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Astro & GW Colloquium

The First Large Absorption Survey in HI: A history of cold gas in the Universe

Speaker: Dr James Allison (University of Oxford)
Date: Wednesday 28 November 2018
Time: 14:00
Venue: Queens Buildings N/3.28

The First Large Absorption Survey in HI with the Australian SKA Pathfinder (ASKAP) will provide a unique perspective on the cool (< 1000 K) gas that fuels star formation and black hole growth in galaxies throughout cosmic history. By detecting the HI 21-cm line in absorption towards distant radio-loud active galactic nuclei (AGN), we will use ASKAP to construct a census of neutral gas in intervening galaxies over the past 8 billion years. I will discuss a recent paper in which I proposed a method for measuring the fraction of cold-phase atomic hydrogen using a statistical approach based on the number of expected detections. I will also present early science results from ASKAP, which have successfully demonstrated the feasibility of carrying out such an all-sky survey.