Past Colloquia
Clustering Redshifts: A New Era of Distance Measurement
Cody Hall
Mubdi Rahman, John Hopkins University
February 19, 2016
14:00 - 15:00
Measuring the true distance of objects seen on the celestial sphere is a challenge that has plagued astronomy from its earliest days. The classical solution to this problem for extragalactic systems has been measuring the regression velocity through spectroscopy to determine a redshift-related distance. However…
Toward a Holistic View of Star Formation
Cody Hall
Rob Gutermuth (UMASS Amherst)
February 12, 2016
14:00 - 15:00
Abstract: Our general picture of the process of forming stars from molecular clouds has held together quite well for the past few decades, but a detailed, predictive theory of star formation remains frustratingly out of reach. What determines the clustering of newborn stars? What sets…
An Astronomical Time Machine: Light Echoes from Historic Supernovae and Eruptions
Cody Hall
Armin Rest (Space Telescope Science Institute)
February 05, 2016
14:00 - 15:00
Tycho Brahe’s observations of a supernova (SN) in 1572 challenged the teachings of Aristotle that the celestial realm was unchanging. We have discovered a way to see the same light that Tycho saw 440 years ago by observing SN light that only now reaches Earth…
Stellar Magnetic Fields and Stellar Evolution
Cody Hall
Gregg Wade (RMC/Queens University)
January 29, 2016
14:00 - 15:00
All stars are natural magnets, thanks to the dynamic, electrically conductive gases that compose them. And because the magnetic fields of stars can be very strong, they represent a basic physical ingredient in the theory of stellar structure and evolution. In recently years it has…
Satellite galaxies and the baryon cycle
Cody Hall
Michael Balogh, University of Waterloo
January 22, 2016
14:00 - 15:00
Abstract: Late-time galaxy evolution is driven by a variety of non-linear processes such as radiative cooling, supernova feedback and AGN accretion, which together act to largely decouple baryonic structure growth from that of the dark matter. It remains a formidable challenge to untangle these processes…
Probing Gravity: Galaxies, CMB Lensing, and Intensity Mapping
Cody Hall
Anthony Pullen (Carnegie Mellon)
January 15, 2016
14:00 - 15:00
We discuss recent work exploring the use of large-scale structure to probe gravity. We first consider using CMB lensing and galaxy surveys to probe E_G, the ratio between curvature and velocity perturbations. This quantity is independent of galaxy clustering bias and is distinct for various…
Sean McGee (Birmingham)
Cody Hall
Sean McGee (University of Birmingham)
December 18, 2015
14:00 - 15:00
details to follow
Probing the Dark Halo of the Milky Way
Cody Hall
Nitya Kallivayalil (University of Virginia): Kamper Lecture
December 11, 2015
14:00 - 15:00
The Local Group, the regime in which detailed star-by-star studies can be done, is becoming a major testbed for the concordance Lambda (Dark Energy) + Cold Dark Matter model of our Universe. The dwarf galaxies of the Local Group, in particular, pose a variety of…
The Large Synoptic Survey Telescope
Cody Hall
Steven M. Kahn (Stanford University and SLAC National Accelerator Laboratory)
December 04, 2015
14:00 - 15:00
The Large Synoptic Survey Telescope (LSST) is a large aperture, wide-field, ground-based telescope designed to provide a deep multicolor imaging survey of the entire southern hemisphere of sky every few nights. As such, it will enable a wide variety of scientific investigations, all using a…
Imaging the Invisible with the Little Canadian Radio Telescope that Could
Cody Hall
Jo-Anne Brown (University of Calgary)
November 27, 2015
14:00 - 15:00
Magnetic fields are an important constituent in the interstellar medium, but unlike gas, dust, and cosmic rays, they do not radiate, and consequently cannot be observed directly. Instead, observers identify signatures of the field in an effort to piece together its topology. Determining the structure of…