Séminaire / Seminar GReCO |
| « Shedding Light on Dark Energy: First Results from BOSS-Lyman-alpha » |
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Nicolas Busca |
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The acceleration in the expansion of the Universe, discovered in the late 90's from SNe data, was a big surprise and remains a mystery. Is it due to an incorrect understanding of gravity or to the presence of the mysterious "dark energy"? Baryon acoustic oscillations in the primordial universe imprint a distance scale in the distribution of matter. The BOSS survey exploits this calibrated distance scale to measure the expansion rate with a low-redshift probe -galaxies at z~0.6- and a high-redshift probe -the Lyα forests of distant quasars, at z ~ 2.3. In particular, the Lyα technic is novel at was introduced by BOSS for the first time.
In this talk I will describe the BOSS-Lyα survey and its cosmological context. I will discuss also its first results which, in particular, demonstrate the deceleration of the Universe which predates the acceleration. |
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mardi 21 février 2012 - 14:00 Amphithéâtre Henri Mineur Institut d'Astrophysique de Paris |
| Pages web du séminaire / Seminar's webpage |