What is the fine-grained topic of the following text: Flares: C8.5/1N long duration event peaking at 01:19, M1.3 at 02:12, C2.6 at 05:00, C1.8 at 06:53, impulsive X1.1/2N at 08:38, C1.0 at 10:42, C1.0 at 14:37, C7.1 at 15:17, C5.2 at 15:35, C1.1 at 16:20, C4.8 at 16:51, C2.3 at 18:30, M1.0 at 19:10 and C1.5 at 20:39 UTC. Only return the topic.
Solar flare activities and their classifications