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arXiv 1207.3528astro-ph.CO
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GOODS-Herschel:UV选定高红移星系的尘埃衰减特性

GOODS-Herschel:dust attenuation properties of UV selected high redshift galaxies

V. Buat, S. Noll, D. Burgarella, E. Giovannoli, V. Charmandaris, M. Pannella, H. S. Hwang, D. Elbaz, M. Dickinson, G. Magdis, N. Reddy, E. J. Murphy

摘要:

我们研究了尘埃在高红移的紫外波长的衰减,其中紫外线红移到观察到的可见光。特别是,我们寻找一个紫外线颠簸和相关的影响,尘埃衰减的测定。我们使用的CDFS中的数据,在中,宽带过滤器获得的MUSYC项目,采样的UV静止框架的751个星系0.95<z<2.2。当可用时,Herschel/PACS数据(GOODS-Herschel项目)和Spitzer/MIPS测量,用于估计粉尘排放。每个源的SED使用CIGALE代码拟合。粉尘衰减量和粉尘衰减曲线作为SED拟合过程的输出以及与SFH相关的其他参数获得。在紫外波长的尘埃衰减的全球量被发现增加恒星质量和减少紫外光度的增加。在20%的星系中安全地检测到2175 A的UV隆起,并且样品的隆起的平均振幅与在LMC超壳层区域中观察到的相似。这个振幅在具有非常高SSFR的星系中被发现较低,并且90%的星系在z<1.5时表现出安全的隆起。20%的星系的衰减曲线比本星系的衰减曲线陡。发现这两个参数描述的衰减规律的大色散很可能反映了星系之间的衰减规律的广泛多样性。尘埃衰减,红外-紫外线通量比,和紫外线连续的斜率之间的关系推导出的平均衰减曲线为我们的样品。偏离平均趋势被发现与年轻恒星星族的年龄和衰减曲线的形状相关。(删节)

英文摘要:

We study dust attenuation at UV wavelengths at high redshift, where the UV is redshifted to the observed visible. In particular, we search for a UV bump and related implications for dust attenuation determinations. We use data in the CDFS, obtained in intermediate and broad band filters by the MUSYC project, to sample the UV rest-frame of 751 galaxies with 0.95<z<2.2. When available, Herschel/PACS data (GOODS-Herschel project), and Spitzer/MIPS measurements, are used to estimate the dust emission. The SED of each source is fit using the CIGALE code. The amount of dust attenuation and the dust attenuation curve are obtained as outputs of the SED fitting process, together with other parameters linked to the SFH. The global amount of dust attenuation at UV wavelengths is found to increase with stellar mass and to decrease as UV luminosity increases. A UV bump at 2175A is securely detected in 20% of the galaxies, and the mean amplitude of the bump for the sample is similar to that observed in the LMC supershell region. This amplitude is found to be lower in galaxies with very high SSFRs, and 90% of the galaxies exhibiting a secure bump are at z<1.5. The attenuation curve is confirmed to be steeper than that of local starburst galaxies for 20$% of the galaxies. The large dispersion found for these two parameters describing the attenuation law is likely to reflect a wide diversity of attenuation laws among galaxies. The relations between dust attenuation, IR-to-UV flux ratio, and the slope of the UV continuum are derived for the mean attenuation curve found for our sample. Deviations from the average trends are found to correlate with the age of the young stellar population and the shape of the attenuation curve.(abriged)

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