New maps of cosmic background radiation have helped scientists realize that the “reionization” process could be more recent than estimated until now.
Reionization, a key process in cosmology, is associated with star formation, which cosmologists date back to after the “dark ages” of the Universe, when there was still no starlight.
The NASA WMAP satellite, launched in 2001, had given an initial estimate of the period when the process may have taken place.
The discovery, which still requires validation by the measurements that Planck is still able to provide that will be published in about a year’s time, is associated with the publication of maps of “polarized” cosmic background radiation (the first light in the Universe produced by the Big Bang).
WMAP was the first satellite to attempt to provide this map, but today new Planck data suggest that reionization may have occurred approximately 550 million years after the Big Bang, i.e., 100 million years later than WMAP had estimated.
“According to Planck’s observations, stars may be younger than believed, in bearing with other independent astrophysical indicators, and this finding may have major consequences on our attempts to understand the dark components of the Universe”, explains Carlo Baccigalupi, SISSA
cosmologist and coordinator of the SISSA group involved in the Planck experiment. The contribution of the Trieste team involved in producing maps for the LFI on board Planck – consisting of SISSA and INAF-OATS scientists coordinated by Andrea Zacchei – was to generate new maps of the polarized light seen by the LFI which cover the whole sky.
“Now we’re awaiting data from the high-frequency instrument (HFI), whose maps are mostly constructed by the French team. These additional maps should provide confirmation and a clearer picture of the evidence we detected” said Baccigalupi.