Assembly history of massive galaxies
Assembly history of massive galaxies
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DOI：
10.1051/0004-6361/202040186
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发表时间：
2021-03
影响因子：
6.5
通讯作者：
M. Spavone;D. Krajnovi'c;E. Emsellem;E. Iodice;M. den Brok
中科院分区：
文献类型：
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作者：
M. Spavone;D. Krajnovi'c;E. Emsellem;E. Iodice;M. den Brok
在本文中，我们展示了来自MUSE最大质量星系（M3 G）项目的三个大质量（M* 1012 M）星系的VEGAS调查的新深度图像，距离范围为151 ≤ D ≤ 183 Mpc：PGC 007748，PGC 015524和PGC 049940。VST的OmegaCam的长积分时间和宽视场使我们能够将光和颜色分布映射到μg/30 mag arcsec-2和μ g/2 Re。深层数据对于估计不同星系成分的贡献至关重要，特别是恒星晕中的吸积分数。可用的MUSE积分场观测覆盖了每个星系的有限部分（到1 Re），但从成像分析中，我们发现它们映射了第一过渡半径以外的运动学和恒星人口，吸积分量的贡献开始占主导地位。这项工作的主要目标是将来自图像分析的不同分量的尺度与来自MUSE数据的运动学和恒星种群分布相关联。这些结果被用来在理论预测的帮助下解决这三个星系的组装历史。我们的研究结果表明，PGC 049940具有最低的吸积质量分数为77%。PGC 007748和PGC 015524的较高吸积质量分数（分别为86%和89%）与平坦的λR剖面相结合，表明大部分质量是通过主要合并获得的，这也形成了在较大半径处观察到的较浅的金属丰度剖面。
In this paper we present the new deep images from the VEGAS survey of three massive (M* ≃ 1012 M⊙) galaxies from the MUSE Most Massive Galaxies (M3G) project, with distances in the range 151 ≤ D ≤ 183 Mpc: PGC007748, PGC015524, and PGC049940. The long integration time and the wide field of view of the OmegaCam at the VST allowed us to map the light and color distributions down to μg ≃ 30 mag arcsec−2 and out to ∼2Re. The deep data are crucial for estimating the contribution of the different galaxy components, in particular the accreted fraction in the stellar halo. The available integral field observations with MUSE cover a limited portion of each galaxy (out to ∼1Re), but from the imaging analysis, we find that they map the kinematics and stellar population beyond the first transition radius, where the contribution of the accreted component starts to dominate. The main goal of this work is to correlate the scales of the different components derived from the image analysis with the kinematics and stellar population profiles from the MUSE data. The results were used to address the assembly history of the three galaxies with the help of theoretical predictions. Our results suggest that PGC049940 has the lowest accreted mass fraction of 77%. The higher accreted mass fraction estimated for PGC007748 and PGC015524 (86% and 89%, respectively) combined with the flat λR profiles suggest that a great majority of the mass has been acquired through major mergers, which have also shaped the shallower metallicity profiles that are observed at larger radii.