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Astrophysics Colloquium: Ryan Foley, Center for Astrophysics, Harvard University: "Improving Dark Energy Measurements through a Detailed Understanding of Supernova Physics"

Event Type
Astronomy Department
134 Astronomy
Feb 12, 2013   4:00 pm  
Ryan Foley
Originating Calendar
Astronomy Colloquium Speaker Calendar

Cosmology with Type Ia supernovae (SNe Ia) is at a crossroads.  Previous SN surveys have been extremely successful, discovering the Universe's accelerated expansion (leading to the 2011 Nobel prize in physics) and providing ever-smaller constraints on the nature of dark energy.  However, we have amassed enough data that simply increasing the samples will not improve our knowledge of cosmological parameters.  Instead, we must produce novel techniques of reducing systematic uncertainties.  Some of the largest systematic uncertainties are related to the nature of the SN progenitors and dust reddening.  I will present evidence that multiple progenitor systems create SNe Ia and the discovery of the first link between the SN environment and the explosion, and discuss possible effects for SN cosmology.  I will discuss a new and novel way of precisely determining the intrinsic color of SNe Ia, which improves our measurement of dust reddening, and thus distance estimates.  I will also discuss a large (100 orbit) HST program that largely avoids the problems of dust by observing high-redshift SNe Ia in the NIR.  Finally, I will discuss how future surveys such as DES and LSST can apply these techniques and knowledge to provide the best cosmological constraints with observations of SN Ia.

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