论文标题
SN 2018BS：一种I型超浮肿超新星，带有非球形杂物材料
SN 2018bsz: a Type I superluminous supernova with aspherical circumstellar material
论文作者
论文摘要
我们提出了I型超浮肿超新星（SLSN-I）的光谱分析，SN 2018BSZ。尽管它与Slsne-I非常相似，但以$ \ sim30 $ d后最大速率出现的多组分H $α$线是最非典型的。 H $α$的特征是两个排放组件，一个为$+3000 $ km/s，第二秒为$ -7500 $ km/s，延迟后出现了第三个，接近零的速度组件。蓝色和中央组件可以通过中间宽度的高斯曲线来描述，但是红色成分明显更宽和洛伦兹。蓝色组件以较低的速度发展，然后以$ 100 $ d的峰值淡出，同时与轻曲线断裂。在包括PA $β$在内的其他氢管中观察到了多组分曲线，以及Ca II和He I的线。在（10.2 d）之前获得的光谱极化法和（38.4 d）之后（38.4 d）H线的出现在Stokes $ Q $ - $ Q $ - $ $ U $平面上的较大变化与SN 2018 Blance Onserment Adgational Adenterment Adenters and Adenters Oft and Adental inttral intals and and Adental intal intal int and Adental inttral intt and Adental int and Adental in s sn snitals intt and s sn s n ofers plastical intt的自由主义变化。假设SN在10.2 d时几乎不偏振，则在38.4 d时的连续性极化达到$ p \ sim1.8 \％$表示高度不对称的配置。我们建议可以通过高度非球形CSM来解释SN 2018BS的观察到的演变。 SN爆炸后，CSM迅速被弹射器所取代，但是随着Photosephere开始退缩，不同的CSM区域重新出现产生特殊的线条配置文件。根据H $α$的首次出现，如果预峰高原与创建CSM的喷发有关，则可以将CSM的距离限制为小于$ 430 $ au，甚至更低（$ <87 $ au）。对于其他SLSNE-I，已经推断出CSM的存在。但是，尚不清楚SN 2018BSZ的罕见性能是否可以推广到SLSNE-I或它们是不常见的进化路径的结果，可能涉及二进制伴侣。
We present a spectroscopic analysis of Type I superluminous supernova (SLSN-I), SN 2018bsz. While it closely resembles SLSNe-I, the multi-component H$α$ line appearing at $\sim30$ d post-maximum is the most atypical. The H$α$ is characterised by two emission components, one at $+3000$ km/s and a second at $-7500$ km/s, with a third, near-zero velocity component appearing after a delay. The blue and central components can be described by Gaussian profiles of intermediate width, but the red component is significantly broader and Lorentzian. The blue component evolves towards lower velocity before fading at $100$ d post-peak, concurrently with a light curve break. Multi-component profiles are observed in other hydrogen lines including Pa$β$, and in lines of Ca II and He I. Spectropolarimetry obtained before (10.2 d) and after (38.4 d) the appearance of the H lines show a large shift on the Stokes $Q$ -- $U$ plane consistent with SN 2018bsz undergoing radical changes in its geometry. Assuming the SN is almost unpolarised at 10.2 d, the continuum polarisation at 38.4 d reaches $P \sim1.8\%$ implying a highly asymmetric configuration. We propose that the observed evolution of SN 2018bsz can be explained by highly aspherical CSM. After the SN explosion, the CSM is quickly overtaken by the ejecta, but as the photosphere starts to recede, the different CSM regions re-emerge producing the peculiar line profiles. Based on the first appearance of H$α$, we can constrain the distance of the CSM to be less than $430$ AU, or even lower ($<87$ AU) if the pre-peak plateau is related to an eruption that created the CSM. The presence of CSM has been inferred for other SLSNe-I. However, it is not clear whether the rare properties of SN 2018bsz can be generalised for SLSNe-I or whether they are the result of an uncommon evolutionary path, possibly involving a binary companion.
