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Past Colloquia

Towards observational constraints on mapping between cosmological redshift and cosmic scale factor

Cody Hall

Radek Wojtak (Stanford University)

January 13, 2017
14:00 - 15:00

The standard relation between the cosmological redshift and cosmic scale factor is arguably one of a few unverified theoretical inputs underlying the computation of cosmological observables and modern cosmological inference. However, the richness of cosmological observations allows to change its theoretical status and the relation…

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Low Mass Galaxies and their Gas at the Peak Epoch of Star Formation

Cody Hall

Dawn Erb (University of Wisconsin–Milwaukee)

December 09, 2016
14:00 - 15:00

Because faint, low mass galaxies are numerous at high redshifts, their impact on the Universe is expected to be significant. They may host a substantial fraction of the Universe’s star formation, provide many of the energetic photons needed to reionize the intergalactic medium, and affect…

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Filaments: Fad or Fundamental?

Cody Hall

Alyssa Goodman (Harvard University)

December 02, 2016
14:00 - 15:00

As the resolution of imaging of the dense interstellar medium has improved, we have gone from a very blobby view, featuring interstellar “clouds,” to a much more “stringy” view, featuring interstellar “filaments.” Some three-dimensional shapes in the ISM have a very limited set of possible…

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Puzzles in Galaxy Scaling Relations

Cody Hall

Stephane Courteau (Queen’s University)

November 25, 2016
14:00 - 15:00

Galaxies like our Milky Way can be described in terms of their structure, dynamics, and stellar populations. Some very robust correlations between galaxy structural properties, such as total luminosity, maximum circular velocity, and size display rather small scatter, hinting at well-regulated galaxy formation processes. A…

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The Thermal Odyssey of the ionized Intergalactic Medium

Cody Hall

Matt McQuinn (University of Washington)

November 18, 2016
14:00 - 15:00

I will summarize the history of IGM temperature measurements from the Lyman-alpha forest as well as the theory for the IGM temperature after reionization. I will show that the simplest theory for thermal evolution, which has little parametric freedom, works remarkably well at reproducing recent…

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DESI and Beyond: Design Considerations for Massive Redshift Surveys

Cody Hall

David Schlegel (Lawrence Berkeley National Laboratory)

November 11, 2016
14:00 - 15:00

The Dark Energy Spectroscopic Instrument (DESI) is under construction to measure the expansion history of the Universe using the Baryon Acoustic Oscillation technique. The DESI instrument is designed to efficiently measure galaxy redshifts to z=1.6, quasars at all redshifts, and the 3-dimensional Lyman-alpha forest at…

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White Dwarf Supernovae: Distances and Differences

Cody Hall

Saurabh W. Jha (Rutgers University)

November 04, 2016
14:00 - 15:00

Most exploding white dwarfs are normal type-Ia supernovae (SN Ia) that have proven so useful as standardizable candles to measure cosmic distances and discover the accelerating Universe. I will describe current cosmological applications of SN Ia and future prospects with upcoming flagship projects like LSST…

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The Connection between Binarity and Large-Scale Magnetic Fields in Hot, Massive Stars

Cody Hall

Jason Grunhut (Dunlap Institute)

October 28, 2016
14:00 - 15:00

Ordered magnetic fields are found in a variety of astrophysical objects, ranging from planets to Galaxies and beyond. While the details are not fully understood, magnetic fields in most objects are the result of dynamo processes that convert bulk mechanical motion into magnetic energy. Unlike…

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Science Prospects with the Current and Future Network of Gravitational Wave Detectors

Cody Hall

Frédérique Marion (Laboratoire d'Annecy-le-Vieux de physique des particules (LAPP), CNRS)

October 21, 2016
14:00 - 15:00

As the second generation of ground-based gravitational wave interferometric detectors has come live and observed the first signals from binary black hole mergers, future observing runs will keep collecting data at unprecedented sensitivities, with an expanding network of detectors. The talk will discuss the plans…

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Peculiar Transients as Probes of Stellar Evolution and Mass Loss

Cody Hall

Maria Drout (The Carnegie Observatories/Dunlap Institute)

October 14, 2016
14:00 - 15:00

The recent advent of wide-field time-domain surveys has launched an upheaval in field of stellar evolution. These surveys are uncovering new types of astronomical transients that not only challenge existing models for supernova explosions but also our understanding of what physical processes can occur during…

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