NASA/GSFC Chuck Bennett (PI) Bob Hill Gary Hinshaw Al Kogut Michele Limon Nils Odegard Janet Weiland Ed Wollack Princeton Chris Barnes Norm Jarosik Eiichiro Komatsu Michael Nolta UBC Mark Halpern Chicago Stephan Meyer Brown Greg Tucker UCLA Ned Wright Science Team: WMAP A partnership between NASA/GSFC and Princeton Lyman Page Hiranya Peiris David Spergel Licia Verde
WMAP Spacecraft MAP990422 thermally isolated instrument cylinder secondary reflectors focal plane assembly feed horns back to back Gregorian optics, 1.4 x 1.6 m primaries upper omni antenna line of sight deployed solar array w/ web shielding medium gain antennae passive thermal radiator warm spacecraft with: - instrument electronics - attitude control/propulsion - command/data handling - battery and power control 60K 90K 300K
Why low 1/f ? One of 20 Spin rate A-B-A-BB-A-B-A Differential design... ….mK thermal stability Amplifiers from NRAO, M. Pospieszalski design Noise in maps Gaussian over five decades. Jarosik et al.
Physical temperature of receivers Sun referenced azimuth WMAP computer error rate GOES proton flux Physical temperature of primary Limon et al.
Trajectory 100 days to L2, 1.5e6 km from Earth. Lunar swingby Phasing loops Co-rotating potential. Official arrival date: Oct 1, 2001
Scan pattern Need to scan in a criss-cross pattern to avoid striping and to minimize pixel-pixel correlations. (Wright and Tegmark) 1) Phase switch 2.5 KHz 2) Spin at 2.2 min/rev 3)Precess through 30% of the sky in 1 hour. 4) Full sky every 6 months. Four fold switching: Precession Rate: 1rph 22.5° half-angle A-side Line of sight B-side Line of sight Spin rate 0.464 rpm MAP at L2 Earth Sun 1.5 x 10 8 km North Ecliptic Pole South Ecliptic Pole +90°+45°
Of special importance... 1) Remove dipole from time ordered data. 2) Bin 40 days of data synchronously with the Sun position. 3) Find: There are no corrections for spin synchronous artifacts!
COBE-WMAP Comparison COBE WMAP Temperature (µK) +200-200 Temperature (µK) +200-200
COBE-WMAP Comparison Difference Noise Temperature (µK) +100-100
Internal Linear Combination CMB Temperature (µK) +200-200
SUMDIFFERENCE Q V W Passband mismatch Less coverage K and Ka for foregrounds
Best fit model Prediction based on TT, no free params. cosmic variance Temperature Temperature- polarization 1 deg 85% of sky
The Future: Systematics Refined parameters Lensing Polarization http://lambda.gsfc.nasa.gov Data available through: WMAP is funded for 4 y. Satellites & Balloon PLANCK & CMBPOL Large ground based CMB telescopes Boomerang... ACT, APEX, SPT, …..