Stellar intensity interferometry over kilometer baselines: Laboratory simulation of observations with the Cherenkov Telescope Array

Dainis Dravins, Tiphaine Lagadec

Research output: Chapter in Book/Report/Conference proceedingPaper in conference proceedingpeer-review

6 Citations (SciVal)


A long-held astronomical vision is to realize diffraction-limited optical aperture synthesis over kilometer baselines. This will enable imaging of stellar surfaces and their environments, show their evolution over time, and reveal interactions of stellar winds and gas flows in binary star systems. An opportunity is now opening up with the large telescope arrays primarily erected for measuring Cherenkov light in air induced by gamma rays. With suitable software, such telescopes could be electronically connected and used also for intensity interferometry. With no optical connection between the telescopes, the error budget is set by the electronic time resolution of a few nanoseconds. Corresponding light-travel distances are on the order of one meter, making the method practically insensitive to atmospheric turbulence or optical imperfections, permitting both very long baselines and observing at short optical wavelengths. Theoretical modeling has shown how stellar surface images can be retrieved from such observations and here we report on experimental simulations. In an optical laboratory, artificial stars (single and double, round and elliptic) are observed by an array of telescopes. Using high-speed photon-counting solid-state detectors and real-time electronics, intensity fluctuations are cross correlated between up to a hundred baselines between pairs of telescopes, producing maps of the second-order spatial coherence across the interferometric Fourier-transform plane. These experiments serve to verify the concepts and to optimize the instrumentation and observing procedures for future observations with (in particular) CTA, the Cherenkov Telescope Array, aiming at order-of-magnitude improvements of the angular resolution in optical astronomy.
Original languageEnglish
Title of host publicationOptical and Infrared Interferometry IV
Publication statusPublished - 2014
EventConference on Optical and Infrared Interferometry IV - Montreal, Canada
Duration: 2014 Jun 232014 Jun 27

Publication series

ISSN (Print)1996-756X
ISSN (Electronic)0277-786X


ConferenceConference on Optical and Infrared Interferometry IV

Subject classification (UKÄ)

  • Astronomy, Astrophysics and Cosmology


  • Intensity interferometry
  • Hanbury Brown - Twiss
  • Aperture synthesis
  • Second-order coherence
  • Stellar surface imaging
  • Exoplanet imaging
  • Cherenkov telescopes
  • Cherenkov Telescope Array


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