McCall Research Group Illinois

Dr. Nick Indriolo

Benjamin McCall
June 15, 2011 - 4:31 PM

Nick Indriolo recently defended his PhD thesis!

On June 2, Nick Indriolo successfully defended his PhD dissertation, entitled "Investigating the Cosmic-Ray Ionization Rate in the Galactic Interstellar Medium through Observations of H3+."

Nick's thesis work was centered around a comprehensive survey of H3+ in diffuse interstellar clouds. His survey included 50 sight lines, and resulted in detections in 21 of these. In collaboration with Brian Fields of the Illinois astronomy department, Nick took his work a step further, and modeled the theoretical spectrum of interstellar cosmic-rays in an attempt to reproduce H3+ observations, light element abundances, and other observables. That work suggested that in addition to the general "background" of cosmic rays, many diffuse clouds are also exposed to a large flux of low energy (~2 MeV) cosmic rays, which might be produced by supernova remnants but would not propagate large distances in the interstellar medium. Most recently, Nick began a search for H3+ in sightlines that pass through supernova remnants, and saw huge absorption signals -- thus validating his hypothesis. Nick has pushed the envelope of mid-infrared astronomical absorption spectroscopy, and has changed the way that astrophysicists think about low-energy cosmic rays.

In July, Nick will begin a postdoctoral position in the group of Professor David Neufeld in the Department of Physics and Astronomy of the Johns Hopkins University. At Hopkins, Nick plans to extend his work on astrochemistry and cosmic rays by using the Herschel space observatory to study OH+, H2O+, and H3O+ in diffuse clouds. He also hopes to continue working on H3+, and to use all four of these ions to better constrain the nature of the interstellar cosmic ray flux. We wish Nick all the best in his new endeavors!