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首页> 外文期刊>The Astrophysical journal >Giant Molecular Outflows Powered by Protostars in L1448
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Giant Molecular Outflows Powered by Protostars in L1448

机译:L1448中由原恒星驱动的巨大分子流出

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We present sensitive (T ≈ 0.1 K), large-scale (47' × 7'—corresponding to 4 pc × 0.6 pc at the source) maps of the CO J = 1 → 0 emission of the L1448 dark cloud at 55'' resolution. These maps were acquired using the on-the-fly (OTF) capability of the NRAO 12 m telescope atop Kitt Peak in Arizona. CO outflow activity is seen in L1448 on parsec scales for the first time. Careful comparison of the spatial and velocity distribution of our high-velocity CO maps with previously published optical and near-infrared images and spectra has led to the identification of six distinct CO outflows. Three of these are powered by the Class 0 protostars, L1448C, L1448N(A), and L1448N(B). L1448 IRS 2 is the source of two more outflows, one of which is newly identified from our maps. The sixth newly discovered outflow is powered by an as yet unidentified source outside of our map boundaries. We show the direct link between the heretofore unknown, giant, highly collimated, protostellar molecular outflows and their previously discovered, distant optical manifestations. The outflows traced by our CO mapping generally reach the projected cloud boundaries. Integrated intensity maps over narrow velocity intervals indicate there is significant overlap of blue- and redshifted gas, suggesting the outflows are highly inclined with respect to the line of sight, although the individual outflow position angles are significantly different. The velocity channel maps also show that the outflows dominate the CO line cores as well as the high-velocity wings. The magnitude of the combined flow momenta, as well as the combined kinetic energy of the flows, are sufficient to disperse the 50 M⊙ NH3 cores in which the protostars are currently forming, although some question remains as to the exact processes involved in redirecting the directionality of the outflow momenta to effect the complete dispersal of the parent cloud.
机译:我们呈现了55英寸L1448暗云的CO J = 1→0发射的敏感(T≈0.1 K),大规模(47'×7'-对应于源4 pc×0.6 pc)的图。解析度。这些地图是使用亚利桑那州基特峰顶上的NRAO 12 m望远镜的即时(OTF)功能获得的。在L1448中,首次以秒差距尺度观察到CO流出活动。仔细比较我们的高速CO映射的空间和速度分布与先前发布的光学和近红外图像和光谱,已识别出六个不同的CO流出。其中三个由等级0的原星提供动力,即L1448C,L1448N(A)和L1448N(B)。 L1448 IRS 2是另外两个流出的来源,其中一个是从我们的地图中新发现的。第六个新发现的流出源由地图边界之外的一个尚未确定的来源提供动力。我们显示了迄今为止未知的,巨大的,高度准直的,原恒星的分子外流与其先前发现的远距离光学表现之间的直接联系。通过我们的CO映射跟踪的流出量通常会到达预计的云边界。在狭窄的速度区间上的综合强度图表明,蓝移和红移气体存在明显的重叠,这表明流出物相对于视线高度倾斜,尽管各个流出物的位置角明显不同。速度通道图还显示出流出主要控制CO管线芯以及高速机翼。合并的流动动量的大小以及流动的合并的动能足以分散目前正形成原恒星的50M⊙NH3核,尽管仍然存在一些有关重新定向氢原子的确切过程的问题。流出力矩的方向性,以影响母云的完全散布。

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