标题： MUSE观测揭示超新星遗迹0540-69.3中冲击发射的光学日冕铁线 显示英文标题

标题： MUSE Observations Reveal Optical Coronal Iron Lines from Shock Emission in Supernova Remnant 0540-69.3

摘要： 我们使用来自VLT的MUSE积分场单元数据，研究大麦哲伦星云超新星遗迹0540-69.3（SNR 0540）的光学激波辐射。 观测覆盖光谱范围4650-9300 $Å$，并提供一个 $1\times1$ 弧分 $^{2}$ 的视场，涵盖了整个遗迹。 我们分析与激波相关的发射线的空间和光谱特性，并识别出团状的光学激波辐射，例如 来自[S II]$\lambda\lambda$6716,6731双线和日冕[Fe XIV]$\lambda$5303线（通常在径向速度$\lesssim|100|$km s$^{-1}$和$\lesssim|170|$km s$^{-1}$，分别为）。这些特征追踪了之前X射线研究中看到的冲击波壳层。 冲击后电子密度估计，基于[S II]线比值，显示出空间变化，在西方的明亮结中密度最高($\sim10^4$ cm$^{-3}$)，而在东方的密度较低($\sim3\times10^3$ cm$^{-3}$)。北部(西南部)的密度似乎显著较低(较高)，但由于信号有限，仍无法确定。 我们还使用[Fe XIV]$\lambda$5303/[Fe XI]$\lambda$7892 比例估计爆炸波冲击速度，发现低速度（$\sim400$km s$^{-1}$），与之前的研究一致。 所有这些结果支持爆炸波与周围星际介质相互作用的情景，尤其是在西部区域。 此外，我们在脉冲星横向速度方向南侧$\sim$2000-3000 km s$^{-1}$处检测到四条未识别的发射线，但其起源尚不清楚。 可能的解释包括高速抛射物团块中的铁线，但所有解释都面临挑战。 我们的研究结果突显了SNR 0540周围环状和星际介质的复杂性。 显示英文摘要

摘要： We investigate the optical shock emission from the Large Magellanic Cloud supernova remnant 0540-69.3 (SNR 0540) using MUSE integral-field-unit data from the VLT. The observations cover the spectral range 4650-9300 $\r{A}$ and provide a $1\times1$ arcmin$^{2}$ field of view, encompassing nearly the entire remnant. We analyse the spatial and spectral properties of shock-related emission lines, and identify clumpy optical shock emission e.g. from [S II] $\lambda\lambda$6716,6731 doublet and the coronal [Fe XIV] $\lambda$5303 line (typically at radial velocities $\lesssim|100|$ km s$^{-1}$ and $\lesssim|170|$ km s$^{-1}$, respectively). These features trace the blast-wave shell seen in previous X-ray studies. Post-shock electron density estimates, based on the [S II]-line ratio, reveal spatial variation, with the highest densities ($\sim10^4$ cm$^{-3}$) in the bright knots in the west, and lower densities ($\sim3\times10^3$ cm$^{-3}$) in the east. The density in the north (southwest) appears significantly lower (higher) but remains unconstrained due to limited signal. We also estimate blast-wave shock velocities using the [Fe XIV] $\lambda$5303/[Fe XI] $\lambda$7892 ratio, finding low velocities ($\sim400$ km s$^{-1}$), consistent with previous studies. All these results support the scenario that the blast wave is interacting with the surrounding interstellar medium, particularly in the western regions. Additionally, we detect four unidentified emission lines, $\sim$2000-3000 km s$^{-1}$ south from the pulsar in transverse velocity, but their origin remains unclear. Possible explanations, including Fe lines from a high-velocity ejecta clump, all present challenges. Our findings highlight the complex nature of the circum- and interstellar medium surrounding SNR 0540.