探测SN 2024ggi周围星周物质的性质：寻找前身星爆发发射及射电观测的约束
Probing the Nature of the Circumstellar Material Surrounding SN 2024ggi: A Search for Precursor Emission and Constraints from Radio Observations
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中文总结 AI 辅助
本研究通过分析SN 2024ggi爆发前光变曲线和射电观测，未发现前身星爆发证据，推断其致密星周物质可能由稳定的脉动驱动超风形成。
中文摘要 AI 辅助
我们展示了邻近超新星SN 2024ggi爆发前光学光变曲线和爆发后射电观测的分析。SN 2024ggi是一颗在距离约7.2 Mpc的NGC 3621星系中发现的II型超新星。早期光谱证实SN 2024ggi显示出“类IIn”特征，表明其周围存在致密的星周物质（CSM）。我们使用ATClean在ATLAS数据中搜索了爆发前长达8年的光变曲线中的前身星爆发发射，ATClean清理了光变曲线并有效地将其与多个时间尺度的滚动高斯函数卷积。未发现前身星变异的显著证据。对于时间尺度为2天和300天的爆发，我们分别发现80%的探测阈值对应的绝对星等为-11.28等和-8.98等。我们使用澳大利亚望远镜致密阵列（ATCA）进行的射电观测与类风状的CSM密度轮廓一致，假设风速度为$v_{\rm wind} = 50$ km s$^{-1}$，推断的质量损失率约为${\sim} 8 \times 10^{-5} M_\odot$ yr$^{-1}$。然而，结合文献中的CSM密度估计，整体CSM密度轮廓呈现双组分结构，在较小半径（$\lesssim 6\times10^{14}$ cm）处存在更致密的内层结构，在较大半径处则呈现延伸的类风状轮廓。我们得出结论，SN 2024ggi周围的致密CSM可能并非由喷发式爆发沉积。相反，我们倾向于质量损失率较低但更稳定的情景，例如脉动驱动的超风、具有延伸色球层的模型，或两者的组合。
英文摘要
We present an analysis of the pre-explosion optical light curve and post-explosion radio observations of the nearby supernova (SN) 2024ggi, a Type II SN discovered in NGC 3621 at a distance of ~7.2 Mpc. Early spectra confirmed that SN 2024ggi showed ``IIn-like'' features, suggesting the presence of dense circumstellar material (CSM). We searched for precursor emission in the light curve up to 8 years pre-explosion from ATLAS using ATClean, which cleaned the light curve and effectively convolved it with rolling Gaussians of several timescales. No significant evidence for precursor variability was found. We find 80% detection thresholds on the absolute magnitude of -11.28 mag and -8.98 mag for outbursts with timescales of 2 and 300 days, respectively. Our radio observations taken with the Australia Telescope Compact Array (ATCA) are consistent with a wind-like CSM density profile, with an inferred mass-loss rate of ${\sim} 8 \times 10^{-5} M_\odot$ yr$^{-1}$, assuming $v_{\rm wind} = 50$ km s$^{-1}$. However, including CSM density estimates from the literature implies a two-component structure in the overall CSM density profile, with a denser inner structure at smaller radii ($\lesssim 6\times10^{14}$ cm) and an extended wind-like profile at larger radii. We conclude that the dense CSM around SN 2024ggi is likely not deposited there by eruptive outbursts. Instead, we favor a scenario with a lower but more stable mass-loss rate, such as pulsation-driven superwinds, a model with extended chromospheres, or a combination of both.
发表机构
- University of Toronto（多伦多大学）
- The Hebrew University of Jerusalem（耶路撒冷希伯来大学）
- Western Sydney University（西悉尼大学）
- Gifu University（岐阜大学）
- California Institute of Technology（加州理工学院）
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