论文标题
SN 2014AB:一个非球型的IIN超新星,具有低极化
SN 2014ab: An Aspherical Type IIn Supernova with Low Polarization
论文作者
论文摘要
我们提出了超新星(SN)2014AB的光度法,光谱和光谱法,该光度法是通过$ \ sim 200 $在峰值亮度后获得的。 SN 2014AB是一种发光的IIN型SN($ M_V <-19.14 $ mag),在其宿主星系的核心附近,VV 306C附近发现了峰值亮度。偏见的上限将爆炸时间限制在发现前200天内。尽管在我们的观察过程中,SN 2014AB被$ \ sim 1 $ mag下降,但观察到的频谱保持不变。光谱表现出不对称的发射线曲线,其蓝光成分始终如一,表明SN的远侧和近侧之间存在灰尘或缺乏对称性。 PA $β$发射线显示出与H $α$非常相似的轮廓,这意味着这种较强的蓝光成分是通过大型尘土粒的遮挡,光学厚的材料掩盖或在相互作用区域的远侧和远处缺乏对称性引起的。尽管有这些不对称的线曲线,但我们的光谱学数据表明,SN 2014AB在考虑了星际极化后几乎没有检测到的极化。这表明我们看到的是从光球中排放的,该光球与圆形对称面对面的偏差很小。我们很可能会在正常视线的平面中看到一个几乎圆形的对称性的SN IIN,但是在我们的视线沿线的界面密度或sn ejecta的密度中,大颗粒灰尘或明显的不对称性。我们建议SN 2014AB和SN 2010JL(以及其他SNE IIN)可能是从不同方向观看的类似事件。
We present photometry, spectra, and spectropolarimetry of supernova (SN) 2014ab, obtained through $\sim 200$ days after peak brightness. SN 2014ab was a luminous Type IIn SN ($M_V < -19.14$ mag) discovered after peak brightness near the nucleus of its host galaxy, VV 306c. Prediscovery upper limits constrain the time of explosion to within 200 days prior to discovery. While SN 2014ab declined by $\sim 1$ mag over the course of our observations, the observed spectrum remained remarkably unchanged. Spectra exhibit an asymmetric emission-line profile with a consistently stronger blueshifted component, suggesting the presence of dust or a lack of symmetry between the far side and near side of the SN. The Pa$β$ emission line shows a profile very similar to that of H$α$, implying that this stronger blueshifted component is caused either through obscuration by large dust grains, occultation by optically thick material, or a lack of symmetry between the far side and near side of the interaction region. Despite these asymmetric line profiles, our spectropolarimetric data show that SN 2014ab has little detected polarization after accounting for the interstellar polarization. This suggests that we are seeing emission from a photosphere that has only small deviation from circular symmetry face-on. We are likely seeing a SN IIn with nearly circular symmetry in the plane normal to our line of sight, but with either large-grain dust or significant asymmetry in the density of circumstellar material or SN ejecta along our line of sight. We suggest that SN 2014ab and SN 2010jl (as well as other SNe IIn) may be similar events viewed from different directions.