Barred galaxies in the EAGLE cosmological hydrodynamical simulation
Barred galaxies in the EAGLE cosmological hydrodynamical simulation
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DOI：
10.1093/mnras/stx1008
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发表时间：
2016-09
影响因子：
4.8
通讯作者：
D. Algorry;J. Navarro;M. Abadi;L. Sales;R. Bower;R. Crain;C. D. Vecchia;C. Frenk;M. Schaller;J. Schaye;T. Theuns
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文献类型：
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作者：
D. Algorry;J. Navarro;M. Abadi;L. Sales;R. Bower;R. Crain;C. D. Vecchia;C. Frenk;M. Schaller;J. Schaye;T. Theuns
我们在 EAGLE 项目的 ΛCDM 宇宙流体动力学模拟中研究了棒盘星系的特性。我们的研究跟踪了在 z = 0 处恒星质量范围 10.6 < log M★/M⊙ < 11 中确定的 269 个盘的形成过程。这些盘显示出广泛的棒强度，从无棒盘 (≈60%) 到弱棒 (≈20%) 到强棒系统 (≈20%)。这些系统中的条形图在红移 ≈1.3 之后形成，其时间尺度敏感地取决于图案的强度。在圆盘主导、气体贫乏且旋转曲线下降的系统中，强棒发展相对较快（几吉里，或大约~10个圆盘旋转周期）。在盘的引力不太重要的系统中，弱条发展得更慢，并且在 z = 0 时仍在增长。无条星系是相对富含气体的盘，其旋转速度不会超过它们所居住的晕的最大圆周速度。条形长度与观测结果相当，范围为包含 90% 恒星的半径的 0.2 到 0.8 倍。条状体在生长过程中速度减慢得非常快，导致周围暗晕的内部区域扩大。当 z = 0 时，模拟星系中的强棒的共转半径大约是棒长度的十倍。这种慢条与少数通过观测测量或推断模式速度的情况不一致，这种差异如果得到证实，可能会对ΛCDM中的盘状星系形成构成挑战。
We examine the properties of barred disc galaxies in a ΛCDM cosmological hydrodynamical simulation from the EAGLE project. Our study follows the formation of 269 discs identified at z = 0 in the stellar mass range 10.6 < log M★/M⊙ < 11. These discs show a wide range of bar strengths, from unbarred discs (≈60%) to weak bars (≈20%) to strongly barred systems (≈20%). Bars in these systems develop after redshift ≈1.3, on timescales that depend sensitively on the strength of the pattern. Strong bars develop relatively quickly (in a few Gyr, or roughly ∼10 disc rotation periods) in systems that are disc dominated, gas poor, and have declining rotation curves. Weak bars develop more slowly in systems where the disc is less gravitationally important, and are still growing at z = 0. Unbarred galaxies are comparatively gas-rich discs whose rotation speeds do not exceed the maximum circular velocity of the halos they inhabit. Bar lengths compare favourably with observations, ranging from 0.2 to 0.8 times the radius containing 90% of the stars. Bars slow down remarkably quickly as they grow, causing the inner regions of the surrounding dark halo to expand. At z = 0 strong bars in simulated galaxies have corotation radii roughly ten times the bar length. Such slow bars are inconsistent with the few cases where pattern speeds have been measured or inferred observationally, a discrepancy that, if confirmed, might prove a challenge for disc galaxy formation in ΛCDM.