Bicep2-list February 2013

bicep2-list@lists.fas.harvard.edu

7 participants
14 discussions

BICEP2 Team meeting today (8 Jan 2013) noon Eastern

by John Kovac

Hi all, A reminder of our first BICEP2 team meeting of the new year, back at our usual time today: Tuesday 8 Jan 2013 9:00 am Pacific, 12:00 eastern, 6:00am Pole Phone: 1-866-890-3820 (toll: 1-334-323-7229) Passcode:59702175 As the agenda below reflects, I expect we will have a very limited pipeline discussion today. Walt, can you please take notes? 1) General business: - online logbook updated for Nov/Dec? [Jon, Colin, …] - status of getting B2 summer data onto odyssey [Walt, Colin] - votes on telecon time for next 5 weeks: 9am or 11am Pacific? 2) Organizing efforts toward results: BICEP2 operations are complete. We'll be reorienting these meetings toward organizing our efforts to produce and publish results. As we discussed in our last (28 Dec) meeting, we'll be starting to match individuals with assignments for "final reports" on B2 sub-threads on reduction and instrument characterization. These are an evolution of the threads we started outlining in November. On the B2 analysis call today Walt volunteered to start a separate index page for these reports, which we see as roughly mapping into sections of papers. Proposed guidelines: 1. unlike logbook postings, these documents get edited and updated until we publish 2. each report connects the topic to what is needed for the B2 science results--what final numbers or tests are needed, and why. 3. review past experiments experience, esp. B1 approach 4. provide an overview of tasks remaining 5. summarize (with links) work done in postings, and where appropriate summarize the existing B2 data. 6. Format can be either html or google doc. Authors should seek and incorporate all group feedback to converge on a consensus doc, ready to extract conclusions for publication. Example report topics: - thermal systematics - magnetic systematics - spectral response - temporal transfer function - RPS-derived polarization chi's and epsilons - pol cal consistency checks from Yukical / pixel polrasters - far sidelobes ... To drive this forward we need your buy-in both on format and assignments. Thread coordinators, please think about topics within your threads that need reports. Those who can't join tomorrow, send feedback and/or offers to take assignments. Today we'll agree on format, organization of topics under threads, and initial assignments. Walt will continue this process on next Tuesday's meeting (I'll be in transit). For future meetings I hope we can schedule reviews of specific reports. 3) B-spectrum Pipeline limited attendance expected today brief update on data reduction [Walt, Angiola] brief update from Jamie T on few degree sidelobes T->P sims (Jamie=monopole, Chris=quadrupole) other updates from ongoing work 4) AOB -- ___________________________________________________________________ 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

11 years

BICEP2 telecon 2013-feb-12

by Walt Ogburn

We had a very brief telecon on Tuesday. Notes follow. - Walt ----- On the line: Stanford: Jamie, Walt, Chao Lin Harvard: Colin, Immanuel, Chin Lin NIST: Justus San Diego: Jon, Angiola Minnesota: Chris Caltech: Randol, Jeff 1) General business (brief) - online log for Nov/Dec data at Pole [ Jon, Colin ] AI: Jon to communicate with Colin over e-mail AI: Jon to find relevant text files 2) updates on analysis threads - transfer function [ Justus ] Looks consistent with MCE/GCP filters Need to window properly to get rid of ripple - Human eye review Still in progress Please start -- even if only a few schedules - Planning for reports Randol still looking for feedback from main beams - Jon has adequate feedback for now Needs to finish analysis on active thermal control - AI: Walt to organize paper topics page into outline for paper with more comprehensive list of topics - No paper topic report for next week; will leave time to catch up on recent analysis postings.

11 years, 2 months

Data directories from Pole

by Walt Ogburn

Hi all, In addition to the RAID'ed disk arrays from Pole, we're asking John to bring a copy (on non-RAID disk) of the following: * working GCP copy from bicep33 / control machine * /data/cryo from bicep32 / MAS machine If there are any additional items that should be copied onto a non-RAID disk, please send them ASAP. I believe today is the last working day at Pole. - Walt

11 years, 2 months

Re: [Bicep2-list] Analysis note: half-scan jackknife

by Clem Pryke

> Walt has identified a feature in BICEP2 EE that is clearly systematics Likely there is equal contamination in EE as BB. When I went to look for it by eyeball I concluded it was going to be mostly lost in the real E-mode. I wonder if WMAP has enough s/n at low ell to clean some of that away... 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 **********************************************************************

