Sciences and Exploration Directorate

Floyd William Stecker



Org Code: 663

Mail Code: 663
Greenbelt, MD 20771

Employer: EMERITUS

Brief Bio

Dr. Stecker's body of research primarily concerns the application of particle physics to high energy astrophysics and also has included theoretical work on infrared astronomy and galactic structure. His research contributions include publishing the first book on gamma-ray astronomy, the calculation of galactic gamma-ray emission mechanisms and making the first detailed calculation of the cutoff of the ultrahigh energy cosmic ray spectrum owing to interactions with the cosmic background radiation (the GZK effect). In addition, he showed how gamma-ray astronomy could be used for galactic structure studies, showed that the observed diffuse galactic gamma-ray distribution implies a galactic origin for most cosmic rays and predicted generation mechanisms for and fluxes of galactic and extragalactic high energy neutrinos. His work has also involved calculating the spectra of secondary particles and gamma-rays from the annihilations of supersymmetric dark matter particles, predicting an observable flux of high energy neutrinos from the cores of active galaxies, showing how absorption features in high energy gamma-ray spectra of active galaxies could be used as a probe of the intergalactic infrared radiation and predicting extragalactic sources of TeV gamma-rays and their fluxes, calculating the extragalactic gamma-ray background from blazars and showing that blazars could account for most of the observed extragalactic gamma-ray background, calculating the spectral energy distribution of the extragalactic infrared background radiation and also showing that the highest energy cosmic ray events observed -- those beyond the "GZK cutoff" -- could be from partially photodisintegrated cosmic-ray nuclei. He and Sheldon Glashow used cosmic gamma-ray observations to place constraints on violations of special relativity and on quantum gravity models which predict such violations and he has published several other papers on this subject. His body of work has received over 11,120 citations according to the Astrophysics Data System (ADS). Dr. Stecker has been awarded the NASA Medal for Exceptional Scientific Achievement and the John C. Lindsay Memorial Award for Space Science. He has presented 82 invited lectures at international meetings and has published 282 papers as of Sept., 2015, 67 of which have been cited over 50 times and 31 of which have been cited over 100 times. He is a Fellow of the American Physical Society and an Adjunct Professor of the UCLA Dept. of Physics and Astronomy.

Research Interests

Research Areas

Astrophysics: Gamma-ray Astrophysics

Cosmic Ray and High Energy Astrophysics, Gamma-ray Astrophysics, Applications of Particle Theory to Cosmology, Cosmic Ray Origin, Galaxy Structure and Formation, Infrared Astrophysics, Neutrino Astrophysics

Current Projects

Current Projects

Gamma-ray Astrophysics

Fermi Gamma Ray Space Telescope

Advanced Energetic Pair Telescope


Previous Positions

Scientific Editor of the Astrophysical Journal, January, 1998 - December 2001. University of California Regents Professor, UCLA Campus, 1994-1995. Astrophysicist, Theoretical Studies Group, NASA Goddard Space Flight Center, 1968- 1977. National Academy of Sciences, National Research Council, Postdoctoral Resident Research Associate, NASA Goddard Space Flight Center, l967-8. Smithsonian Institution Predoctoral Intern, Harvard-Smithsonian Center for Astrophysics, Cambridge - see above

2015 - Present

Professional Societies

Fellow of the American Physical Society, International Astronomical Union

1995 - Present

Professional Service

Referee for Physical Review, Astrophysical Journal, Astroparticle Physics, Nature, Monthly Notices of the Royal Astronomical Society


1968 - Ph. D., Harvard University, Astrophysics
1965 - A. M., Harvard University, Astrophysics
1963 - S. B., Massachusetts Institute of Technology, Physics
1960 - Bronx High School of Science, New York City