Kumar, J and Dutta, P and Choudhuri, S and Roy, N (2022) Calibration requirements for Epoch of Reionization 21-cm signal observations - II. Analytical estimation of the bias and variance with time-correlated residual gains. In: Monthly Notices of the Royal Astronomical Society, 512 (1). pp. 186-198.
Full text not available from this repository.Abstract
Observation of redshifted 21-cm signals from neutral hydrogen holds the key to understanding the structure formation and its evolution during the reionization and post-reionization era. Apart from the presence of orders of magnitude larger foregrounds in the observed frequency range, the instrumental effects of the interferometers combined with the ionospheric effects present a considerable challenge in the extraction of 21-cm signals from strong foregrounds. The systematic effects of time- and frequency-correlated residual gain errors originating from the measurement process introduce a bias and enhance the variance of the power spectrum measurements. In this work, we study the effect of time-correlated residual gain errors in the presence of strong foreground. We present a method to produce analytic estimates of the bias and variance in the power spectrum. We use simulated observations to confirm the efficacy of this method and then use it to understand various effects of the gain errors. We find that as the standard deviation in the residual gain errors increases, the bias in the estimation supersedes the variance. It is observed that an optimal choice of the time over which the gain solutions are estimated minimizes the risk. We also find that the interferometers with higher baseline densities are preferred instruments for these studies.
| Item Type: | Journal Article |
|---|---|
| Publication: | Monthly Notices of the Royal Astronomical Society |
| Publisher: | Oxford University Press |
| Additional Information: | The copyright for this article belongs to the Authors. |
| Keywords: | Cosmology; Interferometers; Numerical methods; Risk perception; Systematic errors, Bias and variance; Cosmology: dark age, reionization; Gain errors; Method: numerical; Methods:analytical; Methods:statistical; Reionization; Residual gains; Technique: interferometric; Time-correlated, Power spectrum |
| Department/Centre: | Division of Physical & Mathematical Sciences > Physics |
| Date Deposited: | 24 Jun 2022 11:25 |
| Last Modified: | 24 Jun 2022 11:25 |
| URI: | https://eprints.iisc.ac.in/id/eprint/73657 |
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