Project: Chromatic effect on the 21-cm global EoR signal

I am involved in experiments to measure two aspects of the 21-cm signal from the epochs of Cosmic Dawn and Reionization. The first is the global (or all sky) componenet of the signal. This is the mean level of the signal on which fluctuations reside. The second aspect is the spatial fluctuations on top of the global mean level. The global 21-cm tell us about the bulk ionization and thermal state of the Universe. This component is also brighter, and can in principle be measured within a day based on signal to noise ratio argument. However, as always, spectral (frequency domain) calibration is the biggest hurdle. In this project, I evaluated two sources of spectral contamination- a frequency dependent instrumental beam, and frequency dependent ionispheric refraction and absorption. I also developed a data processing strategy (using Princical Component Analysis) that can mitigate these spectral corruptions.

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Earth's atmosphere