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The Australia Telescope National Facility Colloquium
12:30 Thu 13 Sep to 01:30 Thu 13 Sep 2012

Basement Conference Room

Rennan Barkana

(Tel Aviv University)

Detecting the First Stars at Redshift 20 -- Rennan Barkana Seminar

Understanding the formation and evolution of the first stars and galaxies is one of the exciting frontiers in astronomy. Since the universe was filled with neutral hydrogen at early times, the most promising method for observing the epoch of the first stars is using the prominent 21-cm spectral line of hydrogen. Current observational efforts are focused on the reionization era (around redshift 10), with earlier times considered much more challenging. We show that stars at redshift 20 may be observable as a result of a recently noticed effect of relative velocity between the dark matter and gas. We produce simulated maps of the first stars and show that the relative velocity effect significantly enhances large-scale clustering and produces a prominent cosmic web on 100 comoving Mpc scales in the 21-cm intensity distribution. The particular signature of this clustering should make it
easier to confirm the existence of million solar-mass halos at early times.

More information


Ryan Shannon

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