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arXiv 1905.06960astro-ph.GA
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揭示红移2处亚毫米星系的恒星质量和尘埃分布

Revealing the Stellar Mass and Dust Distributions of Submillimeter Galaxies at Redshift 2

P. Lang, E. Schinnerer, Ian Smail, U. Dudzevičiūtė, A. M. Swinbank, Daizhong Liu, S. K. Leslie, O. Almaini, Fang Xia An, F. Bertoldi, A. W. Blain, S. C. Chapman… 展开作者

P. Lang, E. Schinnerer, Ian Smail, U. Dudzevičiūtė, A. M. Swinbank, Daizhong Liu, S. K. Leslie, O. Almaini, Fang Xia An, F. Bertoldi, A. W. Blain, S. C. Chapman, Chian-Chou Chen, C. Conselice, E. A. Cooke, K. E. K. Coppin, J. S. Dunlop, D. Farrah, Y. Fudamoto, J. E. Geach, B. Gullberg, K. C. Harrington, J. A. Hodge, R. J. Ivison, E. F. Jiménez-Andrade, B. Magnelli, M. J. Michałowski, P. Oesch, D. Scott, J. M. Simpson, V. Smolčić, S. M. Stach, A. P. Thomson, S. Toft, E. Vardoulaki, J. L. Wardlow, A. Weiss, P. van der Werf

摘要:

利用高分辨率ALMA和HST/CANDELS观测数据,结合20个亚毫米星系(SMG)的亮静止坐标系光学观测数据(Ks < 22.9),研究了它们的尘埃和恒星成分的分辨结构特性。我们推导出二维恒星质量分布,这些分布是从基于静止帧光学颜色的空间质光比(M/L)校正推断出来的。由于我们的SMG中尘埃的中心柱密度很高,我们的质量分布可能代表了真实中心质量密度的下限。推断的恒星质量和尘埃分布之间的质心位置在1.1千秒差距内一致,表明两个组成部分之间总体上具有良好的空间一致性。我们的大多数源表现出紧凑的尘埃配置相对于恒星的组成部分(与有效半径Re,尘埃/Re,Mstar = 0.6的中位数比)。这一比率不随比恒星形成率(sSFR)的变化而变化,我们的目标跨越了30倍,对“正常”主序星星系的轨迹进行采样,直到星暴区域,log(sSFR/sSFRMS)> 0.5。我们的研究结果意味着,大规模的SMG正在经历中央增强的恒星形成不同于典型的螺旋星系在本地宇宙。我们的SMG的大小和恒星密度与z=1.5时的被动星族一致,表明这些系统是z~2 SMG的后代。

英文摘要:

We combine high-resolution ALMA and HST/CANDELS observations of 20 submillimeter galaxies (SMGs) predominantly from the AS2UDS survey at z~2 with bright rest-frame optical counterparts (Ks < 22.9) to investigate the resolved structural properties of their dust and stellar components. We derive two-dimensional stellar-mass distributions that are inferred from spatial mass-to-light ratio (M/L) corrections based on rest-frame optical colors. Due to the high central column densities of dust in our SMGs, our mass distributions likely represent a lower limit to the true central mass density. The centroid positions between the inferred stellar-mass and the dust distributions agree within 1.1 kpc, indicating an overall good spatial agreement between the two components. The majority of our sources exhibit compact dust configurations relative to the stellar component (with a median ratio of effective radii Re,dust/Re,Mstar = 0.6). This ratio does not change with specific star-formation rate (sSFR) over the factor of 30 spanned by our targets, sampling the locus of "normal" main sequence galaxies up to the starburst regime, log(sSFR/sSFRMS) > 0.5. Our results imply that massive SMGs are experiencing centrally enhanced star formation unlike typical spiral galaxies in the local Universe. The sizes and stellar densities of our SMGs are in agreement with those of the passive population at z=1.5, consistent with these systems being the descendants of z~2 SMGs.

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