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Update on QUaD

Update on QUaD. Sarah Church QUaD Collaboration. Funded: National Science Foundation Astronomy Program and Office of Polar Programs. U. of Chicago Clem Pryke (Data Analysis Lead) John Carlstrom Tom Culverhouse Robert Friedman Erik Leitch (JPL) Robert Schwarz (over winterer)

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Update on QUaD

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

  2. 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 • 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

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

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

  5. QUaD Summary

  6. Stokes Sampling • 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 Azimuth scan Rotation of the entire telescope

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

  8. Polarization Calibration Co Polar Cross Polar Chopped thermal source with pol grid

  9. 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 e

  10. Slightly processed data Picture credit: Pryke

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

  12. 150 GHz temperature map

  13. 150 GHz temperature map

  14. 150 GHz Stokes U map

  15. 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

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

  17. 150 GHz Field-differences Stokes U map

  18. Smoothed maps show polarization Picture credit: Wu

  19. Smoothed maps show polarization Picture credit: Wu

  20. Power Spectrum Determination Data analysis method • 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

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

  22. QUaD first year power spectra Season 1 100GHz/150GHz Cross-correlation • 67 days mapping 60 square degrees of sky • Only ~30% of final data set • Submitted paper at arXiv:0705.2359 (Feb 10th ApJ) • Bandpowers are publicly available

  23. Observing Strategy Allows for Many Jack-knife Tests

  24. Observing Strategy Allows for Many Jack-knife Tests

  25. Power spectra are consistent with -CDM

  26. QUaD cosmological parameter estimates • Using the polarization data only Using priors: 0.0<h<1 <0.8 0.0<As<2.5 0<ns<2

  27. Preview of next data release Not Data!

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

  29. 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

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