Dr. Anže Slosar: Measuring the large-scale structure of the Universe at redshifts above 2

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    Measuring the large-scale structure of the Universe at  redshifts above 2

    Dr. Anže Slosar, Brookhaven National Laboratory, Upton, NY (http://www.cosmo.bnl.gov/)

The Lyman-alpha forest is a series of absorption features in the spectra of distant quasars, blue-ward of the Lyman-alpha emission line. These features arise as the light from the quasar is absorbed by the intervening neutral hydrogen. This gives one-dimensional information about the fluctuations in the neutral hydrogen density along the line of sight to the quasar. When spectra of many quasars are combined, it allows one to build a three-dimensional image of the fluctuations in the neutral hydrogen density and thus infer the corresponding fluctuations in the matter density. This makes the Lyman-alpha forest a unique probe of the distant Universe, opening a novel window on understanding dark energy, dark matter, neutrino properties and inflation. BOSS experiment has detected, for the first time, correlations in the Lyman-alpha forest fluctuations to cosmological distances. It will measure around 160,000 high redshift quasars and constrain dark energy. BigBOSS will be even fierecer and measure spectra of around a million high-redshift quasars.