Quenching and the UVJ Diagram in the SIMBA Cosmological Simulation
Quenching and the UVJ Diagram in the SIMBA Cosmological Simulation
复制标题
DOI：
10.3847/1538-4357/ac5d3a
复制
发表时间：
2021-05
期刊：
影响因子：
--
通讯作者：
H. Akins;D. Narayanan;K. Whitaker;R. Dav'e;S. Lower;R. Bezanson;R. Feldmann;M. Kriek
中科院分区：
文献类型：
--
作者：
H. Akins;D. Narayanan;K. Whitaker;R. Dav'e;S. Lower;R. Bezanson;R. Feldmann;M. Kriek
在过去的十年中，静止框架颜色-颜色图已成为选择高红移静止星系的流行工具，打破了静止星系和尘红色恒星形成星系之间的颜色简并性。在这项工作中，我们通过采用宇宙星系形成模拟的模拟观测来研究一种这样的颜色选择工具——静止框架 U – V 与 V – J 图。特别是，我们进行了数值实验，评估 UVJ 空间中星系特性的趋势以及大质量星系在红移 z ∼ 1-2 处淬灭时的颜色演化。我们发现我们的模型广泛地再现了在 z = 1-2 处观测到的 UVJ 图，包括（在宇宙学模拟中首次）再现了 UVJ 图右上角的极度尘埃红色星系群。然而，我们的模型主要在该区域填充低质量星系，并且不会像观测中那样在恒星形成和静止星系之间产生清晰的双峰性。前一个问题是由于低质量星系中尘埃过多以及大质量星系中相对灰色的衰减曲线造成的，而后者则是由于辛巴绿谷人口过多造成的。在研究 UVJ 图上星系的时间演化时，我们发现 UVJ 图上的猝灭路径与猝灭时间尺度无关，而主要取决于猝灭开始前 1 Gyr 内的平均特定恒星形成速率。我们的结果支持对不同猝灭路径的解释，即对应于星暴后和绿谷星系的发散演化。
Over the past decade, rest-frame color–color diagrams have become popular tools for selecting quiescent galaxies at high redshift, breaking the color degeneracy between quiescent and dust-reddened star-forming galaxies. In this work, we study one such color–color selection tool—the rest-frame U − V versus V − J diagram—by employing mock observations of cosmological galaxy formation simulations. In particular, we conduct numerical experiments assessing both trends in galaxy properties in UVJ space and the color–color evolution of massive galaxies as they quench at redshifts z ∼ 1–2. We find that our models broadly reproduce the observed UVJ diagram at z = 1–2, including (for the first time in a cosmological simulation) reproducing the population of extremely dust-reddened galaxies in the top right of the UVJ diagram. However, our models primarily populate this region with low-mass galaxies and do not produce as clear a bimodality between star-forming and quiescent galaxies as is seen in observations. The former issue is due to an excess of dust in low-mass galaxies and relatively gray attenuation curves in high-mass galaxies, while the latter is due to the overpopulation of the green valley in simba. When investigating the time evolution of galaxies on the UVJ diagram, we find that the quenching pathway on the UVJ diagram is independent of the quenching timescale, and instead dependent primarily on the average specific star formation rate in the 1 Gyr prior to the onset of quenching. Our results support the interpretation of different quenching pathways as corresponding to the divergent evolution of post-starburst and green valley galaxies.