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arXiv 1409.6791astro-ph.GAastro-ph.CO
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The KMOS^3D Survey:设计、初步结果和0.7<z<2.7的星系运动学演化

The KMOS^3D Survey: design, first results, and the evolution of galaxy kinematics from 0.7<z<2.7

E. Wisnioski, N. M. Förster Schreiber, S. Wuyts, E. Wuyts, K. Bandara, D. Wilman, R. Genzel, R. Bender, R. Davies, M. Fossati, P. Lang, J. T. Mendel, A. Beifior… 展开作者

E. Wisnioski, N. M. Förster Schreiber, S. Wuyts, E. Wuyts, K. Bandara, D. Wilman, R. Genzel, R. Bender, R. Davies, M. Fossati, P. Lang, J. T. Mendel, A. Beifiori, G. Brammer, J. Chan, M. Fabricius, Y. Fudamoto, S. Kulkarni, J. Kurk, D. Lutz, E. J. Nelson, I. Momcheva, D. Rosario, R. Saglia, S. Seitz, L. J. Tacconi, P. G. van Dokkum

摘要:

我们提出了KMOS ^3D巡天,这是一项使用甚大望远镜(VLT)上的KMOS对600多个星系在0.7<z<2.7处进行的新的积分场巡天。KMOS ^3D巡天利用与多波长地面和天基巡天的协同作用,从5 Gyr宇宙历史的均匀样本中追踪空间分辨运动学和恒星形成的演化。从3D-HST巡天的质量选定的母样本中绘制的目标均匀地覆盖了恒星形成-恒星质量($M_*$)和静止框架$(U-V)-M_*$平面。我们描述了目标的选择,观察和数据减少。在第一年的数据中,我们在z=0.7-1.1和z=1.9-2.7的191个$M_*=3\times10^{9}-7\times10^{11}$ Msun星系中检测到H α发射。在目前的样本中,83%的解析星系是旋转主导的,从连续的速度梯度和$v_{rot}/σ>1$确定,这意味着恒星形成的“主序列”(MS)主要是由旋转星系在两个红移制度。当考虑额外的更严格的标准时,Halalpha运动学地图表明至少有70%的解析星系是盘状系统。我们的高质量KMOS数据证实了先前IFS研究中报告的z>0.7时的速度色散升高。对于以旋转为主的圆盘,平均固有速度色散从z~2.3时的50 km/s减少到z~0.9时的25 km/s,而两个红移处的旋转速度相当。结合现有的结果跨越z~0-3,磁盘速度色散遵循近似(1+z)的演变是一致的边缘稳定盘理论预测的气体分数的速度色散的依赖关系。

英文摘要:

We present the KMOS^3D survey, a new integral field survey of over 600 galaxies at 0.7<z<2.7 using KMOS at the Very Large Telescope (VLT). The KMOS^3D survey utilizes synergies with multi-wavelength ground and space-based surveys to trace the evolution of spatially-resolved kinematics and star formation from a homogeneous sample over 5 Gyrs of cosmic history. Targets, drawn from a mass-selected parent sample from the 3D-HST survey, cover the star formation-stellar mass ($M_*$) and rest-frame $(U-V)-M_*$ planes uniformly. We describe the selection of targets, the observations, and the data reduction. In the first year of data we detect Halpha emission in 191 $M_*=3\times10^{9}-7\times10^{11}$ Msun galaxies at z=0.7-1.1 and z=1.9-2.7. In the current sample 83% of the resolved galaxies are rotation-dominated, determined from a continuous velocity gradient and $v_{rot}/σ>1$, implying that the star-forming 'main sequence' (MS) is primarily composed of rotating galaxies at both redshift regimes. When considering additional stricter criteria, the Halpha kinematic maps indicate at least ~70% of the resolved galaxies are disk-like systems. Our high-quality KMOS data confirm the elevated velocity dispersions reported in previous IFS studies at z>0.7. For rotation-dominated disks, the average intrinsic velocity dispersion decreases by a factor of two from 50 km/s at z~2.3 to 25 km/s at z~0.9 while the rotational velocities at the two redshifts are comparable. Combined with existing results spanning z~0-3, disk velocity dispersions follow an approximate (1+z) evolution that is consistent with the dependence of velocity dispersion on gas fractions predicted by marginally-stable disk theory.

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