Cosmology Lunchtime Seminar

All future


Monday, October 23rd 2017
12:15 pm:
Speaker: Colin Hill, Department of Physics, Columbia University
Subject: New Information in Ancient Photons: Novel Approaches to CMB Foregrounds and Secondary Anisotropies

Studies of the cosmic microwave background (CMB) radiation have driven the current era of precision cosmology. The tightest cosmological constraints to date have been derived from the primary CMB anisotropies, which predominantly probe the universe in its infancy. However, CMB experiments have recently entered a new regime in which constraints derived from the secondary anisotropies -- sourced by effects between our vantage point and the surface of last scattering -- substantially improve upon those derived from the primary anisotropies alone. Moreover, the secondary anisotropies contain valuable astrophysical information about the distribution and thermodynamic properties of baryons and dark matter at late times. I will describe new approaches to extract information from these signals, highlighting recent results related to the thermal (tSZ) and kinematic Sunyaev-Zel'dovich (kSZ) effects, which refer to the Compton-scattering of CMB photons off ionized gas with high temperature or non-zero bulk momentum, respectively. In particular, I will show how the kSZ effect probes the abundance of ionized gas in and around modern-day galaxies, which I have used to resolve the long-standing "missing baryon problem". I will then discuss new methods for combining multi-frequency CMB data to extract these signals in the presence of large (and correlated) foregrounds, with additional applications to CMB polarization analyses. I will conclude with a look ahead to such measurements with the Simons Observatory (SO), focusing on methods to determine the optimal frequency coverage of the large-aperture SO telescope for secondary anisotropy science, including CMB lensing.

Faculty Host: Shaul Hanany

Monday, October 30th 2017
12:15 pm:
Speaker: Andrew Matas, UMN
Faculty Host: Vuk Mandic

Monday, November 6th 2017
12:15 pm:
Speaker: Vihang Mehta, UMN
Subject: Galaxy formation
Faculty Host: M. Claudia Scarlata

Monday, November 13th 2017
12:15 pm:
Speaker: Karl Young, UMN
Faculty Host: Shaul Hanany

Monday, November 20th 2017
12:15 pm:
Speaker: Allison Noble, MIT, Kavli Institute
Subject: Dissecting z~1 Galaxy Clusters
Faculty Host: Lawrence Rudnick

Monday, November 27th 2017
12:15 pm:
Speaker: Nader Mirabolfathi, Texas A&M University
Subject: Directional dark matter detector
Faculty Host: Priscilla Cushman

Monday, December 4th 2017
12:15 pm:
Speaker: Larry Rudnick, UMN

Monday, December 11th 2017
12:15 pm:
Speaker: Patrick Kelly, UMN

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