High-resolution (0.15'') Very Large Array observations of 7 mm continuum and H53α line emission toward the hypercompact H II region G28.20-0.04N reveal the presence of large-scale ordered motions. We find a velocity gradient of 103 km s?1 pc?1 along the minor axis of the continuum source. Lower resolution (1.0''-2.3'') radio recombination line observations indicate a systematic increase of line width from H30α to H92α. Under the assumption that the H30α line does not suffer significant pressure broadening, we have deconvolved the contributions of statistical broadening (thermal, turbulent, and pressure) from large-scale motions. The pressure broadening of the H53α, H76α, and H92α lines implies an electron density of 7 × 106, 9 × 105, and 3 × 105 cm?3, respectively.
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机译:对超紧凑型H II区G28.20-0.04N的7mm连续谱和H53α线发射的高分辨率(0.15'')超大型阵列观测结果表明,存在大规模的有序运动。我们发现沿连续源的短轴的速度梯度为103 km s?1 pc?1。较低分辨率(1.0''-2.3'')的无线电重组线观察表明,线宽从H30α到H92α的系统增加。在H30α谱线没有显着压力展宽的假设下,我们将大规模运动的统计展宽(热,湍流和压力)的贡献解卷积。 H53α,H76α和H92α线的压力展宽意味着电子密度分别为7×106、9×105和3×105 cm?3。
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