QUaD: A CMB Polarization Experiment… First Year Results, arXiv:0705.2359v1

Robert B. FriedmanThe University of Chicago

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What I Will Attempt to Cover

CMB Pol.What is QUaD?Analysis Techniques.First Year Results (arXiv:0705.2359v1) & Future

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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

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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

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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

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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

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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

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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.

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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

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Jackknife Spectra

Jackknife tests Difference maps from independent data setsFrequency, Deck Angle, Scan Direction, Focal Plane and Season

Should be consistent w/

ZERO!

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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 modelsBetter control of systematics

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