The structures of distant galaxies – III. The merger history of over 20 000 massive galaxies at z < 1.2
The structures of distant galaxies – III. The merger history of over 20 000 massive galaxies at z < 1.2
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DOI：
10.1111/j.1365-2966.2009.14396.x
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发表时间：
2008-12
影响因子：
4.8
通讯作者：
C. Conselice;Cui Yang;A. Bluck
中科院分区：
文献类型：
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作者：
C. Conselice;Cui Yang;A. Bluck
利用来自两个最大的外场星系巡天——扩展格罗斯带和宇宙演化巡天（COSMOS）的深哈勃太空望远镜成像，我们检查了结构特性，并推导了 21 902 个星系的合并历史，M* > 10 10 Matz 10 10 M� ，合并分数可以通过 f m = f 0 × (1 + z) m 参数化，幂律斜率 m = 2.3±0.4。通过使用 z = 0 之前的最佳可用值，斜率增加到 m = 3.8 ± 0.2，这表明局部合并属性的测量对于推导合并分数的演化至关重要。我们还表明，通过结构导出的合并分数大约比配对分数高 3-6 倍。根据最新的合并宇宙学模拟，我们表明这个比率是预测的，并且两种方法都可能正确地追踪合并分数和速率。我们利用模拟的合并时间尺度以及之前发布的哈勃深场和超深场中的合并分数计算出，M* > 10 10 Min 的星系的合并率在 z = 0.7 和 3 之间线性增加。最后，我们表明，恒星质量为 M* > 10 10 M 的典型星系在 z < 1.2 时会经历 1 到 2 次主要合并。
Utilizing deep Hubble Space Telescope imaging from the two largest field galaxy surveys, the Extended Groth Strip and the Cosmic Evolution Survey (COSMOS), we examine the structural properties, and derive the merger history for 21 902 galaxies withM∗ > 10 10 Matz 10 10 M� , the merger fraction can be parametrized by f m = f 0 × (1 + z) m with the power-law slope m = 2.3 ± 0.4. By using the best available z = 0 prior the slope increases to m = 3.8 ± 0.2, showing how critical the measurement of local merger properties is for deriving the evolution of the merger fraction. We furthermore show that the merger fraction derived through structure is roughly a factor of 3-6 higher than pair fractions. Based on the latest cosmological simulations of mergers, we show that this ratio is predicted, and that both methods are likely tracing the merger fraction and rate properly. We calculate, utilizing merger time-scales from simulations and previously published merger fractions within the Hubble Deep and Ultra Deep Fields, that the merger rate of galaxies with M∗ > 10 10 Mincreases linearly between z = 0.7 and 3. Finally, we show that a typical galaxy with a stellar mass of M∗ > 10 10 Mundergoes between 1 and 2 major mergers at z < 1.2.