CHARACTERIZING ULTRAVIOLET AND INFRARED OBSERVATIONAL PROPERTIES FOR GALAXIES. I. INFLUENCES OF DUST ATTENUATION AND STELLAR POPULATION AGE
CHARACTERIZING ULTRAVIOLET AND INFRARED OBSERVATIONAL PROPERTIES FOR GALAXIES. I. INFLUENCES OF DUST ATTENUATION AND STELLAR POPULATION AGE
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DOI：
10.1088/0004-637x/757/1/52
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发表时间：
2012-08
期刊：
影响因子：
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通讯作者：
Y. Mao;R. Kennicutt;C. Hao;X. Kong;Xu Zhou
中科院分区：
文献类型：
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作者：
Y. Mao;R. Kennicutt;C. Hao;X. Kong;Xu Zhou
在星暴星系研究中发现的红外与紫外光度比与紫外颜色（或紫外光谱斜率）之间的相关性，即IRX-UV（或IRX-β）关系，是校正河外尘埃衰减的普遍方法。然而，在正常星系中发现的这种关系的相当大的分散性使其可用性变得复杂。为了研究色散的原因并更好地理解IRX-UV关系的本质，在本文中，我们选择了五个附近的螺旋星系，并结合紫外和红外成像数据对每个星系进行了空间分辨研究。我们测量每个星系内的所有位置，并将提取的区域划分为年轻的和进化的恒星群体。通过这种方法，我们试图发现尘埃衰减和恒星种群年龄对单个星系的 IRX-UV 关系的单独影响。在这项工作中，除了尘埃衰减之外，恒星种群年龄被解释为IRX-UV函数中的另一个参数，并且建议恒星形成历史的多样性来分散年龄影响。与此同时，强有力的证据表明在解释观测数据时需要更多参数，例如衰减/消光定律的变化。不同成分对星系综合光度的分数贡献表明，对这些由不同种群组成的星系的综合测量将削弱年龄参数对 IRX-UV 图的影响。 IRX-UV 关系对星系中光度和径向距离的依赖性呈现弱趋势，这提供了选择性效应的暗示。显示了 UV 颜色和红外与紫外比率的二维图，并显示了两个星系参数之间空间分布的差异，这提供了 IRX-UV 关系中散射的空间解释。
The correlation between infrared-to-ultraviolet luminosity ratio and ultraviolet color (or ultraviolet spectral slope), i.e., the IRX–UV (or IRX–β) relation, found in studies of starburst galaxies is a prevalent recipe for correcting extragalactic dust attenuation. Considerable dispersion in this relation discovered for normal galaxies, however, complicates its usability. In order to investigate the cause of the dispersion and to have a better understanding of the nature of the IRX–UV relation, in this paper, we select five nearby spiral galaxies, and perform spatially resolved studies on each of the galaxies, with a combination of ultraviolet and infrared imaging data. We measure all positions within each galaxy and divide the extracted regions into young and evolved stellar populations. By means of this approach, we attempt to discover separate effects of dust attenuation and stellar population age on the IRX–UV relation for individual galaxies. In this work, in addition to dust attenuation, stellar population age is interpreted to be another parameter in the IRX–UV function, and the diversity of star formation histories is suggested to disperse the age effects. At the same time, strong evidence shows the need for more parameters in the interpretation of observational data, such as variations in attenuation/extinction law. Fractional contributions of different components to the integrated luminosities of the galaxies suggest that the integrated measurements of these galaxies, which comprise different populations, would weaken the effect of the age parameter on IRX–UV diagrams. The dependence of the IRX–UV relation on luminosity and radial distance in galaxies presents weak trends, which offers an implication of selective effects. The two-dimensional maps of the UV color and the infrared-to-ultraviolet ratio are displayed and show a disparity in the spatial distributions between the two galaxy parameters, which offers a spatial interpretation of the scatter in the IRX–UV relation.