Gemini, SOFIA, and ATCA Reveal Very Young, Massive Protostars in the Collapsing Molecular Cloud BYF 73
Gemini, SOFIA, and ATCA Reveal Very Young, Massive Protostars in the Collapsing Molecular Cloud BYF 73
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DOI：
10.3847/2041-8213/aae6ce
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发表时间：
2018-10
期刊：
影响因子：
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通讯作者：
R. Pitts;P. Barnes;S. Ryder;Dan Li
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文献类型：
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作者：
R. Pitts;P. Barnes;S. Ryder;Dan Li
我们提供有关全球坠落分子云/原恒星团 BYF 73 的多波长数据。其中包括来自平流层红外天文台 (SOFIA) 远红外场成像线光谱仪 (FIFI-LS) 的新远红外 (FIR) 谱线和连续谱数据、使用热区域相机光谱仪进行的中红外 (MIR) 观测双子座南站 (T-ReCS) 和来自澳大利亚望远镜紧凑阵列 (ATCA) 的 3 毫米连续数据，以及来自斯皮策/红外阵列相机 (IRAC)、赫歇尔/光电探测阵列相机和光谱仪 (PACS) 以及光谱和光度成像接收器 (SPIRE) 的档案数据。 [O i] 、[O iii] 、[O i] 和 [C ii] 中的 FIFI-LS 光谱突出显示了致密分子云和 H ii 区域内及其之间的不同气体环境。云和 H ii 区域之间的光解离区域 (PDR) 最好由 [O i] 追踪，密度可能 >1010 m−3，但在最稠密气体中观察到的线比和 λ63 μm/λ158 μm 线比远远超出模型值。 H ii 区域被 [C ii] 很好地追踪到，其线比为 λ158 μm/λ145 μm，表明密度为 108.5 m−3，电离辐射场相对较弱，为 1.5 ≲ log(G/G0) ≲ 2。T-ReCS 数据揭示了云中的 8 个原恒星天体，其中 6 个出现在云中深处（AV > 30m 或更多）。云的中心。 MIR 2 拥有最大的核心，约为 240 M，比所有其他核心的质量总和大十倍，没有明显的气体流出，冷却线排放可忽略不计，其 4.7 × 103 L 光度的 ∼3%–8% 来自重力势能的释放。 MIR 2 的动态年龄可能只有 7000 年。这一事实，以及云中嵌入的恒星总质量远小于其气体质量，证实了 BYF 73 处于相对早期的演化阶段。
We present multi-wavelength data on the globally infalling molecular cloud/protostellar cluster BYF 73. These include new far-infrared (FIR) spectral line and continuum data from the Stratospheric Observatory for Infrared Astronomy’s (SOFIA’s) Far Infrared Field-Imaging Line Spectrometer (FIFI-LS), mid-infrared (MIR) observations with the Thermal-Region Camera Spectrograph (T-ReCS) on Gemini-South, and 3 mm continuum data from the Australia Telescope Compact Array (ATCA), plus archival data from Spitzer/Infrared Array Camera (IRAC), and Herschel/Photodetecting Array Camera and Spectrometer (PACS) and Spectral and Photometric Imaging Receiver (SPIRE). The FIFI-LS spectroscopy in [O i] , [O iii] , [O i] , and [C ii] highlights different gas environments in and between the dense molecular cloud and H ii region. The photo dissociation region (PDR) between the cloud and H ii region is best traced by [O i] and may have density >1010 m−3, but the observed and λ63 μm/λ158 μm line ratios in the densest gas are well outside model values. The H ii region is well-traced by [C ii], with the λ158 μm/λ145 μm line ratio, indicating a density of 108.5 m−3 and a relatively weak ionizing radiation field, 1.5 ≲ log(G/G0) ≲ 2. The T-ReCS data reveal eight protostellar objects in the cloud, of which six appear deeply embedded (AV > 30m or more) near the cloud’s center. MIR 2 has the most massive core at ∼240 M , more massive than all the others combined by up to tenfold, with no obvious gas outflow, negligible cooling line emission, and ∼3%–8% of its 4.7 × 103 L luminosity originating from the release of gravitational potential energy. MIR 2's dynamical age may be as little as 7000 years. This fact, and the cloud’s total embedded stellar mass being far less than its gas mass, confirm BYF 73's relatively early stage of evolution.