APC Colloquium : “Spectroscopic Count Intensity Interferometry with Extremely Large Telescopes

APC laboratory is happy to welcome Albert Stebbins (Fermilab) on Friday this week. Al kindly accepted to give a colloquium entitled “Spectroscopic Count Intensity Interferometry with Extremely Large Telescopes” (abstract below), in 454A at 11am on Friday, October 26.
Title: Optical Intensity Interferometry (Hanbury Brown Twiss) is an astronomical imaging technique that was used to make the first direct measurement of stellar diameters. The technique was abandoned in favor of amplitude interferometry decades ago, however amplitude interferometry is not practical for very long baselines which limits its angular resolution.  Two modern technical developments, the construction of three 30 meter telescopes and extremely fast (picosecond) photon counters, should cause a revival of Intensity Interferometry.   This will allow (crude) optical imaging with nano-arcsecond resolution.  Targets to be imaged include not only stars but also supermassive black holes at cosmological distances and micro-quasars in our Galaxy as well as time dependent phenomena such as kilonovae and the Crab optical pulsar