AI 中文总结
研究IIb型超新星SN 2024aecx，用扩展版\texttt{TransFit}建模其多波段演化，拟合相关参数，推断出有效外半径等数据，支持激波冷却加放射性加热解释，指出其快速光学下降需超出简单放射性扩散的物理机制。
AI 中文摘要
SN 2024aecx是一颗附近快速演化的剥离包层超新星，具有显著的双峰紫外-光学光变曲线。我们用扩展版的\texttt{TransFit}对其多波段演化进行建模，在单一随时间变化的辐射扩散计算中处理早期激波冷却发射和随后的放射性加热。为描述IIb型前身星预期的分层抛射物，采用紧凑内抛射物连接到稀薄扩展外包层，并直接从早期光变曲线拟合外密度斜率。模型再现了短命的第一个峰值、上升到放射性主峰以及整体多波段演化。我们推断有效外半径\(R_0 = 109.6^{+6.6}_{-3.5}\,R_\odot\)，抛射物质量\(M_{\rm ej}=2.14^{+0.21}_{-0.19}\,M_\odot\)，镍质量\(M_{\rm Ni}=0.050\pm0.002\,M_\odot\)，以及陡峭的外密度斜率\(n_{\rm out}=13.33^{+0.11}_{-0.12}\)。陡峭的外轮廓有利于低质量扩展包层，而低抛射物质量解释了主峰的快速演化。然而，具有标准γ射线泄漏的控制模型在最大值后衰减过慢。因此我们引入有效光学输出因子来量化紫外-光学光度的额外后期抑制。这些结果支持对SN 2024aecx的激波冷却加放射性加热解释，但表明其快速光学下降需要超出最简单放射性扩散处方的物理机制。
英文摘要
SN~2024aecx is a nearby, rapidly evolving stripped-envelope supernova with a prominent double-peaked ultraviolet--optical light curve. We model its multiband evolution with an extended version of \texttt{TransFit}, in which the early shock-cooling emission and the subsequent radioactive heating are treated within a single time-dependent radiative diffusion calculation. To describe the stratified ejecta expected for a Type~IIb progenitor, we adopt a compact inner ejecta connected to a dilute extended outer envelope and fit the outer density slope directly from the early light curve. The model reproduces the short-lived first peak, the rise to the radioactive main peak, and the overall multiband evolution. We infer an effective outer radius of $R_0=109.6^{+6.6}_{-3.5}\,R_\odot$, an ejecta mass of $M_{\rm ej}=2.14^{+0.21}_{-0.19}\,M_\odot$, a nickel mass of $M_{\rm Ni}=0.050\pm0.002\,M_\odot$, and a steep outer density slope of $n_{\rm out}=13.33^{+0.11}_{-0.12}$. The steep outer profile favors a low-mass extended envelope, while the low ejecta mass explains the rapid evolution of the main peak. However, a control model with standard $γ$-ray leakage fades too slowly after maximum. We therefore introduce an effective optical-output factor to quantify the additional late-time suppression of the ultraviolet--optical luminosity. These results support the shock-cooling plus radioactive-heating interpretation of SN~2024aecx, but show that its rapid optical decline requires physics beyond the simplest radioactive-diffusion prescription.
Comments9 pages, 3 figures, 2 tables
