Cosmology Seminar

Cosmology Seminars are held at on Mondays at 11 am during the academic year, on the 3rd floor Varian conference room. These are more focused and less didactic than the colloquium, and provide a stage for younger researchers to present their work in more detail.  

Please contact Risa WechslerDaniel GruenJosh Meyers, or Kyle Story for more information.

Probing Dark Energy with Galaxy Clusters

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Location

Campus, Varian 355

Speaker
Hao-Yi (Heidi) Wu (The Ohio State University)

Galaxy cluster surveys have been recognized as one of the most powerful probes of dark energy, but their constraining power is limited by the accuracy of mass calibration.  I will present my research on using simulations to improve mass calibration methods, including galaxy dynamics, weak gravitational lensing, clustering, and X-ray observations.  These results not only mitigate the systematic uncertainties in current cluster surveys but also

Primordial Non-Gaussianities (PNG) and zero bias tracers of the Large Scale Structure

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Location

Campus, Varian 355

Speaker
Emanuele Castorina (Berkeley Center for Cosmological Physics)

The statistical properties of the primordial curvature perturbations are a key ingredient of the success of the LCDM model in explaining the Universe as we observe it today.

 

Testing the nature of dark matter and galaxy formation with small-scale structure

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Location

Campus, Varian 355

Speaker
Anna Nierenberg (UC Irvine)

The abundance of low mass halos provides a fundamental constraint of the nature of dark matter via the free-streaming length. Models with GeV scale dark matter (Cold Dark Matter) match observations of structure remarkably well for mass scales above that of the Milky Way. At lower masses, such comparisons become more difficult as galaxies become fainter, and theoretical predictions for how galaxies form become more uncertain.

Simulating galaxy clusters (and their galaxies!) with IllustrisTNG

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Location

Campus, Varian 355

Speaker
Annalisa Pillepich (Max Planck Institute for Astronomy)

The IllustrisTNG simulations (www.tng-project.org) are a novel laboratory to explore galaxy physics and to quantify the assembly and evolution of galaxy populations across an unprecedented range of halo masses, environments, evolutionary stages and cosmic times.

Edge of darkness: The splashback radius as a physical halo boundary

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Location

Campus, Varian 355

Speaker
Benedikt Diemer (Harvard)

The radii and masses of dark matter halos are an essential input for models of galaxy formation, and for the interpretation of numerous observations. These radii are typically defined through an arbitrary overdensity threshold, largely because the density profiles of halos are thought not to have a well-defined edge.

Hyper Suprime-Cam Weak Lensing Measurement of Galaxy Clusters selected by Atacama Cosmology Telescope Polarimeter

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Location

Campus, Varian 355

Speaker
Hironao Miyatake (Institute for Advanced Research, Nagoya University)

Galaxy clusters are one of the most powerful cosmological probes because of an exponential tail at the high-mass end of the cluster mass function. The accuracy of mass function measurement is currently limited by systematic uncertainties in cluster mass estimates due to an uncertain physical assumption, e.g., hydrostatic equilibrium when using X-ray observables.

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