PGFLAG polarisation selection

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PGFLAG polarisation selection

Postby and460 » Sun Mar 09, 2014 2:14 pm

Hi guys,

Quick question about how PGFLAG works when selecting Stokes parameters. The manual for the task says:

Key: stokes
Select Stokes parameter(s) or polarization(s) from:
xx, yy, xy, yx, i, q, u, v,
rr, ll, rl, lr
Default is Stokes i.
If more than one polarization is specified only the LAST one is
If one 'raw' polarization is specified, only that one is flagged.
If multiple 'raw' polarizations or one or more 'converted'
polarizations are specified, all polarizations in the data are

Just to be clear, if I select Stokes = I,Q,U,V, then the display device will display Stokes V data, but data from all four products will be flagged. Am I correct in thinking that while the process and results for the other products will not be displayed, the Stokes I flags are derived from the Stokes I data, the Stokes Q flags from the Stokes Q data etc?

I ask because in tasks like Mirflag, the flags are derived based solely on analysis of the first listed polarisation parameter, and these flags are then applied to all subsequently listed parameters. E.g. stokes = v,i,q,u,v would flag all products based on stokes v outliers. This is NOT how PGFLAG works, correct?
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Joined: Thu Sep 01, 2011 12:23 pm

Re: PGFLAG polarisation selection

Postby ste616 » Sun Mar 09, 2014 2:30 pm

Hi Craig,

No, I think that pgflag figures out what to flag from the displayed polarisation, then applies those same flags to every other selected polarisation.
Jamie Stevens
ATCA Senior System Scientist
Site Admin
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Location: Paul Wild Observatory Narrabri NSW

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