PhoSim-NIRCam: Photon-by-photon image simulations of the James Webb Space Telescope's near-infrared camera

Colin J. Burke, John R. Peterson, Eiichi Egami, Jarron M. Leisenring, Glenn H. Sembroski, Marcia J. Rieke

Research output: Contribution to journalArticlepeer-review

5 Scopus citations


Recent instrumentation projects have allocated resources to develop codes for simulating astronomical images. Physics-based models are essential for understanding telescope, instrument, and environmental systematics in observations. A deep understanding of these systematics is especially important in the context of weak gravitational lensing, galaxy morphology, and other sensitive measurements. We present an adaptation of a physics-based ab initio image simulator: the photon simulator (PhoSim). We modify PhoSim for use with the near-infrared camera (NIRCam)-the primary imaging instrument aboard the James Webb Space Telescope. This photon Monte Carlo code replicates the observational catalog, telescope and camera optics, detector physics, and readout modes/electronics. Importantly, PhoSim-NIRCam simulates both geometric aberration and diffraction across the field of view. Full field- and wavelength-dependent point spread functions are presented. Simulated images of an extragalactic field are presented. Extensive validation is planned during in-orbit commissioning.

Original languageEnglish (US)
Article number038002
JournalJournal of Astronomical Telescopes, Instruments, and Systems
Issue number3
StatePublished - Jul 1 2019


  • Image simulation
  • Instrumentation
  • James Webb Space Telescope's near-infrared camera
  • Photon simulator
  • Systematic
  • Weak lensing

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Control and Systems Engineering
  • Instrumentation
  • Astronomy and Astrophysics
  • Mechanical Engineering
  • Space and Planetary Science


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