Past Events | Department of Astronomy and Astrophysics

2020

A&A Colloquium: Sarah Vigeland (University of Wisconsin at Milwaukee)

3:30–4:30 pm Zoom - TBA

“Supermassive Black Holes and Merging Galaxies: Low-Frequency Gravitational Wave Detection with Pulsar Timing Arrays”

Observations have shown that nearly all galaxies harbor massive or supermassive black holes at their centers. Gravitational wave (GW) observations of these black holes will shed light on their growth and evolution, and the merger histories of galaxies. Pulsar timing arrays (PTAs) use observations of millisecond pulsars to detect low-frequency GWs with frequencies ~1-100 nHz, and can detect GWs emitted by supermassive black hole binaries, which form when two galaxies merge. In this talk, I will discuss the current status of the North American Nanohertz Observatory for Gravitational Waves (NANOGrav) PTA, with an emphasis on results from our most recent search for the GW background. I will also discuss future prospects for detecting and characterizing GWs from individual supermassive binary black holes with PTAs.

Oct 28

Open Group Seminar: Yi-Kuan Chiang (Ohio State University)

1:30–2:30 pm Zoom Room

Yi-Kuan Chiang, Ohio State University, “Probing The Cosmic Energy Density Inventory With Tomographic Intensity Mapping”

Oct 22

KICP Seminar: Austin Schneider (MIT)

12:00–1:00 pm Zoom Room

Austin Schneider, MIT, “IceCube and the high-energy neutrino landscape”

Oct 22

KICP Colloquium: Lavinia Heisenberg (ETH, Zurich)

3:30–4:30 pm Zoom Room (online)

Lavinia Heisenberg, ETH, Zurich, “Gravitational Symphony”

Oct 21

Tuesday Lunch Seminar: Richard Anantua (CfA, Harvard): "Towards Understanding Near-Horizon Physics of Sgr A* from Movies and Polarization Maps"

1:00–2:00 pm Zoom

Recent radio observations of emitting magnetized plasma in the vicinity of Sagittarius A* (Sgr A*) in our Galactic Center are linked to simple electron temperature parametric models based on turbulent heating and conversion of magnetic to particle energy in general relativistic magnetohydrodynamic (GRMHD) simulations and related analytic models. GRMHD-based intensity map movies simulating hourly timescales show that these models aggregate into at least four morphological types: 1.) Thin, asymmetric photon ring; 2.) Coronal boundary layer with thin photon ring; 3.) Thick photon ring; and 4.) Extended outflow. Positrons are added in a semi-analytic, radiatively inefficient accretion flow model for which polarization maps are sensitive to positron effects of decreasing intrinsic circular polarization and increasing Faraday conversion.

Oct 20

KICP Seminar: Cynthia Chiang (McGil Universityl)

12:00–1:00 pm Zoom Room

Cynthia Chiang, McGill University, “Illuminating the Dark Universe with Radio Observations”

Oct 15

A&A Colloquium: Lisa Kewley (Australian National University)

3:30–4:30 pm Zoom - for link please contact lrebeles@oddjob.uchicago.edu

“ASTRO 3D”

The ARC Centre of Excellence for All Sky Astrophysics in 3 Dimensions (ASTRO 3D) isa $40M Centre of Excellence, which is producing a comprehensive picture of the build up of mass, angular momentum, and the chemical elements from the first stars, to (and including) the Milky Way. Our surveys include the measurement of the power spectrum at the Epoch of Reionization with the Murchison Widefield Array (MWA), large HI surveys with the Square Kilometre Array Pathfinder (ASKAP), the ongoing Australian optical integral field surveys of 10^5 galaxies (SAMI, followed by HECTOR), a large galaxy evolution program combining HST, Keck, and ESO spectroscopy of galaxies from z=6 to z=0.5, and the major Australian Galactic Archaeology program (GALAH) to track the chemical history and accretion history of our Milky Way through GAIA and the HERMES instrument on the Anglo Australian Telescope. I will describe the recent discoveries made in ASTRO 3D, as well as providing an update on our ambitious equity and diversity programs, and our nationwide education and public outreach programs.

Oct 14