Dr. Jarron Leisenring: Infrared Translator

In a conference room, Jarron Leisenring uses a life size replica to show how NIRCam works, pointing at the 3D-printed parts and gold-colored surfaces to show where a coronagraph blocks the haze of bright stars, where wavelengths of light are separated, where a colorful filter wheel rotates, and the place where finely-tuned electronics are nested.  A million miles away aboard the James Webb Space Telescope, the real instrument pulls in infrared data that helps us understand the oldest galaxies in the universe as well as the youngest stars in our own Milky Way. The actual coronagraph (which Leisenring helped fine-tune) suppresses ambient starlight using aluminum masks dotted on sapphire glass. The model that Leisenring shows is only one half of the whole NIRCAM apparatus. Aboard JWST, two identical layouts sit on top of one another, for redundancy. Of all the instruments on JWST, “NIRCAM is the only one that, if it failed, the entire mission would just be gone,” Leisenring explains. “It aligns all the telescope mirror segments.”  Leisenring has been working on the project for a decade, since Marcia Rieke recruited him for his experience working with infrared instrumentation and in particular his knowledge of SIDECAR electronics. This was his primary responsibility during the testing of JWST: ensuring that the tiny SIDECAR ASIC microprocessors—notoriously finicky—were tuned and optimized before launch. These extraordinary electronics—small enough to fit in the palm of the hand—create very little noise as they collect faint signals from the edge of the universe.

With a PhD from University of Virginia and experience in instrument design across various projects including the Large Binocular Telescope Interferometer and the ETH Infrared Detector Lab in Zurich, Leisenring sees his role with the powerful and collaborative NIRCam team as that of a translator.  He speaks the languages of both science and engineering, and he helps build bridges between the two. He coaches colleagues in the internal workings of instruments so that scientists can design programs that best suit the equipment, and he works with engineers to help align instrumentation to the needs of astronomers. “I feel deeply privileged,” he says, “being a small cog in the giant machine.”

Leisenring’s deepest research interest is the search for exoplanets. Much of this work involves programming and coding to differentiate faint true planetary signals from mere noise.  He’s involved in designing swifter ground-based equipment that can detect longer infrared wavelengths—“better for colder, dustier things”—without getting flooded by sky photons emitted from our own atmosphere. An instrumentation goal of his for the future is to help find better ways to lower noise levels for infrared detectors for the next generation of space telescopes, so that Earth-sized planets, with Earth-like biosignatures—can show up more clearly.

In Leisenring’s work, the extreme ends of emotion he often experiences are focus—the slow and diligent work necessary to ensure that everything is working properly—and exhilaration, when everything works as intended. When he’s not scheming up detector hardware innovations, he likes to get his hands on rock, scaling Mt. Lemmon’s walls while dreaming of other distant earths.

To find out more about his work email him at jarronl@arizona.edu