| The CMB Sky The image shows part of the cosmic microwave background (CMB) sky as measured by three different experiments. In the upper left corner are COBE1 data at a resolution of 7 degrees. Next is the CMB as seen at 94GHz by WMAP2, with a resolution of ~15 arcm. Instrument noise dominates at the pixel scale, so the image has been smoothed to the angular resolution at which it was measured. Next is a strip in which WMAP data from all bands are combined and smoothed, controlling foreground emission and noise at the expense of angular resolution. Next is simulated Planck temperature data, smoothed to 5 arcm. The increase in resolution of Planck compared to the other two experiments is apparent. Finally, simulated Planck polarization data, smoothed to 15 arcm, are shown superimposed on the temperature anisotropies using a vector field visualization technique described below. Planck’s sensitivity, angular resolution, and frequency coverage will allow it to extract essentially all available information on primary CMB temperature anisotropies, and make a dramatic advance in measurements of CMB polarization. 1Smoot, et al. 1991, ApJL, 371, L1 2Bennett, et al, 2003, ApJS, 148, 1 |
| The Planck Satellite The photographs show the construction and integration of Planck at Alcatel in Cannes, with the spacecraft bus, V-groove radiators, and telescope easily visible. The Cryogenic Qualification Model (CQM) is shrouded. The Flight Model in these photos includes only the spacecraft bus and the V-groove assembly, which provides thermal isolation and radiative cooling between the warm spacecraft bus and the cold telescope and instrument assembly. The images at the bottom show the CQM being shipped from Alcatel to CSL in Liege for thermal/vacuum testing. In flight, the telescope temperature is expected to be well below 50 K. Below is the Planck payload qualification model at Alcatel (Cannes), in the configuration used for acoustic testing. The qualification model of the primary reflector can be seen.  |
| Visualizing
Polarization It is difficult  simultaneously to represent CMB temperature
fluctuations and the direction and magnitude of the CMB’s partial
polarization on the same 2-dimensional sky map. The approach we
have used is a line integral convolution technique suggested by Cabral
and Leedom3. The detail in the image is
much finer than a printer can show. An enlarged version of part
of
the map is shown to the right. The direction of the ‘stripes’
indicates the direction of the polarization. Darker stripes
indicate stronger polarization; the stripes fade away as the
polarization drops to zero. All of this is overlaid on the conventional
temperature map.3Cabral and Leedom 1993, Proceedings of the 20th Annual Conference on Computer Graphics and Interactive Techniques, p263-270 |