A Warp in the Large Magellanic Cloud Disk?
A Warp in the Large Magellanic Cloud Disk?
复制标题
大麦哲伦云盘中的扭曲？
DOI：
10.1086/342739
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发表时间：
2002
期刊：
影响因子：
--
通讯作者：
C. Salyk
中科院分区：
文献类型：
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作者：
K. Olsen;C. Salyk
我们提出了一个大麦哲伦云（LMC）盘的形状的研究。我们使用Cerro Tololo Inter-American Observatory 0.9 m望远镜观测到的50个随机选择的LMC场的V-I， I色星等图中确定的核心氦燃烧红团星的亮度来测量与这些场的相对距离。随机光度误差和标定误差控制在小于1%。通过红团的颜色对变红进行校正后，我们求解LMC倾斜平面节点线的倾角和位置角，得到i = 35。°8±2。θ = 145°±4°。我们的解决方案要求我们排除LMC西南部15个红团星等比拟合平面亮0.1等的场。在这些场的基础上，我们认为LMC盘是扭曲和扭曲的，包含了延伸到平面外2.5 kpc的特征。我们认为，产生比预期更亮的红团星的其他方法，如恒星年龄和金属丰度的变化，不太可能解释我们的观察结果。
We present a study of the shape of the Large Magellanic Cloud (LMC) disk. We use the brightnesses of core helium burning red clump stars identified in V-I, I color-magnitude diagrams of 50 randomly selected LMC fields observed with the Cerro Tololo Inter-American Observatory 0.9 m telescope to measure relative distances to the fields. Random photometric errors and errors in the calibration are controlled to ≲1%. Following correction for reddening measured through the color of the red clump, we solve for the inclination and position angle of the line of nodes of the tilted plane of the LMC, finding i = 35.°8 ± 2.°4 and θ = 145° ± 4°. Our solution requires that we exclude 15 fields in the southwest of the LMC that have red clump magnitudes ∼0.1 mag brighter than the fitted plane. On the basis of these fields, we argue that the LMC disk is warped and twisted, containing features that extend up to 2.5 kpc out of the plane. We argue that alternative ways of producing red clump stars brighter than expected, such as variations in age and metallicity of the stars, are unlikely to explain our observations.