1. VERITAS Observations Of M 31 and some results about my recent work 2015.11.24

2. 1.Gamma-ray emission in M31 M31 is the closest galaxy to the Milky Way. extend to 3.2*1degree^2, allowing its internal structure to be studied in detail. It has a gas rich star forming ring ~10kpc from galaxy center. There are two main contributors to the VHE emission from M 31: a. diffuse emission from the interaction of cosmic rays with the interstellar medium. b. unresolved point-source emission.

3. For diffuse emission, the emission is more diffuse and coming from regions away from potential sources. it will suggest that the emission is caused by cosmic-rays diffusing large distances through the galaxy from their sources. Since hadronic cosmic rays have a significantly longer life time than leptonic cosmic rays this would provide good evidence for a hadronic origin. Another significant evidence for hadronic origin is pion-bump around 0.1 GeV. For unresoved point sources. It could be regions where there are a number of potentially unresolved point sources, suggesting the sources themselves, or cosmic rays that are only diffusing a short distance from the source population, that are producing the signal.

4. Process of Fermi LAT Data six and half year pass7 data, 0.1-300 GeV. ROI=15 degree Fermi Science Tool v9r33p0 IRF: P7REP_SOURCE_V15 background models : galactic diffuse model gll_iem_v05_rev1, isotropic diffuse model iso_source_v05, point sources from the 3FGL catalogue add a point source at (RA, Dec (J2000)) = (00h 40m 53s.43,+42 15’ 02".0)

5. spatial templates of M31

6. Ralph Bird et al.

7. VERITAS Observation and results VERITAS is an array of four imaging atmospheric Cherenkov telescopes (IACT) located at the Fred Lawrence Whipple Observatory (FLWO) in southern Arizona. Each telescope has a mirror area of 110m2 and is equipped with a 499-pixel camera of 3:5 diameter field-of-view (FoV) with an angular resolution of 0.1 deg at 1TeV Energy range from 85GeV to > 30TeV 54.69 hours of data are used

9. results of VERITAS observation

11. results of my work

14. spectrums

16. Thank you!