标题： 鲸鱼座-仙后座星系的近红外观测：II. 消光效应和盘面不透明度 显示英文标题

标题： Near-infrared observations of galaxies in Pisces-Perseus: II. Extinction effects and disk opacity

摘要： 我们研究了H波段盘和核球结构参数以及I-H颜色分布与倾斜度的相关性，针对154个螺旋星系的样本，以检测由于尘埃内部消光可能产生的影响。 样本的选择确保了不同倾斜度的星系在本质上没有差异，因此观察到的相关性代表了所考虑参数的真实行为。 所有参数都是通过对星系图像的二维拟合得到的。 我们发现，尽管在近红外波长下消光较小，但仍足以产生可观察的效果。 特别是，在高倾斜度下观测到的平均盘尺度长度的增加和盘的I-H颜色变红，是尘埃存在的明显标志。 总H波段盘光度对倾斜度的依赖性很小；另一方面，对于H波段中心盘亮度和盘尺度长度的面朝上视角进行了显著修正。 核球参数表现出对倾斜度的很小或没有依赖性。 使用一个用于内部消光星系的简单模型进行的模拟表明，这些结果意味着中心H波段光学深度在0.3到0.5之间。 显示英文摘要

摘要： We study the correlations with inclination of H-band disk and bulge structural parameters and I-H colour profiles for a sample of 154 spiral galaxies, in order to detect possible effects due to internal extinction by dust. The selection of the sample assures that galaxies at different inclinations are not intrinsically different, so that the observed correlations represent the real behaviour of the parameter considered. All the parameters are derived from a bi-dimensional fitting of the galaxy image. We find that extinction, though small at near infrared wavelengths, is sufficient to produce observable effects. In particular the observed increase of the average disk scalelength and the reddening of the disk I-H colour at high inclinations are clear signatures of the presence of dust. The total H-band disk luminosity depends little on inclination; on the other hand significant corrections to the face-on aspect are derived for the H-band central disk brightness and the disk scalelength. The bulge parameters exhibit little or no dependence on inclination. Simulations carried out with a simple model for an internally-extincted galaxy show that these results imply a central H-band optical depth between 0.3 and 0.5.