Past Colloquia
Quantitative Polarimetry: from Star Formation to Cosmological Studies
Cody Hall
Thiem Hoang, CITA
May 13, 2016
14:00 - 15:00
We are entering a golden age of multiwavelength polarimetry with numerous CMB experiments (e.g., SPIDER, BICEP/Keck, LiteBIRD) hunting for primordial gravitational waves through B-mode polarization, and a dozen of big instruments designed to elucidate the roles of magnetic fields in star formation (e.g., SOFIA, SMA,…
Observations of Intra-Halo Matter at High Redshift, and Associated Instrumentation Research for Magellan and GMT
Cody Hall
Rob Simcoe (MIT)
May 06, 2016
14:00 - 15:00
I will describe recent results on the early metal enrichment of loosely-bound galactic halo gas, inferred from our group’s quasar absorption line observations at Magellan. These surveys utilize optical and infrared spectra of 100 sightlines with the FIRE infrared spectrograph, including 35 objects at z>5.7. …
The Growth of the Most Massive Galaxies in the Highest Density Regions: Evidence for In-Situ Star Formation in SpARCS Brightest Cluster Galaxies
Cody Hall
Tracy Webb (McGill University)
April 29, 2016
14:00 - 15:00
The most massive galaxies in the local universe reside at the centres of galaxy clusters. Often called Brightest Cluster Galaxies (BCGs), they exhibit, as a class, highly uniform properties and are distinct from the general galaxy population. This suggests formation processes which are themselves distinct…
How to identify a habitable planet? Thinking inside (and a bit outside) the box
Cody Hall
Lisa Kaltenegger (Cornell, Carl Sagan Institute)
April 22, 2016
14:00 - 15:00
Abstract: Among the thousand of exoplanets detected, several are within the so-called Habitable Zone and some of them are called “the most Earth-like”. But what is the data behind those claims? The talk will discuss several important topics in the search for other habitable worlds….
Asteroseismology Reveals Strong Magnetic Fields in the Cores of Red Giant Stars
Cody Hall
Jim Fuller (Caltech)
April 15, 2016
14:00 - 15:00
Internal stellar magnetic fields are inaccessible to direct observations and little is known about their amplitude, geometry and evolution. I will discuss how strong magnetic fields in the cores of red giant stars can be identified with asteroseismology. The fields manifest themselves via depressed dipole…
Dreams of Streams: Exploring the stellar outskirts of nearby galaxies
Cody Hall
Daniel Dale (University Wyoming)
April 08, 2016
14:00 - 15:00
I will review highlights from the Spitzer Extended Disk Galaxy Exploration Science (EDGES) survey, a Warm Mission program to obtain sensitive infrared imaging for 92 nearby galaxies. Highlights will include the radial trends in their star formation histories as well as characterizations of their outermost…
Rogue Waves on Pulsating White Dwarf Stars
Cody Hall
JJ Hermes (U. of North Carolina)
April 01, 2016
14:00 - 15:00
While it has been an efficient planet-discovery machine, the unblinking photometry of the Kepler space telescope has also revolutionized the way we look at pulsating stars. I will discuss some of the rapid advances Kepler has enabled in our understanding of white dwarf stars, including…
Extrasolar Storms: Cloud Physics and Atmospheric Dynamics in Brown Dwarfs and Exoplanets
Cody Hall
Daniel Apai (University of Arizon)
March 18, 2016
14:00 - 15:00
Observations of directly imaged and transiting exoplanets and brown dwarfs reveal the wide-spread presence of condensate clouds. These clouds profoundly influence the energy transport through ultracool atmospheres and impact their pressure-temperature profiles. Yet, the structure and properties of these cloud layers remain mostly unknown and…
Direct imaging of extrasolar planets and the Gemini Planet Imager
Cody Hall
Bruce Macintosh (Stanford)
March 11, 2016
14:00 - 15:00
Abstract: While thousands of extrasolar planets and candidates have now been detected, but almost all through indirect methods such as transit photometry or radial velocity. Though statistically powerful, these techniques provide in most cases just a basic measurement of an object’s size and orbital parameters,…
Convection in Cool Stars, as Revealed through Stellar Brightness Variations
Cody Hall
Fabienne Bastien (Penn State)
March 04, 2016
14:00 - 15:00
Abstract: As a result of the high precision and cadence of surveys like MOST, CoRoT, and Kepler, we may now directly observe the very low-level light variations arising from stellar granulation in cool stars. Here, we discuss how this enables us to more accurately determine…