2013/01/31 by Gregory Paciga, Joshua G. Albert, Kevin Bandura +10 · 1 citation
Physics and Astronomy · #astro-ph.CO
paper · pdf · doi:10.1093/mnras/stt753
10 pages, 11 figures, accepted for publication in MNRAS
arxiv created 2013/05/13 · arxiv updated 2015/06/12
The GMRT Epoch of Reionization (EoR) experiment is an ongoing effort to measure the power spectrum from neutral hydrogen at high redshift. We have previously reported an upper limit of (70 mK)2 at wavenumbers of k=0.65 h/Mpc using a basic piecewise-linear foreground subtraction. In this paper we explore the use of a singular value decomposition to remove foregrounds with fewer assumptions about the foreground structure. Using this method we also quantify, for the first time, the signal loss due to the foreground filter and present new power spectra adjusted for this loss, providing a revised measurement of a 2-sigma upper limit at (248 mK)2 for k=0.50 h/Mpc. While this revised limit is larger than previously reported, we believe it to be more robust and still represents the best current constraints on reionization at z=8.6.