标题： 由O型年轻恒星形成的动量驱动喷流辐射：射电喷流与分子喷流的比较 显示英文标题

标题： Momentum-driven outflow emission from an O-type YSO: Comparing the radio jet with the molecular outflow

摘要： 目标：我们想要研究靠近O型年轻恒星物体（YSO）的电离喷流发射的物理特性，并估计从小尺度到大尺度喷流的能量和动量传递效率。 方法：我们在22和45 GHz频率下对高质量恒星形成区G023.01-00.41中的紧凑且微弱的射电连续谱辐射进行了Karl G. Jansky甚大阵列（VLA）观测，角分辨率在0.3"到0.1"之间，热均方根约为10 uJy/beam。 结果：我们在O型YSO内1000 AU范围内发现了一束准直的热（轫致辐射）喷流发射，在45 GHz时的射电光度（L_rad）为24 mJy kpc^2。 该射电热喷流的张开角度为44度，动量率约为8 10^-3 M_sun yr^-1 km/s。 通过将新数据与之前对分子喷流和水脉泽冲击波的观测相结合，我们可以从驱动源开始追踪喷流辐射，穿过分子云块，跨越两个数量级的长度（500 AU-0.2 pc）。 我们发现，内部喷流发射与被卷入的周围气体的扩展喷流之间的动量传递效率接近于1。 这一结果表明，大尺度流动是由来自高质YSO内1000 AU范围内的射电喷流发射的机械力所推动的。 显示英文摘要

摘要： Aims: We want to study the physical properties of the ionized jet emission in the vicinity of an O-type young stellar object (YSO), and estimate how efficient is the transfer of energy and momentum from small- to large-scale outflows. Methods: We conducted Karl G. Jansky Very Large Array (VLA) observations, at both 22 and 45 GHz, of the compact and faint radio continuum emission in the high-mass star-forming region G023.01-00.41, with an angular resolution between 0.3" and 0.1", and a thermal rms of the order of 10 uJy/beam. Results: We discovered a collimated thermal (bremsstrahlung) jet emission, with a radio luminosity (L_rad) of 24 mJy kpc^2 at 45 GHz, in the inner 1000 AU from an O-type YSO. The radio thermal jet has an opening angle of 44 degrees and brings a momentum rate of 8 10^-3 M_sun yr^-1 km/s. By combining the new data with previous observations of the molecular outflow and water maser shocks, we can trace the outflow emission from its driving source through the molecular clump, across more than two order of magnitude in length (500 AU-0.2 pc). We find that the momentum-transfer efficiency, between the inner jet emission and the extended outflow of entrained ambient gas, is near unity. This result suggests that the large-scale flow is swept-up by the mechanical force of the radio jet emission, which originates in the inner 1000 AU from the high-mass YSO.