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arXiv 0902.4701astro-ph.CO
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SINS巡天:模拟z~2星系的动力学和高z Tully-Fisher关系

The SINS survey: modeling the dynamics of z~2 galaxies and the high-z Tully-Fisher relation

G. Cresci, E. K. S. Hicks, R. Genzel, N. M. Foerster Schreiber, R. Davies, N. Bouche', P. Buschkamp, S. Genel, K. Shapiro, L. Tacconi, J. Sommer-Larsen, A. Burk… 展开作者

G. Cresci, E. K. S. Hicks, R. Genzel, N. M. Foerster Schreiber, R. Davies, N. Bouche', P. Buschkamp, S. Genel, K. Shapiro, L. Tacconi, J. Sommer-Larsen, A. Burkert, F. Eisenhauer, O. Gerhard, D. Lutz, T. Naab, A. Sternberg, A. Cimatti, E. Daddi, D. K. Erb, J. Kurk, S. L. Lilly, A. Renzini, A. Shapley, C. C. Steidel, K. Caputi

摘要:

本文用H α谱线模拟了18个恒星形成星系在z ~ 2处的SINFONI积分场动力学。星系是从大样本的银河系巡天,根据突出的有序旋转运动相对于更复杂的合并诱导动力学。这些数据的质量使我们能够仔细选择运动学以旋转为主的系统,并使用合适的指数盘模型来模拟整个星系的气体动力学。我们得到了动力学质量和恒星质量之间的良好相关性,发现需要大的气体分数(Mgas~M*)来解释这两个量之间的差异。我们使用推导出的恒星质量和最大旋转速度Vmax的建模构建的第一次恒星质量Tully-Fisher关系在z ~ 2.2。得到的关系显示出类似于在较低的红移观察到的斜率,但我们检测到的零点的演变。我们发现在z ~ 2.2处,对于给定的相对于局域宇宙的0.41+-0.11的旋转速度,log(M*)中存在偏移。这一结果与最新的N体/流体动力学模拟的磁盘形成和演化的预测是一致的,该模拟在细丝和冷却流中将气体吸积到形成的磁盘上。这一假设与其他来自星系晕的动力学证据一致,其中来自星系晕的气体吸积需要再现大部分z ~ 2星系的观测性质。

英文摘要:

We present the modeling of SINFONI integral field dynamics of 18 star forming galaxies at z ~ 2 from Halpha line emission. The galaxies are selected from the larger sample of the SINS survey, based on the prominence of ordered rotational motions with respect to more complex merger induced dynamics. The quality of the data allows us to carefully select systems with kinematics dominated by rotation, and to model the gas dynamics across the whole galaxy using suitable exponential disk models. We obtain a good correlation between the dynamical mass and the stellar mass, finding that large gas fractions Mgas~M*) are required to explain the difference between the two quantities. We use the derived stellar mass and maximum rotational velocity Vmax from the modeling to construct for the first time the stellar mass Tully-Fisher relation at z ~ 2.2. The relation obtained shows a slope similar to what is observed at lower redshift, but we detect an evolution of the zero point. We find that at z ~ 2.2 there is an offset in log(M*) for a given rotational velocity of 0.41+-0.11 with respect to the local Universe. This result is consistent with the predictions of the latest N-body/hydrodynamical simulations of disk formation and evolution, which invoke gas accretion onto the forming disk in filaments and cooling flows. This scenario is in agreement with other dynamical evidence from SINS, where gas accretion from the halo is required to reproduce the observed properties of a large fraction of the z ~ 2 galaxies.

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