标题： IIb型超新星2016gkg的前身星及其早期演化 显示英文标题

标题： The progenitor and early evolution of the Type IIb SN 2016gkg

摘要： 我们报告了对邻近星系NGC 613中的II型b超新星2016gkg的初步观察和分析。 在早期演化过程中，SN 2016gkg表现出明显的双峰光曲线，这得到了我们密集的光谱和测光后续观测的证实。 SN 2016gkg与其他II型b超新星有很强的相似性，特别是与在光学和近红外波段爆炸后观察到的\he 发射特征有关。 $\sim\,9\,\rm{days}$ SN 2016gkg的演化速度比典型的II型b超新星1993J更快，在第一个峰值之后的衰减与SN 2011dh相似。 档案中的{\it 哈勃空间望远镜}图像表明在SN 2016gkg的位置存在爆炸前的天体，这表明前身星具有$\sim$中F型光谱类型和初始质量$15-20$\msun ，具体取决于用于NGC 613的距离模数。 模拟爆炸中$5\,\rm{days}$内的温度演变，我们得到一个前身星半径为$\sim\,60-120$\rsun ，与从爆炸前图像获得的光谱类型一致。 显示英文摘要

摘要： We report initial observations and analysis on the Type IIb SN 2016gkg in the nearby galaxy NGC 613. SN 2016gkg exhibited a clear double-peaked light curve during its early evolution, as evidenced by our intensive spectroscopic and photometric follow-up campaign. SN 2016gkg shows strong similarities with other Type IIb SNe, in particular with respect to the \he emission features observed $\sim\,9\,\rm{days}$ after explosion in both the optical and near infrared. SN 2016gkg evolved faster than the prototypical Type IIb SN 1993J, with a decline similar to that of SN 2011dh after the first peak. Archival {\it Hubble Space Telescope} images indicate a pre-explosion source at SN 2016gkg's position, suggesting a progenitor star with a $\sim$mid F spectral type and initial mass $15-20$\msun, depending on the distance modulus adopted for NGC 613. Modeling the temperature evolution within $5\,\rm{days}$ of explosion, we obtain a progenitor radius of $\sim\,60-120$\rsun, consistent with the spectral type obtained from the pre-explosion images.