在NGC628的JWST“幻影”图像中看到的千秒差距大小的超级气泡的恒星星族
The stellar population responsible for a kiloparsec size superbubble seen in the JWST "phantom" images of NGC628
摘要：
本文研究了晚型旋涡星系NGC 628中千秒级超气泡的多波段性质。超级气泡是使用JWST/MIRI过滤器追踪多环芳烃（PAH）排放的早期发布图像中看到的许多孔中最大的一个。超气泡位于距银心东南方向约3 kpc的臂间区域。在HI、CO和H α中可以检测到超级气泡周围的壳层，其膨胀速度为12 km/s，并且在气体中包含多达2x10^7 Msun的质量，其中大部分是分子形式。我们发现，与HST/ACS图像上周围的圆盘相比，气泡内有明显过量的蓝色明亮恒星。这些多余的蓝色明亮恒星是质量为10^5 Msun的恒星星族的一部分，这些恒星族是在过去5千万年的不同恒星形成时期形成的，这是通过使用贝叶斯技术分析色星等图确定的。这些星族中的大质量恒星注入的机械能足以提供壳层气体膨胀所需的能量。缓慢而稳定的能量注入，而不是猛烈的能量注入，可能是维持千秒差距尺度上的壳结构的原因。根据JWST 21微米（F2100 W滤镜）和Halpha图像推断，膨胀的壳层目前是触发恒星形成的场所。
英文摘要：
We here study the multi-band properties of a kiloparsec-size superbubble in the late-type spiral galaxy NGC628. The superbubble is the largest of many holes seen in the early release images using JWST/MIRI filters that trace the Polycyclic Aromatic Hydrocarbon (PAH) emissions. The superbubble is located in the interarm region ~3 kpc from the galactic center in the south-east direction. The shell surrounding the superbubble is detected in HI, CO, and Halpha with an expansion velocity of 12 km/s, and contains as much as 2x10^7 Msun of mass in gas that is mostly in molecular form. We find a clear excess of blue, bright stars inside the bubble as compared to the surrounding disk on the HST/ACS images. These excess blue, bright stars are part of a stellar population of 10^5 Msun mass that is formed over the last 50 Myr in different star formation episodes, as determined from an analysis of color-magnitude diagrams using a Bayesian technique. The mechanical power injected by the massive stars of these populations is sufficient to provide the energy necessary for the expansion of the shell gas. Slow and steady, rather than violent, injection of energy is probably the reason for the maintenance of the shell structure over the kiloparsec scale. The expanding shell is currently the site for triggered star formation as inferred from the JWST 21 micron (F2100W filter) and the Halpha images.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
