| Description: | The Epoch of Reionisation (EoR) marks the cosmic period during which the neutral hydrogen that pervaded the Universe transitioned to an almost entirely ionised state. The most promising probe of the EoR is the redshifted 21 cm line, which has the potential to characterise the 3-dimensional distribution of neutral hydrogen. The statistical detection of its spatial fluctuations is a prime objective of modern low-frequency radio interferometers, though instrumental systematics and calibration errors pose an immense challenge. In this talk, I will discuss a calibration-independent method of detecting the cosmological signal fluctuations using the interferometric closure phase. I discuss recent developments in the interpretation of the closure phase delay power spectrum and present constraints on it obtained from a full season of observations from the Hydrogen Epoch of Reionization Array (HERA). |
