Performance study of dedicated 4-m telescope arrays for microarcsecond compact-star intensity interferometry

Résumé fourni par la source

Stellar intensity interferometry (SII) measures correlations in photon-arrival fluctuations recorded by telescopes observing bright celestial sources. It can resolve angular scales far smaller than those accessible to a single optical telescope and is largely insensitive to atmospheric turbulence. After the first demonstration of SII on Sirius in 1956, Hanbury Brown and Twiss used the technique to measure the diameters of 32 stars. More recently, VERITAS, MAGIC, H.E.S.S., and CTAO’s LST-1 have revived the method, although observations remain restricted to bright targets because of the optical design of these facilities.We present an end-to-end photon-counting simulation for dedicated 4-m telescopes optimised for picosecond timing and 1000 simultaneous wavelength channels. The simulation includes stellar spectra, atmospheric extinction, detector quantum efficiency, night-sky background, coincidence statistics, projected baselines, and uniform-disc diameter fitting. Its absolute sensitivity scale is validated against MAGIC measurements of Adhara and Alkaid. We then compare two-telescope, 2x2 array, ELT-assisted, and logarithmic-spiral configurations.A two-telescope system can reach V-band magnitudes of approximately 9.5--10.7 within tens of hours of observing time. A configuration of three dedicated 4-m telescopes combined with the ELT at its centre reaches magnitude 14, while a 60-telescope array reaches magnitude 13 and samples a large region of the $uv$ plane, making it promising for future model-independent image recovery.

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