Modeling CO emission from hydrodynamic simulations of nearby spirals, starbursting mergers, and high-redshift galaxies
Modeling CO emission from hydrodynamic simulations of nearby spirals, starbursting mergers, and high-redshift galaxies
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通过附近螺旋星系、星暴合并和高红移星系的流体动力学模拟来模拟二氧化碳排放
DOI：
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发表时间：
2014
期刊：
影响因子：
--
通讯作者：
R. Teyssier
中科院分区：
文献类型：
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作者：
F. Bournaud;E. Daddi;A. Weiss;F. Renaud;C. Mastropietro;R. Teyssier
我们建立了CO分子发射线强度的模型，该模型基于流体动力学对螺旋、合并和高红移星系的模拟，具有非常高的分辨率（3 pc和10 3 M μ），以及星际气体相空间结构的详细模型，包括激波加热、恒星反馈过程和星系风。采用大速度梯度（LVG）模型对模拟结果进行了分析，计算了各分辨率元各分子谱线的局部发射、辐射传递、不透明效应和来自星系的强度，生成了CO分子各种跃迁的合成光谱。该模型再现了已知的CO光谱和CO-to- h2转化因子在附近螺旋和星爆大合并中的特性。合并中CO谱线的高激发是由过量的高密度气体主导的，高湍流速度和压缩产生了这种密集的气体过剩，导致谱线宽和低CO强度- h2质量比。当应用于高红移的富含气体的盘状星系时，同样的模型预测它们的CO-to-H2转换因子几乎和附近的螺旋星系一样高，比恒星爆发合并要高得多。虽然CO（1−0）到CO（3−2）的发射主要由密度最大的团块周围的低激发气体主导，但高红移盘星系包含巨大的恒星形成团块，这些团块拥有与空间集中的恒星反馈源加热的气体相关的高激发成分。这些结果通常强调了CO激发和CO-to- h2转换因子对星系类型的强烈依赖，即使在相似的恒星形成速率或密度下也是如此。潜在的过程是由星际介质结构和湍流及其对恒星反馈的响应驱动的，这取决于整体星系结构，进而影响CO的发射特性。
We model the intensity of emission lines from the CO molecule, based on hydrodynamic simulations of spirals, mergers, and highredshift galaxies with very high resolutions (3 pc and 10 3 M� ) and detailed models for the phase-space structure of the interstellar gas including shock heating, stellar feedback processes, and galactic winds. The simulations are analyzed with a large velocity gradient (LVG) model to compute the local emission in various molecular lines in each resolution element, radiation transfer, opacity effect, and the intensity emerging from galaxies to generate synthetic spectra for various transitions of the CO molecule. This model reproduces the known properties of CO spectra and CO-to-H2 conversion factors in nearby spirals and starbursting major mergers. The high excitation of CO lines in mergers is dominated by an excess of high-density gas, and the high turbulent velocities and compression that create this dense gas excess result in broad linewidths and low CO intensity-to-H2 mass ratios. When applied to high-redshift gas-rich disks galaxies, the same model predicts that their CO-to-H2 conversion factor is almost as high as in nearby spirals, and much higher than in starbursting mergers. High-redshift disk galaxies contain giant star-forming clumps that host a high-excitation component associated to gas warmed by the spatially concentrated stellar feedback sources, although CO(1−0) to CO(3−2) emission is dominated overall by low-excitation gas around the densest clumps. These results generally highlight a strong dependence of CO excitation and the CO-to-H2 conversion factor on galaxy type, even at similar star formation rates or densities. The underlying processes are driven by the interstellar medium structure and turbulence and its response to stellar feedback, which depend on global galaxy structure and in turn affect the CO emission properties.
DOI：
10.1088/0004-637x/768/1/74
发表时间：
2012-11
期刊：
The Astrophysical Journal
影响因子：
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作者：
L. Tacconi;R. Neri;R. Genzel;F. Combes;A. Bolatto;M. Cooper;S. Wuyts;F. Bournaud;A. Burkert-
通讯作者：
L. Tacconi;R. Neri;R. Genzel;F. Combes;A. Bolatto;M. Cooper;S. Wuyts;F. Bournaud;A. Burkert-
DOI：
10.1088/0004-637x/779/1/42
发表时间：
2013-04
期刊：
The Astrophysical Journal
影响因子：
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作者：
E. Schinnerer;S. Meidt;J. Pety;A. Hughes;D. Colombo;S. García-Burillo;K. Schuster;G. Dumas;C. Dobbs;A. Leroy;C. Kramer;T. Thompson;M. Regan
通讯作者：
E. Schinnerer;S. Meidt;J. Pety;A. Hughes;D. Colombo;S. García-Burillo;K. Schuster;G. Dumas;C. Dobbs;A. Leroy;C. Kramer;T. Thompson;M. Regan
DOI：
10.1088/0004-637x/739/1/45
发表时间：
2011-04
期刊：
The Astrophysical Journal
影响因子：
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作者：
N. F. Schreiber;A. Shapley;R. Genzel;N. Bouché;G. Cresci;R. Davies;D. Erb;S. Genel;D. Lutz
通讯作者：
N. F. Schreiber;A. Shapley;R. Genzel;N. Bouché;G. Cresci;R. Davies;D. Erb;S. Genel;D. Lutz