Robust Foregrounds Removal for 21-cm Experiments

How well can we measure and understand foregrounds with 21 cm experiments?

Before it becomes a sensitive probe of the Epoch of Reionization, the Dark Ages, and fundamental physics, 21 cm tomography must successfully contend with the issue of foreground contamination. Broadband foreground sources are expected to be roughly four orders of magnitude larger than any cosmological signals, so precise foreground models will be necessary. Such foreground models often contain ...

A method for 21 cm power spectrum estimation in the presence of foregrounds

Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. The MIT Faculty has made this article openly available. Please share how this access benefits you. Your story matters. The technique of 21 cm tomography promises to be a powerful tool for estimating cosmological parameters, constraini...

Foregrounds for redshifted 21 cm studies of reionization : GMRT 153 MHz observations

Foreground subtraction is the biggest challenge for future redshifted 21 cm observations to probe reionization. We use a short GMRT observation at 153MHz to characterize the statistical properties of the background radiation across ∼ 1◦ to sub-arcminutes angular scales, and across a frequency band of 5MHz with 62.5 kHz resolution. The statistic we use is the visibility correlation function, or ...

An improved method for 21-cm foreground removal

21-cm tomography is expected to be difficult in part because of serious foreground contamination. Previous studies have found that line-of-sight approaches are capable of cleaning foregrounds to an acceptable level on large spatial scales, but not on small spatial scales. In this paper, we introduce a Fourier space formalism for describing the line-of-sight methods, and use it to introduce an i...

Global 21 cm signal experiments : A designer ’ s guide