剥离包层超新星的高效恒星形成区
The efficient star-forming regions of stripped-envelope supernovae
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中文总结 AI 辅助
该研究计算富氢超新星与剥离包层超新星所在区域的恒星形成效率，发现剥离包层超新星爆发于恒星形成效率为富氢超新星8倍的区域，为其前身星性质提供了观测约束。
中文摘要 AI 辅助
质量大于8倍太阳质量的大质量恒星通过恒星反馈在塑造星系的星际介质中发挥关键作用，但这些恒星在坍缩成核心坍缩超新星（SNe）爆炸前的形成与演化过程仍不明确。我们首次计算了富氢超新星（H-rich SNe）和剥离包层超新星（SESNe）所在位置的恒星形成效率（SFEs），以约束其前身星性质。我们利用甚大望远镜（VLT）的多单元光谱探测器（MUSE）和阿塔卡马大型毫米波/亚毫米波阵列（ALMA）的观测数据，分别追踪暖电离气体和冷分子气体的发射线Hα/Hβ与CO(2-1)；两种观测在约100秒差距的云尺度空间分辨率下分辨出单个H II区和巨分子云，结合这些数据我们通过恒星形成率（SFR）与分子气体质量（M_mol）的比值计算恒星形成效率，即SFE = SFR/M_mol。我们发现，SESNe爆发的环境当前恒星形成效率是H-rich SNe环境的8倍（在分子气体质量相近时，SESNe的恒星形成率更高）。一方面，若初始质量函数偏倚于大质量端，这与大部分SESNe由质量大于20倍太阳质量的极质量恒星形成的情景相符；另一方面，若双星系统形成率的提升与湍流相关，进而与恒星形成效率的提高相关，那么大多数SESNe前身星通道由质量小于20倍太阳质量的相互作用双星形成，而双星比例的增加可解释增强的Hα光度。综上，SESNe优先发生在剧烈、高效的恒星形成区域，而非仅气体含量更高的区域。
英文摘要
Massive stars ($> 8~\rm{M}_{\odot}$) play a key role in shaping the interstellar medium of galaxies through stellar feedback. However, how these stars form and evolve before exploding as core-collapse supernovae (SNe) remains elusive. We compute for the first time the star-formation efficiencies (SFEs) at the locations of hydrogen-rich (H-rich) SNe and stripped-envelope SNe (SESNe) to constrain their progenitor properties. We used VLT/MUSE and ALMA observations of H$α$/H$β$ and CO(2-1) emission lines to trace the components of the warm ionised gas and cold molecular gas, respectively. Both observations resolve individual H II regions and giant molecular clouds at spatial resolutions on cloud-scales ($\sim$100 pc). This combined data allows us to compute the SFE from the star formation rate (SFR) and the molecular gas mass (M$_{\rm{mol}}$) as SFE = SFR/M$_{\rm{mol}}$. We find that SESNe explode in environments that are currently forming stars eight times more efficiently than those of H-rich SNe (higher SFR for SESNe with similar M$_{\rm{mol}}$). On one hand, this is consistent with the scenario in which the majority of SESNe are produced from very massive stars ($> 20~\rm{M}_{\odot}$) if the initial mass function is top-heavy. On the other hand, most of SESN progenitor channels are formed from interacting binaries ($< 20~\rm{M}_{\odot}$) if an increased binary system formation rate is connected with turbulences and, in turn, with the boost to SFE. Then, an increased binary fraction could explain the enhanced H$α$ luminosities. In summary, SESNe preferentially occur in regions of intense, efficient star formation rather than simply higher gas content.
