Dwarfs in Void Environments (DIVE): The Stellar Kinematics of Void Dwarf Galaxies Using the Keck Cosmic Web Imager
Dwarfs in Void Environments (DIVE): The Stellar Kinematics of Void Dwarf Galaxies Using the Keck Cosmic Web Imager
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DOI：
10.3847/1538-4357/acd189
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发表时间：
2023-01
期刊：
影响因子：
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通讯作者：
Mithi A. C. de los Reyes;E. Kirby;Z. Zhuang;C. Steidel;Yuguang Chen;Coral Wheeler
中科院分区：
文献类型：
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作者：
Mithi A. C. de los Reyes;E. Kirby;Z. Zhuang;C. Steidel;Yuguang Chen;Coral Wheeler
位于密度极低的宇宙空洞中的矮星系是解开大尺度环境对星系形成和演化影响的绝佳试验台。我们展示了矮星在空洞环境调查中的第一个结果，该调查使用 Keck 宇宙网络成像仪获得了位于宇宙空洞内部 (N = 21) 和外部 (N = 9) 的低质量星系 (M ⋆ = 107–109 M ⊙) 的积分场光谱。利用恒星视线旋转速度 v rot 和速度色散 σ ⋆ 的测量，我们测试了潮汐搅拌假说，该假说假设矮椭球星系是通过与更大质量的主星系的潮汐相互作用形成的。我们测量了孤立矮星系样本的 v rot/σ ⋆ ≲ 2 的低值，并且我们发现 v rot/σ ⋆ 和从大质量星系 dL⋆ 到 dL⋆∼10 Mpc 的距离之间没有趋势。这些表明，即使没有潮汐相互作用等环境影响，矮星系也可以成为色散支持的“蓬松”系统。我们还发现了 v rot/σ ⋆ 和星系恒星质量之间呈上升趋势的迹象，这或许意味着恒星盘的形成取决于质量而不是环境。尽管我们的一些结论可能会因系统效应而略有修改，但我们的主要结果仍然成立：孤立的低质量星系可能形成并保持为蓬松的系统，而不是经典星系形成理论预测的动态冷盘。
Dwarf galaxies located in extremely underdense cosmic voids are excellent test beds for disentangling the effects of large-scale environments on galaxy formation and evolution. We present the first results of the Dwarfs in Void Environments Survey, which has obtained integral field spectroscopy for low-mass galaxies (M ⋆ = 107–109 M ⊙) located inside (N = 21) and outside (N = 9) cosmic voids using the Keck Cosmic Web Imager. Using measurements of stellar line-of-sight rotational velocity v rot and velocity dispersion σ ⋆, we test the tidal stirring hypothesis, which posits that dwarf spheroidal galaxies are formed through tidal interactions with more massive host galaxies. We measure low values of v rot/σ ⋆ ≲ 2 for our sample of isolated dwarf galaxies, and we find no trend between v rot/σ ⋆ and the distance from a massive galaxy dL⋆ out to dL⋆∼10 Mpc. These suggest that dwarf galaxies can become dispersion-supported, “puffy” systems even in the absence of environmental effects like tidal interactions. We also find indications of an upward trend between v rot/σ ⋆ and galaxy stellar mass, perhaps implying that stellar disk formation depends on mass rather than environment. Although some of our conclusions may be slightly modified by systematic effects, our main result still holds: that isolated low-mass galaxies may form and remain as puffy systems rather than the dynamically cold disks predicted by classical galaxy formation theory.