arXivDaily arXiv每日学术速递 周一至周五更新
arXiv周末暂无论文更新，休息一下吧，周末愉快~~
arXiv 0810.2661astro-ph
收藏

SN 1987 A星环谱线发射的时间演化及其热点

Time evolution of the line emission from the inner circumstellar ring of SN 1987A and its hot spots

Per Groeningsson, Claes Fransson, Bruno Leibundgut, Peter Lundqvist, Peter Challis, Roger A. Chevalier, Jason Spyromilio

备注：
25 Pages, 12 Figures, accepted for publication in A&A
阅读 PDF
arXiv 页面 ↗HTML 原文 ↗

摘要：

我们提出了七个时期之间的1999年10月和2007年11月的高分辨率VLT/UVES阶梯光谱的SN 1987 A的喷射物环碰撞。在此期间，来自未受冲击气体的大多数窄线的通量减少了2-3倍，这与冲击爆发引起的初始电离的衰减一致。然而，[O III]特别显示增加至约6800天。这与辐射冲击模型一致，其中预冲击气体被来自冲击的软X射线加热。当冲击波扫过更多的气体时，来自冲击波气体的线辐射迅速增加。我们发现，中性和高电离线大致遵循巴耳末线的演化，而中间电离线的演化速度较慢。直到6800天，光学光变曲线的演化与软X射线的演化相似。[O III]和[Ne III]在第6500天和第7000天之间的断裂可能是由于复合到较低的电离水平。然而，[Fe XIV]线的演化，以及来自最低电离阶段的线，继续遵循软X射线的演化，正如预期的那样。低电离线和中电离线的线轮廓与早期日冕线的线轮廓有明显的差别。这表明这些线来自不同物理条件的区域，至少有一部分日冕线来自绝热激波。然而，在以后的时期，低电离线的线宽增加并接近[Fe X-XIV]的高电离线的线宽。在最新时期，H-alpha线轮廓可以追踪到~500 km/s。这与冲击波传播到密度为（1-4）× 10^4 cm-3时的冷却时间是一致的。

英文摘要：

We present seven epochs between October 1999 and November 2007 of high resolution VLT/UVES echelle spectra of the ejecta-ring collision of SN 1987A. The fluxes of most of the narrow lines from the unshocked gas decreased by a factor of 2-3 during this period, consistent with the decay from the initial ionization by the shock break-out. However, [O III] in particular shows an increase up to day ~6800. This agrees with radiative shock models where the pre-shocked gas is heated by the soft X-rays from the shock. The line emission from the shocked gas increases rapidly as the shock sweeps up more gas. We find that the neutral and high ionization lines follow the evolution of the Balmer lines roughly, while the intermediate ionization lines evolve less rapidly. Up to day ~6800, the optical light curves have a similar evolution to that of the soft X-rays. The break between day 6500 and day 7000 for [O III] and [Ne III] is likely due to recombination to lower ionization levels. Nevertheless, the evolution of the [Fe XIV] line, as well as the lines from the lowest ionization stages, continue to follow that of the soft X-rays, as expected. There is a clear difference in the line profiles between the low and intermediate ionization lines, and those from the coronal lines at the earlier epochs. This shows that these lines arise from regions with different physical conditions, with at least a fraction of the coronal lines coming from adiabatic shocks. At later epochs the line widths of the low ionization lines, however, increase and approach those of the high ionization lines of [Fe X-XIV]. The H-alpha line profile can be traced up to ~500 km/s at the latest epoch. This is consistent with the cooling time of shocks propagating into a density of (1-4)x10^4 cm-3.

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。

↑