AI 中文总结
该研究针对78个OB型恒星周围红外弓形激波候选体开展Hα成像巡天，结合多地基设施观测与存档中红外图像，测量几何参数并分类，发现部分候选体有可检测电离气体结构，恒星风动量和辐射压力影响结构塑造，为后续研究提供方向。
AI 中文摘要
大质量恒星周围的弓形激波通常在中红外巡天中被识别。相比之下，对这些结构的系统光学研究仍然稀缺，目前仅有少数可能的探测报告。我们对从文献目录中汇编的78个红外弓形激波候选体进行了有针对性的Hα成像巡天。利用多个地基设施进行观测，并辅以斯皮策和WISE的存档中红外图像。对于检测到的弓形结构，测量了几何参数，并根据其中心恒星的参数、测量的间隔距离和采用的合理星际介质条件对弓形进行分类。在15个天体中检测到清晰的弧形Hα星云，另外偶然发现了一个弓形激波。另有35个天体表现出与复杂背景结构相关的弥漫Hα发射，28个没有可检测到的Hα发射。Hα和红外形态通常追踪相同的大尺度结构，尽管大多数红外弧稍微更靠近恒星，并且比它们的光学对应物更宽。我们发现几个系统与辐射支持的弓形激波、弓形波或尘埃波一致，而其他系统仍然与经典的风支持的弓形激波兼容。这项巡天表明，OB恒星周围的一部分红外弓形激波候选体在Hα中也表现出可检测的电离气体结构，恒星风动量和辐射压力都可以有助于塑造这些结构。未发现Hα弓形激波的检测与恒星参数之间的相关性，并且在Hα和射电波段观测到的天体重叠太小，无法得出确定结论。未来需要进行光谱观测，以确定电离气体的物理条件和运动学，并进一步限制这些弓形激波系统的性质。
英文摘要
Bow shocks (BSs) around massive stars are commonly identified in mid-infrared (MIR) surveys. In contrast, systematic optical investigations of these structures remain scarce with only a few possible detections reported so far. We performed a targeted Halpha imaging survey of 78 IR BS candidates compiled from literature catalogues. Observations were obtained with multiple ground-based facilities and complemented with archival MIR images from Spitzer and WISE. For the detected bow structures, geometrical parameters were measured, and the bows were classified based on the parameters of their central stars, the measured stand-off distances and adopted plausible ISM conditions Clear arc-shaped Halpha nebulae are detected in 15 objects, with one additional BS discovered serendipitously. A further 35 objects exhibit diffuse Halpha emission associated with complex background structures, while 28 show no detectable Halpha emission. The Halpha and IR morphologies generally trace the same large-scale structures, although most of the IR arcs lie slightly closer to the star and appear broader than their optical counterparts. We find that several systems are consistent with radiation-supported BSs, bow waves or dust waves, while others remain compatible with classical wind-supported BSs. This survey demonstrates that a fraction of IR BS candidates around OB stars also exhibit detectable ionised gas structures in Halpha, and both stellar wind momentum and radiation pressure can contribute to shaping these structures. No correlation is found between the detection of an Halpha BS and the stellar parameters, and the overlap in objects observed in Halpha and in the radio regime was too small for firm conclusions. Future spectroscopic observations will be required to determine the physical conditions and kinematics of the ionised gas and to further constrain the nature of these BS systems.
Comments23 pages, 8 figures, 6 tables, accepted for publication in A&A
