Colloquium

Status, challenges, and new perspectives for detecting structures in the very early Universe

Abstract: Direct detection of evolving neutral Hydrogen structures from the Cosmic Dawn and Reionization Epochs (EoR) will reveal the nature of the first stars and galaxies as well as complete our understanding of a significant evolutionary phase of the Universe. In contrast with some recent exciting results from the EDGES experiment, many experiments such as the MWA, LOFAR, and PAPER that commenced in the last decade with the promise of high significance statistical detection of the EoR have so far only weakly constrained models owing to underestimation of challenges from bright foreground sources and instrument systematics. These include chromatic effects from wide-field effects, antenna apertures, reflections from the mechanical and electrical interfaces in the instrument, antenna position errors, calibration errors, etc. I will describe results from my work that focuses on identifying, characterizing and providing design and analysis solutions to these various challenges which will be critical to not only enable a detection but also to place meaningful cosmological and astrophysical constraints. One of the primary limitations in analysis arises from the challenge of very high precision calibration. I will discuss a novel and a complementary approach using bi-spectrum phase that bypasses the stringent calibration requirements limiting existing approaches and could potentially improve the prospects of detecting structures during cosmic reionization. I will discuss pathways to estimating the HI brightness temperature fluctuations and its evolution with redshift in this approach. ----------

Followed by wine and cheese in Pupin 1402.

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