发表机构
HUN-REN CSFK Konkoly Observatory; ELTE Eötvös Loránd University; University of Szeged; University of Texas at Austin（匈牙利科学院研究中心孔科利天文台; 厄特沃什·罗兰大学; 塞格德大学; 得克萨斯大学奥斯汀分校）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究通过181条光谱分析56个Ia型超新星的高速特征，发现其速度、强度与衰退率等观测性质相关，并指出双爆轰模型最有前景，但其他模型仍不可排除。
AI 中文摘要
在Ia型超新星（SNe Ia）的早期光谱中，Ca II和Si II的高速吸收线（高速特征，HVFs）很常见，但其物理起源仍知之甚少。我们使用了56个SNe Ia的181条光学光谱，这些光谱至少在Ca II近红外三重线中显示出HVFs，以更好地理解HVFs的性质。为了模拟HVFs的轮廓，我们应用了高斯拟合以及使用SYNOW代码的光谱合成建模。我们发现，与SYNOW相比，高斯拟合通常会低估HVFs的速度，并推导出一个线性校正公式。与许多先前研究一致，HVFs的观测性质（速度、强度、持续时间）被发现与SNe Ia的一般观测量（衰退率、光谱亚型）相关。较亮、衰退较慢的SNe通常表现出更强、更高速度的HVFs，而较暗的天体通常表现出弱、低速度的HVFs。在我们的样本中，早型星系中的SNe Ia与晚型星系中的事件相比，表现出较弱和较慢的HVFs。将这些观测发现与理论预测进行比较，我们得出结论，HVFs的整体物理图像相当复杂，可以用多种模型来解释。双爆轰爆炸模型很有前景，因为它本质上能够解释可能产生HVFs的高速壳层的形成，但不能排除非对称延迟爆轰模型或与星周物质的相互作用。
英文摘要
High velocity absorption lines of Ca II and Si II (high-velocity features, HVFs) are common in the early spectra of Type Ia supernovae (SNe Ia), but their physical origin is still poorly understood. We used 181 optical spectra of 56 SNe Ia that show HVFs in at least the Ca II NIR triplet to better understand the nature of HVFs. To model the profiles of HVFs we applied Gaussian fitting as well as spectrum synthesis modeling with the SYNOW code. We found that Gaussian fitting usually underestimates the velocity of HVFs compared to SYNOW, and derived a linear formula for correction. In accord with many previous studies, the observed properties of HVFs (velocity, strength, duration) were found to correlate with the general observables of SNe Ia (decline rate, spectral subtype). Brighter, slow-declining SNe usually exhibit stronger, higher velocity HVFs, while fainter objects typically show weak, low velocity HVFs. SNe Ia in early-type galaxies showed weaker and slower HVFs compared to events in late-type galaxies in our sample. Comparing these observational findings with theoretical predictions, we conclude that the overall physical picture of HVFs is quite complex, and could be explained by multiple models. A double detonation explosion model is promising as it is inherently capable of explaining the creation of high-velocity shells that may produce HVFs, but an asymmetric delayed detonation model or interaction with circumstellar material cannot be ruled out.
CommentsAccepted for publication by ApJ
