A Method for 21cm Power Spectrum Estimation in the Presence of Foregrounds
arXiv:1103.0281 · doi:10.1103/PhysRevD.83.103006
Abstract
21cm tomography promises to be a powerful tool for estimating cosmological parameters, constraining the epoch of reionization, and probing the so-called dark ages. However, realizing this promise will require the extraction of a cosmological power spectrum from beneath overwhelmingly large sources of foreground contamination. In this paper, we develop a unified matrix-based framework for foreground subtraction and power spectrum estimation, which allows us to quantify the errors and biases that arise in the power spectrum as a result of foreground subtraction. We find that existing line-of-sight foreground subtraction proposals can lead to substantial mode-mixing as well as residual noise and foreground biases, whereas our proposed inverse variance foreground subtraction eliminates noise and foreground biases, gives smaller error bars, and produces less correlated measurements of the power spectrum. We also numerically confirm the intuitive belief in the literature that 21cm foreground subtraction is best done using frequency rather than angular information.
24 pages, 11 figures; replaced with accepted PRD version (minor editorial changes to text; methods, results, and conclusions unchanged)
References in corpus (11)
- Baryon Acoustic Oscillation Intensity Mapping as a Test of Dark Energy
- How accurately can 21 cm tomography constrain cosmology?
- Foreground simulations for the LOFAR - Epoch of Reionization Experiment
- An Improved Method for 21cm Foreground Removal
- Toward Empirical Constraints on the Global Redshifted 21 cm Brightness Temperature During the Epoch of Reionization
- Power spectrum extraction for redshifted 21-cm epoch of reionization experiments: the LOFAR case
- Non-parametric foreground subtraction for 21cm epoch of reionization experiments
- Will point sources spoil 21 cm tomography?
- De-contamination of cosmological 21-cm maps
- Constraining massive neutrinos using cosmological 21 cm observations
- Cosmological and Astrophysical Parameter Measurements with 21-cm Anisotropies During the Era of Reionization