Bicep2-list October 2013

bicep2-list@lists.fas.harvard.edu

18 participants
30 discussions

Re: [Bicep2-list] New convention for ell values at which to plot our bandpowers...please speak now or forever hold you peace.

by Clem Pryke

Hi John, I think shifting the nominal ell of that first bin is a no brainer. I have slight reservation about moving them all about by epsilon amounts. But as you say it doesn't really matter. Clem -- ********************************************************************** Clem Pryke - Associate Professor - Physics University of Minnesota, Room 313 Tate, 116 Church Street S.E. Minneapolis, MN, 55455 Tel: 612-624-7578 Fax: 612-624-4578 email: pryke(a)physics.umn.edu **********************************************************************

10 years, 7 months

Re: [Bicep2-list] posting: WMAP comparison of EE

by Clem Pryke

> An alternative would be to plot our points at the band centers (bpwf > center of mass or similar), instead of the naive band centers. I think this is a good idea. We should update the code in reduc_final to correct the ell value after the iteration over supfac and bpwf. (We should only do this for bins where the shift is significant which is presumably just the lowest one.) Clem -- ********************************************************************** Clem Pryke - Associate Professor - Physics University of Minnesota, Room 313 Tate, 116 Church Street S.E. Minneapolis, MN, 55455 Tel: 612-624-7578 Fax: 612-624-4578 email: pryke(a)physics.umn.edu **********************************************************************

10 years, 7 months

Posting: Satcom in dark SQUIDs and dark detectors

by Walt Ogburn

http://bicep0.caltech.edu/~spuder/keck_analysis_logbook/analysis/20131002_s… Many dark detectors see the signal. Dark SQUIDs don't see the signal. This confirms that the pickup mechanism requires a live, responsive TES. Also shows that the pickup mechanism doesn't go through the antenna network and lumped element filter. - Walt

10 years, 7 months

Posting: Satcom: Second GOES test results

by Walt Ogburn

Hi all, I have put up a new Keck Array posting: http://bicep0.caltech.edu/~spuder/keck_analysis_logbook/analysis/20131001_s… Robert and the South Pole satcom crew have run a second test on the pickup of GOES transmissions, following up on the previous test (results in [20130925_satcom_goes_test]). There are a few reasons for the second test: the weather got bad during the first test, introducing odd features in some channels, which we wanted to make sure were not related to the satellite comms; and this test varied the power level of the high-power amplifier. This gives us the opportunity to find out whether the signal in our data scales with power or field amplitude (see [20120411_SkyNet...] for a similar test with a different transmitter). I confirm that the bad-weather channels look fine this time and don't seem to have been seeing the ground station. I also find that the signal level is consistent with a linear scaling with power, not field amplitude. - Walt

10 years, 7 months

Re: [Bicep2-list] posting: WMAP comparison of EE

by Clem Pryke

> how about only keeping rel gain deproj and using subtraction for > all beam systematics ? That is of course the logical next question. The planned code changes will allow this and we should take a look at what happens. The absolute amount removed by the 6 main beam modes is rather comparable for jack0. However for deck jack it is order of magnitude higher for diff points (because the dk rot "obs strategy" cancellation is not in effect). Clem -- ********************************************************************** Clem Pryke - Associate Professor - Physics University of Minnesota, Room 313 Tate, 116 Church Street S.E. Minneapolis, MN, 55455 Tel: 612-624-7578 Fax: 612-624-4578 email: pryke(a)physics.umn.edu **********************************************************************

10 years, 7 months

Re: [Bicep2-list] posting: WMAP comparison of EE

by Clem Pryke

> Subtraction based systematic removal might be good enough for TE or EE , but > if our default plan is to use deprojection for BB , it is a slightly > complicated story to tell. If we are forced to do it we will do it. To be clear - I am proposing to switch diff ellip removal from deproj (coeff fitted from CMB data) to subtraction (coeff taken from beam map info) for all spectra. So there is no significant complication to the story. I don't think there is any reason to believe this will not be good enough. As I said the undeproj residual would be need to validated in Chin-Lin's sims using the same scheme. We'll give it a try and see what happens. Clem -- ********************************************************************** Clem Pryke - Associate Professor - Physics University of Minnesota, Room 313 Tate, 116 Church Street S.E. Minneapolis, MN, 55455 Tel: 612-624-7578 Fax: 612-624-4578 email: pryke(a)physics.umn.edu **********************************************************************

