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تسجيل مستخدم جديدSearch for the Gamma-ray Emission from M33 with Fermi LAT
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In the work we search for the $gamma$-ray signal from M33, one of the biggest galaxies in the Local Group, by using the Pass 8 data of Fermi Large Area Telescope (LAT). No statistically significant gamma-ray emission has been detected in the direction of M33 and we report a new upper limit of high energy ($>100,rm MeV$) photon flux of $2.3times 10^{-9},rm ph,cm^{-2},s^{-1}$, which is more strict than previous constrains and implies a cosmic ray density of M33 lower than that speculated previously. Nevertheless the current limit is still in agreement with the correlation of star formation rate and $gamma$-ray luminosity inferred from the Local group galaxies and a few nearby starburst galaxies.
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