This is true for a single pair but of course it is not true when the
non-orthog and/or pol efficiency differs from pair to pair, the pairs cover
only partially overlapping sky, and we have imperfect knowledge with which
to
make corrections. In this case the Q/U maps have spatially varying
normalization and there will be E<->B.
Absolutely. This is sort of dealt with in the first two paragraphs of Sec.
10.3 in the systematics paper, but for variations in T abscal from pair to
pair, which of course doesn't include Q/U abscal variation as one would
expect from varying epsilon from pair to pair.
On Fri, Jul 3, 2015 at 3:57 PM, Clem Pryke <pryke(a)physics.umn.edu> wrote:
> Hi Chris,
>
> In the ideal case rotating a polarized detector through 360 deg while
> looking
> at radiation which has some degree of linear polarization produces a 2
> period
> sinusoid whose mean level is T and whose peak-to-peak/2 is Q (or U). If we
> now
> have 2 detectors A and B which are oriented 90 deg apart their sinusoids
> are
> anti-phase and (A-B)/2=A. If we deviate from 90 deg separation and/or have
> a
> non unit polarization efficiency on either A or B then this just reduces
> the
> amplitude of (A-B)/2.
>
> So I think you are right that none of these effects can in fact mix T->pol.
>
> > Nor can there be any changes in the maxima and minima of A-B, and so
> > there is no E->B.
This is true for a single pair but of course it is not true when the
non-orthog and/or pol efficiency differs from pair to pair, the pairs cover
only partially overlapping sky, and we have imperfect knowledge with which
to
make corrections. In this case the Q/U maps have spatially varying
normalization and there will be E<->B.
>
> Sorry for needing to bounce this off you to get it straight in my head
> again -
> and sorry for spamming this list!
>
> Clem
>
> --
> **********************************************************************
> Clem Pryke - Associate Professor - Physics
> University of Minnesota
> Room 318 Physics and Nanotechnology Building
> 115 Union Street SE, Minneapolis MN 55455
> Tel: 612-624-7578 Fax: 612-624-4578 email: pryke(a)physics.umn.edu
> **********************************************************************
>
>
>
--
**********************************************************************
Christopher Sheehy
KICP Fellow, University of Chicago
5640 S Ellis Ave
LASR 122
Chicago, IL 60637
office: (773) 702-9751
**********************************************************************