Bulletin of the American Physical Society
APS April Meeting 2011
Volume 56, Number 4
Saturday–Tuesday, April 30–May 3 2011; Anaheim, California
Session J3: New Results from the Cosmos |
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Sponsoring Units: DAP Chair: Neil Cornish, Montana State University Room: Garden 3 |
Sunday, May 1, 2011 1:30PM - 2:06PM |
J3.00001: The Backlit Universe: How Distant Quasars Illuminate the Large Scale Structure Invited Speaker: 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. Using the 14,000 quasars from the first year data, the BOSS experiment has detected, for the first time, three-dimensional correlations in the Lyman-alpha forest fluctuations to cosmological distances. The signal has thhe expected amplitude and redshift-space distortions and we find no evidence for overwhelming instrumental or astrophysical contamination. The BOSS experiment was projected to measure the distance to the redshift of $z \sim 2.5$ with a better than 2\% precision through detection of baryonic acoustic signature in the flux correlations. The present results give these forecasts new credibility. [Preview Abstract] |
Sunday, May 1, 2011 2:06PM - 2:42PM |
J3.00002: Catching Shadows: Kepler's Year-Two Transit Census Invited Speaker: Launched in March, 2009, NASA's Kepler Mission is poised to determine the abundance of earth-size planets in the Galaxy. The project has hosted two major data releases, providing the astronomical community with four months of nearly continuous, high-precision photometry of all stars targeted as part of the Kepler planet search. A catalog of nearly 1,000 stars with transiting planet candidates, more than 70\% of which are smaller than Neptune, accompanied the data release (Borucki et al. 2011). Ground-based follow-up observations, transit timing observations, and blend analyses have all played a major role in validating the planet interpretation, leading to major mission milestones such as the discovery of Kepler's first rocky planet, Kepler-10b, and the discovery of six transiting planets orbiting the same star, Kepler-11. Multiple transiting planet candidate systems are abundant in the released data. Dynamical studies suggest that the false-positive rate for these systems will likely be less than 10\%, and the potential for determining planet masses via transit timing variations hold much promise for confirming the smallest planet candidates. I will present an overview of Kepler's recent discoveries and our progress towards the ultimate objective which is to determine the frequency of habitable, earth-size planets. [Preview Abstract] |
Sunday, May 1, 2011 2:42PM - 3:18PM |
J3.00003: Herschel/Planck Invited Speaker: |
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