Science Potential of Imaging Air Cherenkov Telescope arrays as Intensity Interferometry receivers

David Kieda, Stephan LeBohec and Paul Nunez
University of Utah


The Intensity Interferometry technique (II) has the potential to open up high-resolution stellar 
imaging into frequency bands which are traditionally inaccessible to classical Michelson 
Interferometry (such as UBV ). The II technique requires use of very large area optical dishes 
(3-10 meter diameter or greater), distributed over baselines of tens to hundreds of meters, in 
order to reconstruct high resolution images of stellar disks. Projects under development in the 
field of very high energy gamma ray astronomy (such as CTA and AGIS) involve kilometer scale 
telescope arrays of up to one hundred large light collectors (8-20 m diameter) with optical 
properties very similar to those used by the Narrabri Stellar Intensity Interferometer nearly fifty 
years ago.

These new gamma-ray telescope arrays, combined  with tremendous developments in signal processing 
and detector technology, can make a modern implementation of the Intensity Interferometry technique 
competitive with Michelson Interferometry. In this talk, we will present the capabilities of a 
realistic stellar II array and discuss the unique science capabilities of this observatory. We will 
also describe an international effort that is underway to successfully develop the first modern 
implementation of the II technique since it was abandoned 40 years ago.