1. Fermi’s Gamma-Ray Burst Monitor (GBM) Julie E. McEnery Fermi Project Scientist

2. Before launch Large Area Telescope Gamma-ray Burst Monitor NaI detectors (6 of 12) Gamma-ray Burst Monitor BGO detector (1 of 2)

3. GBM Trigger Rate since launch Terrestrial Gamma-ray Flashes (TGFs) are short bursts of gamma-rays, seen from space, that originate deep within the Earth’s atmosphere.

4. Thunderstorms hurl antimatter into space The Fermi Gamma-Ray Burst Monitor (GBM) observes positrons from Terrestrial Gamma-Ray Flashes (TGFs) Michael S. Briggs (UA Huntsville) and Joseph R. Dwyer (Florida Institute of Technology) And the GBM Team: Valerie Connaughton, Colleen Wilson- Hodge, Robert D. Preece, Gerald J. Fishman, R. Marc Kippen, P. N. Bhat, William S. Paciesas, Vandiver L. Chaplin, Charles A. Meegan, Andreas von Kienlin, Jochen Greiner, and David M. Smith of UA Huntsville, MSFC, MPE, FIT, and UCSC

5. GBM has observed 130 TGFs

6. TGFs observed by GBM Typical TGFUnusual TGF TGFs are concentrated in the tropics near thunderstorms

8. Producing the “mirror” peak

9. Positrons annihilating on Fermi 511,000 eV lineFour of 130 TGFs show strong line at 511 keV from electron-positron annihilation

10. Inside a thundercloud: Strong electric fields accelerate electrons to nearly the speed of light. These electrons emit gamma-rays. Electric field Gamma-rays High-energy runaway electrons

11. TGFs Produce Gamma-rays and Charged Particles

13. Summary Fermi GBM has detected 130 Terrestrial Gamma-ray Flashes since launch in 2008 Four of these events clearly show the creation of anti-matter associated with thunderstorms One unusual TGF occurs far from a thunderstorm, but is detected (twice!) by GBM due to connection with Earth’s magnetic field which channels electrons and positrons

14. Backup Possibly use this slide with embedded animation instead of Michael’s first two slides.

15. Typical TGFUnusual TGF GBM has observed 130 TGFs : They are in areas of high thunderstorm and lightning activity.