11 years, 2 months

Re: [Bicep2-list] Analysis note: half-scan jackknife and possible culprit

by Clem Pryke

Hi Walt, This is very interesting stuff and the kind of free thinking we are very much in need of. I agree with John that sim comparison is required - if I am understanding correctly the two halves of the split are differently filtered versions of the sky and hence not expected to match. I find it hard to guess the degree of mismatch expected. > It always starts at the same phase, so it will be in phase from one > scanset to another, and will add up over tags rather than averaging down. > It dies down over tens of minutes, so it does not form a fixed pattern in > all the half-scans of a scanset. This is meant as an illustration of the > type of signal that would not be effectively removed by our current > filtering and ground subtraction, and would't be caught by our > existing jackknife tests. I agree it wouldn't be removed by ground subtraction. However I think it would fail deck jack unless it was the same in every pair. And if it was the same in each pair the false signal would be nearly the same row-to-row in the maps. (A pair specific signal would fail deck jack unless each pair somehow "knew" to adopt the same false signal as the pair previously at that elevation when the array was rotated.) 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 **********************************************************************

11 years, 2 months

Analysis note: half-scan jackknife and possible culprit

by Walt Ogburn

Hi all, I have constructed a new jackknife that splits the first 53 vs. last 53 half-scans in a scanset. This is intended to test whether we could have an instrumental signal that's repeatable from scanset to scanset, but changes from one half-scan to another. An example would be a thermal oscillation that dies down as you get farther from the partial load curve. The pairmaps are still in progress, but with a coadd through Oct. 2010 I find this jackknife fails. The EE and BB power in the differenced map is a good match for the EE and BB power at low ell in our jack0 coadds. I also find a significant mismatch in the T map between the two splits. You can find the note here: http://bicep0.caltech.edu/~spuder/analysis_logbook/analysis/20130207_scanja… I still need to complete the pairmaps and coadd for the two-year data set, and repeat the same analysis for a signal+noise sim. The preliminary results look promising, though, that this could be what we've been looking for. - Walt

11 years, 2 months

Re: [Bicep2-list] Analysis note: half-scan jackknife and possible culprit

by Clem Pryke

> Is this jackknife unique in that regards ? No - but in all other cases we have s+n sim to look at to judge the degree of expected failure. 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 **********************************************************************

11 years, 2 months

Re: [Bicep2-list] [Bispud-pipeline-list] BICEP2 Team meeting tomorrow (05 Feb 2013) noon Eastern

by Clem Pryke

> The rms we expect from WMAP-B2, based on simulations, goes from 8.21 uK to > 8.29 uK. It seems the assumption of negligible B2 noise was a decent one. That is very interesting. More work is probably called for here. How accurate is the WMAP noise model which we are using? What does the 2d aps of the WMAP-B2 temperature map look like? 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 **********************************************************************

11 years, 2 months

Re: [Bicep2-list] BICEP2 Team meeting tomorrow (05 Feb 2013) noon Eastern

by Clem Pryke

Hi all, Sorry that we got cut off and you had to listen to me and John debating things. To reiterate: - I do not disagree with John - we should approach the process of setting upper limits on un-deprojected residuals in a systematic manner a la Takahashi et al. But these are upper limits - in full blown sims there are often additional cancellations (Cf Chris' inductive cross talk sims). - However, based on what I am seeing in terms of: - beam maps constaints on sidelobes - degree to which false B-mode disappears in jackknifes - full blown sims of uniform monopole and quadrupole sims from Chris and Jamie T - degree of sidelobe which is consistent with WMAP cross comparison I am skeptical that there is room to produce a false B as big as we are seeing without violating some of these. But I may be wrong! I would like to hear a consensus summary from Jamie T and Chris: In which of the existing sims so far have you managed to produce false B equal in magnitude to the real data but also passing jackknifes? How absurd (or not) are these scenarios? 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 **********************************************************************

