Mapping the Supernovae Driven Winds of the Large Magellanic Cloud in Hα Emission I
Mapping the Supernovae Driven Winds of the Large Magellanic Cloud in Hα Emission I
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DOI：
10.3847/1538-4357/abd320
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发表时间：
2021-01
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影响因子：
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通讯作者：
D. Ciampa;K. Barger;N. Lehner;M. Horn;Michael Hernandez;L. M. Haffner;B. Smart;Chad Bustard;Sam Barber;Henry Boot
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作者：
D. Ciampa;K. Barger;N. Lehner;M. Horn;Michael Hernandez;L. M. Haffner;B. Smart;Chad Bustard;Sam Barber;Henry Boot
我们展示了第一张光谱解析的大麦哲伦星云 (LMC) 银河风的 Hα 发射图。通过将新的威斯康星州 H-alpha 制图器观测结果 (I Hα ≳ 10 mR) 与现有的 H i 21 cm 发射观测结果相结合，我们 (1) 在 +50 ≤ v LSR ≤ +250 km s−1 的本地静止标准 (LSR) 速度范围内绘制了 LMC 的近侧银河风图，(2) 确定了其形态和范围，(3) 估计了其质量、流出速率、 和质量载荷系数。我们观察到这种风的 Hα 发射通常偏离 LMC 的 H i 盘 1°。从运动学角度来看，我们发现相对于 LMC 的 H i 盘，这种风的热电离相中的扩散气体持续存在低速 (≲100 km s−1) 和高速 (≳100 km s−1)。此外，我们发现高速分量在空间上与最强烈的恒星形成区域剑鱼座 30 对齐。因此，我们得出的结论是，这种高速物质追踪着活跃的流出。我们估计近侧 LMC 流出的热 (T e ≈ 104 K) 电离相的质量是低速和高速分量的组合。假设电离分数为 75%，并且风关于 LMC 盘对称，我们估计其总（中性和电离）质量为 ，质量流量为 ，质量负载因子为 η ≈ 4.54。我们的平均质量负载因子结果大约比之前的 Hα 成像和紫外吸收线研究大 2.5 倍，这表明这些研究遗漏了流出物中近一半的气体。
We present the first spectroscopically resolved Hα emission map of the Large Magellanic Cloud’s (LMC) galactic wind. By combining new Wisconsin H-alpha Mapper observations (I Hα ≳ 10 mR) with existing H i 21 cm emission observations, we (1) mapped the LMC’s nearside galactic wind over a local standard of rest (LSR) velocity range of +50 ≤ v LSR ≤ +250 km s−1, (2) determined its morphology and extent, and (3) estimated its mass, outflow rate, and mass-loading factor. We observe Hα emission from this wind to typically 1° off the LMC’s H i disk. Kinematically, we find that the diffuse gas in the warm-ionized phase of this wind persists at both low (≲100 km s−1) and high (≳100 km s−1) velocities, relative to the LMC’s H i disk. Furthermore, we find that the high-velocity component spatially aligns with the most intense star-forming region, 30 Doradus. We, therefore, conclude that this high-velocity material traces an active outflow. We estimate the mass of the warm (T e ≈ 104 K) ionized phase of the nearside LMC outflow to be for the combined low and high-velocity components. Assuming an ionization fraction of 75% and that the wind is symmetrical about the LMC disk, we estimate that its total (neutral and ionized) mass is , its mass-flow rate is , and its mass-loading factor is η ≈ 4.54. Our average mass-loading factor results are roughly a factor of 2.5 larger than previous Hα imaging and UV absorption line studies, suggesting that those studies are missing nearly half the gas in the outflows.