Update on QUaD Sarah Church QUaD Collaboration Funded: National Science Foundation Astronomy Program and Office of Polar Programs

Stanford University Sarah Church (US PI) Melanie Bowden (now industry) James Hinderks (now Goddard) Ben Rusholme (now IPAC) Keith Thompson Ed Wu Cardiff University Walter Gear (UK PI) Peter Ade Sujata Gupta Simon Melhuish (now Manchester) Lucio Piccirillo (now Manchester) Nutan Rajguru (now industry) Angiola Orlando (now Caltech) Abigail Turner Mike Zemcov (now Caltech) Collège de France Ken Ganga U. of Chicago Clem Pryke (Data Analysis Lead) John Carlstrom Tom Culverhouse Robert Friedman Erik Leitch (JPL) Robert Schwarz (over winterer) N.U.I Maynooth Anthony Murphy Gary Cahill Creidhe O’Sullivan U. of Edinburgh Andy Taylor Michael Brown (now Cambridge) Patricia Castro (now Lisbon) Yasin Memari Caltech / JPL Jamie Bock John Kovac Andrew Lange

The QUaD CassegrainTelescope 2.6m primary Secondary supported with foam cone Re-imaging lenses “Deck” rotation axis

The QUaD Focal Plane metal-mesh resonant grid filters define the band JFETs at 4K Focal plane at 250 mK Load resistors Corrugated feed Bolometers Vespel legs isolate the stages 440 mK plate 4K plate

QUaD Summary Freq (GHz) Beam (arcmin) No. feeds Fractional Bandwidth NEQ per pair (  K s 1/2 ) (5.6)12 (9) (4.5)19 (17)

Stokes Sampling Azimuth scan Rotation of the entire telescope  Difference 2 PSBs to get Q or U, depending on orientation  Rotate telescope and instrument about the optic axis (allowed rotation is +/- 60 degrees) to change the orientation of instrumental polarization with respect to sky.  Scan in azimuth, reacquire source, rescan.  Very redundant observing strategy

Beams  No accessible planets  Measured from several sources  HII regions (RCW38) o Extended structure  Quasar o Dim and variable  5.1’ (100 GHz)  3.7’ (150 GHz)  ~ 10% uncertainty

Polarization Calibration Chopped thermal source with pol grid Cross PolarCo Polar

Gain Calibration  Relative Calibration  El nods: Frequent nods in elevation provides large correlated signal across all channels.  Cal source: Flip mirror inserts rotating polarized source into beam.  Row cals: Raster all pixels across RCW38.  Skydips, loadcurves  Absolute Calibration  Temperature: Correlate full- season T-maps against BOOMERANG  Polarization: Use T calibration corrected by measured 

Slightly processed data Picture credit: Pryke

QUaD is a good polarimeter QUaD maps of Cen A QUaD map of the Moon Polarization levels in these maps are 1-2%

150 GHz temperature map

150 GHz Stokes U map

100 Degree Sidelobe  ~ 1% of total power in a narrow circular sidelobe at 100 deg. to the boresight  Source of contamination from the ground and the moon  Lead/Trail field differencing removes ground pickup  Data cuts remove moon contamination

Field differencing is used to mitigate ground pickup Picture credit: Pryke

150 GHz Field-differences Stokes U map

Smoothed maps show polarization Picture credit: Wu

Smoothed maps show polarization Picture credit: Wu

Data analysis method Power Spectrum Determination  Monte-Carlo based analysis  Noise only simulations, based on measured noise correlation properties, used to correct noise bias in the power spectrum  Signal-only simulations, based on WMAP best fit parameters, are used to estimate the effects of sky cut and filtering  The scatter in the power spectrum from multiple simulations corrected as above gives the error bars on the band powers

Season 1 100GHz/150GHz Cross-correlation QUaD first year power spectra One pipeline uses full spherical harmonic analysis using HEALPIX, other uses flat sky approx. and 2D FFTs

Season 1 100GHz/150GHz Cross-correlation QUaD first year power spectra  67 days mapping 60 square degrees of sky  Only ~30% of final data set  Submitted paper at arXiv: (Feb 10 th ApJ)  Bandpowers are publicly available

Observing Strategy Allows for Many Jack-knife Tests

Power spectra are consistent with  -CDM

QUaD cosmological parameter estimates  Using the polarization data only Using priors: 0.0<h <1  < <A s <2.5 0<n s <2

Preview of next data release

Other science from 3 rd season data  Measurements of galactic dust – spectral index and polarization  Map above shows 2 days of QUaD observations from season 3

Summary  QUaD first data published and power spectra are publicly available  Three observing seasons are complete  Next data release probably ~ mid-late April  Also work taking place on  High-ell T spectrum  Polarized galactic emission  Foreground limits