AI 中文总结
研究对超新星SN 2022xus进行光学观测，利用光谱和光曲线建模等方法，发现它具有IIP型和IIL型超新星的混合特性，是两者间的过渡事件，为两类超新星间存在连续体提供了证据。
AI 中文摘要
我们展示了对II型超新星SN 2022xus的光学光度和光谱观测。该超新星在爆炸后约7天内达到V波段峰值星等-16.32等，随后是持续约94天的平台期，下降速率约为1.2等/（100天）。早期光谱显示出由几条高电离线混合引起的宽特征。与典型IIP型超新星相比，SN 2022xusus的Hα吸收与发射比更小。通过星云阶段光谱和热光度曲线建模，估计前身星质量在12至15 M⊙范围内。利用REDBACK进行多波段光曲线建模得出类似结果。SN 2022xus兼具IIP型和IIL型超新星的混合特性，被确定为两者之间的过渡事件，为这两类超新星之间存在连续体提供了进一步证据。
英文摘要
We present optical photometric and spectroscopic observations of the Type~II supernova SN~2022xus. The SN reached its peak {\em V} band magnitude of $-16.32$ mag within $\sim$7 days of explosion, followed by a plateau phase lasting $\sim$94 days with a declination rate of $\sim$1.2 mag (100 day)$^{-1}$. Early time spectra exhibit broad features that could be caused by the blending of several high-ionisation lines, likely arising from a relatively weak interaction between the SN ejecta and the surrounding circumstellar medium (CSM). Compared to typical Type~IIP SNe, SN~2022xus exhibits a smaller H$α$ absorption-to-emission ratio ($a/e$), indicating a relatively small hydrogen envelope mass at the time of explosion. From nebular-phase spectroscopy and bolometric light curve modelling, the progenitor mass is estimated to be in the range of 12 -- 15 M$_\odot$. The multi-band light curve modelling using \texttt{REDBACK} infers a similar progenitor mass, a low mass-loss rate, and a confined CSM. Although several photometric and spectroscopic characteristics place the SN within the Type~IIL population, it displays mixed properties of both Type~IIP and Type~IIL SNe and cannot be cleanly classified into either subclass. We therefore identify SN~2022xus as a transitional event between Type~IIP and Type~IIL SNe, providing further evidence for a continuum between these two classes.
CommentsAccepted for publication in MNRAS, 14 pages, 14 figures, 9 tables
