标题： X射线爆发的X射线光谱中黑体成分的全面观点 显示英文标题

标题： A comprehensive view of blackbody components in the X-ray spectra of GRBs

摘要： 一些伽马射线暴（GRBs）在X射线光谱中表现出黑体辐射，其起源尚有争议。为了更全面地理解这一现象，我们对116个已知红移的GRBs进行了搜索，这些GRBs是由{\it 斯威夫特}~XRT 观测到的。进行了时间分辨的光谱分析，并相对于吸收幂律模型评估了黑体的显著性。我们报告了九个新的检测结果，并确认了之前报道的GRB~171205A中的黑体。结合我们之前的结果，在13年期间由{\it 斯威夫特}观测的199个GRBs样本中，总共有19个GRBs显示出显著的黑体辐射。这些检测包括一个短时GRB和两个低光度GRBs。我们从黑体成分中估计了火球参数，并注意到黑体光度与温度和推导出的洛伦兹因子相关。黑体成分和光曲线的性质存在很大差异，这表明辐射有不同的起源。大约三分之一的GRBs中，黑体明显与喷流的晚期瞬时发射有关。其余样本包括与巢状结构预期完全一致的情况，以及可能由高纬度发射或更具能量的巢状结构解释的情况。这些结果表明，热辐射与喷流的所有部分有关。 显示英文摘要

摘要： A small fraction of gamma-ray bursts (GRBs) exhibit blackbody emission in the X-ray spectra, the origin of which is debated. In order to gain a more complete understanding of this phenomenon, we present a search for blackbody components in 116 GRBs with known redshifts observed by {\it Swift}~XRT. A time-resolved spectral analysis is carried out and the significance of the blackbody is assessed with respect to an absorbed power-law model. We report nine new detections and confirm the previously reported blackbody in GRB~171205A. Together with our previous results, there are a total of 19 GRBs with significant blackbody emission in a sample of 199 GRBs observed by {\it Swift} over 13 years. The detections include one short GRB and two low-luminosity GRBs. We estimate fireball parameters from the blackbody components and note that the blackbody luminosity is correlated with the temperature and inferred Lorentz factor. There is a large spread in the properties of the blackbody components and the light curves, which points to different origins for the emission. In about a third of the GRBs, the blackbody is clearly associated with late prompt emission from the jet. The rest of the sample includes cases that are fully consistent with the expectations from a cocoon, as well cases that may be explained by high-latitude emission or more energetic cocoons. These results indicate that thermal emission is associated with all parts of the jet.