ASASSN-14 lp：观察到的UV抑制的两种可能解决方案
ASASSN-14lp: two possible solutions for the observed UV suppression
摘要：
我们测试的紫外（UV）光谱表征Ia型超新星（SN）喷出物的外部结构的充分性。为此，我们进行光谱分析ASASSN-14 lp，一个正常的SN Ia显示低连续在中紫外区。为了解释强烈的紫外线抑制，两个可能的起源进行了研究，映射的化学配置文件的一个重要部分，其喷出物。我们适合光谱时间序列与中紫外线覆盖之前和周围的最大光HST，补充地面光学观测的最早时期。合成光谱计算与一维MC辐射传输程序TARDIS从自洽喷出物模型。在几个物理参数中，我们约束了9种化学元素的丰度分布。我们发现，分布的$^{56}$镍（和其他铁族元素），延伸到最高的速度再现所观察到的紫外线通量。喷出物外层存在放射性物质，如果得到证实，就意味着对可能发生的爆炸情景有很大的限制。我们用辐射转移程序TURTLS研究了推断的$^{56}$ Ni分布对早期光变曲线的影响，并将结果与ASASSN-14 lp的观测光变曲线进行了对比。推断的丰度与观测到的光度测定并不矛盾。我们还测试是否可以复制的UV抑制，如果在光球的辐射是显着低于纯普朗克函数的UV制度。在这种情况下，太阳的金属丰度可能足以在最高速度下重现紫外线抑制。
英文摘要：
We test the adequacy of ultraviolet (UV) spectra for characterizing the outer structure of Type Ia supernova (SN) ejecta. For this purpose, we perform spectroscopic analysis for ASASSN-14lp, a normal SN Ia showing low continuum in the mid-UV regime. To explain the strong UV suppression, two possible origins have been investigated by mapping the chemical profiles over a significant part of their ejecta. We fit the spectral time series with mid-UV coverage obtained before and around maximum light by HST, supplemented with ground-based optical observations for the earliest epochs. The synthetic spectra are calculated with the one dimensional MC radiative-transfer code TARDIS from self-consistent ejecta models. Among several physical parameters, we constrain the abundance profiles of nine chemical elements. We find that a distribution of $^{56}$Ni (and other iron-group elements) that extends toward the highest velocities reproduces the observed UV flux well. The presence of radioactive material in the outer layers of the ejecta, if confirmed, implies strong constraints on the possible explosion scenarios. We investigate the impact of the inferred $^{56}$Ni distribution on the early light curves with the radiative transfer code TURTLS, and confront the results with the observed light curves of ASASSN-14lp. The inferred abundances are not in conflict with the observed photometry. We also test whether the UV suppression can be reproduced if the radiation at the photosphere is significantly lower in the UV regime than the pure Planck function. In this case, solar metallicity might be sufficient enough at the highest velocities to reproduce the UV suppression.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