11 years, 2 months

B2 analysis summary

by Chris Sheehy

Hi, I'm re-sending my list of analyses in a separate email, fixing a couple things Clem wanted clarified. Hi All, I've gone ahead and tried to cover other sims and analyses I've done, in addition to ones that have actually *caused* spurious BB. I've bolded items that actually cause excess BB: 1) http://bicep0.caltech.edu/~spuder/analysis_logbook/analysis/20130125_ellipt… - comparison of B2 to WMAP temperature maps (thus far only in map space, not in ell space) rules out few degree FWHM sidelobes with more than ~20% the power of the main beam. *In fact, the WMAP/B2 comparison looks to even *suggest* an unmodeled sidelobe.* - *Given Randol's figure 7* ( http://bicep0.caltech.edu/~spuder/analysis_logbook/analysis/20130124_zemax_…) *it looks like we *do* have a stacked beam that can be described well as a Gaussian main beam plus a few degree FWHM, **few percent power sidelobe.* 2) http://bicep0.caltech.edu/~spuder/analysis_logbook/analysis/20130125_ellipt… - *A 3 degree FWHM elliptical sidelobe, with 10% the power of the main beam, 10% ellipticity, 90 degrees offset between A and B, and in which the ellipses are oriented at 45 degrees to the detector pol angles, induces false B at about the level we're seeing.* (When the ellipse angle is coaligned with the detector pol angle, it causes no noticeable spurious BB.) - It does almost nothing to any of the BB jackknifes, as we'd expect for a pure quadrupole. - *However, even though it causes spurious BB, the TB pattern that results looks inconsistent with what we observe.* 3) http://bicep0.caltech.edu/~spuder/analysis_logbook/analysis/20130121_ellipt… - Turning ground subtraction off impacts the real maps more than sims (i.e. we're seeing some scan fixed pick up) but appears to be operating at an ell range below where we're taking to be excess BB. - Excess BB is probably not due to a failure of ground subtraction. 4) http://bicep0.caltech.edu/~spuder/analysis_logbook/analysis/20130121_ellipt… - Spurious BB is not a random fluctuation. - Spurious BB is definitely not there in Keck. - Spurious BB does not go away by deprojecting real data with a WMAP W-band template (but does get a tad noisier.) 4) http://bicep0.caltech.edu/~spuder/analysis_logbook/analysis/20121210_relgai… - *Simulating a 5.0% random relgain mismatch causes BB at about the level we're seeing.* - *Simulating a 0.5% systematic relgain mismatch causes BB at about the level we're seeing.* *- The 0.5% systematic mismatch causes a TB pattern like what we observe.* *- I might be crazy, but I see an X pattern in the real BB spectrum. I also see an X pattern in the 0.5% systematic relgain sim.* - *However, both these effects deproject cleanly. Deprojecting with a noiseless template yields basically the same deprojected spectrum.* - Simulating relgain mismatch that reproduces Walt's empirically derived abscals yields no sprious BB, even without deprojecting. - A 1 degree systematic pol angle error causes no BB. 5) http://bicep0.caltech.edu/~spuder/analysis_logbook/analysis/20121217_xtalk_… - Simulating 1.0% inductive crosstalk (even effectively doing so *before* elnod relgain calibration, c.f. http://bicep0.caltech.edu/~spuder/analysis_logbook/analysis/20130121_ellipt…) yields no spurious BB, owing to strong natural cancellation. - The correct explanation for that cancellation is here: http://bicep0.caltech.edu/~spuder/analysis_logbook/analysis/20121228_xtalk_… 6) http://bicep0.caltech.edu/~spuder/analysis_logbook/analysis/20121217_new_re… - Deprojecting by scanset leaves discrete B modes that we're identifying as spurious in place (while adding noise to the BB spectrum, of course.) 7) http://bicep0.caltech.edu/~spuder/analysis_logbook/analysis/20121210_sim123… - Adding beamwidth or ellipticity deprojection to A/B offset deprojection does nothing. 8) http://bicep0.caltech.edu/~spuder/analysis_logbook/analysis/20121204_sim123… - Accounting for point sources in V-band that are not the same at 100 GHz does not alter the BB spectrum, even if it does alter the dk jack. 9) http://bicep0.caltech.edu/~spuder/analysis_logbook/analysis/20121125_new_te… - Messing around with simulated template noise and assumed WMAP beam profile does not really alter the simulated BB spectra. -- ********************************************************************** 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 **********************************************************************

11 years, 2 months

2024

2023

2022

2021

2020

2019

2018

2017

2016

2015

2014

2013

2012

Bicep2-list February 2013