电离氢区（HII区）附近的致密核
Dense Cores in the Vicinity of an HII Region
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中文总结 AI 辅助
本研究结合ALMA、VLA观测与astrodendro分析，探究HII区对分子云IRAS 18530+0215中致密核的影响，发现HII区反馈延伸至0.3 pc，可提升致密核的速度弥散、温度与维里参数，但未促进大质量致密核形成。
中文摘要 AI 辅助
大质量恒星通过辐射和力学反馈强烈影响其周围环境，但这种反馈对亚秒差距（sub-pc）尺度下致密气体结构的影响仍知之甚少。本研究调查了新形成的大质量恒星的反馈对纤维状分子云IRAS 18530+0215中致密核的影响。我们分析了ALMA Band 6对1.3毫米尘埃连续谱及DCN、N₂D⁺、¹³CS谱线的观测，结合VLA K波段连续谱与NH₃的观测数据。使用astrodendro识别致密核，并推导其温度、质量、速度弥散和维里参数；通过能量与压强估算，研究超致密HII区的动力学状态。该HII区半径约0.1 pc，膨胀速度约2.5 km s⁻¹，对应壳层动力学年龄约0.06 Myr。DCN和¹³CS致密核集中在HII区附近，而N₂D⁺致密核更倾向于分布在更远区域；致密核温度和速度弥散随与HII区的投影距离增加而降低，维里参数在内部约0.3 pc范围内上升，超出该尺度后急剧下降，致密核质量则无明显的距离依赖趋势。在约0.2 pc处发现强恒星形成迹象，而更远区域仍存在宁静的冷致密核。该致密HII区似乎被限制或阻塞在约0.1 pc范围内，但其反馈至少延伸至约0.3 pc；在该范围内，反馈会增大致密核的速度弥散、气体温度和维里参数，但未发现其促进更大质量致密核形成的证据。
英文摘要
Massive stars strongly influence their surroundings through radiative and mechanical feedback, but its effects on dense gas structures at sub-pc scales remain poorly constrained. We investigate how feedback from a newly formed massive star affects dense cores in the filamentary molecular cloud IRAS 18530+0215. We analyze ALMA Band 6 observations of 1.3 mm dust continuum and DCN, N$_2$D$^+$, and $^{13}$CS line emission, together with VLA K-band continuum and NH$_3$ observations. Dense cores are identified with astrodendro, and their temperatures, masses, velocity dispersions, and virial parameters are derived. The dynamical state of the ultra-compact H II region is examined through energy and pressure estimates. The H II region has a radius of $\sim$0.1 pc and an expansion velocity of $\sim$2.5 km s$^{-1}$, corresponding to a shell dynamical age of $\sim$0.06 Myr. DCN and $^{13}$CS cores are concentrated near the H II region, whereas N$_2$D$^+$ cores preferentially lie farther away. Core temperatures and velocity dispersions decrease with projected distance from the H II region. Virial parameters increase within the inner $\sim$0.3 pc but decline sharply beyond this scale, while core masses show no significant trend with distance. Strong star formation signatures are found at $\sim$0.2 pc, whereas more distant regions still host quiescent, cold dense cores. The compact H II region appears trapped or choked within $\sim$0.1 pc, while its feedback extends to at least $\sim$0.3 pc. Within this region, feedback enhances core velocity dispersions, gas temperatures, and virial parameters, with no evidence that it promotes the formation of more massive dense cores.
