Fermi LAT & SNRs

1. Zhou ping Main Ref: Daniel Castro and Patrick Slane et al. 2010 "Supernova Remnants and Pulsar Wind Nebulae" in 2009 Fermi Symposium Fermi LAT & SNRs

2. outline • Brief introduction of • γ-ray ＆ SNRs in dense environment • Fermi Obs of 4 SNRs interacting with MCs

4. Fermi Gamma-Ray Space Telescope • Energy Range: 8keV –300GeV • 2 instruments: • the Large Area Telescope (LAT) • the GLAST Burst Monitor (GBM)

5. LAT • Large FOV : 2Sr • Energy Range: 30MeV-300GeV • Location accuracy: <1‘ • Reject 99.999% of signals generated by cosmic rays 4 main subsystems: tracker Calorimeter Anticoincidence Detector Data Acquisition System

6. What Fermi Explore? • …., Cosmic rays and SNRs, ... • In theory… "But we want to see that on a local scale," says Thompson. "We want to see it happening at the sources, which are thought to be supernova remnants. The LAT has the sensitivity and spatial resolution to do the job.“

7. Origin of Gamma-Ray in SNRs

9. Fermi Obs of SNRs interacting with MCs • 4 SNRs: G349.7+0.2 CTB 37A, 3C 391 G8.7-0.1 • MeV-Gev: important to identify signatures of neutral pion decay. • Masers: useful tool to indicate the shocked clouds of dense molecular materials.

10. G349.7+0.2

11. CTB 37A

12. 3C 391

13. G8.7-0.1

14. Obs discussion • γ-ray emissions come from shells or pulsars? • SED: for pulsar, power law +exponential cutoff in 1~6keV • ATNF pulsar database

15. Obs discussion • Clumpy region • instabilitiesin the post-shock flow result in considerable clumping of material. The denser regions would then not be expected to yield significant X-ray emission. • the energetic particles that escape the particle acceleration region and encounter dense molecular clouds, then dramatically enhance the gamma-ray emission.

16. Thanks