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Published byRoland Daniel Modified over 9 years ago
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QUaD: A CMB Polarization Experiment … First Year Results, arXiv:0705.2359v1 Robert B. Friedman The University of Chicago GLCW8 - 5.31.07
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What I Will Attempt to Cover CMB Pol. What is QUaD? Analysis Techniques. First Year Results ( arXiv:0705.2359v1) & Future GLCW8 - 5.31.07
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CMB Polarization Science Curves are WMAP3 EE Polarization alone cannot compete with TT for parameters (save for ) It’s a paradigm check BB is the hot stuff!!! Likely below the reach of current experiments (QUaD) Probes inflation & foregrounds through lensing QUaD will nail these GLCW8 - 5.31.07
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Who is QUaD? Chicago Clem Pryke, Tom Culverhouse, myself, John Carlstrom, Erik Leitch (JPL), Robert Schwartz (SP) Caltech John Kovac, Ken Ganga (Paris), Andre Lange, Jamie Bock Stanford Sarah Church, Ed Wu, Jamie Hendricks, Ben Rusholme, Melanie Bowden, Keith Thompson Cardiff Walter Gear, Mike Zemcov, Nutan Rajguru, Angiola Orland, Peter Ade, Simon Melhuish, Lucio Piccirillo Edinburgh Andy Taylor, Michael Brown, Patricia Castro (Lisbon) Maynooth Anthony Murphy, Creidhe O’Sullivan, Gary Cahill GLCW8 - 5.31.07
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What is QUaD? QUaD stands for QUEST at DASI QUEST is the bolometer array receiver DASI interferometer first detected polariztion High Resolution sensitive to modes up to l ~2500 Receiver focal plane consists of 31 Polarization Sensitive Bolometer pairs 19 at 150GHz and 12 at 100GHz. 2.6m Cassegrain focus assembly mounted on the DASI platform tri-axial orientation; AZ, EL, DK foam cone secondary support GLCW8 - 5.31.07
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The Foam Cone Typical radio telescopes use metallic secondary support legs Can induce spurious polarization Foam Cone made from mm-wave transparent Zotefoam. Axially symmetric rigid cone structure adds stability ME GLCW8 - 5.31.07
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Map Making Time Ordered Data (TOD) is “field differenced” first Cancels common ground signal 3rd order polynomial removed from raw TOD Cuts down “1/f noise” (mostly atmosphere ie. large scale variations like clouds). PSB pair TOD summed and differenced Sum produces Intensity or T signal Difference used for stokes Q & U Inverse variance weighting applied to summations Variance map simultaneously constructed GLCW8 - 5.31.07
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QUaD E and B Maps Top Row: E & B Polarization Signal No BB signal expected! Bottom Row: “Deck” Jackknife … should look like noise. GLCW8 - 5.31.07
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Spectra Estimation Procedure Generate random CMB realizations, observe with simulated telescope Signal only, noise only and signal plus noise sim TOD for sum/diff Include all known parameters and uncertainties (ie. beam shapes, polarization efficiencies, etc.) Construct maps from sim TOD and calculate sim spectra from them Use sims to correct observed power spectra and estimate error bars Subtract noise power measured from noise only sim spectra Estimate filter/beam suppression measured as the ratio of signal only sim spectra vs. input spectra variance per band in signal plus noise spectra is the ~error GLCW8 - 5.31.07
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Jackknife Spectra Jackknife tests Difference maps from independent data sets Frequency, Deck Angle, Scan Direction, Focal Plane and Season Should be consistent w/ ZERO! GLCW8 - 5.31.07
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The Future of QUaD Preliminary 1st Season Analysis Represents 67 of ~200 days already in the can. See results paper @ arXiv:0705.2359v1 3rd Season observations currently underway. Will likely provide at least another ~70 more days Coming Soon… Reduced errorbars (more time) New and improved beam models Better control of systematics GLCW8 - 5.31.07
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