Events Archive

Dwarf galaxies are extremely diverse in their morphology, from rotationally-supported star-forming disks to gas-free spheroidal stellar systems with no star-formation and negligible rotation.

Abstract | From satellites orbiting about the Earth to the large-scale structure of the universe, all astrophysical systems are dominated by gravitational forces. In theory, this should make it easy for us to test General Relativity (GR) and its many proposed extensions.

The Cosmology Large Angular Scale Surveyor (CLASS) is an experiment to measure the signature of a gravitational-wave background from inflation in the polarization of the cosmic microwave background (CMB). CLASS is a multi-frequency array of four telescopes operating from a high-altitude site in the Atacama Desert in Chile.

Abstract: I will show weak lensing results from the Sloan Digital Sky Survey and the Dark Energy Survey. From Sloan data we use new methods to measure the mass distributon and clustering of cosmic voids and filaments. We also measure the ellipticity of galaxy and cluster halos and relate it to the light.

Talk 1 Title: Backsplash in dark matter halos Abstract: Recent work has shown that halos in cosmological N-body simulations exhibit a pronounced feature in their density profiles at large radii. I will explain the origin of this newly discovered feature, and describe how it could be used as a ruler to probe cosmology.

Magnetars are surrounded by diffuse relativistic plasma in magnetic field strengths well above the quantum electrodynamic (QED) critical value. We derive equations of ``quantum force-free electrodynamics'' for this plasma using an effective field theory approach where electron field fluctuations are integrated out of the QED action.