Intensity Interferometer Results on Sirius with 0.25 m Telescopes

          @misc{ pirsa_PIRSA:24100097,
            doi = {10.48660/24100097},
            url = {https://pirsa.org/24100097},
            author = {Mozdzen, Tom},
            keywords = {Cosmology},
            language = {en},
            title = {Intensity Interferometer Results on Sirius with 0.25 m Telescopes},
            publisher = {Perimeter Institute},
            year = {2024},
            month = {oct},
            note = {PIRSA:24100097 see, \url{https://pirsa.org}}
          }
          

Abstract

We present the design and initial results of a stellar intensity interferometer using small 0.25 m Newtonian-style telescopes in an urban backyard setting. The primary purpose of the interferometer is to measure the angular diameters of stars. Recent advances in low jitter time-tagging equipment and Single Photon Avalanche Detectors have made the detection of second-order correlation signals, necessary for Intensity Interferometry as demonstrated by Hanbury Brown and Twiss in 1956, feasible with small telescopes. Using Sirius as a target star, we observe a strong second-order correlation spike with an integrated signal to noise ratio (SNR) ∼7 after 13.55 h of integration over a three-night period using a 3.3 m baseline. The measured signal agrees with the theoretical estimates of both coherence time, 𝜏coh = 0.74 ± 0.26 ps and SNR. We discuss the future expansion of this technique with multiple wavelengths simultaneously via a prism grating and multiple detectors.