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IIb型超新星SN~2016gkg的初步观测和分析。 SN~2016gkg在其早期演化过程中表现出清晰的双峰光变曲线，这得到了我们密集的测光后续观测的证实。 SN~2016gkg与其他IIb型超新星有很强的相似性，特别是与在光学和近红外波段观测到的\he ~发射特征有关。 SN~2016gkg的演化速度比典型的IIb型超新星SN~1993J更快，在第一峰值之后的衰减类似于SN~2011dh。 档案中的{\it 哈勃空间望远镜}图像分析表明，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光谱类型和初始质量$15-20$\msun ，具体取决于为NGC~613采用的距离模数。 模拟爆炸中$5\,\rm{days}$的温度演化，我们得到一个前身星半径为$\sim\,48-124$\rsun ，小于从爆炸前图像分析得到的值（$240-320$\rsun ）。 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 photometric follow-up campaign. SN~2016gkg shows strong similarities with other Type IIb SNe, in particular with respect to the \he~emission features observed 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. The analysis of 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 $\sim\,48-124$\rsun, smaller than that obtained from the analysis of the pre-explosion images ($240-320$\rsun).