Justin,
We don't need the slope. Please just put a file in aux_data/abscal which
contains the 2014 ukpv parameter.
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
**********************************************************************
> what does per detector abscal have to with differential
> ellipticity subtraction?
The gain is required to normalize the subtraction templates. See
reduc_coaddpairmaps subfunc regress_templates
> I guess in the current analysis we don't ever read from the
> aux_data/abscal folder
That is incorrect. get_array_info reads the files under aux_data/abscal and
returns p.ukpv
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
**********************************************************************
It seems there is an error in the diff ellip sub (dp1102) for all 2014
analysis so far - see below.
Clem
Subject: 2014 per detector abscals
From: Clem Pryke <pryke(a)physics.umn.edu>
Date: Sat, 04 Jul 2015 01:50:46 -0500
To: Justin Willmert <willmert(a)physics.umn.edu>
Cc: pryke(a)physics.umn.edu
Justin,
It looks like in this post:
http://bicep.caltech.edu/~spuder/keck_analysis_logbook/analysis/20141211_ke…
14_perdet-abscals
you derived 2014 per detector abscals. But these don't appear to have been
committed to the aux_data/abscal directory.
This means we are analyzing 2014 data using 2013 abscal numbers. I am not sure
of the impact of this. But since these numbers are used for the scaling of the
subtraction coefficients it likely means that dp1102 is not being done
correctly.
Please put this file in place asap.
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
**********************************************************************
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
**********************************************************************
> the plot of response vs. pol angle for a given detector looks like a sine
> wave of pi periodicity. The troughs are at T and the peaks are at T+P
Is that right? Isn't T the average level and half the amplitude of the
variation is Q?
Seems we will need to settle this is to run a sim with simopt.rndeps turned
on...
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
**********************************************************************
Hi Chris,
SPT are worrying about their T->P in their sims. In a pair differencing
analysis what effects can and can't cause T->P?
A/B beam mismatch of course can.
I think non-orthogonal pair angles can't - that is only an additional
calibration of the pair diff and getting it systematically or randomly wrong
across pairs can only mix E<->B.
But what about polarization efficiency (epsilon)? If this differs between A
and B of pairs systematically or randomly that will leak T-pol in the
timestream. And our analysis would not fix this even if we knew the per
detector efficiencies perfectly? However this effect is indistinguishable from
relgain and would therefore deproject out.
Where is this possibility mentioned in your paper? Sec 9.7 talks about
"Cross-polar response" but seems to say that this causes only E->B.
I note that what I have written above is specifically contradicted in our
Instrument Paper where it says:
"The crosspolar response enters the analysis only as a small adjustment to the
overall gain of the E and B polarization, but cannot create any false B-mode
signal."
That's certainly true so long as chi is equal for A and B of each pair. But is
it really true when is differs between A and B?
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
**********************************************************************
Hi All,
I'm looking to get some 6N Aluminum (which I believe is what was used for
the pulse tube cold head heat strap for Keck), but the only supplier I
found is in Japan and is not very responsive. Does anyone know of a more
local supplier?
Thanks
-Jon
Hi Kirit,
In your posting we just looked at one notes that for 150 going 1100->1102->
1101 there is considerable further improvement in the second step. Is this a
known/understood effect? Presumably the subtraction coefficients which are
used for 1102 come from the beam map data itself so it it odd for deprojection
to do better than subtraction?
Best,
Clem
P.S. Stefan pointed to the post 20140710_keck2014_chflags - although it is
true that the channel selection cuts on A/B offset are being done as fraction
of beam width it is also true that the 96GHz channels look very well behaved
in this metric - switching it to absolute at the same level as 150 would
likely not change the 95 channel selection.
--
**********************************************************************
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
**********************************************************************
Hi All,
As Brian mentioned on today's telecon, he and I are part of a committee
organizing a conference about Cosmic Polarization Rotation (e.g.
birefringence, etc.) in Florence, September 7-8 of this year. The
conference will be held in Galileo's house, where he was confined to house
arrest until his death for his heretical ideas.
Please see our website <http://www.arcetri.astro.it/cpr/index.html> for
more information and for registration. Registration is open now! We hope
you will join us!
-Jon
