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John W Hewitt

Associate Professor

Physics | College of Arts & Sciences

Areas of Expertise

Observational Astronomy, High-Energy and Particle Astrophysics


Ph.D. Physics & Astronomy, Northwestern University (2009)


I am an astrophysicist interested in energetic processes that occur in our own Milky Way and nearby galaxies. I focus on the acceleration and propagation of cosmic rays, which drive chemistry in interstellar clouds. I am also studying the unique environment at our galaxy's center, which hosts the highest density of massive stars and the closest massive black hole.  My research uses ground and space observatories that span the entire electromagnetic spectrum from radio to infrared to gamma rays. 


I grew up in Jeddah, Saudi Arabia before moving to Lake Mary, Florida for high school. I attended college at Northwestern University, where I received a BA in 2004 and my PhD in 2009. My doctoral research with Prof. Farhad Yusef-Zadeh focused on the shock interaction between supernova blast waves and dense interstellar clouds, using NRAO’s Very Large Array and Green Bank radio telescopes. As part of my dissertation, I also spent time working with Dr. Jeonghee Rho to analyze data from NASA’s Spitzer Space Telescope at Caltech’s IPAC in 2007-8.


In the fall of 2009 I began a three year NASA postdoctoral fellowship with Dr. Rob Petre, head of the X-ray Astrophysics Lab at Goddard Space Flight Center in Greenbelt, Maryland. In 2012, I moved down the hall to the Astroparticle Physics Lab and joined the Fermi LAT collaboration to work on gamma-ray observations of particle acceleration in supernova remnants.


I joined the faculty of UNF in the fall of 2015. Students working with me in my lab at UNF pursue research on supernovae and compact objects such as black holes and pulsars. As a member of the Fermi LAT collaboration, I work with ~300 other scientists around the world to explore the universe in gamma-rays. This work is supported by grants from the National Science Foundation and NASA. Students who have worked on research projects with me have gone on to graduate school at the Univ. of Maryland, UC Berkeley and Princeton.


I'm active in public astronomy outreach through Astronomy Nights at UNF and #popscope, an urban astronomy movement that promotes sidewalk astronomy.


I am a full member of the Fermi LAT collaboration, the American Astronomical Society and the American Physics Society. I am also an associate member of the VERITAS collaboration.

Publications & Presentations

For a complete list of publications, see NASA ADS or Google Scholar.


Select Publications

  • “The 1st Fermi Lat Supernova Remnant Catalog,” Fermi LAT collaboration. 2016, accepted to the Astrophysical Journal [arXiv]
  • “Shocked Gas from the supernova remnant G357. 7+0.3,” J. Rho, J.W. Hewitt, W.T. Reach, et al. 2016, submitted
  • “An X-ray and Radio Study of the Varying Expansion Velocities in Tycho's Supernova Remnant,” B.J. Williams, L. Chomiuk, J.W. Hewitt, et al. 2016, submitted [arXiv]
  • “Discovery of X-ray Emission from the Galactic Supernova Remnant G32. 8-0.1 with Suzaku,” A. Bamba, Y. Terada, J.W. Hewitt, et al. 2016, submitted [arXiv]
  • “Observations of supernova remnants and pulsar wind nebulae at gamma-ray energies,” J.W. Hewitt & M. Lemoine-Goumard. 2015, Comptes Rendus Physique, 16, 674 [arXiv]
  • “Detection of Extremely Broad Water Emission from the molecular cloud interacting Supernova Remnant G349.7+0.2,” J. Rho, J.W. Hewitt, A. Boogert, et al. 2015, The Astrophysical Journal 812, 44 [journal]
  • “Searching for dark matter annihilation in the Smith high-velocity cloud,” A. Drlica-Wagner, GA Gómez-Vargas, JW Hewitt, et al. 2014, the Astrophysical Journal 790, 24 [arXiv]
  • “Detailed Investigation of the Gamma-Ray Emission in the Vicinity of SNR W28 with FERMI-LAT,” Y Hanabata, H Katagiri, JW Hewitt, et al. 2014, the Astrophysical Journal, 786, 145 [arXiv]
  • ”Detection of the characteristic pion-decay signature in supernova remnants,” Fermi LAT collaboration. 2013, Science 339 (6121), 807-811 [arXiv]
  • “Fermi LAT and WMAP observations of the supernova remnant HB 21,” G Pivato, JW Hewitt, L Tibaldo, et al. 2013, the Astrophysical Journal 779, 179 [arXiv]
  • Interacting Cosmic Rays with Molecular Clouds: A Bremsstrahlung Origin of Diffuse High-energy Emission from the Inner 2°× 1° of the Galactic Center,” F. Yusef-Zadeh, J.W. Hewitt, M. Wardle, et al. 2012, The Astrophysical Journal 762 (1), 33 [arXiv]
  • “Fermi-LAT and WMAP observations of the Puppis A supernova remnant,” JW Hewitt, M-H Grondin, M Lemoine-Goumard, et al. 2012, the Astrophysical Journal, 759, 89 [arXiv]

Recent Invited Talks

  • "Mapping supernova remnants and pulsar wind nebulae across decades of energy," 15th High Energy Astrophysics Division Meeting, Naples, FL (2016)
  • “The Supernova Remnant Origin of Cosmic Rays,” Florida Tech Physics & Space Sciences Colloquium, Melbourne, Florida (2016)
  • “Fermi on the Origin of Cosmic Rays,” Univ. of Michigan Astronomy Colloquium, Ann Arbor, Michigan (2016)
  • "Resolving the Hadronic Accelerator IC 443: A Joint Study with Fermi-LAT and VERITAS,” 6th International Fermi Symposium, Washington, D.C. (2015) [slides]


Last updated: April 28, 2016

Contact Information

(904) 620-2729