10 years, 7 months

posting: Satcom traffic: Searching for GOES 2

by Walt Ogburn

I've put up a new BICEP2 posting: http://bicep0.caltech.edu/~spuder/analysis_logbook/analysis/20130930_satcom… In this note I take another look at the two scansets in March 2012 where the satcom signal appeared to turn on when it should turn off (at the end of the GOES pass). In at least one of them, I find that there's actually a weak signal there all along, and it just gets stronger and shifts around half-scan 60. There's a lot of variation in pair-diff signal level during GOES passes, depending on unknown factors. It seems likely that in these two scansets we happened to have a low but nonzero level of contamination, and at the end of the GOES pass something happened to give us a much larger signal. This step up could perhaps be a different transmitter, for TDRS for example. Another idea: perhaps the antenna stopped tracking and went to its standby position, but the high-power amplifier was inadvertently left powered on. This would move whatever sidelobe we're seeing, perhaps changing the power level and the spatial pattern. - Walt

10 years, 7 months

Re: [Bicep2-list] posting: WMAP comparison of EE

by Clem Pryke

I think there may be a much simpler way to deal with this issue. Instead of deprojecting diff ellip we can instead just subtract it. We are presumably very confident that the coefficients are not time varying and hopefully we have reasonable s/n on them from the beam maps. Adding the ability to subtract rather than deproject to the reduc_coaddpairmaps was something I John and I had already decided should be done. We could have something like coaddopt.deproj=[1,1,0,2] specify that for diff ellip the coefficients should be taken from get_array_info's output rather then regressed. We will want to take some care that for sims the "as simulated" values are used. We can make the real maps for this new dp1102 type and see if the high ell TB/EB goes away as it does for dp1101. If it does we would need to re-run the sim set for this new option. We would also need to do this new option in Chin-Lin's sims to validate it in terms of residual false BB. I will take a look at the code and talk with Chris about how to implement this in the cleanest possible way - right now vector coaddopt.deproj does something else... Clem -- ********************************************************************** Clem Pryke - Associate Professor - Physics University of Minnesota, Room 313 Tate, 116 Church Street S.E. Minneapolis, MN, 55455 Tel: 612-624-7578 Fax: 612-624-4578 email: pryke(a)physics.umn.edu **********************************************************************

10 years, 7 months

Re: [Bicep2-list] posting: WMAP comparison of EE

by Clem Pryke

> We should discuss what we want to do for TE. The problem is not just for TE. Look at the supfac plot http://bicep.caltech.edu/~spuder/analysis_logbook/analysis/20130909_sim1450… and click between "dp+rg" and "rg+dp+diff-ellipt". Deprojecting diff ellip causes the EE curve (red) to go up around ell=175! This is craziness - filtering modes from the map increases polarized power? It is presumably only possible because of the bias on the deprojection coefficients - they have a DC offset which is presumably a transfer of power from T to pol at these ells? Things look fine in the final EE plots because we force this effect away by renormalizing the sim output to match input (and because the real sky is apparently LCDM like these sims). We notice a problem in TE simply because (due to the technical problem of zero crossings) we don't normally use a direct TE suppression factor. Instead we use gmean(TT,EE) and this apparently isn't correct so we notice an in/out mismatch. We need to think about this more. Right now I am highly skeptical that the EE (and TE) points with diff ellip deproj on will ever be trustworthy enough for cosmological parameter analysis. Clem -- ********************************************************************** Clem Pryke - Associate Professor - Physics University of Minnesota, Room 313 Tate, 116 Church Street S.E. Minneapolis, MN, 55455 Tel: 612-624-7578 Fax: 612-624-4578 email: pryke(a)physics.umn.edu **********************************************************************

10 years, 7 months

posting: WMAP comparison of EE

by Sarah Stokes Kernasovskiy

Hi, I put up a (mini) post showing the 1450/1350 data compared to WMAP. Nothing surprising. We have very good data through the second peak. The second bin, which we have sometimes fretted about (the last simset didn't have any E modes as large as our data), is in complete agreement with WMAP. http://bicep.caltech.edu/~spuder/analysis_logbook/analysis/20130930_wmappol… -Sarah

10 years, 7 months

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Bicep2-list October 2013