The inner halo of M 87: a first direct view of the red-giant population
The inner halo of M 87: a first direct view of the red-giant population
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DOI：
10.1051/0004-6361/201014876
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发表时间：
2010-09
影响因子：
6.5
通讯作者：
S. Bird;W. Harris;J. Blakeslee;C. Flynn
中科院分区：
文献类型：
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作者：
S. Bird;W. Harris;J. Blakeslee;C. Flynn
哈勃太空望远镜 ACS 对处女座超巨星 M 87 的异常深度 (V, I) 成像数据集成功解析了其最亮的红巨星，达到 M I (lim) = ―2.5。在评估光度完整性和偏差后，我们使用这种材料来估计 M 87 内晕的金属丰度分布，发现分布非常广泛，并且可能在 [m/H] ≃ -0.4 附近达到峰值，甚至可能更高。 MDF的形状与附近的巨型E星系NGC 5128的内晕非常相似。作为我们研究的副产品，我们还使用TRGB（红巨星分支尖端）方法获得了到M 87距离的初步测量；结果是 (m ― M) 0 = 31.12±0.14 (d = 16.7 ± 0.9 Mpc)。将此结果与其他三种最新技术进行平均，得出加权平均值 d(M 87) = (16.4 ± 0.5) Mpc。
An unusually deep (V, I) imaging dataset for the Virgo supergiant M 87 with the Hubble Space Telescope ACS successfully resolves its brightest red-giant stars, reaching M I (lim) = ―2.5. After assessing the photometric completeness and biasses, we use this material to estimate the metallicity distribution for the inner halo of M 87, finding that the distribution is very broad and likely to peak near [m/H] ≃ -0.4 and perhaps higher. The shape of the MDF strongly resembles that of the inner halo for the nearby giant E galaxy NGC 5128. As a byproduct of our study, we also obtain a preliminary measurement of the distance to M 87 with the TRGB (red-giant branch tip) method; the result is (m ― M) 0 = 31.12±0.14 (d = 16.7 ± 0.9 Mpc). Averaging this result with three other recent techniques give a weighted mean d(M 87) = (16.4 ± 0.5) Mpc.