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arXiv 0910.4488astro-ph.CO
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引力透镜半导体的分辨光谱学:恢复亚发光z~2-3半导体相干速度场

Resolved Spectroscopy of Gravitationally-Lensed Galaxies: Recovering Coherent Velocity Fields in Sub-Luminous z~2-3 Galaxies

Tucker Jones, Mark Swinbank, Richard Ellis, Johan Richard, Dan Stark

摘要:

我们目前的空间分辨动力学为6个强透镜恒星形成星系在z=1.7-3.1,每个放大的线性放大系数~8。使用Keck激光导星AO系统和OSIRIS积分场单元光谱仪,我们以前所未有的保真度解决了样品中的运动学和形态学细节,在某些情况下实现了~100 pc的空间分辨率。除了一个例外,我们的源的直径范围从1-7千秒差距,恒星形成率为2-40兆太阳/年(未进行消光校正),动力学质量为10^(9.7-10.3)兆太阳。有了这个精致的分辨率,我们发现,六个星系中的四个显示相干速度场符合一个简单的旋转盘模型,这只能恢复与自适应光学和强引力透镜的组合,大大提高了空间分辨率和采样。我们的模型拟合暗示了系统运动与随机运动的比值,V sin(i)/sigma,范围为0.5-1.3,Toomre圆盘参数Q<1。在我们的样本中,很大一部分有序的速度场与在此红移下分析的更大、更亮的光源的数据一致。我们的高分辨率数据进一步揭示,所有六个星系都包含多个巨大的恒星形成HII区域,其分辨直径在300 pc - 1.0 kpc的范围内,与色散支持情况下预期的Jeans长度一致。这些区域的恒星形成密度比在局部螺旋中观察到的高约100倍;如此高的数值只有在最明亮的局部恒星爆发中才能看到。在这些HII区域的恒星形成的全球动力学和人口统计表明,蓬勃的恒星形成主要是由原始旋转盘的引力不稳定性。

英文摘要:

We present spatially-resolved dynamics for six strongly lensed star-forming galaxies at z=1.7-3.1, each enlarged by a linear magnification factor ~8. Using the Keck laser guide star AO system and the OSIRIS integral field unit spectrograph we resolve kinematic and morphological detail in our sample with an unprecedented fidelity, in some cases achieving spatial resolutions of ~100 pc. With one exception our sources have diameters ranging from 1-7 kpc, star formation rates of 2-40 Msun/yr (uncorrected for extinction) and dynamical masses of 10^(9.7-10.3) Msun. With this exquisite resolution we find that four of the six galaxies display coherent velocity fields consistent with a simple rotating disk model, which can only be recovered with the considerably improved spatial resolution and sampling from the combination of adaptive optics and strong gravitational lensing. Our model fits imply ratios for the systemic to random motion, V sin(i)/sigma, ranging from 0.5-1.3 and Toomre disk parameters Q<1. The large fraction of well-ordered velocity fields in our sample is consistent with data analyzed for larger, more luminous sources at this redshift. Our high resolution data further reveal that all six galaxies contain multiple giant star-forming HII regions whose resolved diameters are in the range 300 pc - 1.0 kpc, consistent with the Jeans length expected in the case of dispersion support. The density of star formation in these regions is ~100 times higher than observed in local spirals; such high values are only seen in the most luminous local starbursts. The global dynamics and demographics of star formation in these HII regions suggest that vigorous star formation is primarily governed by gravitational instability in primitive rotating disks.

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