1. Physics Colloquium

    "Detection of Baryonic Acoustic Oscillations in Lyman-alpha forest"

    Presented by Anze Slosar, BNL

    Tuesday, March 19, 2013, 3:30 pm
    Large Seminar Room, Bldg. 510

    Hosted by: Peter Petreczky

    The biggest problem in astronomy has always been measurement of the distances to astronomical objects. The same is true of cosmology, where measuring distances in physical units as a function of redshift allows one to measure the expansion history of the universe and thus constrain properties of components of the universe, such as dark energy and dark matter. Baryonic acoustic oscillations are one technique to measure distances in the Universe by using a feature in the correlation function of large scale structure in the universe as a ruler of a known physical length. We present a first measurement of baryon acoustic oscillation features at z ~ 2.4 in the three-dimensional correlation function of the transmitted flux fraction in the Lyman-alpha forest of BOSS quasars. Our results are derived from a sample of ~50K high-redshift quasars from the Data Release 9 of the Baryon Oscillation Spectroscopic Survey (BOSS), part of the Sloan Digital Sky Survey (SDSS-III). This measurement deep in the decceleration regime is capable of uniquely detecting some types of deviations from the LCDM model such as early dark energy.