Previous
abstract 
Next
abstract
Session 85 - Cosmology: Observations.
Display session, Friday, January 09
Exhibit Hall,
Positive values of the cosmological constant, lambda, have been suggested to resolve a number of problems in observational cosmology, incuding the possible discrepancy between stellar ages and the inverse of Hubble's constant. In closed cosmological models with positive lambda, a distant source can produce a "ghost image," an image lying 180 degrees away from the source (Petrosian and Saltpeter, Ap. J., 1968). Previous searches (Solheim, Nature, 1968 and Biraud amp; Mavrides, A. amp; A., 1980) have failed to find such ghost images, but were compromised because they did not consider aberration produced by the motion of the earth. We have made a much more intensive search using the recently compiled NVSS catalog and a correction for aberration, and yet have found no evidence for ghost images. Our results constrain values of lambda, and some multiply connected models for the topology of the Universe.
