Extending the sensitivity of air Čerenkov telescopes

Over the last decade, the Imaging Air Čerenkov technique has proven itself to be an extremely powerful means to study very energetic γ-radiation from a number of astrophysical sources in a regime which is not practically accessible to satellite-based instruments. The further development of this approach in recent years has generally concentrated on increasing the density of camera pixels, increasing the mirror area and using multiple telescopes. Here we present a practical method to substantially improve the sensitivity of Atmospheric Čerenkov Telescopes using wide-field cameras with a relatively course density of photomultiplier tubes. The two-telescope design considered here is predicted to be more than ∼3 times more sensitive than existing/planned arrays in the regime above 300 GeV for continuously emitting sources; up to ∼10 times more sensitive for hour-scale emission (relevant for episodic sources, such as AGN); significantly more sensitive in the regime above 10 TeV; and possessing a sky coverage which is roughly an order of magnitude larger than existing instruments. It should be possible to extend this approach for even further improvement in sensitivity and sky coverage.