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Bar Classification Based on the Potential Map
The Astrophysical Journal ( IF 4.8 ) Pub Date : 2020-08-14 , DOI: 10.3847/1538-4357/aba4a4
Yun Hee Lee 1 , Myeong-Gu Park 1, 2 , Hong Bae Ann 3 , Taehyun Kim 1 , Woo-Young Seo 4
Affiliation  

We introduce a new approach to classify barred galaxies that utilizes the transverse-to-radial force ratio map (ratio map, hereafter) in a different manner from previous studies. When we display the ratio map in polar coordinates, barred galaxies appear as four aligned, horizontal thick slabs. This characteristic feature enables us to successfully classify barred and nonbarred galaxies with an accuracy of 87%. It yields the bar fraction of 53%, including both SBs and SABs, when applied to 884 nearby (z < 0.01) spiral galaxies from the Sloan Digital Sky Survey/DR7. It also provides the bar strength and length measurements, in particular, separated from the spiral arms. They show good correlations with the measures estimated from ellipse fitting and Fourier analysis. However, we find different tendencies of the bar strength measurements in terms of the Hubble sequence: as the Hubble sequence increases (towards late-type), the bar strength and bar ellipticity increase, whereas the dipole Fourier amplitude decreases. We show that the bulge affects the estimation of the bar strength differently, depending on the classification methods. The bulge causes the bar length to be overestimated in all three methods. Meanwhile, we find that barred galaxies show two types of radial profiles of the angle-averaged force ratio: one has a maximum peak (type M) and the other a plateau (type P). Comparison with numerical simulations suggests that type M bars are more mature than type P bars in terms of evolutionary stage.

中文翻译:

基于势图的条形分类

我们引入了一种新方法来对棒星系进行分类,该方法以不同于以往研究的方式利用横向与径向力的比率图(比率图,下文)。当我们在极坐标中显示比率图时,棒状星系显示为四个对齐的水平厚板。这一特征使我们能够以 87% 的准确率成功地对棒星系和非棒星系进行分类。当应用于来自斯隆数字巡天/DR7 的 884 个附近 (z < 0.01) 螺旋星系时,它产生 53% 的棒状分数,包括 SB 和 SAB。它还提供钢筋强度和长度测量值,尤其是与螺旋臂分离的测量值。它们与从椭圆拟合和傅立叶分析估计的度量显示出良好的相关性。然而,我们发现根据哈勃序列测量棒强度的不同趋势:随着哈勃序列的增加(朝向晚型),棒强度和棒椭圆度增加,而偶极子傅立叶振幅减小。我们表明,根据分类方法,凸起对钢筋强度的估计有不同的影响。凸起导致在所有三种方法中都高估了钢筋长度。同时,我们发现棒星系显示出两种角平均力比的径向分布:一种具有最大峰值(M 型),另一种具有平台(P 型)。与数值模拟比较表明,M 型钢筋在演化阶段比 P 型钢筋更成熟。棒强度和棒椭圆度增加,而偶极子傅立叶幅度减小。我们表明,根据分类方法,凸起对钢筋强度的估计有不同的影响。凸起导致在所有三种方法中都高估了钢筋长度。同时,我们发现棒星系显示出两种角平均力比的径向分布:一种具有最大峰值(M 型),另一种具有平台(P 型)。与数值模拟比较表明,M 型钢筋在演化阶段比 P 型钢筋更成熟。棒强度和棒椭圆度增加,而偶极子傅立叶幅度减小。我们表明,根据分类方法,凸起对钢筋强度的估计有不同的影响。凸起导致在所有三种方法中都高估了钢筋长度。同时,我们发现棒星系显示出两种角平均力比的径向分布:一种具有最大峰值(M 型),另一种具有平台(P 型)。与数值模拟比较表明,M 型钢筋在演化阶段比 P 型钢筋更成熟。我们发现棒星系显示出两种类型的角平均力比的径向分布:一种具有最大峰值(M 型),另一种具有平台(P 型)。与数值模拟比较表明,M 型钢筋在演化阶段比 P 型钢筋更成熟。我们发现棒星系显示出两种类型的角平均力比的径向分布:一种具有最大峰值(M 型),另一种具有平台(P 型)。与数值模拟比较表明,M 型钢筋在演化阶段比 P 型钢筋更成熟。
更新日期:2020-08-14
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