On 1/20/13 2:47 PM, Chao-Lin Kuo wrote:
Once we are messing with a non constant T->B
leakage "smooth function"
in fourier space we are talking about a beam effect. The FT of this smooth
function is the beam systematics. Starting from the observed TB in the
fourier space as you are advocating will be a faster way to find the right
"beam effect", comparing to what Chris and Jamie are doing right now
in real space.
Yes, absolutely. I agree this is a beam effect we are talking about.
This is the plan I've been advocating:
1) Construct the T->B leakage "smooth function" implied by our TB
2) Use this to deproject "false B" (the part correlated with T
according to this function), and judge whether it removes most of our
false B.
3) If yes, study the implied beam effect by linking the T->B function
via ifft, accounting for dk angles and E/B-Q/U transformation to an
implied form of net A-B mismatch.
But I do think that the sims that Jamie and Chris are running--which
they said were quick and easy to do--could give us insight into whether
the most obvious unconstrained beam effects could reproduce this
effect. I think it is worth seeing that answer, since it is easy.
To me that sounds like a good plan. But we should keep
in mind that :
(1) relgain deprojection might be incomplete somehow.. (2) TB might not
be the only problem - wait for a posting from Walt.
I am eager to see it! Is this
related to the "Roger effect" revealed in
Walt's early 2012 postings on the RPS, producing E->B?
John
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___________________________________________________________________
John Kovac jmkovac(a)cfa.harvard.edu
Assistant Professor, Astronomy and Physics, Harvard University
160 Concord Ave rm 310, Cambridge MA 02138, 617-496-0611