标题： 高光度超新星与伽马射线暴 II. GRB 140506A余辉中的明亮蓝 bump 显示英文标题

标题： Highly luminous supernovae associated with gamma-ray bursts II. The luminous blue bump in the afterglow of GRB 140506A

摘要： 与伽马射线暴（GRBs）相关的超新星（SNe）通常被视为一个同质化的群体，但在亮度以及谱能分布（SED）方面至少存在一个例外。 然而，这个事件，即SN 2011kl，与超长GRB 111209A相关联。 对于更典型的GRBs是否存在类似的异常现象？ 在对GRB相关超新星的光变特征进行系统分析的过程中，我们发现在GRB 140506A之后的晚期瞬变中存在一个异常隆起。 本文旨在证明这一隆起比普通的GRB之后的超新星显著更亮且更蓝。 我们收集了文献中的所有可用数据，并对Swift紫外光学望远镜（UVOT）数据进行了全面分析，这使我们能够从最初的几分钟一直追踪到宿主星系的光曲线，同时也构建了一个扩展的余辉广域SED，该SED基于地面光谱分析。 我们发现，在余辉之后存在一个稳健的晚期隆起/平台，显示出强烈的颜色变化迹象，谱线斜率在光谱的蓝区变得更平坦。 这一隆起可以被解释为一种亮度较高的超新星隆起，其光谱特性与典型的GRB-SNe不同。 对其修正视线消光后得到的极端值表明，与GRB 140506A相关的超新星是迄今为止检测到的最亮的一个。 即便如此，它仍然符合GRB-SNe的亮度-持续时间关系。 尽管缺乏光谱证据支持，但140506A之后的蓝色隆起很可能是光谱特性不同于经典GRB-SNe且更类似于SN 2011kl的超新星的标志——尽管它与平均GRB相关联，这表明GRB-SN群体比目前认为的更加多样化，其亮度可达到与超亮超新星相当的水平。 显示英文摘要

摘要： The supernovae (SNe) associated with gamma-ray bursts (GRBs) are generally seen as a homogenous population, but at least one exception exists, both in terms of luminosity as well as Spectral Energy Distribution (SED). However, this event, SN 2011kl, was associated with an ultra-long GRB 111209A. Do such outliers also exist for more typical GRBs? Within the context of a systematic analysis of photometric signatures of GRB-associated SNe, we found an anomalous bump in the late-time transient following GRB 140506A. We hereby aim to show this bump is significantly more luminous and blue than usual SNe following GRBs. We compile all available data from the literature, and add a full analysis of the Swift UVOT data, which allows us to trace the light curve from the first minutes all the way to the host galaxy, as well as construct a broad SED of the afterglow that extends the previous SED analysis based on ground-based spectroscopy. We find robust evidence for a late-time bump/plateau following the afterglow which shows evidence for a strong colour change, with the spectral slope becoming flatter in the blue region of the spectrum. This bump can be interpreted as a luminous SN bump which is spectrally dissimilar to typical GRB-SNe. Correcting it for the large line-of-sight extinction results in extreme values which make the SN associated with GRB 140506A the most luminous detected so far. Even so, it would be in agreement with a luminosity-duration relation of GRB-SNe. While not supported by spectroscopic evidence, it is likely the blue bump following GRB 140506A is the signature of a SN which is spectrally dissimilar to classical GRB-SNe and more similar to SN 2011kl -- while being associated with an average GRB, indicating the GRB-SN population is more diverse than thought so far, and can reach luminosities comparable to those of superluminous SNe.