Title: Interaction of SN~Ib 2004dk with a Previously-Expelled Envelope Show Chinese title

Title: SN~Ib 2004dk 与先前抛出的包层的相互作用

Abstract: The interaction between the expanding supernova (SN) ejecta with the circumstellar material (CSM) that was expelled from the progenitor prior to explosion is a long-sought phenomenon, yet observational evidence is scarce. Here we confirm a new example: SN 2004dk, originally a hydrogen-poor, helium-rich Type Ib SN that reappeared as a strong H$\alpha$-emitting point-source on narrowband H$\alpha$ images. We present follow-up optical spectroscopy that reveals the presence of a broad H$\alpha$ component with full width at half maximum of ~290 km/s in addition to the narrow H$\alpha$ +[NII] emission features from the host galaxy. Such a broad component is a clear sign of an ejecta-CSM interaction. We also present observations with the XMM-Newton Observatory, the Swift satellite, and the Chandra X-ray Observatory that span 10 days to 15 years after discovery. The detection of strong radio, X-ray, and H$\alpha$ emission years after explosion allows various constraints to be put on pre-SN mass-loss processes. We present a wind-bubble model in which the CSM is "pre-prepared" by a fast wind interacting with a slow wind. Much of the outer density profile into which the SN explodes corresponds to no steady-state mass-loss process. We estimate that the shell of compressed slow wind material was ejected ~1400 yr prior to explosion, perhaps during carbon burning, and that the SN shock had swept up about 0.04 M_sun of material. The region emitting the H$\alpha$ has a density of order $10^{-20}$ g/cc. Show Chinese abstract

Abstract: 超新星（SN）爆发物与前身星爆炸前释放的周围星际物质（CSM）之间的相互作用是一个长期寻求的现象，但观测证据很少。 在这里，我们确认了一个新的例子：SN 2004dk，最初是一颗缺乏氢、富含氦的Ib型超新星，在窄带H$\alpha$图像上重新出现为一个强H$\alpha$发射点源。 我们提供了后续的光学光谱，显示除了来自宿主星系的窄H$\alpha$ +[NII]发射特征外，还存在一个宽H$\alpha$成分，其半高全宽约为290 km/s。 这种宽成分是爆发物-CSM相互作用的明确迹象。 我们还提供了XMM-Newton天文台、Swift卫星和钱德拉X射线天文台的观测数据，时间跨度从发现后10天到15年。 在爆炸后多年检测到强烈的射电、X射线和H$\alpha$辐射，使得可以对超新星前的质量损失过程施加各种限制。 我们提出了一种风泡模型，其中CSM通过快速风与慢速风的相互作用“预先准备”。 大部分SN爆炸所处的外部密度分布对应于没有稳态质量损失过程的情况。 我们估计，压缩慢速风物质的壳层是在爆炸前约1400年被抛出的，可能是在碳燃烧期间，且SN冲击波已经收集了大约0.04 M_sun 的物质。 发射H$\alpha$的区域的密度约为$10^{-20}$克/立方厘米。