伽玛射线暴（简称伽玛暴）是指来自宇宙空间的伽玛射线突然爆发的现象，其持续时间从毫秒量级到几千秒不等。自2004年Swift卫星上天后，大多数伽玛暴都探测到光学与X射线余辉，至今已经积累了大批的多波段余辉数据。本项目拟对这些光学余辉数据进行大样本的统计和分析，具体内容包括：采用早期光学余辉来定量限定长时标伽玛暴的暴周环境；统计研究Swift时代光学耀发和多波段的平台辐射观测样本，探究它们的物理起源。本项目的研究有助于解决伽玛暴及其余辉辐射中的一些基本问题，如伽玛暴光学耀发的物理起源、伽玛暴暴周环境、余辉平台辐射的物理机制等。

Gamma-ray bursts (GRBs) are flashes of gamma rays that last from milliseconds to thousands of seconds from cosmological distances. The optical and X-ray afterglows in most GRBs have been detected since the launch of Swift satellite in 2004. A large sample of GRBs with multi-wavelength afterglows has been accumulated. We plan to perform statistical analysis on the GRBs sample with optical afterglows. Our studies include: (1) quantitatively constrain the circum-burst environmental medium with early optical afterglow data; (2), investigate the physical origins of optical flares and multi-wavelength plateaus in the afterglow phase based on statistical studies. These studies may be helpful to understand the physical origins of optical flares, the circum-GRB environment, and the dynamics and radiation mechanism of the plateau emission.