Galaxy And Mass Assembly (GAMA): refining the local galaxy merger rate using morphological information
Galaxy And Mass Assembly (GAMA): refining the local galaxy merger rate using morphological information
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DOI：
10.1093/mnras/stu1799
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发表时间：
2014-09
影响因子：
4.8
通讯作者：
Kevin R. V. Casteels;C. Conselice;S. Bamford;E. Salvador-Solé;P. Norberg;N. Agius;I. Baldry;S. Brough;Michael J. I. Brown;M. Drinkwater;S. Driver;A. Graham;J. Bland-Hawthorn;A. Hopkins;L. Kelvin;Á. López-Sánchez;J. Loveday;A. Robotham;J. A. Vázquez-Mata
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文献类型：
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作者：
Kevin R. V. Casteels;C. Conselice;S. Bamford;E. Salvador-Solé;P. Norberg;N. Agius;I. Baldry;S. Brough;Michael J. I. Brown;M. Drinkwater;S. Driver;A. Graham;J. Bland-Hawthorn;A. Hopkins;L. Kelvin;Á. López-Sánchez;J. Loveday;A. Robotham;J. A. Vázquez-Mata
我们使用星系和质量大会（GAMA）调查测量当地宇宙质量相关的合并分数和合并率使用星系对和CAS（浓度，不对称性和平滑度）结构方法，该方法确定高度不对称的合并候选星系。我们的目标是确定哪种类型的合并产生高度不对称的星系，并提供一个新的测量本地星系主要合并率。我们研究的星系对恒星质量的限制，M* = 108 M的质量比为4：1）的低质量的同伴变得高度不对称，而较大的星系的影响要小得多。对于质量最大的星系，具有主要合并伴星系的高度不对称配对星系的比例最高，并随着质量的减小而逐渐下降。我们计算出，在109.5 < M* < 1011.5 M的范围内，与质量相关的主要合并分数相当恒定，为1.3%-2%，在较低质量时增加到1.4%。当考虑到可观测时间尺度时，发现主要的合并率在我们考虑的质量范围内近似为三倍。在108.0 < M* < 1011.5 M的范围内，总的同动体积主要合并率为（1.2 ± 0.5）× 10−3 h370 Mpc−3 Gyr−1。
We use the Galaxy And Mass Assembly (GAMA) survey to measure the local Universe mass-dependent merger fraction and merger rate using galaxy pairs and the CAS (concentration, asymmetry, and smoothness) structural method, which identifies highly asymmetric merger candidate galaxies. Our goals are to determine which types of mergers produce highly asymmetrical galaxies and to provide a new measurement of the local galaxy major merger rate. We examine galaxy pairs at stellar mass limits down to M* = 108 M⊙ with mass ratios of 4:1) the lower mass companion becomes highly asymmetric, whereas the larger galaxy is much less affected. The fraction of highly asymmetric paired galaxies which have a major merger companion is highest for the most massive galaxies and drops progressively with decreasing mass. We calculate that the mass-dependent major merger fraction is fairly constant at ∼1.3–2 per cent within 109.5 < M* < 1011.5 M⊙, and increases to ∼4 per cent at lower masses. When the observability time-scales are taken into consideration, the major merger rate is found to approximately triple over the mass range we consider. The total comoving volume major merger rate over the range 108.0 < M* < 1011.5 M⊙ is (1.2 ± 0.5) × 10−3 h370 Mpc−3 Gyr−1.