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arXiv 1102.1571astro-ph.CO
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星系AKARI-SDSS-GALEX样本的光谱能量分布

Spectral energy distributions of an AKARI-SDSS-GALEX sample of galaxies

V. Buat, E. Giovannoli, T. T. Takeuchi, S. Heinis, F. T. Yuan, D. Burgarella, S. Noll, J. Iglesias-Paramo

摘要:

附近的宇宙仍然是了解星系物理性质的最佳实验室,也是与高红移观测进行任何比较的参考。从紫外线(UV)到远红外线(far-IR)进行的全天空(或非常大)调查为我们提供了具有非常大波长覆盖范围的大型数据集,以进行参考研究。我们想研究尘埃衰减特性以及恒星形成率(SFR)校准的样本附近的星系观察超过13个波段,从0.15到160微米。363个星系的样本是建立从AKARI /FIS的所有天空调查交叉相关的SDSS和GALEX调查。宽带光谱能量分布拟合与CIGALE代码优化,以分析尘埃衰减曲线和SFR测量的变化,并基于恒星和尘埃排放之间的能量预算。我们的星系样本主要是在远红外线中选择的,主要由大质量的、活跃的恒星形成星系组成。有一些证据表明尘埃衰减规律比星爆星系的衰减规律稍陡,但我们无法限制在220 nm处是否存在凸起。我们确认,时间依赖的灰尘衰减是必要的,以执行最佳的拟合。各种校准的灰尘衰减在紫外线作为一个功能的紫外光学颜色进行了讨论。本文提出了一种结合紫外辐射和红外辐射的恒星形成率的校准方法,并对老恒星对尘埃的加热进行了精确的估算:对于整个样本,17%的尘埃总光度与最近的恒星形成无关

英文摘要:

The nearby universe remains the best laboratory to understand physical properties of galaxies and is a reference for any comparison with high redshift observations. The all sky (or very large) surveys performed from the ultraviolet (UV) to the far-infrared (far-IR) gives us large datasets with a very large wavelength coverage to perform a reference study. We want to investigate dust attenuation characteristics as well as star formation rate (SFR) calibrations on a sample of nearby galaxies observed over 13 bands from 0.15 to 160 microns. A sample of 363 galaxies is built from the AKARI /FIS all sky survey cross-correlated with SDSS and GALEX surveys. Broad band spectral energy distributions are fitted with the CIGALE code optimized to analyze variations in dust attenuation curves and SFR measurements and based on an energetic budget between the stellar and dust emission. Our galaxy sample is primarily selected in far-IR and mostly constituted of massive, actively star forming galaxies. There is some evidence for a dust attenuation law slightly steeper than that used for starburst galaxies but we are unable to constrain the presence or not of a bump at 220 nm. We confirm that a time dependent dust attenuation is necessary to perform the best fits. Various calibrations of the dust attenuation in the UV as a function of UV-optical colours are discussed. A calibration of the current star formation rate combining UV and total IR emissions is proposed with an accurate estimation of dust heating by old stars: for the whole sample 17 % of the total dust luminosity is not related to the recent star formation

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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