Optimizing global 21cm signal measurements with spectral and spatial information
Adrian Liu
MIT
Despite major advances in cosmology within the last few decades, there is
still considerable uncertainty as to how the first luminous objects formed
during the Epoch of Reionization (EoR). Measuring the 21cm line at the
relevant redshifts has been shown to be a promising way to probe this era,
at least in theory. In practice, such observations are difficult because
the cosmological signals are expected not only to be extremely faint,
but also to be contaminated by overwhelming bright foreground sources.
In this talk, I will focus on a particular flavor of 21cm experiments
-- the "global signal" measurements, where the 21cm signal is averaged
over the entire sky and measured as a function of redshift. I will
argue that is difficult (if not impossible) to mitigate foreground
contamination without fine angular resolution, even though the ultimate
goal is a signal averaged over the entire sky. Using a combination of
simulations and analytic calculations, I will show that with the right
data analysis/foreground subtraction techniques, an experiment with good
angular resolution should be able to detect a cosmological 21cm signal
at extremely high significance. This is encouraging news, for it suggests
that even with severe foreground contamination, it should be possible to
place interesting constraints on the EoR using global 21cm experiments.
Date: | Mercredi, le 25 janvier 2012 |
Heure: | 14:30 |
Lieu: | Université McGill |
| Ernest Rutherford Physics Building, R.E. Bell Conference Room (room 103) |
Contact: | Robert Rutledge |
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