APEC Seminar (Astronomy - Particle Physics - Experimental Physics - Cosmology)

Speaker: Aravind Natarajan (Kavli IPMU)
Title: The end of the dark ages
Date (JST): Thu, Jan 15, 2015, 11:00 - 12:00
Place: Seminar Room D
Abstract: The study of reionization is crucial to our understanding of the nature of the earliest luminous objects, and the formation of the first galaxies. In the coming years, experiments measuring the 21 cm radiation background and the cosmic microwave background will provide data that can probe reionization, and shed light on theories of structure formation. We describe a new radio experiment that attempts to measure the redshifted 21 cm brightness temperature in the frequency range 50-120 MHz, i.e. at redshifts 10<z<25. We discuss preliminary results from our test run, and plans for future deployments. We then discuss how CMB experiments can constrain reionization models. We describe a new technique that can detect patchy reionization using correlations between large and small scales in the CMB temperature maps. We test our patchy reionization estimator using realistic ionization and CMB maps obtained using numerical simulations. We discuss how future data can determine the mean redshift of reionization, as well as its duration.