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OATS-DAUT SEMINAR
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Speaker: Fabrizio Nicastro (INAF/Oss. Astr. Monteporzio)

Title: The Missing Baryon Hunt

Date: Wednesday, November 21th, 2007
Time: 12:00
Venue: Villa Bazzoni

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Abstract:
Despite recent progress in cosmology in assaying the composition of the energy-mass budget of the Universe, within the framework of our Standard Cosmological Model (SCM), very little is still known about nature and origin of 95 % of these constituents: dark Energy and dark Matter. These have the name 'dark' mainly to label our inability to directly detect and identify them. Less well known is that the situation is only conceptually better for the remaining 5 % of Omega: these are baryons, i.e. the constituents of the ordinary matter of which stars, planets, and ourselves are made. Today we can account for less than 50% of the baryons that the SCM predicts, implying that at least 50 % of the baryons are now missing. Finding and counting these baryons is therefore vital to our understanding of the Universe, and a necessary condition to validate the SCM. After a brief introduction of the problem, I will review all the different and independent pieces of evidence for these baryons, and will show that the majority of them is indeed still missing. In the second part of my talk I will then try to identify new promising lines of research, which will hopefully allow us in the near future to hone our techniques of hunt and to converge toward a possible solution of this important and still open astrophysical problem.
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contact: Pierluigi Monaco (DAUT)