Multicomponent decompositions for a sample of S0 galaxies
Multicomponent decompositions for a sample of S0 galaxies
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DOI：
10.1111/j.1365-2966.2005.09404.x
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发表时间：
2005-08
影响因子：
4.8
通讯作者：
E. Laurikainen;H. Salo;R. Buta
中科院分区：
文献类型：
--
作者：
E. Laurikainen;H. Salo;R. Buta
我们通过应用二维多分量分解方法，估算了 24 个 SO、S0/a 和 Sa 星系样本在 Ks 波段的核球与总光比 (B/T)。对于圆盘，使用指数函数，凸起由 Sersic R 1/n 函数拟合，条形和椭圆形由 Sersic 或 Ferrers 函数描述。为了避免非物理解决方案，通过检查取向参数的径向分布和低方位角波数傅立叶振幅和相位来对结构部件进行初步表征。为了识别内部结构，创建了不清晰的掩模：在 NGC 1415 中发现了以前未检测到的内部螺旋臂，在 NGC 3941 中发现了少量的内部螺旋臂。最重要的是，我们发现 S0 的平均 (B/T) K 比率为 0.24 ± 0.11，这明显小于文献中普遍报道的平均 (B/T) R = 0.6。此外，S0 中凸起的表面亮度分布比通常假设的更呈指数分布，凸起的平均形状参数 = 2.1 ± 0.7。我们没有找到缺乏盘成分的棒状 S0 的例子，但我们发现一些星系（NGC 718、1452 和 4608）在棒状区域具有非指数盘。据我们所知，我们的研究是首次尝试将多成分分解方法应用于中等大小的早期盘状星系样本。
We have estimated the bulge-to-total (B/T) light ratios in the Ks band for a sample of 24 SO, S0/a and Sa galaxies by applying a two-dimensional multicomponent decomposition method. For the disc an exponential function is used, the bulges are fitted by a Sersic R 1/n function and the bars and ovals are described either by a Sersic or a Ferrers function. In order to avoid non-physical solutions, preliminary characterization of the structural components is made by inspecting the radial profiles of the orientation parameters and the low azimuthal wavenumber Fourier amplitudes and phases. In order to identify also the inner structures, unsharp masks were created: previously undetected inner spiral arms were found in NGC 1415 and marginally in NGC 3941. Most importantly, we found that S0s have a mean (B/T) K ratio of 0.24 ± 0.11, which is significantly smaller than the mean (B/T) R = 0.6 generally reported in the literature. Also, the surface brightness profiles of the bulges in S0s were found to be more exponential-like than generally assumed, the mean shape parameter of the bulge being = 2.1 ± 0.7. We did not find examples of barred S0s lacking the disc component, but we found some galaxies (NGC 718, 1452 and 4608) having a non-exponential disc in the bar region. To our knowledge, our study is the first attempt to apply a multicomponent decomposition method for a moderately sized sample of early-type disc galaxies.