SN 2023gfo：一颗具有高光度和正常 plateau 持续时间的特殊 IIP 型超新星
SN 2023gfo: A Peculiar Type IIP Supernova with High Luminosity and Normal Plateau Duration
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中文总结 AI 辅助
本研究发现特殊超新星 SN 2023gfo 光度极高但 plateau 持续时间正常，推断其前身星半径异常大，排除 ejecta-CSM 强相互作用的高光度成因。
中文摘要 AI 辅助
我们给出了近邻星系 NGC 4995（距离 $d = 26.4 \pm 3.2$ Mpc）中高红化 IIP 型超新星（SN）2023gfo 的近红外（NIR）和光学观测结果，该超新星达到了 $M_V = -18.6$ 星等的高峰值光度。该超新星最初被探测为一个暗弱的红色事件，在 plateau 阶段开始时 $B-V = 0.8$ 星等。通过与模板对比，我们估计总消光量为 $A_V = 2.1$ 星等。校正该消光后，我们得到峰值准热光度为 $(5.9 \pm 1.5) \times 10^{42}$ 尔格每秒，这一数值使该事件跻身最亮的 IIP 型超新星之列，而其 plateau 持续时间仍处于正常范围。早期光学光谱显示出 H$\alpha$ 的 P-Cygni 轮廓，具有 $V = 13{,}800$ 千米每秒的宽吸收线，这是在相近时期观测到的 IIP 型超新星中最高的数值之一。高光度与正常的 plateau 持续时间表明该事件属于异常值。应用解析模型，我们推断出异常大的前身星半径，这可能表明前身星在爆炸前不久经历了从核心到包层的极端能量注入，导致半径大幅膨胀。虽然 ejecta-星周物质（CSM）相互作用原则上可以解释高光度，但我们未发现支持强相互作用的观测证据。
英文摘要
We present near-infrared (NIR) and optical observations of the highly reddened Type IIP supernova (SN) 2023gfo in the nearby galaxy NGC 4995 ($d = 26.4 \pm 3.2$ Mpc), which reached a high peak luminosity of $M_V = -18.6$ mag. The SN was initially detected as a faint red event, with $B-V = 0.8$ mag at the beginning of the plateau phase. By comparison with template, we estimate a total extinction of $A_V = 2.1$ mag. After correcting for this extinction, we derive a peak quasi-bolometric luminosity of $(5.9 \pm 1.5)\times10^{42}$ erg s$^{-1}$, placing this event among the most luminous SNe IIP, while its plateau duration remains within the normal range. The early-phase optical spectrum exhibits a P-Cygni profile of H$α$, with a broad absorption of $V$ = $13{,}800$ km s$^{-1}$, which is among the highest observed for SNe IIP at comparable epochs. The high luminosity and the normal plateau duration suggest that this event represents an outlier. Applying an analytical model, we infer an unusually large progenitor radius. This may indicate that the progenitor experienced an extreme energy injection from the core to the envelope shortly before explosion, resulting in a substantially inflated radius. While ejecta-circumstellar matter (CSM) interaction could in principle account for the high luminosity, we find no observational evidence supporting strong interaction.
