Supernova Interaction with a Dense Detached Shell in SN 2001em
Supernova Interaction with a Dense Detached Shell in SN 2001em
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DOI：
10.3847/1538-4357/abb460
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发表时间：
2020-08
期刊：
影响因子：
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通讯作者：
P. Chandra;R. Chevalier;N. Chugai;D. Milisavljevic;C. Fransson
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文献类型：
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作者：
P. Chandra;R. Chevalier;N. Chugai;D. Milisavljevic;C. Fransson
本文对超新星SN 2001 em进行了19年的综合分析。SN 2001 em是已知最古老的超新星，它经历了从剥离的包层到相互作用的超新星的蜕变。早期的光谱表明它是一颗Ib型超新星。后来，喷出物赶上了一个致密的拱星H壳层，在爆炸前几千年喷出，引发超新星喷出物和致密壳层之间的相互作用，产生无线电，X射线和Hα发射。我们在射电波段使用甚大阵列的存档数据，在X射线波段使用钱德拉、XMM-牛顿和斯威夫特-XRT的存档数据，沿着已发表的Hα测量数据。我们结合联合收割机这些数据与我们的低无线电频率观测与巨型米波射电望远镜在两个时代，涵盖三个频率。虽然观测结果错过了冲击波进入致密壳层的阶段，但X射线表明，冲击波在大约1750天左右从致密壳层中出来。这些数据表明X射线发射的前向激波来源。无线电数据显示，在3 GHz左右的后期（天）有一个光谱反转，这模仿了SN 1986 J中看到的中心吸收分量的特性。一个可能的解释是SN 2001 em的前身是一个巨大的双星系统，经历了一段共同的包络演化。SN 2001 em的氢包层可能是由于二元相互作用而丢失的。
We carry out a comprehensive analysis of supernova SN 2001em covering a period of 19 yr since discovery. SN 2001em is the oldest supernova known to have undergone a metamorphosis from a stripped envelope to an interacting supernova. An early spectrum indicates it exploded as a Type Ib supernova. Later, the ejecta caught up with a dense circumstellar H-shell, ejected a few thousand years before the explosion, triggering interaction between the supernova ejecta and the dense shell, producing radio, X-ray, and Hα emission. We use archival data with the Very Large Array in radio bands and with Chandra, XMM-Newton, and Swift-XRT in X-ray bands, along with published Hα measurements. We combine these data with our low radio frequency observations with the Giant Metrewave Radio Telescope at two epochs covering three frequencies. While the observations missed the phase when the shock entered the dense shell, the X-rays indicate that the shock came out of the dense shell at around 1750 days. The data suggest a forward shock origin of the X-ray emission. Radio data show a spectral inversion at late epochs ( days) at around 3 GHz, which mimics the properties of the central absorbed component seen in SN 1986J. A possible explanation for this component is that the progenitor of SN 2001em was a massive binary system that had undergone a period of common-envelope evolution. The hydrogen envelope from the SN 2001em progenitor may have been lost as a result of binary interaction.