Physics with Planck Surveyor mission

Department of Physics and Helsinki Institute of Physics, University of Helsinki

Planck is a European Space Agency (ESA) satellite, launched on May 14, 2009. Its purpose is to measure the cosmic microwave background (CMB) over the entire sky, with high resolution and sensitivity, and wide frequency coverage. These measurements will surpass earlier measurements by a wide margin, and Planck data will be the most important cosmological data set of the coming decade. The best CMB data before Planck is from the WMAP satellite. Planck measures the CMB at 9 different frequency ranges, centered at 30, 44, 70, 100, 143, 217, 353, 545, and 857 GHz. Both temperature and polarization variations are measured. The detectors for these different frequencies are grouped into two instruments. The three lowest frequencies make up the Low Frequency Instrument (LFI), and use a different technology than the detectors for the six highest frequencies which make up the High Frequency Instrument (HFI). Finnish engineers have developed and built the 70 GHz detectors. This is an important frequency channel, because at these frequencies the cosmological signal is the least contaminated by microwave radiation from other astrophysical sources (the microwave "foreground").

Read more about CMB and Planck, and the impact on cosmology here.

In the Planck project we are part of the LFI Consortium and Working Group 3, also known as the CTP Working Group (C(l),Temperature and Polarisation).

Currently we contribute especially to the map-making and closely related parts of the data analysis. We developed two map-making codes, Polar and Madam, which are based on the destriping approach. The difference between them was that Madam utilizes prior knowledge on the detector noise properties, whereas Polar does not. The two codes have now been merged into one, called Madam, where the use of prior noise information is optional. Madam is the main map-making code of the LFI Data Processing Center (Trieste, Italy). Some maps made by Polar and Madam can be seen in the two posters we have prepared for Planck Consortium meetings: