Tufts/CfA/MIT Cosmology Seminar, at Tufts:

                      Tuesday March 10, 1998
                             2:30 pm
                          Robinson 250
     Refreshments at 2:00 pm in Robinson 251 (Knipp Library)

   "Constraints on Cosmological Models from High-z Supernovae"
                         Peter Garnavich
           Harvard-Smithsonian Center for Astrophysics

Abstract: 

The discovery of a correlation between the light curve shape and
intrinsic brightness has made Type Ia supernovae exceptionally
accurate distance indicators out to cosmologically interesting
redshifts. Ground-based searches and follow-up as well as Hubble
Space Telescope observations of Type Ia supernovae have produced
a significant number of objects with redshifts between 0.3 and
1.0. The distant SNe, when combined with a local sample analyzed
in the same way, provide reliable constraints on the deceleration
and age of the Universe. The results imply that the matter
density is low; either the Universe is open, or if flat, then a
cosmological constant makes a considerable contribution.