and phase against frequency channel .
Comments.
Scan at 0/22:44 is missing some subbands on the EVN antennas. Probably related to the tape change immediately before this scan.
Jb, Fd: missing from 2007+777 plots.

The uncalibrated amplitude and phase of the crosshand correlations against frequency channel (not available) .
Comments.
not applicable

TSYS against time .
Comments.
On, Mc: too many Tsys points are delivered for AIPS to handle. The antab file was modified for these antennas, every third point being retained.
Nl, Sc: bumps in Tsys, possibly due to precipitation.
Ov: steep gradient in Tsys at beginning is quite normal and due to this telescope pointing towards the White Mountains.

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.
All antennas have close to the expected sensitivity. Tr shows worrying variations though, probably due to a bad gain curve.

Fringe-fit phase solutions (including Parallactic Angle correction).
Comments.
Ef: variation is due to parallactic angle.
Ridiculous phase variation in second half of experiment is due to change in reference antenna from Ef to Nl.

Fringe-fit delay solutions .
Comments.
Change in reference antenna is also responsible for the slope in delay. Differential delay between the reference antenna and other VLBA antennas is actually very small.

Fringe-fit rate solutions .
Comments.
Change in reference antenna is also responsible for the jump in rate.

Telescope bandpasses .
Comments.
Wb: phase solutions are large as always.

Calibrated amplitude and phase against time (a priori amplitude calibration and fringe-fit solutions applied).
Comments.
Fringe fitting does not appear to have been completely succesful or else the phase reference source is resolved. Systematic deviations in the calibrated phase from zero are apparent. Phases look particularly bad on Eb-Sc baseline towards the end of the experiment.

Calibrated amplitude and phase against frequency channel .
Comments.
None.

Naturally weighted dirty map produced before self-cal of:
0552+398: postscript , or FITS .
2007+777: postscript , or FITS .
P1152: postscript , or FITS .
Comments.
None.

Uniformly weighted dirty map produced before self-cal of:
0552+398: postscript , or FITS .
2007+777: postscript , or FITS .
P1152: postscript , or FITS .
Comments.
None.

Phase corrections applied to a priori calibrated and fringe-fitted data by self-calibration.
0552+398.
2007+777.
P1152.
Comments.
2007+777: first solution is not good.
P1152: corrections do seem to be compensating for the problems identified in the fringe fit.

Amplitude corrections applied to a priori calibrated and fringe-fitted data by self-calibration.
0552+398: postscript , or text file .
2007+777: postscript , or text file .
P1152: postscript , or text file .
Comments.
0552+398: 20% downward corrections in all subbands for Tr.
2007+777: corrections for EVN antennas are much bigger than for the VLA and generally down.
P1152: Tr's bad gain curve is being corrected. A large positive correction for Sc towards the end is probably due to phase decorrelation.

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.
Tr: curve is now much flatter.

Residual closure phase (visibility closure phase with model closure phase subtracted) for:
0552+398 .
2007+777 .
P1152 .
Comments.
Dodgyness in phase on Sc baselines is clear.

Calibrated visibilities and the source model of:
0552+398 .
2007+777 .
P1152 .
Comments.
The model would appear to indicate that the source is partially resolved.

Calibrated visibilities against u,v distance for:
0552+398. postscript , or png (smaller)
2007+777. postscript , or png (smaller)
P1152. postscript , or png (smaller)
Comments.
0552+398: very nice.
2007+777: lots of bad data needs flagging.
P1152: Source is pretty bright and this reveals that there is a lot of low amplitude data at (at least) low u,v distances. This data is not apparent in the VPLOT plot above. This can't be source structure.

u,v coverage for:
0552+398. postscript , or png (smaller)
2007+777. postscript , or png (smaller)
P1152. postscript , or png (smaller)
Comments.
None.

0552+398: postscript , or FITS .
2007+777: postscript , or FITS .
P1152: postscript , or FITS .
Comments.
P1152: source definitely looks resolved. Peak in the map is about half a Jansky whilst UVPLT shows the source to be ~1Jy.