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Past Colloquia

The case for stochastic orbital migration in proto-planetary disks and Saturn’s rings

MP 203

Hanno Rein (IAS/ Princeton)

March 28, 2013
13:00 - 14:00

Many of the 869 known extra-solar planets are in multi-planetary systems.  These systems are the most interesting ones to study because they allow us to place tight constraints on planet formation. The protoplanetary disk in which planets form is turbulent and therefore stochastic forces are…

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FIRE & Ice: The Discovery and Spectral Characteristics of Room-Temperature Brown Dwarfs

Cody Hall

Adam Burgasser (UCSD)

March 26, 2013
16:00 - 17:00

Our view of the immediate Solar Neighborhood has changed dramatically in the past decade with the discovery of an ever-growing population of cool, dim brown dwarfs.  These objects, incapable of sustained hydrogen fusion, are intrinsically long-lived, time-variable objects, making them potential probes of (sub)stellar star…

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Quasar and star formation feedback throughout the cosmic epochs

Cody Hall

Roberto Maiolino (Cambridge)

March 22, 2013
14:00 - 15:00

Over the entire life of the Universe only 4% of the baryons have been converted into stars, while gravitational collapse and gas cooling would predict that locally about 80% of the baryons should be in stars. Hence, rather than understanding how stars have formed throughout…

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Unshrouding the Milky Way with the APOGEE Survey

Cody Hall

Jennifer Johnson (Ohio State)

March 15, 2013
14:00 - 15:00

Many questions of the formation and evolution of galaxies can be tested by observations of the closest galaxy: the Milky Way. We have now entered the era of large stellar surveys of the Milky Way and are starting to map the Galaxy as we have…

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Stellar streams and stellar clouds around the Milky Way: formation, properties and interpretation

Cody Hall

Kathryn Johnston (Columbia)

March 08, 2013
14:00 - 15:00

Larger structures in the Universe are thought to form hierarchically from the mergers of many smaller structures. Dramatic evidence for hierarchical structure formation can be seen around our own Galaxy in the form of streams and clouds of stellar debris left over from the destruction…

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Photodynamics: revealing the secrets of the lowest-mass planets and stars

Cody Hall

Josh Carter (CfA)

March 01, 2013
14:00 - 15:00

Eclipsing systems are famous for providing abundant opportunities to study the basic properties of stars and planets — but eclipsing systems with more than two bodies present truly extraordinary opportunities. This is because non-Keplerian effects can be observed and used to  determine precise masses, radii,…

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Galaxy Clusters During the Era of Cluster Formation

Cody Hall

Anthony Gonzalez (UFL)

February 15, 2013
14:00 - 15:00

The redshift regime 1<z<2 corresponds to the epoch during which the first massive galaxy clusters assemble. It is also during this era that the present day star-formation density relation is established, with star formation rates in cluster galaxies decreasing to well below the field level….

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Astrometry and Adaptive Optics Enables Tests of Star Formation in Extreme Environments

Cody Hall

Jessica Lu (U of Hawaii)

February 13, 2013
14:00 - 15:00

Ground-based telescopes equipped with adaptive optics systems have overcome the blurring effects of the Earth’s atmosphere and now routinely provide diffraction-limited images at infrared wavelengths. This has led to a revolution in astrometry, and we can now measure stars’ relative positions with 150 micro-arcsecond precision,…

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Detecting and Characterizing Exoplanets with a New Generation of Sky Surveys

Cody Hall

Nicholas Law (Dunlap)

February 06, 2013
14:00 - 15:00

Modern optical sky surveys like the Palomar Transient Factory and Pan-STARRs open new windows into a vast and dynamic sky, and their enormous datasets demand dramatic improvements in both data-mining algorithms and follow-up instrumentation. I will describe Robo-AO, a recently-commissioned robotic laser adaptive optics system,…

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Galactic Dynamics and the Nature of Dark Matter

MP 102

Matthew Walker (Harvard)

February 04, 2013
15:00 - 16:00

I will explain how to use the motions of stars to learn about the nature of particles.  More specifically, I will translate the stellar kinematics that I observe in the nearest, smallest and `darkest’ galaxies into a test of the standard hypothesis that dark matter…

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