Outflow structure and velocity field of Orion source - I. ALMA imaging of SiO isotopologue maser and thermal emission
Outflow structure and velocity field of Orion source - I. ALMA imaging of SiO isotopologue maser and thermal emission
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Orion源的流出结构和速度场-I. SiO同位素微波激射和热发射的ALMA成像
DOI：
10.1051/0004-6361/201220292
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发表时间：
2012
影响因子：
6.5
通讯作者：
C. Goddi
中科院分区：
文献类型：
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作者：
F. Niederhofer;E. Humphreys;C. Goddi
利用阿塔卡马大毫米/亚毫米阵列(ALMA)的科学验证数据，我们在214~246 GHz的频率范围内，对三种单氧硅同位素28SiOv=0，1，2和29SiOv=0A和28Si18Ov=0朝向猎户座BN/KL区的5个转动跃迁(J=5-4和J=6-5)进行了识别和成像。基态2 8SiO、2 9SiO和2 8Si18O的发射在射电源I处呈东北-西南方向扩展的双极形状，表明这些同位素示踪了一个由这个嵌入的高质量年轻恒星(YSo)驱动的流出(∼18 km S−1，P A∼50◦，∼5 0 0 AU)。然而，在小尺度(10-1000AU)上，源I的流出具有良好的空间和速度结构，正如SiO脉泽的甚长基线干涉成像所探测到的那样，大尺度(500-5000AU)的热SiO与ALMA探测到的大尺度(500-5000AU)显示了复杂的结构和速度场，很可能与BN/KL区环境对源I流出的影响有关。振动激发物种的发射在源I的位置达到峰值。这种发射是紧凑的，不能在∼1.5(∼600 AU，420pC距离)的角度分辨率下分辨。对单个速度通道的二维高斯拟合将发射峰定位在100AU半径内，即它们跟踪流出的最里面的部分。与主频v=1 J=1-0跃迁类似的v=1 J=5-4谱线的窄光谱轮廓和空间分布，为迄今已知的与源I有关的最高旋转激发(频率>；200 GHz)SiO脉泽发射提供了证据。脉泽发射将使我们能够利用未来ALMA最长基线研究I源磁盘流出界面。
Using Science Verification data from the Atacama Large Millimeter/Submillimeter Array (ALMA), we have identified and imaged five rotational transitions (J = 5–4 and J = 6–5) of the three silicon monoxide isotopologues 28 SiO v = 0, 1, 2 and 29 SiO v = 0a nd 28 Si 18 O v = 0 in the frequency range from 214 to 246 GHz towards the Orion BN/KL region. The emission of the ground-state 28 SiO, 29 SiO and 28 Si 18 O shows an extended bipolar shape in the northeast-southwest direction at the position of Radio Source I, indicating that these isotopologues trace an outflow (∼18 km s −1 ,P A∼ 50 ◦ , ∼5000 AU in diameter) that is driven by this embedded high-mass young stellar object (YSO). Whereas on small scales (10–1000 AU) the outflow from Source I has a well-ordered spatial and velocity structure, as probed by Very Long Baseline Interferometry (VLBI) imaging of SiO masers, the large scales (500–5000 AU) probed by thermal SiO with ALMA reveal a complex structure and velocity field, most likely related to the effects of the environment of the BN/KL region on the outflow emanating from Source I. The emission of the vibrationally-excited species peaks at the position of Source I. This emission is compact and not resolved at an angular resolution of ∼1. 5( ∼600 AU at a distance of 420 pc). 2D Gaussian fitting to individual velocity channels locates emission peaks within radii of 100 AU, i.e. they trace the innermost part of the outflow. A narrow spectral profile and spatial distribution of the v = 1 J = 5–4 line similar to the masing v = 1 J = 1–0 transition, provide evidence for the most highly rotationally excited (frequency >200 GHz) SiO maser emission associated with Source I known to date. The maser emission will enable studies of the Source I disk-outflow interface with future ALMA longest baselines.
DOI：
10.1088/0004-637x/727/2/113
发表时间：
2010-11
期刊：
The Astrophysical Journal
影响因子：
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作者：
J. Bally;N. Cunningham;N. Moeckel;M. Burton;N. Smith;A. Frank;Å. Nordlund
通讯作者：
J. Bally;N. Cunningham;N. Moeckel;M. Burton;N. Smith;A. Frank;Å. Nordlund