A hot spot in coma

We study the temperature structure of the central part (r less than or equa l to 18' similar or equal to 0.7 h(50)(-1) Mpc) of the Coma Cluster of gala xies using ASCA data Two different analysis methods produce results in good agreement with each other and reveal the presence of interesting structure s in the gas temperature distribution. Globally, the average temperature in the center of the cluster is 9.0 +/- 0.6 keV, which is in good agreement w ith previous results. Superimposed on this we find a cool area with tempera tures of 4-6 keV associated with a filament of X-ray emission extending sou theast from the cluster center and detected by Vikhlinin and coworkers. We also find a hot spot with a temperature of around 13 keV displaced north fr om the central peak of emission. The distribution of the gas temperatures a nd relative specific entropies suggests that the cool features are most lik ely gas stripped from a galaxy group centered on NGC 4874 and falling towar d the core from outside, while the hot spot located "ahead" of this infalli ng gas is due to shock heating. Thus our results suggest that we are observ ing Coma during a minor merger with a small group of galaxies associated wi th NGC 4874 shortly before the initial core passage.