Measuring type Ia supernova angular-diameter distances with intensity interferometry

Intensity interferometry, based on the Hanbury Brown-Twiss effect, has the potential to measure supernova sizes and distances. With optimized telescope positioning, observing strategy, and advancements in single-photon detection technology, this method can provide precise angular size measurements of supernovae with apparent magnitudes as bright as 12~mag. For type~Ia supernovae, this limiting brightness corresponds to a local volume extending to redshift z ~0.004 and an anticipated discovery rate of approximately 1 event per year. The combination of angular size data with known physical dimensions enables accurate distance determination. As type Ia supernovae serve as standardizable candles for measuring the Universe's expansion history, combining intensity interferometry distances with the supernova Hubble diagram facilitates measurements of the Hubble constant, I will also briefly discuss recent BAO measurements by the DESI collaboration, the connection with Type Ia supernovae, and peculiar velocities.