H I Kinematics of the Large Magellanic Cloud revisited : Evidence of possible infall and outflow
H I Kinematics of the Large Magellanic Cloud revisited : Evidence of possible infall and outflow
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重温大麦哲伦星云的 H I 运动学：可能流入和流出的证据
DOI：
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发表时间：
2014
期刊：
影响因子：
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通讯作者：
A. Subramaniam
中科院分区：
文献类型：
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作者：
G. Indu;A. Subramaniam
根据两个新的自行估计，重新审视了大麦哲伦星云 (LMC) 的中性原子氢 (H I) 运动学。我们分析了 ATCA/Parkes 和 GASS 数据集的强度加权 H I 速度图。我们使用最近的两个自行估计修正了圆盘的系统运动、横向运动、进动运动和章动运动的视线速度场，并估计了 H I 圆盘的运动学参数。使用 ATCA/Parkes 数据估计的运动学主轴位置角 (PA) 值与最近使用恒星示踪剂估计的 PA 相似。进动和章动对 PA 估计的影响被发现是显着的。使用 ATCA/Parkes 数据，发现 LMC 中的大部分 H I 气体位于圆盘中。我们检测到 12.1% 的数据点为运动异常值。我们将众所周知的 Arm E、Arm S、Arm W、Arm B 和新的流 Outer Arm 确定为异常组件的一部分。 GASS 数据分析揭示了麦哲伦桥 (MB) 及其与 LMC 盘的连接的速度细节。我们发现Arm B和Outer Arm与MB相连。我们在大麦哲伦西盘以及MB的西南部和南部地区探测到了高速气体。我们提出了两个模型（平面内和平面外）来解释异常气体。我们认为 Arm B 可能是源自内部 MB 的内落特征。 Arm E 可能是一个流出功能。我们认为，由于冲压压力，可能有来自西部大麦哲伦圆盘以及南部和西南部MB的流出。在MB中观察到的速度模式表明它正在被剪切。我们认为，本研究中发现的各种异常值可能是由于大麦哲伦在银河系（MW）晕中的运动引起的潮汐效应和流体动力效应的组合造成的。
The neutral atomic Hydrogen (H I) kinematics of the Large Magellanic Cloud (LMC) is revisited in light of two new proper motion estimates. We analysed the intensity weighted H I velocity maps of the ATCA/Parkes and GASS data sets. We corrected the line of sight velocity field for the systemic, transverse, precession, and nutation motions of the disk using two recent proper motion estimates, and estimated the kinematic parameters of the H I disk. The value of position angle (PA) of kinematic major axis estimated using ATCA/Parkes data is found to be similar to the recent estimate of the PA using stellar tracers. The effect of precession and nutation in the estimation of PA is found to be significant. Using ATCA/Parkes data, most of the H I gas in the LMC is found to be located in the disk. We detected 12.1% of the data points as kinematic outliers. We identified the well-known Arm E, Arm S, Arm W, Arm B and a new stream, Outer Arm, as part of outlier components. The GASS data analysis brings out the velocity details of the Magellanic Bridge (MB) and its connection to the LMC disk. We find that the Arm B and the Outer Arm are connected to the MB. We detect high velocity gas in the western disk of the LMC and the south-west and southern parts of the MB. We proposed two models (in plane and out of plane) to explain the outlier gas. We suggest that the Arm B could be an infall feature, originating from the inner MB. The Arm E could be an outflow feature. We suggest possible outflows from the western LMC disk and south and south western MB, which could be due to ram pressure. The velocity pattern observed in the MB suggests that it is being sheared. We suggest that the various outliers identified in this study may be caused by a combination of tidal effects and hydrodynamical effect due to the motion of the LMC in the Milky Way (MW) halo.