Superresolution in interferometric imaging of strong thermal sources

Imaging using interferometer arrays based on the Van Cittert-Zernike theorem has been widely used in astronomical observation. Recently it was shown that superresolution can be achieved this system for imaging two weak thermal point sources. Using quantum estimation theory, we consider fundamental limit of resolving transverse separation strong sources arrays, and show resolution is not limited by longest baseline. We propose measurement techniques linear beam splitters photon-number-resolving detection to achieve our bound. Our results demonstrate any strength arrays.