One ring to encompass them all: a giant stellar structure that surrounds the Galaxy
One ring to encompass them all: a giant stellar structure that surrounds the Galaxy
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DOI：
10.1046/j.1365-8711.2003.06545.x
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发表时间：
2003-01
影响因子：
4.8
通讯作者：
R. Ibata;G. Lewis;A. Ferguson;M. Irwin;N. Tanvir
中科院分区：
文献类型：
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作者：
R. Ibata;G. Lewis;A. Ferguson;M. Irwin;N. Tanvir
我们提供的证据表明，斯隆数字巡天在银河系反中心方向发现的奇怪的恒星群延伸到了其他绕过银河系平面的遥远领域。由艾萨克·牛顿望远镜广角相机拍摄的新数据显示，类似的人群沿着视线狭窄地排列，但银河中心的距离从类似于15到类似于20kpc(在天空中类似于100度)。尽管沿着视线狭窄地集中，但该结构相当垂直地延伸到光盘平面之外，垂直比例高度为0.75+/-0.04kpc。这一发现表明，银河系外圈的末端是一个低表面亮度的恒星环。目前可用的数据不能让我们确定该结构的起源。一种可能性是，它是很久以前被银河系吞噬的卫星星系的幽灵，尽管我们更喜欢的解释是，它是圆盘的扰动，可能是古代翘曲的结果。假设星环是光滑的和轴对称的，星体结构中的恒星总质量可能达到2×10(8)米到10(9)米。
We present evidence that the curious stellar population found by the Sloan Digital Sky Survey in the Galactic anticentre direction extends to other distant fields that skirt the plane of the Milky Way. New data, taken with the Isaac Newton Telescope Wide Field Camera, show a similar population, narrowly aligned along the line of sight, but with a galactocentric distance that changes from similar to15 to similar to20 kpc (over similar to100degrees on the sky). Despite being narrowly concentrated along the line of sight, the structure is fairly extended vertically out of the plane of the disc, with a vertical scaleheight of 0.75 +/- 0.04 kpc. This finding suggests that the outer rim of the Galaxy ends in a low surface brightness stellar ring. Presently available data do not allow us to ascertain the origin of the structure. One possibility is that it is the wraith of a satellite galaxy devoured long ago by the Milky Way, although our favoured interpretation is that it is a perturbation of the disc, possibly the result of ancient warps. Assuming that the ring is smooth and axisymmetric, the total stellar mass in the structure may amount to similar to2 x 10(8) M. up to similar to10(9) M(.).