Scientific optimization of a ground-based CMB polarization experiment

• Main Authors: Bowden, M, Taylor, A N, Ganga, K, Ade, P A R, Bock, J J, Cahill, G, Carlstrom, J E, Church, S E, Gear, W K, Hinderks, J R, Hu, W, Keating, B G, Kovács, J, Lange, A E, Leitch, E M, Mallie, O E, Melhuish, S J, Murphy, J A, Piccirillo, L, Pryke, C L, Rusholme, B A, O'Sullivan, C, Thompson, K
• Language: English
• Published: 2003
• Subjects: Astrophysics and Astronomy; South Pole; South pole
• Online Access: http://cds.cern.ch/record/644479

We investigate the science goals achievable with the upcoming generation of ground-based Cosmic Microwave Background polarization experiments and calculate the optimal sky coverage for such an experiment including the effects of foregrounds. We find that with current technology an E-mode measurement will be sample-limited, while a B-mode measurement will be detector-noise-limited. We conclude that a 300 sq deg survey is an optimal compromise for a two-year experiment to measure both E and B-modes, and that ground-based polarization experiments can make an important contribution to B-mode surveys. Focusing on one particular experiment, QUaD, a proposed bolometric polarimeter operating from the South Pole, we find that a ground-based experiment can make a high significance measurement of the acoustic peaks in the E-mode spectrum, and will be able to detect the gravitational lensing signal in the B-mode spectrum. Such an experiment could also directly detect the gravitational wave component of the B-mode spectrum if the amplitude of the signal is close to current upper limits. We also investigate how a ground-based experiment can improve constraints on the cosmological parameters. We estimate that by combining two years of QUaD data with the four-year WMAP data, an optimized ground-based polarization experiment can improve constraints on cosmological parameters by a factor of two. If the foreground contamination can be reduced, the measurement of the tensor-to-scalar ratio can be improved by up to a factor of six over that obtainable from WMAP alone.