The luminosity functions and redshift evolution of satellites of low-mass galaxies in the COSMOS survey
The luminosity functions and redshift evolution of satellites of low-mass galaxies in the COSMOS survey
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DOI：
10.1093/mnras/stab069
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发表时间：
2020-08
影响因子：
4.8
通讯作者：
Daniella M Roberts;A. Nierenberg;A. Peter
中科院分区：
文献类型：
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作者：
Daniella M Roberts;A. Nierenberg;A. Peter
银河系的卫星群，以及银河系质量星系在本地宇宙中，已经被广泛研究以约束暗物质和星系演化物理学。最近，人们开始转向研究恒星质量介于大麦哲伦星云和银河系之间的宿主卫星，因为它们可以进一步了解分层结构的形成、对卫星的环境影响以及暗物质的本质。大多数工作都集中在局域体积上，对于红移较高的低质量宿主星系知之甚少。为了提高我们对低质量宿主卫星星系群演化的理解，我们在COSMOS调查中研究了卫星星系群作为宿主恒星质量9.5 < log(M∗/M) < 10.5和红移0.1 < z < 0.8的函数，这使得这是第一次对宇宙年龄一半的低质量宿主卫星系统的研究。我们发现，低质量宿主星系的卫星群，我们测量到的卫星质量相当于银河系的天炉座矮球体卫星，随着时间的推移基本保持不变。我们观察到宿主恒星质量与每个宿主的卫星数量之间存在微弱的依赖关系，这表明对于低质量星系，宿主的恒星质量处于恒星质量与晕质量关系（M *−Mhalo）的幂律状态。最后，我们测试了我们测量的累积光度函数的约束能力，以计算M *−Mhalo关系的低质量端斜率。这些新的卫星光度函数测量结果与ΛCDM的预测一致。
The satellite populations of the Milky Way, and Milky-Way-mass galaxies in the local universe, have been extensively studied to constrain dark-matter and galaxy-evolution physics. Recently, there has been a shift to studying satellites of hosts with stellar masses between that of the Large Magellanic Cloud and the Milky Way, since they can provide further insight on hierarchical structure formation, environmental effects on satellites, and the nature of darkmatter. Most work is focused on the Local Volume, and little is still known about low-mass host galaxies at higher redshift. To improve our understanding of the evolution of satellite populations of low-mass hosts, we study satellite galaxy populations as a function of host stellar mass 9.5 < log(M∗/M ) < 10.5 and redshifts 0.1 < z < 0.8 in the COSMOS survey, making this the first study of satellite systems of low-mass hosts across half the age of the universe. We find that the satellite populations of low-mass host galaxies, which we measure down to satellite masses equivalent to the Fornax dwarf spheroidal satellite of the Milky Way, remain mostly unchanged through time. We observe a weak dependence between host stellar mass and number of satellites per host, which suggests that the stellar masses of the hosts are in the power-law regime of the stellar mass to halo mass relation (M∗ − Mhalo) for lowmass galaxies. Finally, we test the constraining power of our measured cumulative luminosity function to calculate the low-mass end slope of the M∗ − Mhalo relation. These new satellite luminosity function measurements are consistent with ΛCDM predictions.