K. Ganga – CMB Science and Observations 1 Rencontres du Vietnam /08 The QuaD CMB Polarization Experiment K. Ganga APC

K. Ganga – CMB Science and Observations 2 Rencontres du Vietnam /08 The Collaboration ● Stanford: M. Bowden, S. Church, J. Hinderks, P. Marshall, B. Rusholme, K. Thompson, E. Wu ● Chicago: J. Carlstrom, T. Culverhouse, R. Friedmann, C. Pryke ● JPL/Caltech: J. Bock, J. Kovac, E. Leitch, A. Lange ● Pole: A. Day, R. Schwarz ● Cardiff: P. Ade, O. Mallie, S. Melhuish, A. Orlando, W. Gear, M. Zemcov ● ROE: P. Castro, M. Brown, A. Taylor ● UCL: N. Rajguru ● Mancester: L. Piccirillo ● Maynooth: G. Cahill, A. Murphy, F. Noviello, C. O'Sullivan ● APC: K. Ganga

K. Ganga – CMB Science and Observations 3 Rencontres du Vietnam /08 The QUaD survey The aim of QUaD: – First high-resolution maps of E-type polarisation l=75 – 2500 Cosmological parameters (neutrinos, dark energy, inflation?) – Limits on B-type polarisation from gravitational lensing – Say something about B-type polarisation from gravitational waves The QUaD environment: – 2.6 m primary – 62 PSBs at 250 mK – Operates from South Pole on DASI mount – Almost finished with second season. – Hoping for one, and probably only one, more

K. Ganga – CMB Science and Observations 4 Rencontres du Vietnam /08 Optics metal-mesh filters (Cardiff) JFETs at 4K Focal plane at 250 mK Load resistors Corrugated feed Focal plane (Stanford) 31 Polarization Sensitive Bolometers GHz (~6.5') GHz (~5') Technology similar to Planck

K. Ganga – CMB Science and Observations 5 Rencontres du Vietnam /08 Scanning Strategy Between scans the focal plane can be rotated on the sky by rotating the entire telescope about the optic axis We did 0 and 60 degrees for the first half of the season. Now we're doing -30 and 30.

K. Ganga – CMB Science and Observations 6 Rencontres du Vietnam /08 1 st season’s observations Each hour of observations is split between a lead and trail field – separated by 0.5 hrs (7.5°) in RA – exact same scan pattern with respect to ground. Two 8-hour CMB runs/day: 2 nd run repeats same scan pattern as 1 st with telescope rotated 60° about line of sight axis (deck angle rotation). Relative calibration from source (RCW38) + “el-nods” (small el scan to inject atmospheric ramp). 99 days of CMB data taken in 1 st season covering a 10°×6° patch of the B03 (low-foreground) deep field region. Calibrate using BOOMERanG, which is in turn calibrated on WMAP.

K. Ganga – CMB Science and Observations 7 Rencontres du Vietnam /08 The South Pole NSF

K. Ganga – CMB Science and Observations 8 Rencontres du Vietnam /08 The QUaD Telescope - QUaD is a classical Cassegrain design with 2.6m primary - A foam cone supports the secondary mirror for clean polarization characteristics - Outside work is kept to a minimum

K. Ganga – CMB Science and Observations 9 Rencontres du Vietnam /08 Atmospheric Noise ● The two detectors in a given assembly see essentially the same atmospheric signal: subtracting the two effectively eliminates the atmosphere, but retains the polarization signal – This cannot be used for total power measurements, however Filtered

K. Ganga – CMB Science and Observations 10 Rencontres du Vietnam /08 Moon While this measurement is difficult to interpret quantitatively given the obscuration of the primary mirror, it does give us an important confirmation of the geometry of our focal plane and the detector orientations.

K. Ganga – CMB Science and Observations 11 Rencontres du Vietnam /08 QUaD Sky Coverage 100 sq deg Galactic dust map at 150 GHz (Bowden, Taylor, et al 2003) Obervable sky from South Pole.

K. Ganga – CMB Science and Observations 12 Rencontres du Vietnam /08 These show T, Q & U maps at 100 GHz for our full first season of data. A third order polynomial has been subtracted from each scan to remove low-f atmospheric noise, but that’s about all the filtering that has been applied.

K. Ganga – CMB Science and Observations 13 Rencontres du Vietnam /08 - These are the same maps, but at 150 GHz. Obviously, the sky is a bigger contaminant in T, but PSB differencing does a good job for the polarization fields.

K. Ganga – CMB Science and Observations 14 Rencontres du Vietnam /08 Field differencing Difference lead & trail fields to remove possible ground signal (sensitivity hit: S/N ↓ by √2). 100 GHz T150 GHz T 150 GHz Q150 GHz U

K. Ganga – CMB Science and Observations 15 Rencontres du Vietnam /08 Redundant Processing

K. Ganga – CMB Science and Observations 16 Rencontres du Vietnam /08 - This set of images compares our very early maps to those of B2K and WMAP in the same region of sky. - There is good concordance with previous measurements of this region of the sky. - We will use the comparison with B2K to perform our final absolute calibration. Comparison, Confirmation and Calibration

K. Ganga – CMB Science and Observations 17 Rencontres du Vietnam /08 Jacknives Temperature map Focal Plane Angle Jackknife Map

K. Ganga – CMB Science and Observations 18 Rencontres du Vietnam /08 Foregrounds

K. Ganga – CMB Science and Observations 19 Rencontres du Vietnam /08 Predicted Spectra l -space coverage of QUaD Largest scales determined by sky coverage and scan strategy. Smallest scales determined by beam

K. Ganga – CMB Science and Observations 20 Rencontres du Vietnam /08 Jacknife power spectra – 150 GHz real /sims

K. Ganga – CMB Science and Observations 21 Rencontres du Vietnam /08 Power spectra from simulations

K. Ganga – CMB Science and Observations 22 Rencontres du Vietnam /08 Summary ● First light in Feb ● QUaD has observed for almost two seasons – Should have one more ● First season results should be out “soon”