论文标题
HII区域和高质量无星团候选人II。片段化和诱导的恒星形成以〜0.025 PC量表：Alma Continuum研究
HII regions and high-mass starless clump candidates II. Fragmentation and induced star formation at ~0.025 pc scale: An ALMA continuum study
论文作者
论文摘要
HII区域的电离反馈修改了高质量无星团（HMSC，数百至几千个太阳能块，大小约为0.1-1 PC），例如在团块刻度上的温度和湍流。 HII区域的存在是否会改变HMSC中的核心尺度碎片和恒星形成的问题仍有待探索。我们旨在研究候选HMSC的0.025 PC尺度碎片的差异，而HMSC受到HII区域的强烈影响，而受干扰较小的差异。我们还搜索了受影响的HMSC中质量塑形和诱发恒星形成的证据。使用ALMA 1.3毫米连续体，分辨率约为1.3英寸，我们成像了八个候选HMSC，其中四个受HII区域影响，另外四个位于安静的环境中。较不受影响的HMSCS根据其相似的质量和距离选择了与受影响的相似的质量和距离相似，与这些可能与这些参数相比，与51所用的corme相比，该corme是八个clains clacters。团块在我们有限的样本中，即使HII区域似乎会影响两种类型的HMSC，但在受影响和非影响的HMSC之间的〜025 PC尺度碎片中没有明显的差异。团块}^{th}} $和0.3 $ {λ_{J，块}^{th}} $。在HMSC中，〜025个PC规模。
The ionization feedback from HII regions modifies the properties of high-mass starless clumps (HMSCs, of several hundred to a few thousand solar masses with a size of ~0.1-1 pc), such as temperature and turbulence, on the clump scale. The question of whether the presence of HII regions modifies the core-scale fragmentation and star formation in HMSCs remains to be explored. We aim to investigate the difference of 0.025 pc-scale fragmentation between candidate HMSCs that are strongly impacted by HII regions and less disturbed ones. We also search for evidence of mass shaping and induced star formation in the impacted HMSCs. Using the ALMA 1.3 mm continuum with a resolution of ~1.3", we imaged eight candidate HMSCs, including four impacted by HII regions and another four situated in the quiet environment. The less-impacted HMSCs are selected on the basis of their similar mass and distance compared to the impacted ones to avoid any possible bias linked to these parameters. A total of 51 cores were detected in eight clumps, with three to nine cores for each clump. Within our limited sample, we did not find a clear difference in the ~0.025 pc-scale fragmentation between impacted and non-impacted HMSCs, even though HII regions seem to affect the spatial distribution of the fragmented cores. Both types of HMSCs present a thermal fragmentation with two-level hierarchical features at the clump thermal Jeans length ${λ_{J, clump}^{th}}$ and 0.3${λ_{J, clump}^{th}}$. The ALMA emission morphology of the impacted HMSCs AGAL010.214-00.306 and AGAL018.931-00.029 sheds light on the capacities of HII regions to shape gas and dust in their surroundings and possibly to trigger star formation at ~0.025 pc-scale in HMSCs. Future ALMA surveys covering a large number of impacted HMSCs with high turbulence are needed to confirm the trend of fragmentation indicated in this study.
