Department of Physics
Research, teaching and outreach in Physics at UW–Madison

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NPAC (Nuclear/Particle/Astro/Cosmo) Forum
Peculiar Velocity and its Effects on Cosmology with 21cm Tomography
Date: Thursday, February 3rd
Time: 4:00 pm
Place: 4274 Chamberlin Hall
Speaker: Yi Mao, UT Austin
Abstract: The peculiar velocity of the intergalactic gas responsible for the cosmic 21cm background from the epoch of reionization and beyond introduces an anisotropy in the three-dimensional power spectrum of brightness temperature fluctuations. We review how measurement of this anisotropy by future 21cm surveys is a promising tool for separating cosmology from 21cm astrophysics. A more careful treatment of the effects of peculiar velocity than previously attempted is necessary, however, to fulfill this promise. In this talk, we set out to account for peculiar velocity in every detail, and clarify the roles of thermal vs. velocity broadening and finite optical depth.
We will also find whether nonlinear effect of peculiar velocity may spoil future 21cm measurements. The discussion in this talk, although in the context of the Epoch
of Reionization, may affect the interpretation of the 21cm intensity mapping in the post-reionization epoch.
Host: Peter Timbie and Vernon Barger
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