Hi,
I've updated my posting from last week:
http://bicep0.caltech.edu/~spuder/analysis_logbook/analysis/20130121_ellipt…
...and made a new posting:
http://bicep0.caltech.edu/~spuder/analysis_logbook/analysis/20130121_ellipt…
1) I screwed up last week and instead of simulating ellipses oriented
parallel to detector pol. angles, I simulated ellipses parallel/perp. to
the (r,theta vector). Thus T leaked into E and B equally.
2) I was wrong in claiming that ellipses oriented parallel/perp. to the
pol. angles produce T->B leakage. As John pointed out, it in fact leaks
T->E.
The new posting simulates 1) ellipses oriented parallel to the pol angles;
and 2) ellipses oriented at 45 degrees to the pol angles. The leakage is as
expected.
A 10% elliptical sidelobe with 10% power and oriented at 45 deg. to the
pol. angle *does* cause noticeable spurious BB. We would not see this in
beam maps. I also had a quick look at the reobserved WMAP minus B2 maps,
and it looks like such a sidelobe would also *not* be noticeable in this
analysis. (Actually, we see a little bit higher rms in the WMAP minus B2
maps than would be expected from WMAP noise alone. I wouldn't go so far as
to claim this as evidence for a compact sidelobe, but it's interesting.)
However, the elliptical sidelobe does seem to cause TB correlation of a
form we do not see in the real data, so I think we can rule it out on these
grounds. Nonetheless, it's something to think about.
(Clem, it appears that ellipticity deprojection does *not* do anything to a
compact, 3 degree sidelobe with differential ellipticity.)
-Chris
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Christopher Sheehy - Graduate Student - University of Chicago
University of Minnesota,
Room 220 Tate, 116 Church Street S.E. Minneapolis, MN, 55455
Tel: 612-625-1802 Fax: 612-624-4578 email: csheehy(a)uchicago.edu
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