Infrared very large array for the 21st century

In order to exploit the interferometric resolution advantage to the utmost, an array with a significant number of telescopes and large (and variable) baselines will be required. Achieving the sensitivity needed for a wide range of science opportunities requires large, AO equipped individual apertures. Dual-beam operation will be needed to support good sky coverage. Phasing of the array for resolved sources can be accomplished with wide-band, pair-wise combination, bootstrapping, and phase closure. For the best sensitivity with maximum field of view, the imaging focus must employ direct optical synthesis of the PSF, while for best sensitivity with reduced field-of-view, pupil densification may be used. The suggested concept, for discussion purposes, consists of 27 telescopes of 3.5-m aperture, distributed in a Cornwell circle configuration. Such a facility would most likely have a cost in the range discussed for a next generation large aperture telescope. The technical readiness is good.