A declining major merger fraction with redshift in the local Universe from the largest-yet catalogue of major and minor mergers in SDSS
A declining major merger fraction with redshift in the local Universe from the largest-yet catalogue of major and minor mergers in SDSS
复制标题
从 SDSS 中迄今为止最大的主要和次要合并目录来看，当地宇宙中主要合并的比例随着红移而下降
DOI：
10.1093/mnras/stad911
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发表时间：
2023
影响因子：
4.8
通讯作者：
Vázquez-Mata, J. A.
中科院分区：
文献类型：
--
作者：
Nevin, R.;Blecha, L.;Comerford, J.;Simon, J.;Terrazas, B. A.;Barrows, R. S.;Vázquez-Mata, J. A.
要准确识别星系合并是很困难的，根据质量比或合并阶段对它们进行分类更是一个更大的挑战。在以前的工作中，我们使用了一套模拟合并来创建一种分类技术，该技术使用线性判别分析来识别主要和次要合并。在这里，我们将这项技术应用于SDSS DR16光度星表中的130万个星系，并给出了每个星系是主要或次要合并的概率，按合并阶段(早期、晚期、合并后)进行分类。我们给出了一个迄今最大的星系样本的公开可用的成像预测数值和所有上述分类。我们测量主要和次要合并分数(Fmerg)，并建立一个星系的完整质量样本，我们将其归结为恒星质量和红移的函数。对于较大的合并，我们发现恒星质量与合并成正斜率，合并成负斜率，恒星质量为10.5Lt；M*( M⊙)<；11.6时，红移为0.03<；z<；0.19。当我们不对质量进行入库或制作完整的样品时，我们能够重现具有红移的主要合并分数的人工正斜率，证明了质量完整性和质量入库的重要性。我们确定，主要合并分数与恒星质量的正趋势与分级组装情景一致。红移的负趋势需要一个额外的组装机制，如重子反馈，在局部宇宙中占主导地位。
It is difficult to accurately identify galaxy mergers and it is an even larger challenge to classify them by their mass ratio or merger stage. In previous work we used a suite of simulated mergers to create a classification technique that uses linear discriminant analysis to identify major and minor mergers. Here, we apply this technique to 1.3 million galaxies from the SDSS DR16 photometric catalogue and present the probability that each galaxy is a major or minor merger, splitting the classifications by merger stages (early, late, post-coalescence). We present publicly available imaging predictor values and all of the above classifications for one of the largest-yet samples of galaxies. We measure the major and minor merger fraction (fmerg) and build a mass-complete sample of galaxies, which we bin as a function of stellar mass and redshift. For the major mergers, we find a positive slope offmergwith stellar mass and negative slope offmergwith redshift between stellar masses of 10.5 <M*(log M⊙) < 11.6 and redshifts of 0.03 <z< 0.19. We are able to reproduce an artificial positive slope of the major merger fraction with redshift when we do not bin for mass or craft a complete sample, demonstrating the importance of mass completeness and mass binning. We determine that the positive trend of the major merger fraction with stellar mass is consistent with a hierarchical assembly scenario. The negative trend with redshift requires that an additional assembly mechanism, such as baryonic feedback, dominates in the local Universe.