Gravity Group Astrophysics|Cosmology Lunch: Renee Hlozek, "Planck Data Reconsidered"(More about event)
We re-analyze the Planck data and find that the 217GHz x 217GHz detector set spectrum used in the Planck analysis is responsible for some of the tension between the Planck parameters and other astronomical measurements. We will describe our map-based foreground cleaning procedure, which relies on a combination of 353 GHz and 545 GHz maps to reduce residual foregrounds in the intermediate frequency maps used for cosmological inference. While in broad agreement with the results reported by the Planck team, the parameters we obtain using our foreground cleaning imply a universe with a lower matter density of Omega_m=0.302 +- 0.015, and parameter values generally more consistent with pre-Planck CMB analyses and astronomical observations. We compare our cleaning procedure with the foreground modeling used by the Planck team and find good agreement. The difference in parameters between our analysis and that of the Planck team is mostly due to our use of cross-spectra from the publicly available survey maps instead of their use of the detector set cross-spectra which include pixels only observed in one of the surveys. We show evidence suggesting residual systematics in the detector set spectra used in the Planck likelihood code, which is substantially reduced for our spectra.
Location: Joseph Henry Room
Date/Time: 04/04/14 at 12:00 pm - 04/04/14 at 1:30 pm
Category: Gravity Group Seminar