Speaker
Description
Stellar intensity interferometry (SII) is an emerging technique for high-resolution astrophysics. In recent years, it has been implemented as a dual-use instrument on Cherenkov telescopes with large mirror areas, including VERITAS, MAGIC, LST, and H.E.S.S., and is also planned for CTA. However, these telescopes were designed for gamma-ray astronomy, and their optical quality limits sensitivity upgrades based on ultrafast sensors or many spectral channels. Even the full CTA array is expected to remain limited to about magnitude 6-7, making operation with thousands of optical channels or ultrafast sensors impractical.
To fully exploit SII, a dedicated telescope design is required. It must provide sufficient optical quality for spectrometers with at least 1000 wavelength channels, isochronicity better than 3 ps, and a relatively large mirror area. Existing optical telescopes could be used, but observing time is limited and shared with conventional programs. Moreover, when multiple telescopes are connected into an array, SII enables imaging through phase-recovery techniques, making a dedicated array the natural long-term solution.
Such telescopes should be 10-50 times cheaper than conventional optical telescopes while still meeting the optical requirements for multi-wavelength SII and ultrafast sensors. We present extensive realistic simulations of different array configurations, together with first design concepts and laboratory measurements for a two-telescope pathfinder array targeting a sensitivity of magnitude 8-9.
