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arXiv 1012.5186astro-ph.CO
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Herschel-ATLAS:过去50亿年来星系中尘埃的快速演化

Herschel-ATLAS: Rapid evolution of dust in galaxies in the last 5 billion years

L. Dunne, H. Gomez, E. da Cunha, S. Charlot, S. Dye, S. Eales, S. Maddox, K. Rowlands, D. Smith, R. Auld, M. Baes, D. Bonfield, N. Bourne, S. Buttiglione, A. Ca… 展开作者

L. Dunne, H. Gomez, E. da Cunha, S. Charlot, S. Dye, S. Eales, S. Maddox, K. Rowlands, D. Smith, R. Auld, M. Baes, D. Bonfield, N. Bourne, S. Buttiglione, A. Cava, D. Clements, K. Coppin, A. Cooray, A. Dariush, G. de Zotti, S. Driver, J. Fritz, J. Geach, R. Hopwood, E. Ibar, R. Ivison, M. Jarvis, L. Kelvin, E. Pascale, M. Pohlen, C. Popescu, E. Rigby, A. Robotham, G. Rodighiero, A. Sansom, S. Serjeant, P. Temi, M. Thompson, R. Tuffs, P. van der Werf, C. Vlahakis

摘要:

我们提出了第一个直接和公正的测量星系的尘埃质量函数的演变在过去的50亿年的宇宙历史中使用的数据从赫歇尔-ATLAS的科学演示阶段。该样本由在250μm处选择的星系组成,这些星系在z < 0.5的SDSS中具有可靠的对应物,并包含1867个源。尘埃质量是使用光谱能量分布的单温度灰体模型和具有多个温度分量的模型来计算的。两种模型的尘埃温度都没有随红移而变化的趋势。将样本分成红移的区间,揭示了最大质量星系的尘埃性质的强烈演化。在z = 0.4 - 0.5时,大质量星系的尘埃质量大约是本地宇宙的五倍。与此同时,尘埃与恒星的质量比大约大3-4倍,用能量平衡模型拟合UV-sub-mm数据得到的光学厚度也更高。在高红移的大质量星系中尘埃含量的增加很难用标准的尘埃演化模型来解释,需要快速的气体消耗时间尺度,以及更头重脚轻的IMF,有效的地幔生长,更少的尘埃破坏或三者的组合。尘埃质量的这种演变可能与整体ISM质量的变化有关,并指出在早期宇宙时期恒星形成的燃料供应增强。

英文摘要:

We present the first direct and unbiased measurement of the evolution of the dust mass function of galaxies over the past 5 billion years of cosmic history using data from the Science Demonstration Phase of the Herschel-ATLAS. The sample consists of galaxies selected at 250μm which have reliable counterparts from SDSS at z < 0.5, and contains 1867 sources. Dust masses are calculated using both a single temperature grey-body model for the spectral energy distribution and also using a model with multiple temperature components. The dust temperature for either model shows no trend with redshift. Splitting the sample into bins of redshift reveals a strong evolution in the dust properties of the most massive galaxies. At z = 0.4 - 0.5, massive galaxies had dust masses about five times larger than in the local Universe. At the same time, the dust-to-stellar mass ratio was about 3-4 times larger, and the optical depth derived from fitting the UV-sub-mm data with an energy balance model was also higher. This increase in the dust content of massive galaxies at high redshift is difficult to explain using standard dust evolution models and requires a rapid gas consumption timescale together with either a more top-heavy IMF, efficient mantle growth, less dust destruction or combinations of all three. This evolution in dust mass is likely to be associated with a change in overall ISM mass, and points to an enhanced supply of fuel for star formation at earlier cosmic epochs.

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